News Archive

Zum Jahresende gibt Stefan Brönnimann in "TeleBärn" Auskunft über weisse Weihnachten, über Schnee im Dezember, über den Klimawandel und über unsere Handlungsoptionen.

After another extraordinary year, the Climatology Group wishes everyone a peaceful holiday season, merry Christmas and a happy new year.

Jianquan Dong started in November as a Visiting PhD Student in the Climatology Group. Before coming to Bern, he did his PhD at Peking University in Beijing and focuses on extreme heat risk assessment and its mitigating approaches. Now during his visiting, he will further assess and analyze the spatial-temporal variabilities of extreme heat risk of China and Bern based on multi-sources datasets.

This week the COST Action FAIRNESS (FAIR network of micrometeorological measurements) was officially launched. It is based on the conviction that managing weather-induced agricultural losses, water use for irrigation, new invasive species and disease vectors, plant diseases and pests, urban energy consumption and other problems requires making better use of available micrometeorological data. The Action intends to build a micrometeorological knowledge share platformwith an inventory of available and quality proven micrometeorological in-situ data , recommendations for measurement and data management in order to meet FAIR principles and examples of rural and urban FAIR data sets. The platform will link across various stakeholder groups and is carried by a transboundary network of researchers from 25 European countries, including the climatology group of the University of Bern.  

Heinz Wanner, emeritierter Professor und Saba Baer, Masterstudentin, erzählen in einem Beitrag des Regionaljournals Bern von ihren Erfahrungen in der Klimaforschung. Angesichts des fortschreitenden Klimawandels werden auch die langjährigen Warnungen der Wissenschaft thematisiert.

Within the framework of PALAEO-RA, Eric Samakinwa and co-authors from the climatology group of the University of Bern present monthly resolved SST and SIC fields for the period 1000–1849, which is suitable as boundary conditions for AGCM simulations. The 50-member ensemble spatially complete dataset is based on an existing coarse resolution annual mean temperature reconstruction, augmented with intra-annual and sub-grid scale variability that is physically consistent with information from models, proxies, and observations. With this new, freely available dataset, published in the Nature journal Scientific Data, science will gain new insights from AGCM simulations driven by realistic and temporally varying ensemble boundary conditions.

The climatology group offers a number of interesting topics for Bachelor and Master theses. Have a look at the most recent list.

Please note the new program of the Colloquium in Climatology, Climate Impact and Remote Sensing during autumn semester 2021. There will be many interesting talks and exciting discussions about various topics. Feel free to join the colloquium on Wednesdays at 14:15 on site or via Zoom according to the program.

Das neue Buch von Christian Pfister und Heinz Wanner ist jetzt im Buchhandel erhältlich. Die beiden Autoren liefern mit ihrem reichhaltigen Buch ein neues Standardwerk zur Klimageschichte. Es zeigt die vielschichtigen Verknüpfungen zwischen Klimaschwankungen und historischen Entwicklungen, basierend auf einem riesigen Korpus an historischen Quellen und Rekonstruktionen sowie profunden Analysen. Dies erlaubt eine Beurteilung der aktuellen, rasanten Klimaerwärmung und der damit einhergehenden Herausforderungen für die Gesellschaft.

Seit diesem Sommer wurde durch die Stadtklimagruppe ein interaktiver Hitzespaziergang entlang der Hot- und Coldspots in der Stadt Bern erstellt. Mithilfe von abwechslungsreichen Quiz-Aufgaben können Einblicke in die Themen Klimawandel, Stadthitze und klimaverträgliche Stadtentwicklung gewonnen werden. Der Hitzespaziergang kann hier abgerufen werden.

Since this summer, an interactive heat walk along the hotspots and coldspots in the city of Bern has been created by the urban climate group. With the help of diverse tasks, insights can be gained into the topics of climate change, urban heat and climate-friendly urban development. The heat walk is only available in German and can be accessed here.

Renuka Shastri started in February as a research assistant in the Climatology Group. Before coming to Bern she did her Master at the University of Pune, India. For her master thesis, she examined the individual and combined impact of Atlantic Nino and El Nino Southern Oscillation (ENSO) on Indian Summer Monsoon Rainfall (ISMR). Now during her year as a research assistant, she will perform a simulation of the Föhn storm 1925 using the Palm Model.

Please note the new program of the Colloquium in Climatology, Climate Impact and Remote Sensing during spring semester 2021. There will be many interesting talks and exciting discussions about various topics. Feel free to join the colloquium on Wednesdays at 14:15 via Zoom according to the program.

The climatology group offers a number of interesting topics for Bachelor and Master theses. Have a look at the most recent list.

Laura Hövel started in February as a PhD Student in the Climatology Group. Before coming to Bern she did her Master in Hamburg and wrote her thesis about decadal predictability of Marine Heatwaves. Now during her PhD she will continue to analyse decadal climate variability of past climate in model simulations with a focus on historical extreme events.

Duncan Pappert recently completed his Masters in Climate Sciences in the Climatology Group. In his thesis he evaluated weather observations from the Palatine Meteorological Society and used this data to reconstruct temperature and pressure fields over Europe for the winter 1788/89. Starting in February he will stay on at the GIUB as a research assistant and work on publishing the findings of his thesis, thereby contributing to the SNF Project WeaR.

The collaboration between climate scientists and historians has a long tradition. Work on historical measurements is a prime example how developments on the two disciplines can further stimulate the mutual benefit. Historian Chantal Camenisch and climatologist Stefan Brönnimann discuss their views in a NZZ article. Also non-scientists can contribute to gaining climate data. A recent Euronews feature with Stefan Brönnimann addresses the role of citizen science in climate research.

Even an extraordinary year comes to an end. The Climatology Group wishes everyone a peaceful holiday season, merry Christmas and a happy new year.

Dr. Martin Wegmann started this autumn as a PostDoc for a 1-year project in the Climatology Group. After doing PostDocs in France and Germany and being a science coordinator at WMO in Geneva, he found his way back to the GIUB, as he already did his Master and PhD here. His project WINTER (Winter clImate predictionN wiTh machinE leaRning) will focus on using machine learining tools to fill in gaps in our knowledge about past winter climates, specifically the last 400-500 years.

Moritz Burger started this autumn as a PhD in the Climatology Group. He was already at the GIUB during his Masters in Climate Science and studied the spatial pattern of the urban heat in Bern for his master thesis. He will intensify this research for his PhD in order to identify and evaluate local adaption strategies for the global climate crisis.

Lucas Pfister started this autumn as a PhD in the Climatology Group. He has already written his master thesis at GIUB, studying statistical reconstruction of daily temperature and precipitation fields in Switzerland back to 1864. In his PhD-project, he will work with dynamical downscaling and data assimilation for climate events back to the early 19th century.

Eine filmische Dokumentation statt Jubiläumssymposium im COVID-Jahr. Stefan Brönnimann zeigt mit Archivmaterial und aktuellen Interviews wissenschaftsgeschichtlich und persönlich, wie die Berner Geographie an der Schnittstelle von internationaler Forschung zu Gesellschaft, Politik und Verwaltung wirkt. Produziert wurde die Collage zusammen mit dem mLAB des Geographischen Instituts. Zum Interview und einer ausführlicheren Mitteilung.

Gleichzeitig zum Film erscheint in diesen Tagen auch die Broschüre «Klimawandel und Jahreszeiten». Wie wirkt sich der Klimawandel auf die Veränderungen in den Jahreszeiten – konkret auf Pflanzenwelt, Tiere, Landwirtschaft, Gewässer und Schnee – aus? In der Broschüre erläutern neuen Beiträge anhand von phänologischen Beobachtungen bei Pflanzen, Schnee und Nebel, die Freiwillige seit 1970 im Rahmen des BernClim Beobachtungsnetzes erheben.

Das wissenschaftliche Publizieren befindet sich im Wandel. Spätestens seit Forschungsförderungsinstitutionen "Open Access" einfordern und Universitäten Repositorien eingerichtet haben, bewegt sich die Wissenschaft als Ganzes in Richtung Open Science. Im Bern "Open Science Blog" berichtet Stefan Brönnimann über seine Erfahrungen mit Open Access.

The climatology group offers a number of interesting topics for Bachelor and Master theses. Have a look at the most recent list.

Please note the new program of the Colloquium in Climatology, Climate Impact and Remote Sensing during autumn semester 2020. There will be many interesting talks and exciting discussions about various topics. Feel free to join the colloquium on Wednesdays at 14:15 in room 116, Mittelstrasse 43, or via Zoom according to the program.

Das SRF-Wissenschaftsmagazin "Einstein" begleitete Doktorand Moritz Gubler und Masterstudent Moritz Burger beim Aufhängen der Sensoren für unsere diesjährige Messkampagne zur städtischen Hitzebelastung in Bern. Die Sendung thematisiert unterschiedliche Aspekte zum Thema "Urban Heating", wobei Messungen der kleinräumigen Variabilität der Lufttemperatur eine zentrale Rolle zur Validierung von Stadtklimamodellen sowie für die Planung, Umsetzung und das Monitoring von Massnahmen gegen die Stadthitze zukommt. 

Analyses of the BernClim phenology observation network run by the climatology group reveals extreme observations for the last winter and spring season. For the first time on record, snow observations at the Lake of Thun left almost a blank observation sheet and only the last two days in February with snow on the ground according to the observations guide. Accordingly, the observer in the Emmental valley noted fewer than ten days with snow cover for the first time since starting the observations in the 1970s. Subsequently, plant development was up to one month earlier than the longterm mean for hazel and dandelion flowering. Fruit tree flowered about two weeks earlier than on average. These observations are in general agreement with Swiss observations from MeteoSwiss’ phenology network that shows an overall advancement of spring development of 11 days. Summer arrived with ripe strawberry and cherry fruit roughly one month ahead leading to the note of one observer: „Five summer months in Central Europe“.

With the end of the Ice Saints, the hibernation of our urban heat measuring network has also come to an end: Once more, 65 temperature loggers are in use to track the heat load of the city of Bern. After two successful measurement campaigns with several intense heat waves, our extensive measurement network is now in use for the third year in a row. We are looking forward to the exciting insights, hypotheses, and surprises that the summer 2020 will bring!

Mit dem Ende der Eisheiligen endet auch der Winterschlaf unseres Stadthitze-Messnetzes: Auch dieses Jahr sind wieder 65 Temperaturlogger im Einsatz, um der Hitzebelastung der Stadt Bern auf die Spur zu kommen. Nach zwei erfolgreichen Messkampagnen mit intensiven Hitzewellen ist unser umfangreiches Messnetz nun bereits das dritte Jahr in Folge im Einsatz. Wir sind gespannt, welche spannenden Erkenntnisse, Hypothesen und Überraschungen der Sommer 2020 bereithält!

Historical weather observations help to understand atmospheric processes behind weather and climate events. The weather diary of the Kirch family from Berlin covers almost a century and provides the basis for the longest measurement series in Germany. In his Sabbatical, Stefan Brönnimann photographed the diary in Berlin. In this video he explains his work.

Dr. Andrew Friedman will join the climatology group with a prestigious Marie-Skłodovska Curie individual fellowship. Global warming is projected to have pronounced impacts on the hydroclimate — including rainfall and river flow — in the tropical Atlantic basin, which contains the world’s largest river systems and rainforests, and growing populations. The project “AQUATIC” (Assessing and QUantifying the ATlantic Instrumental hydroclimate) will compile recently-recovered measurements of precipitation, river discharge, and surface salinity from different archival sources to develop an integrated record of tropical Atlantic regional hydroclimate back to the late 19th century. The historical data will contribute to an understanding of the mechanisms of hydroclimate variability and constrain future climate projections.

On 1 April, a new SNF project started in the climatology group. The project "Weather Reconstruction" (WeaR) aims at studying climatic anomalies during the last 350 years from a daily weather perspective. This includes sequences of dry summers, such as around 1800, as well as cold winters, such as 1708/9, which will be put in the context of atmospheric circulation. Using historical instrumental and documentary data, combined with analog reconstruction techniques and machine learning approaches, WeaR will produce daily weather reconstructions for central Europe back to the late 17th century. It draws from the recently finished SNF projects CHIMES and REUSE and supplements the ERC-Project PALAEO-RA by adding the daily scale to their monthly reconstructions. Furthermore, simulations with the regional model WRF will be performed to better understand extreme events. Noemi Imfeld, Lucas Pfister, and Peter Stucki will be the main researchers working on the project, which will last four years.

Due to the current situation we unfortunately have to cancel the colloquium of this spring semester 2020. Instead of the upcoming talks we provide a collection of E-Learning tools and presentations on our website. We are also happy to add (former) presentations of the planned speakers to this collection, if they wish to share them with us. We are sorry for the inconvenience and thank you for your understanding.

Did you know that in Switzerland, prior to the start of MeteoSwiss in 1863, over 330 meteorological records from over 200 locations were measured? Within the successfully concluded project CHIMES (funded by the Swiss National Science Foundation) and the ongoing projects "Long Meteorological Series" (GCOS) and PALAEO-RA (ERC), these measurements were rescued. A detailed inventory was produced and imaged data sheets and the digitised data were published in public repositories. A first series of papers, most of them written by students, is now published in "Geographica Bernensia". Each paper describes the historical information on one of the series. A second series of papers on further series will follow. These data will form the basis for a daily weather reconstructions of the past centuries and for the generation of a set of ca. 10 long homogenised Swiss series.

Zwischen 1970 und 1987 erschien am Geographischen Institut im Selbstverlag die Schriftenreihe "Beiträge zur Klimatologischen Grundlagenforschung". Sie zeugt von den Ursprüngen der Klimaforschung am Institut. Die klingenden Namen der Autoren - Heinz Wanner, François Jeanneret, Bruno Messerli, Christian Pfister, Matthias Winiger - und die vielversprechenden Titel der Artikel - „Klima und Planung“, „Luft- und Satellitenbilder als mögliche Datenquellen bei der Schneekartierung“, „Klima, Phänologie und Mensch“, „Verteilung der Spätfrostschäden“, oder „Die Klimageschichte – eine vergessene Wissenschaft?“ - haben auch heute nichts an Aktualität verloren. Die Schriftenreihe wurde eingescannt und ist jetzt online verfügbar.

A wealth of old climate records still only exist in original form, such as paper or tape, and are at risk of being lost; the process of making these observations usable in digital form is called ‘data rescue’. Even small amounts of rescued data can make a big difference; filling in a gap in the records often opens up whole new avenues to explore. That is why  the Copernicus Climate Change Service (C3S) has launched a new Data Rescue Portal. The Portal is part of a wider project which aims to make historical observations available via the Climate Data Store. Ultimately, C3S’s goal is to combine assets from archives all around the world to make one comprehensive dataset that anyone can use, containing every single observation that has ever been found anywhere. The new Portal has been developed in collaboration with a consortium that includes Stefan Brönnimann and Yuri Brugnara representing the University of Bern.

Press Release: https://climate.copernicus.eu/new-portal-allows-sharing-historical-weather-observations-climate-research

New numerical methods can make use even of short meteorological measurement series to produce global weather reconstructions far back in time. These short records have not received much attention so far. According to a study led by Stefan Brönnimann and published in the "Bulletin of the American Meteorological Society", there are thousands of such records in archives and libraries worldwide prior to the start of National Weather Services, enabling new insights from past weather.

The western USA is frequently affected by multi-annual summer droughts. They can be separated into two groups with distinct spatial patterns, often termed Dust Bowl-type droughts and 1950s-type droughts. A recently published study by Angela-Maria Burgdorf, Stefan Brönnimann and Jörg Franke of the PALAEO-RA group analyzes the atmospheric circulation during these multi-annual drought events in EKF400, a novel global monthly three-dimensional reconstruction of the atmosphere back to 1600. Results confirm the two distinct drought types and show that they differ with respect to atmospheric circulation as well as sea surface temperatures. These insights may be useful in the context of drought prediction and analysis. The paper was highlighted by the journal and published on December 19, 2019, in “Climate of the Past”.

The EUSTACE (EU Surface Temperature for All Corners of Earth) global dataset of temperature observations including data from over 35,000 land stations was recently published. The Climatology Group at the GIUB mainly contributed to the joint effort information on station temperature measurements, data homogeneity, quality, and resolution, allowing the users to apply filters on the data depending on their needs. A paper describing the dataset has been recently published on Geoscience Data Journal and the dataset itself is available in the CEDA data archive. EUSTACE is a European project funded by the Horizon 2020 Programme with the aim of reconstructing global daily temperature fields back to 1850 by combining surface and satellite observations. The project ran from 2015 to 2019 and involved eight partners in four countries (UK, Denmark, Netherlands, and Switzerland).

In some regions of the world, climate projections are not particularly reliable. Even current climate may not be well specified, while climate data would be particularly valuable for decision making. Some African countries face the problem that many long climate records are known but inaccessible for various reasons. A recent story in "Nature" explains why this is the case and points to the value of data rescue. Data Rescue Services, to which the Climatology Group contributes as part of Copernicus Climate Change Services (C3S), will provide a platform for such activities. This was also acknowledged at the C3S General Assembly held this week in Warsaw, Poland.

Long-term climate records are fundamental to climate science. Switzerland has two long temperature time series, Basel and Geneva, reaching back to the mid-18th century. These series have been constructed in the 1950s and 1960s based on many short records, often supplemented with data from other stations. In the mean time, many further records from these two sites have been found which allow constructing new series. Additionally, data from other locations, particularly Zurich, have been found that might also provide long series. A new project funded by the Global Climate Observing System (GCOS) Switzerland aims at reassessing and establishing long, quality-controlled and homogenised meteorlogical series for Switzerland. It will provide additional information for assessing Swiss pre-industrial climate and its variability. The project lasts until autumn 2021.

Since 1st October, Noemi Imfeld is back in the Climatology Group as a Research Assistent in projects on Data Rescue. Noemi studied Climate Sciences at the University of Bern. After her Master she worked in the CLIMANDES-2 project, first in our group, later at MeteoSwiss. Welcome back!

Mussie Fessehaye Gebregiorgis joined the climatology group with a Swiss Government Excellence Scholarship for postdocs. The project is entitled "Statistical modeling of Eritrean highland precipitation with respect to Indian Ocean sea surface temperature" and builds on the existing and successful collaboration with the group. Mussie will stay in the climatology group for 12 months.

A new study estimates for the first time how the eruption changed the probability of the cold and wet European ‘year without a summer’ of 1816. The group around Andrew Schurer form the University of Edinburgh combined model simulations with climate reconstructions using a so-called detection and attribution technique. They found that the observed cold conditions were almost impossible without the eruption, and the wet conditions would have been less likely. The paper appeared today in "Environmental Research Letters".

Reference: Schurer, A. P., G. C. Hegerl, J. Luterbacher, S. Brönnimann, T. Cowan, S. Tett, D. Zanchettin, and C. Timmreck (2019) Disentangling the causes of the European year without a Summer of 1816. Environmental Research Letters

On 14 September 1769, exactly 250 years ago, Alexander von Humboldt was born in Berlin. He influenced geography, biology and geology like no other scientist, and numerous places, minerals, plants and streets carry his name (including in Bern; Photo). To commemorate his birthday, Oliver Lubrich and Thomas Nehrlich from the University of Bern now published all of Humboldt's articles in the "Berner Ausgabe". This monumental edition encompasses ca. 800 articles stretching over seven decades as well as accompanying commentaries. A selection of Humboldt's writings is published in "Der andere Kosmos". The CD audio book "Der unbekannte Kosmos" (with contributions from Heinz Veit, Stefan Brönnimann, and many others) provides further insights and comments.

Der Druck von der Strasse, vor allem vonseiten der Jugenddemonstrationen, aber auch die Hitzeperioden der letzten Wochen, veranlassen immer mehr Politikerinnen und Politiker sowie Persönlichkeiten aus der Wirtschaft, zu Klimafragen Stellung zu nehmen. Dabei lassen sich diese Personen entweder beraten oder finden, dass sie aufgrund ihrer Erfahrung dazu berufen sind, auch zu fachlich schwierigen Klimafragen Stellung zu nehmen. Heinz Wanner äussert sich zu immer wieder kolportierten, laienhaften oder falschen Aussagen.

People have been fascinated by glaciers for centuries. Glaciers were seen as a danger, then as a curiousity, later a dramatized and finally a more and more realistic artistic motif. With worldwide  melting of ice masses since the 19th century, glaciers make climate change a perceptible reality.  The two glaciers of Grindelwald are among the most researched glaciers worldwide. The exhibit at Kunsthaus Interlaken, conceived by Heinz Zumbühl, former professor in the climatology group, shows on the one hand the scientific background and on the other hand art works on the two Grindelwald glaciers from a number of artists since the 18th century. The exhibit is open from 16 June to 25 August 2019.

Since the hot summer 2003, 8 out of 16 spring-summer periods were outstanding according the statistic of the last 664 years. In the Paris temperature measurements since 1659, April-to-July temperature reached the highest value ever in 2018. New research from interdisciplinary team of historians and climatologists including Stefan Brönnimann from the climatology group shows that outstanding hot and dry years in the past were outliers, whereby they became the norm since the transition to rapid Global Warming in 1988. After that year, harvests began 13 days earlier than the period before when harvest dates averaged on September 28. Under the lead of Thomas Labbé, the scientists reassessed grape harvest dates from original archival sources rather than nineteenth century publications. The study has just been published in Climate of the Past and caught wide media attention. It was highlighted in Nature.

Yesterday's group excursion focused on the essentials. Given the unfavourable weather forecast, we decided not to undertake the planned hike. Instead, This Rutishauser invited us to Münsingen, where we baked "Pizza Lenticularis" in the wood-fired oven of Batzen-Brot. Thank you, This!

Why were floods in central Europe more frequent in the mid- and late 19th century than during much of the 20th century? This long-standing issue has now been analysed by the climatology group, results are published in "Climate of the Past". Using a daily weather type classification that goes back to 1763, it could be shown this change was related to a change in the frequency of flood-prone weather types. The flow over Western Europe was more cyclonic during the 19th century, perhaps due to a southward shift in the general circulation. Model simulations with prescribed sea-surface temperatures do not reproduce the increased cyclonic flow in the 19th century, but a decrease in the mid 20th century, suggesting that oceanic modes but also atmospheric variability matter.

In contrast to pre-industrial climate fluctuations, current, anthropogenic climate change is occurring across the whole world at the same time. In addition, the speed of global warming is higher than it has been in at least 2,000 years. That’s according to two studies published in Nature from the University of Bern with contributions from Stefan Brönnimann and Jörg Franke of the PALAEO-RA team.

A new study by Stefan Brönnimann and co-authors published in Nature Geosciences shows that the pre-industrial climate was not constant: if one takes the cold period of the early 19th century as the starting point for current global warming, the climate has already warmed up more than assumed in the current discussions. “Given the large climatic changes seen in the early 19th century, it is difficult to define a pre-industrial climate,” explains lead author Stefan Brönnimann, “a notion to which all our climate targets refer.” Five large volcanic eruptions occurred in the early 19th century. They caused cooling, drying in the monsoon regions and glaciers growing in the Alps.

Stefan Brönnimann from the PALAEO-RA project of the Institute of Geography has released an e-learning tool for weather reconstructions. On www.weather-reconstruction.org, students and anyone interested can learn step-by-step how historical manuscript data can eventually lead to complex climate information such as hazard maps. The tool focuses on sources of uncertainty and the application of reanalysis data and other data products in a meaningful way. Data can be downloaded for analyses in statistical software and visualization tools. The sections Climate Data, Global Reanalyses and Downscaling and Applications each starts with a very short text and the video followed by 2-4 subsections, typically with an exercise.

Last week, with temperatures rising to 35 °C, eight heat-resistant students participated in the urban climate and micrometeorology field course in Zollikofen. The topics covered in the course ranged from measuring Sky View Factors in the city of Bern to leading interviews on human well-being and performing eddy covariance measurements of carbon dioxide fluxes. From Tuesday to Friday, the student group and several volunteer helpers performed 18 bicycle rides through the city and surroundings, measuring temperature, water vapour and carbon dioxide. Together with the dense network of temperature loggers installed in Bern by Moritz Gubler, these data allow a detailed mapping of the heatwave.

Wenige Wissenschaftlerinnen und Wissenschaftler haben die Disziplin der Geographie so nachhaltig geprägt wie Alexander von Humboldt. Seine umfassende Betrachtung der Natur, seine vergleichende Perspektive und auch sein Interesse für die Menschen machen ihn zu einem Vordenker für viele Teilbereiche der Geographie. Zum Humboldtjahr anlässlich seines 250. Geburtstags haben Stefan Brönnimann und Jeannine Wintzer ein Themenheft der GeoAgenda herausgegeben. Die Beiträge im Heft diskutieren Alexander von Humboldts Schaffen aus gegenwärtiger Sicht, aber sie richten den Blick auch nach vorne und zeigen, welche Debatten in der Geographie noch zu führen sind.

Während Hitzewellen ist es im Zentrum von Bern nachts bis 3 Grad wärmer als in den Aussenquartieren oder in den Vorortsgemeinden. Auch innerhalb von Bern gibt es Hitzeunterschiede. Das zeigen die Ergebnisse des dichten Temperatumessnetzes, das Moritz Gubler in der Stadt installiert hat und das jetzt den zweiten Sommer in Betrieb ist. Stefan Brönnimann besuchte mit "Schweiz Aktuell" vier Standorte in Bern. In der Sendung gibt er Auskunft zum Thema Stadthitze.

Vor 40 Jahren wurde am Geographischen Institut Pionierarbeit im Bereich Stadtklimaforschung geleistet. Die damals erstellten Grundlagen werden teils bis heute verwendet. Geographica Bernensia hat daher den entsprechenden Bericht mit seinen grossformatigen Karten digitalisiert und online gestellt, mit einem Vorwort von Heinz Wanner. Diese Karten dienen auch dem Vergleich mit neuen Arbeiten am Institut wie den Hitzekarten Berns, die derzeit erstellt werden.

Heinz Wanner äussert sich auf INFOsperber zur Klimadebatte und erläutert die unterschiedlichen Sichtweisen in der Diskussion.

A comprehensive overview of the PALAEO-RA-project is now accessible online. On www.palaeo-ra.unibe.ch, we have compiled the most important information about the project, members, outcome, news and publications. A specific page will make available all the data from historical input data to simulations and reanalyses. Enjoy surfing: www.palaeo-ra.unibe.ch 

Elin Lundstad from Norway started as a PhD student at GIUB in April 2019. During her MA studies at the University of Bergen, Norway, she specialized in historical climatology. After her MA she has worked for the Norwegian Meteorological Institute and the Norwegian hydropower company Statkraft. Her PhD project is on “Variability of weather and climate since I700 from early instrumental observations”.

Dr. Ralf Hand is the new Postdoc in the Climatology group. Ralf did his PhD on midlatitude ocean-atmosphere interactions at the GEOMAR Helmholtz Centre for Ocean Research in Kiel. Afterwards he became a Postdoc at the Max Planck Institute for Meteorology in Hamburg, analyzing North Atlantic decadal variability in different simulations with the MPI Earth System Model. From there he moved to GIUB, where he will work in the modeling part of the PALAEO-RA project.

Das Thema Klimawandel erregt zur Zeit die Gemüter und füllt die Blogs. In der heutigen Ausgabe der "Neuen Zürcher Zeitung" kommentieren Nicolas Gruber und Stefan Brönnimann acht oft von Klimaskeptikern vorgebrachte Argumente.

Junge Menschen nehmen an Klimastreiks teil, weil sie den Klimawandel als ernsthafte Krise anerkennen, den Handlungsbedarf der Politik als gross einschätzen und um die Zukunft von Umwelt und Menschheit besorgt sind. Jene, die nicht teilnehmen, lassen sich in erster Linie von der Furcht vor negativen Konsequenzen abhalten. Dies ergab eine Online-Befragung durch Forschende der Universität Bern und der Pädagogischen Hochschule Bern (Blog-Artikel).

The climatology group offers a number of interesting topics for Bachelor and Master theses. Have a look at the most recent list.

Please note the new program of the Colloquium in Climatology, Climate Impact and Remote Sensing during spring semester 2019. There will be many interesting talks and exciting discussions about various topics. Feel free to join the colloquium on Wednesdays at 14:15 in room 124, Mittelstrasse 43, according to the program.

The climatology group is involved in two projects of the European "Copernicus Climate Change Services" (C3S). The four-year project "Data Rescue Services" started in 2017 and will produce a portal to support data rescue activities world wide with data bases, quality control code and digitising support. The new project "C3S In Situ Upper Air Database CISUAD" had its kick-off meeting last Friday in Reading, UK. The goal is to provide, until summer 2021, a global upper-air data base in support of future reanalysis activities. 

On February 1st Eric Samakinva started his PhD in Climate Science at the Graduate School of Climate Sciences of the Oeschger Center supervised by Prof. Dr. Stefan Brönnimann. Before joining the climatology group, he obtained his master's degree in Environmental Physics at the University of Bremen, with a thesis focusing on modeling the mid-Pliocene warm period. For his PhD, Eric Samakinva will be working within the framework of the ERC project PALAEO-RA by reconstructing sea-surface temperature back into the 15th century based on available reconstructions, proxies, as well as instrumental records. This will be used to drive an ocean model, and the resulting fields will be used to investigate mechanisms behind episodes of slowed and enhanced warming.

Neuigkeiten aus der Welt der Physik, von Wissenschaftlerinnen für Studierende und Interessierte aus Praxis oder Schule verfasste Hauptartikel, dazu hochwertiger Wissenschaftsjournalismus zu einem breiten Themenspektrum. Das war das Konzept der Zeitschrift "Physik in unserer Zeit" und ist es bis heute. Die Zeitschrift, in der Stefan Brönnimann im Kuratorium und die Gruppe für Klimatologie immer wieder mit Beiträgen vertreten ist, feiert ihr 50-Jähriges.

From mid-January to mid-April 2019, Fernando Jaume Santero visits the climatology group. He is a PhD student at Universidad Complutense de Madrid in Spain under the supervision of Dr. Natalia Calvo, Dr. Ricardo García-Herrera, and Dr. David Barriopedro. With a solid background in physics from his BSc, he specialized in paleoclimatology during his master's degree in atmospheric sciences at Université du Québec à Montréal in Canada. His work within the STREAM group is mainly focused on the optimization of last millennium climate field reconstructions through evolutionary algorithms, and the analysis of regional climates by means of sparse climate datasets.

Im Interview mit Nau TV spricht Stefan Brönnimann über den Klimawandel, die Veränderung der Schneetage und weisse Weihnachten in der Zukunft.

Happy Holiday Season!

Successful Swiss Geoscience Meeting

New People

Climate Data Empathy

CH2018 - New Swiss Climate Scenarios

Today, the new Swiss climate scenarios CH2018 are introduced to the public. The scenarios replace the existing CH2011 scenarios and are based on the most recent EURO-CORDEX set of simulations. The CH2018 report also has a Chapter on past climate trends, to which the climatology group has contributed and which documents the uniqueness of the summer temperature increase of the last 40 years.

Phenoclass project finished

Phenological data are some of the most direct indicators of climate. Without using an instrument, observations of plant phases in spring provide evidence for climatic changes. But how good are the data? In the Phenoclass project, funded by GCOS Switzerland/MeteoSwiss, the climatology group developed a procedure for the Quality Assurance of phenological data. The results generally confirm a high quality of phenolocial series. The final report has now been published.

Extremes Hochwasser 1868 im Tessin/Graubünden

Eine bei NHESS erschienene Studie analysiert das katastrophale Hochwasser 1868 aus Sicht der Umweltgeschichte, Meteorologie und Hydrologie. Die simulierte Wetter- und Abflussdynamik stimmt gut mit den damaligen Beobachtungen und Schadensberichten überein. Die Studie zeigt u.a., wie weit zurück regionale Wettermodelle eingesetzt werden können, oder wie das Wald/Hochwasserschutz-Paradigma entstand und die Schweizer Landschaft bis heute prägt.

New people in the PALAEO-RA team

On 1 October the ERC Advanced Grant project "A Palaeoreanalysis To Understand Decadal Climate Variability" (PALAEO-RA) has started in the climatology group. The starting team of the Excellent Science project includes the current and former group members Jörg Franke (data assimilation), Andrey Martynov (climate modeling, data management, and IT), This Rutishauser (outreach, phenology) and Angela-Maria Burgdorf (historical hydrometeorology and documentary data) and is led by Stefan Brönnimann. The group is joined by student assistants Saba Baer, Delia Reichenbach and Kathrine Link, who are busy searching (and finding) as well as digitising large amounts of historical instrumental data. The project, that lasts until 2023, will be presented on Wednesday, 17 October, 14.15 in our colloquium (Mittelstrasse 43,  seminar room 120)

Project site on Cordis: https://cordis.europa.eu/project/rcn/216182_en.html

New colloquium program now available

Please note the new program of the Colloquium in Climatology, Climate Impact and Remote Sensing during autumn semester 2018. There will be many interesting talks and exciting discussions about various topics. Feel free to join the colloquium on wednesday at 14:15 in room 120, Mittelstrasse 43 according to the program.

Early Instrumental Meteorological Data

From 18-21 June an international conference and workshop on early instrumental meteorological data was held at the University of Bern. The presentations at the conference covered all continents and revealed not only how many meteorological records have been digitised in recent years, but also how much more could potentially become available. The goal of the workshop was to create a global inventory of all potential climate records prior to 1850, including those which are known to have existed but have not yet been digitised or even located in archives. Such an inventory will help to prioritise data rescue work and eventually should form the basis for extending observation-based large-scale climate data products back to the 18th century.

New Bachelor and Master Topics

The climatology group offers a number of interesting topics for Bachelor and Master theses. Have a look at the most recent list.

1868 – ein Hochwasser prägt die Schweiz

Vor 150 Jahren liessen zwei Starkniederschlagsphasen zahlreiche Flüsse und Seen über die Ufer treten. Die Bewältigung des Ereignisses veränderte den Umgang mit Naturkatastrophen, mit Auswirkungen auf die heutige Landschaft. Heute erlauben neue Methoden die detaillierte Rekonstruktion der Niederschlagsereignisse und der Überschwemmungen. In einem heute erschienenen Heft stellen verschiedene Gruppen des Geographischen Instituts und des Oeschger-Zentrums den Stand der Hochwasserforschung dar.

Historical Climate Encyclopedia published

"The Palgrave Handbook of Climate History", edited by Sam White, Christian Pfister and Franz Mauelshagen, provides a state-of-the-art overview of the field of climate history and historical climatology. Bringing together dozens of international specialists from the sciences and humanities, this volume (to which the climatology group contributed) describes the methods, sources, and major findings of historical climate reconstruction and impact research.  Its chapters take the reader through each key source of past climate and weather information and each technique of analysis; through each historical period and region of the world; through the major topics of climate and history and core case studies; and finally through the history of climate ideas and science.
https://www.palgrave.com/de/book/9781137430199

Der Berner Stadthitze auf der Spur

Ein für die Schweiz einzigartig dichtes Temperaturmessnetz in Bern zeichnet ein detailliertes räumliches Bild der Hitzewellen dieses Sommers. Die Unterschiede zwischen einzelnen Messpunkten innerhalb der Stadt Bern und zwischen Bern und den umliegenden Gemeinden betragen bis zu 4 °C, wie Moritz Gubler zeigt. Diese Information ist wichtig für die Planung von Massnahmen gegen die Hitzebelastung. Volle Medienmitteilung

Hitze und Trockenheit in der Schweiz

Die Schweiz erlebt einen der trockensten Sommer seit Messbeginn. Hitze und Trockenheit machen vielen zu schaffen. Stefan Brönnimann erklärt auf Telebärn, wie dieser Sommer einzuordnen ist und worauf wir uns in Zukunft einstellen müssen.

Future changes in heavy precipitation

Heavy precipitation events in Switzerland are expected to become more intense, but the seasonality also changes. Analysing a large set of model simulations, a team of climatologists from University of Bern and ETH Zurich finds that annual maximum rainfall events become less frequent in late summer and more frequent in early summer and early autumn. The seasonality shift is arguably related to summer drying. Results suggest that changes in the seasonal cycle need to be accounted for when preparing for moderately extreme precipitation events. The paper was published in "Natural Hazards and Earth System Science".

Phenology observation guide now available online

The reference guide for plant phenological observations in Switzerland is now available again. «Plants in Changing Seasons» («Pflanzen im Wandel der Jahreszeiten») originally published by Robert Brügger and Astrid Vassella in 2003 just appeared in Geographica Bernensia Publishers. The observation guide with colored pictures and black-and-white drawings also contains the phenological definitions of Swiss observation networks of ‹GIUB BernClim›, MeteoSwiss ‹Swiss phenology network›  and ‹PhaenoNet› (German) by GLOBE. Newly available online are two publications on the BernClim Observation Network ‹G 87› and a general introduction to phenology and seasonality ‹U 26›, both in German.

Popular CLIMANDES papers 

The two recent publications by Stefan Hunziker on the CLIMANDES project receive a lot of online attention. "Identifying, attributing, and overcoming common data quality issues of manned station observations" was one of the 20 most downloaded papers of the International Journal of Climatology in 2017. The follow-up paper "Effects of undetected data quality issues on climatological analyses" is currently within the 10 most downloaded articles of Climate of the Past in the last 12 months. The CLIMANDES project is aimed at improving the training in meteorology and climatology in Peru and was funded by the Swiss Agency for Development and Cooperation (SDC).

Historische Wetterdaten

Seit der Aufklärung haben Privatpersonen und Institutionen das Wetter gemessen. Heute werden diese Daten wieder wertvoll. Sie erlauben quantitative Analysen des vergangenen Wetters und können so in die Wetterrisikobeurteilung einfliessen. Das Video von Lucas Pfister und Lukas Meyer illustriert dies am Beispiel von Hochwassern in Bern. Eine englische Version des Videos folgt in Kürze.

Representation of Extratropical Cyclones, Blocking Anticyclones, and Alpine Circulation Types in Multiple Reanalyses and Model Simulations

Reanalysis datasets are widely used in geosciences and thus their evaluation and intercomparison is crucial. In an effort to assess the mid-latitudinal atmospheric circulation, we compared the representation of blocks, cyclones and Central-European circulation types in a multitude of different reanalyses. The complete study by Marco Rohrer and colleagues finds a convergence for recent full-input reanalyses, although some metrics such as the depth of a cyclone still varies among datasets.

High-resolution assessment of the summertime urban heat load of Bern

In the context of the PhD project of Moritz Gubler, we recently established an extensive measurement network of about 80 low-cost temperature loggers within and around the city of Bern. Distributed over different urban structures, vegetation types as well as topographical and infrastuctural settings, the sensors placed within a self-made radiation shield will measure air temperatures every 10 minutes between May and September 2018. The goals of this project are to (1) assess the summertime urban heat island effect of the city of Bern at a very fine scale in order to create a data-base for (2) the validation of microscale urban climate models as well as (3) for future urban planning strategies taking into account the increasing importance of urban heat stress. Moreover, the results will be used for the (4) development and evaluation of teaching material focussing on local climate change. For further information or in case of questions, please contact Moritz Gubler (moritz.gubler@giub.unibe.ch).

Review of Early Twentieth Century Warming

From ca. 1900 to 1945 the globe warmed considerably, which has remained a mystery in climate sciences. In a new review article in WIREs Climate Change, Gabriele Hegerl and co-authors review the "early twentieth century warming". They find that both natural and anthropogenic forcings contributed, augmented by strong internal variability of the climate system. The early twentieth century warm period had distinct regional expressions, which is a reminder that also future episodes of pronounced internal variability will leave strong regional imprints. 

CERA-20C Reanalysis Paper

The new CERA-20C reanalysis was produced in the ERA-CLIM2 project and published on the website of European Centre for Medium-Range Weather Forecasts (ECMWF). It is a historical reanalysis that reaches back to 1900 and assimilates only air pressure and marine winds, but in contrast to all previous historical reanalyses, it is a coupled reanalysis, providing atmosphere, ocean, land, ocean waves and sea ice. The paper that describes the reanalysis is now published in the "Journal of Advances in Modeling Earth Systems"

An interactive visualisation was by created be the University of Bern.

ERC Advanced Grant for Climate Reconstructions

Stefan Brönnimann receives a grant of ca. 3 million Swiss francs from the European Research Council for the next five years. The goal of the project PALAEO-RA is to produce a comprehensive reconstruction of global climate of the past six centuries, a palaeo-reanalysis. The reconstruction will provide globally complete, three dimensional monthly fields of many variables and thus allows dynamical interpretations of past climate events. The project combines numerical modelling and mathematical techniques with historical documentary data and measurements, and dynamical analyses. 

New Bachelor and Master Topics

The climatology group offers a number of interesting topics for Bachelor and Master theses. Have a look at the most recent list.

New colloquium program now available

Please note the new program of the Colloquium in Climatology, Climate Impact and Remote Sensing during spring semester 2018. There will be many interesting talks and exciting discussions about various topics. Feel free to join the colloquium on wednesday at 14:15 in room 310, Hallerstrasse 10 according to the program.

Society and history imprint on climate data

Measurements of climate are also measurements of the needs of society. This becomes particularly clear when looking at the past. Economic, political and cultural factors have influence the climate observing system. Making use of this information could help to design climate services. This is what Stefan Brönnimann and Jeannine Wintzer argue in a short "Correspondence" in the current issue of "Nature". Climate data products are not just best estimates of physical variables, they are also societal products. Decision making can learn from both.

Neues Lehrbuch "Klimatologie"

Diese Woche erscheint beim Haupt Verlag das neue Lehrbuch "Klimatologie" von Stefan Brönnimann. Das Buch in der Reihe UTB basics erläutert die physikalischen Grundlagen der Klimatologie und darauf aufbauend die Zirkulation von Atmosphäre und Ozean und die daraus resultierenden Klimata. Der letzte Teil behandelt Klimavariabilität und Klimaänderungen sowie die der Klimaforschung zugrunde liegenden Methoden. Das Lehrbuch "Klimatologie" richtet sich an StudienanfängerInnen der Geographie, aber wird diese durch das ganze Studium begleiten. Viele Mitglieder der Gruppe für Klimatologie haben an dem Buch mitgearbeitet. Danke an alle!

Climate Atlas of the Altiplano

Weather on the Altiplano of Bolivia and Peru can be rough. Minimum temperatures below -3 °C are frequent, but to the south-east the weather is often hot and dry. Just how cold, how dry, and how hot? In the framework of the SNF-funded R4D-project DECADE, a climate atlas was produced for the Altiplano, which is now published in "Geographica Bernensia". It provides maps for mean climate and extreme indices for temperature and precipitation. It thus serves as a necessary baseline for risk management and the adaptation to future climate change in this region.

Weather reconstructions

How can we reconstruct the weather of the past? A video by Lucas Pfister and Lukas Meyer of the Climatology Group explains this. The product of this procedure are global, six-hourly three-dimensional weather data. In the framework of the FP7 project ERA-CLIM2, several reanalyses were generated. An interactive visualisation of the University of Bern allows investigating the CERA-20C reanalysis.

In the framework of the final assembly of the FP7 project ERA-CLIM2, the climatology group organised a public symposium on "Climate Reanalyses and Services for Society". The talks in the morning summarised the findings of the ERA-CLIM2 project, while in the afternoon the scope was widened. The presentations addressed future European space capabilities and reanalyses and addressed the role of climate services on the global, European, and the Swiss level.

Students Publish Reanalysis Case Studies

Historical reanalyses allow studying weather events far back in time. They cover more extremes than previous data sets and thus allow more robust statistics. But how good are these data sets? Only by analysing a sufficient number of extreme events individually, we can get an impression of the strengths and limitations of these data sets. Students of the "Seminar in Climatology" did exactly that. Small groups of students past analysed weather extremes - and continued to work even after the seminar was finished. The papers are now published in a special volume in "Geographica Bernensia". Great thanks go to all students who participated in the seminar and the book!

Researcher's night

More then 9000 visitors attended the "Researcher's Night" in Bern on 16 September, despite the cold and partly rainy weather. The climatology group presented the methods of weather reconstruction to the audience. A nice opportunity to get in touch with the public and explain our research. Many thanks go to all group members who helped to make this possible!

Shiny 5th floor

After three months of hard work - and three months of exile for the climatology group - the 5th floor shines in new splendour. Many thanks go to all who were involved in the renovation, who helped moving in and out, all who endured the exile and the 3rd floor people who hosted us.

New people

Franziska Hupfer has joined the Climatology group for a three month stay (mid-August to mid-November 2017). As a historian specialized in History of Science (MA ETH), she supports Stefan Brönnimann’s team to produce a survey of Swiss early instrumental meteorological measurements.

Thirty years of Montreal Protocol

On 16 September 1987, 197 states signed the Montreal Protocol on Substances that Deplete the Ozone Layer. Though constant efforts are necessary to amend the list of substances treated under the protocol and to monitor new compounds, the Montreal Protocol is a success story. Emissions of ozone depleting substances could be reduced strongly, contributing to the protection of the ozone layer. First signs of recovery appear, though the ozone hole still appears every year (the image shows the ozone hole on 11 Sep 2017) and the year-to-year variability is large. As many of the substances treated under the Montreal Protocol are strong greenhouse gases, the Montreal Protocol also made a major contribution to climate change mitigation. Read the article in the Tagesanzeiger.

Valuable Citizen Science Data

Scientific data collected by lay people, termed "Citizan Science Data", can supplement scientific approaches. In her Bachelor thesis, Daria Lehmann compared phenological data, i.e., data on the timing of plant phases, from MeteoSwiss with corresponding data obtained from two Citizen Science projects: PhaenoNet and OpenNature. Although the spatial distribution of the three data sets is different, the thesis shows that Citizen Science data give comparable results for some of the well-observed phenophases (read article in the "Tagesanzeiger" on 28 August). The project was a cooperation between the climatology group and GLOBE SWISS.

Yield losses in Switzerland for a "Year Without a Summer" scenario

The "Year Without a Summer" of 1816 triggered the last famine in Switzerland. Previous studies of the climatology group have focused on explaining the adverse weather conditions in 1816. In this study, Simon Flückiger has modeled the potential yield losses in 1816 and 1817 in Switzerland using a crop model. This formed the basis for a present-day "Year Without a Summer" scenario. The results, which are now published in "Environmental Research Letters" (https://doi.org/10.1088/1748-9326/aa7246), show substantial reductions in potential yields. Potato yields are reduced by 20-50%. Even larger losses are modeled for Maize, which was not yet common in 1816 but is an important crop today. The study, which emerged from close collaboration of different groups of the Oeschger Centre, also shows that socio-economic conditions are extremely relevant for explaining the local effects and the hardship suffered by the population. In isolation, the present Swiss agricultural system could arguably cope with the effects. However, for societies in a state of large vulnerability, such a scenario could still have major implications. On a global scale, a "Year Without a Summer" could have disruptive effects on the food system. 

Excursion: Climate Change Adaptation

How do we deal with flood risk, and will climate change alter the flood hazard? What are the challenges for agriculture when it comes to climate change? Are we prepared for increased frequencies of heat waves? From 19 to 30 June, eleven students dealt with these questions at the occasion of an excursion on climate change adaptation led by Stefan Brönnimann and Renate Auchmann. The excursion started in Prag, where flood protection was the main topic. In Brno, we visited an agroclimatological field site and a laboratory and were informed on drought management. At the last location, Vienna, we analysed strategies for reducing effects of urban heat waves and visited the intensively managed agricultural area north of Vienna.

Ozone hole and its recovery affect rain in tropical Pacific Islands

The ozone hole that opens each spring in the stratosphere over Antarctica has farther reaching consequences than previously thought. A study of the climatology group now finds that even rainfall in the tropical South Pacific Islands is affected. During the period of the largest Antarctic ozone loss, from the 1960s to the 1990s, rainfall increased in French Polynesia in spring and early summer. The region lies near the tip of the so-called South Pacific Convergenze Zone, one of the most intense rainbands on Earth. Using climate models that simulate stratospheric ozone chemistry as well as observations covering the past 60 years, the researchers demonstrated that the ozone hole leads to a high-pressure ridge off New Zealand, from where a wave-like circulation pattern stretches accross the South Pacific and affects the rainband. It is well established that the stratospheric ozone hole strengthens the westerly winds near the surface over the Southern Ocean, but effects on the tropics had so far not been demonstrated. Model simulations suggest that anticipated stratospheric ozone recovery over the next decades will reverse these effects.

Link to paper
Link to press release

Micrometeorological Field Course

From 12 to 16 June, students from University of Bern and ETH Zurich participated in the biannual field course in micrometeorology. The course took place at inforama Rütti in Zollikofen near Bern. Students engaged in making meteorological observations, measuring fluxes of carbon dioxide and water vapour with eddy covariance, determining light absorption within a canopy, and measuring carbon dioxide and temperature on bicycle rides. The excellent weather facilitated the field work.

Model-aided climate reconstructions

Jörg Franke and co-authors form the climatology group present the first monthly resolved three-dimensional global climate reconstruction for the past 400 years. It is based on assimilating historical measurements, documentary reports, and tree-ring data into a large set of climate model simulations. With this new, freely available data, which is now published in the Nature journal „Scientific Data“, science will gain new insights into climate variability, its causes and consequences. Droughts or effects volcanic eruptions can be studied in more detail than hitherto possible.

https://www.nature.com/articles/sdata201776

DECADE project meeting

Last week, scientists from Peru and Bolivia visited the climatology group at the occasion of the annual meeting of the DECADE project (Datos climáticos y eventos extremos para el área central de los Andes, funded by the Swiss Development Corporation Agency and the Swiss National Science Foundation in the R4D programme). The goal of the project is to promote climate services in the Central Andes by improving the climate data record. By meticulously going into the details of the measurements, including numerous station visits, collection of metadata, and careful analysis, the project could achieve a much better quality of climate data over the Altiplano (see Stefan Hunziker's article in International Journal of Climatology). At the meeting, the group discussed the next steps: The production of an atlas of climate extremes, which will be published towards the end of this year.

A weather observer

For over 40 years, Christian Röthlisberger from Grossaffolteren has observed plant phenological phases and has kept a weather station. His meticulous observations are important also for climate research. The data have been collected by the climatology group as part of the BernClim network. Watch this TV documentary (in German): www.loly.ch. Want to observe plant phenological phases as well? Use our portal www.opennature.ch/ to enter your own observation.   

ERA-CLIM2 Reanalyses and Observations

Atmospheric reanalyses are among the most widely used data sets in geosciences and beyond. They are an important part of climate services and are used by decision makers. Generating atmospheric reanalysis, however, is a complex effort that involves the entire atmospheric and climate science community. The ERA-CLIM2 project, which is now in its final year and in which the climatology group was leading a workpackage, has prepared the ground for sustainable reanalysis operations. This involves observation data rescue, post-processing and re-processing of historical in-situ weather observations around the world and satellite climate data records; research and development of coupled assimilation methods, capable of including observations from different Earth system components (land surface, ocean, sea ice, atmosphere, chemical components, …); reanalysis production, and evaluation and uncertainty estimation, including visualisation and evaluation methods capable of indicating uncertainty in the reanalysis. One of the products, CERA-20C reanalysis (a coupled global reanalysis of atmosphere and ocean with 10-members back to 1900, generated from only surface observations), has recently been released on the ecmwf website. A successful test product has been generated that includes upper-air data: the ERA-PreSAT reanalysis from 1939-1967. Future reanalyses will be based on these efforts.
 

Snow shoe day

Last week, the three grops from the 5th floor enjoyed a snow shoe excursion to Col des Neigeux. Fabulous weather accomapined our trip to the Jura mountains. Our excursion was rounded-off by a hot coffee at the restaurant 'Les Gümmenen', where this group picture was taken. Thanks, Peter!
 

Warm mid-Holocene in the Mediterranean

A study of an Oeschger Centre team led by Oliver Heiri shows that during the mid-holocene, Mediterranean climate was considerably warmer than previous studies had suggested. The new temperature reconstruction was obtained from chironomids in the sediments of two lakes in the Apennines. Results are in very good agreement with climate model simulations, whereas earlier studies based on pollen had found much lower temperatures. Arguably, pollen-based reconstructions also reflect environmental effects other than temperature, such as moisture regimes, land use and fire. The study was published in Nature Geoscience (read more).

Reconstruction of Central European daily weather types back to 1763

A new paper by Mikhaël Schwander and co-authors was recently published online in the International Journal of Climatology. A weather type classification from MeteoSwiss was reconstructed back in time based on early instrumental data. The paper presents the method of reconstruction and the new classification (called CAP7) which covers the period 1763-2009. This time series is a unique dataset of weather patterns for the Alpine Region and Central Europe which offers the opportunity to analyse the climate variability over Switzerland and Europe for almost 250 years.

For more information or access to the data: mikhael.schwander@giub.unibe.ch

Schwander M, Brönnimann S, Delaygue G, Rohrer M, Auchmann R, Brugnara Y. 2017. Reconstruction of Central European daily weather types back to 1763.
Int. J. Climatol. doi: 10.1002/joc.4974.

Tambora article in Top 10

The article on the Tambora eruption and the Year without a Summer of 1816 that grew out of the 2015 Bern-Meeting was featured among the top 10 accessed articles of "WIRE's Climate Change" of the year 2016. Check it out, it is open access: http://wires.wiley.com/WileyCDA/WiresCollection/id-58.html

Near-surface ozone: Will climate change jeopardize current success?

Despite large and successful efforts to reduce emissions of precursor gases, air quality standards for ozone in Switzerland are still exceeded on a regular basis. The frequency of extreme peaks has decreased, but not that of moderately high values. The causes are not fully clear, but large-scale emissions of precursors and climate change might have contributed. An increasing number of heat waves will lead to more frequent ozone exceedances. Furthermore, plants emit hydrocarbons in response to high temperatures, which contributed to ozone production. These two mechanisms counteract the success due to decreasing precursor emissions. This is stated in a new fact sheet of the Swiss Academy of Sciences, to which the climatology group has contributed.

Read more (in German)

Happy Holiday Season

December 1916: Deadly Wartime Weather

One of the worst meteorological disasters in history took place in the southeastern Alps during the infamous winter of 1916/17. Avalanches following a massive snowfall event killed thousands of soldiers as well as civilians. Yuri Brugnara and Marcelo Zamuriano of the climatology group now provide a detailed reconstruction of the event based on a reanalysis and subsequent dynamical downscaling. Together with the climate historians Christian Rohr and Daniel Segesser, impacts of the event could be studied. This shows the potential of combining numerical techniques with historical documents.

The study will be presented by Christian Rohr and Stefan Brönnimann:
Wed, 7 Dec 2016, 12.15–13.00, Cantina, Haus der Akademien, Laupenstrasse 7, Bern
http://www.akademien-schweiz.ch/index/Aktuell/News.html

The study (in English, German, and Italian) can be downloaded here:
www.geography.unibe.ch/december1916

The Coldest Decade of the Millennium? How the cold 1430s led to famine and disease

At an Apéro two years ago, Oeschger Centre PhD students Chantal Camenisch, Kathrin Keller and Melanie Salvisberg got talking about a specific past climatic variation: the 1430s, possibly the coldest decade of the millennium in Europe. Out of this grew an international workshop, held in Bern, and a review paper led by the three young scientists. The work linked climatologists with historians, climate modelers with proxy scientists and encompasses a broad range of topics ranging from climate forcings (which do not seem to have been responsible) and internal variability to societal impacts and perceptions. The paper, which is published today, is featured by the European Geosciences Union. Read all about it:
http://www.egu.eu/news/310/the-coldest-decade-of-the-millennium-how-the-cold-1430s-led-to-famine-and-disease/

Focus on Climate in Switzerland

Under the auspices of ProClim, a forum of the Swiss Academy of Sciences (sc.nat), the Swiss climate science community has produced a report that summarizes the relevant findings of IPCC's Fifth Assessment reports with respect to Switzerland as well as specific research on climate change in Switzerland. The climatology group has contributed to this report as well as to the underlying IPCC Assessment. The report "Brennpunkt Klima Schweiz – Grundlagen, Folgen und Perspektiven" is presented to the public today.
(http://www.naturalsciences.ch/organisations/proclim/activities/brennpunkt)

New project on Swiss historical climate observations

On 1 November 2016, project CHIMES ("Swiss Early Instrumental Measurements for Studying Decadal Climate Variability") started in the climatology group. The project, which is funded by the Swiss National Science Foundation is as cooperation with the Institute of History of the University of Bern and MeteoSwiss. The goal is to catalogue, image, and digitise meteorological measurements in Switzerland prior to 1864 (which is when the national network started), including several new series that reach back into the 18th or early 19th century. The new series will be evaluated with respect to decadal variability of weather and climate extremes, and an attempt will be made to produce gridded weather data products for Switzerland back to the early 19th century. As a first step, Lucas Pfister, Lukas Munz and Leonie Villiger now start to work on the catalogue.

Neues Buch: "Die Grindelwaldgletscher. Kunst und Wissenschaft."

Die beiden Grindelwaldgletscher gehören zu den am besten dokumentierten Gletschern der Welt, nicht zuletzt dank der Faszination, die sie auf Maler und Photographen im 18. und 19. Jahrhundert ausübten. Durch die Kombination von historischen Bild- und Schriftquellen mit glazialgeomorphologischen und dendrochronologischen Methoden lassen sich vergangege Vorstoss- und Rückzugsphasen oft jahrgenau untersuchen. In ihrem Buch zeichnen Heinz Zumbühl, Samuel Nussbaumer, Hanspeter Holzhauser und Richard Wolf die Entwicklung der beiden Gletscher über die letzten fünf Jahrhunderte nach und zeigen umfangreiches und einzigartiges Bildmaterial.

Buchpräsentation: «Als Gletscher noch Eis waren», am Dienstag, 25. Oktober im Alpinen Museum (https://www.alpinesmuseum.ch/de/veranstaltungen)

SCOSTEP Workshop

On 4-5 October, the 1st Swiss SCOSTEP (Scientific Committee on Solar-Terrestrial Physics) workshop was held in Bern, organised by the climatology group and Christoph Raible. 31 researchers came together to exchange their expertise in several disciplines ranging from fundamental solar physics, solar variability and its effects on Earth, in particular the climate system, to new measurement techniques and future satellite missions. The workshop successfully delivered an overview of the current activities within these communities and first synergies were identified which are aimed to result in joint research activities in the comings months and years.

New Project: PhenoClass

The Swiss Phenology Network comprises around 160 stations, however its quality and homogeneity has never been assessed comprehensively. The aim of this project is to develop a novel classification scheme for series and stations of the Swiss Phenology Network in close collaboration with MeteoSwiss.

Opening of World Nature Forum

Yesterday, the "World Nature Forum" in Naters, the visitor center of the UNESCO Swiss Alps Jungfrau-Aletsch World Heritage Site, was inaugurated in the presence of federal councillor Doris Leuthard, former federal councillor Adolf Ogi and representatives of politics and economics. In the interactive exhibitions the visitor will experience with all its senses the property and immerse into the thrilling and varying sceneries of the Alps. The Institute of Geography played an important role in the scientific design of the exhibit.

New SNF Project started

In June, the new SNF project "RE-USE" (Reconstructing Climate Using Ensemble Kalman Fitting) started in the climatology group. The goal of this 3-year project is to provide global, monthly, three-dimensional climate reconstructions with a new method that combines climate model simulations, instrumental observations, and proxies. The new approach, which has been successfully tested, will provide new insights on interannual-to-decadal variability of climate and atmospheric circulation over the past 400 years, which encompasses the transition from the "Little Ice Age" climate to the present. The project will be conducted by Dr. Jörg Franke and PhD student Veronika Valler.

New book of Heinz Wanner on Holocene climate and human history

During the Holocene, climate has repeatedly interfered with human history. Societies in various parts of the world - the Pueblos, the Vikings, the Mayas, and many others - were faced with extreme climatic conditions, which did not remain without consequences. The book covers the relation between climate and societies over the past 12'000 years in an accessible way.

More information

Tambora and the “Year Without a Summer” of 1816. A Perspective on Earth and Human Systems Science.

The 1815 Tambora eruption devastated the island of Sumbawa, led to a global cooling and contributed to the last famine in Switzerland. A booklet by Stefan Brönnimann und Daniel Krämer pubished by Geographica Bernensia now provides a synthesis of this event (free online under geography.unibe.ch/tambora, German and English versions):

Brönnimann S, Krämer D. 2016. Tambora and the “Year Without a Summer” of 1816. A Perspective on Earth and Human Systems Science. Geographica Bernensia G90, 48 pp., doi:10.4480/GB2016.G90.01.

Tambora and the „Year Without a Summer“ of 1816

Two hundred years ago, a cold and rainy summer led to the last famine in Switzerland, triggered by a volcanic eruption in Indonesia. In an article in "NZZ am Sonntag", Stefan Brönnimann explains what societies today can learn from the Tambora eruption with respect to dealing with climate risks.

NZZ article (in German)

Faculty Award for Martín Jacques Coper

Martín Jacques Coper receives this year’s University of Bern Faculty Award for Geosciences for his PhD thesis „A multiscale analysis of summer temperature variability in Southern South America during the 20th century“. In his thesis, Martín Jacques Coper analyses temperature variability in Patagonia during austral summer on various time scales, ranging from intraseasonal to interdecadal. The analysis of intraseasonal summer heat waves reveals a characteristic wave pattern of anomalous atmospheric circulation that can be tracked backward across the South Pacific to its origin over Oceania. A link is also found to convection over the western tropical Pacific Ocean. Interestingly, similar patterns are also found for the temperature variability on interannual-to-decadal scales. The work is thus not only relevant with respect to predictability, but also for the interpretation of past climatic changes.

Bern-Grenoble

The climatology group is strengthening its collaboration with the LGGE (Laboratoire de glaciologie et géophysique de l'environnement) of the University Grenoble Alpes. The group visited the Gilles Delaygue and Martin Wegmann at LGGE for a two-day excursion and enjoyed both exciting science and an exciting scenery.

CLIMANDES e-learning course published

The CLIMANDES climate science e-learning course, developed by Stefan Brönnimann, Alena Giesche, Stefan Hunziker, and Martín Jacques-Coper at the Institute of Geography at the University of Bern, was recently published by Geographica Bernensia. This course was developed over the past three years for the CLIMANDES project, which is a collaboration between Peruvian and Swiss government, research, and education institutions. The course is available online:
http://surmx.com/chamilo/climandes/e-learning/ , DOI number: 10.4480/GB2015.U27

Book launch “Climatic Changes since 1700”

Understanding past climatic changes is the key to assessing present and future climate change. In his book “Climatic Changes since 1700”, Stefan Brönnimann provides a new, dynamical perspective of past climatic changes based on novel techniques and data sets of past climate. The book just appeared in Springer’s series “Advances in Global Change Research”. The book also is a tribute to the book with the same title published by Eduard Brückner, then professor at the Institute of Geography, University of Bern, 125 years ago.

Summary (EN (pdf, 120KB), DE (pdf, 118KB))

More information

CLIMANDES E-Learning course

Alena Giesche and Stefan Hunziker led a training workshop for the CLIMANDES E-Learning course at the SENAMHI in Lima, Peru from August 4-7, 2015. The workshop was attended by students and professors from the Universidad Nacional Agraria La Molina, meteorologists from SENAMHI (Peruvian National Service for Meteorology and Hydrology), as well as aviation meteorologists from the Peruvian military. Alena and Stefan were each awarded a medal from the Fuerza Aérea del Perú (Peruvian Air Force) for their contribution to the training of aviation meteorologists in Peru.

Jahreszeiten-Expedition

The GIUB and Foundation Science et Cité are presenting 8 «Jahreszeiten-Expeditionen» as part of SNCATs anniversary tour „Forschung live“. During guided tours at Swiss-German anniversary locations, experts will introduce the participants to natural phenomena and signs of the seasons and their simple, scientific recording. The tours are accompanied by improvisation actors, who will present the scenes in yet another entirely different way. The participants will not only listen but will also do their own research on urban nature and will feed their observations by iPad oder Smartphone into www.OpenNature.ch.

Upcomign tours are in Aarau (August 30), Bern (Sep 5) and Basel (Sep 19).

Reduced activity of the sun by 60%?

Group Member Mikhaël Schwander commented a new study in the newspaper «Tages-Anzeiger» that said that the activity of the sun will be reduced by 60% in the period 2030–2040 on a level similar to the Maunder Minimum. «Im Maunder-Minimum war auch der Einfluss von Vulkanausbrüchen massgebend», Schwander said. The young climate scientist analysis the number of sunspots – an indicator of the sun’s activity – back to 1765 in comparison to weather patterns over Europe.

Read article

Group excursion

This year's excursion of the groups of climatology, climate risks, and remote sensing brought us to Solothurn and from there via Balmberg to the Röti peak (1400 m), from where we had an impressive view of the Swiss Plateau and the Jura. Though rainy in the early morning, the weather improved and we enjoyed a sunny day and a pleasant hike to the Weissenstein.

Field course in micrometeorology

Last week students of the Institute of Geography participated in the micrometeorology field course at Chamau, ZG. The course takes place every two years in collaboration with Prof. Werner Eugster, ETH Zurich. The students performed eddy covariance measurements and conventional meteorological measurements, determined the light absorption within the canopy, launched radiosondes and cycled transects measuring the spatial variability of carbon dioxide. After a hard day's work, a swim in Lake Zug was the perfect refreshment.

Less sea ice, more Siberian snow

This week's issue of Nature features the paper published last week by Martin Wegmann et al. on links between Arctic sea ice and Siberian snow accumulation in autumn (Environ. Res. Lett. 10, 054015 (2015)). The research team investigated Eurasian snow conditions in years with decreased Arctic sea ice cover using more than 800 snow depth measuring weather stations. They could compute that the surplus of moisture responsible for the increased Siberian snow cover in late autumn is indeed originating from the anomalously open Arctic waters in the months before. This moisture is transported to Central Siberia via storm tracks, driven by the overall circulation and fueled by the relatively warm surface of the ice free sea.

Students Analyse Historical Flood Events

This spring, students of the "Proseminar Klimatologie" have analysed ten historical flood events in Switzerland in the new "Twentieth Century Reanalysis" v2c dataset. The students found that the data set quite accurately reproduces the large scale flow for strong, historical events such as the June 1876 heavy precipitation and flood (photo). It also provides a realistic depiction for less well documented events such as the 1852 or 1868 floods. However, the precipitation distribution and timing is not always well reproduced and details of the weather events may not be captured. This Proseminar continues a series of Seminars in which students have analysed extreme weather events in new historical weather data sets. Selected papers have been published in Geographica Bernensia.

Interview: Citizen Science

Is Citizen Science an alternative to the elitist world of science? On the occasion of the new citizen science project of the climatology group, This Rutishauser's "OpenNature", the university magazine "unipress" has interviewed climatologist Stefan Brönnimann and philosopher Claus Beisbart to find out what citizen science is, whether it can be theme-setting and what the value of a deeper dialog between scientists and lay people might be.

Read article

Podcast: interview with Stefan Brönnimann

Project: OpenNature

Successful Tambora Meeting

The international conference on "Volcanoes, Climate and Society", which took place last week in Bern, was a great success. The conference at the occasion of the bicentenary of the 1815 Tambora eruption attracted ca. 140 scientists from a wide range of disciplines. Volcanologists, atmospheric chemists and physicists, paleoclimatologists, climatologists, climate modellers and historians discussed the current knowledge on the Tambora eruption and its impact on climate and society. One of the highlights was the presentation of a a dynamical reanalysis of the years 1815-1817. The bicentenary was also reported in the media: "Einstein" and Radio SRF2.

Pacemakers of warming and hiatus periods

Westerly winds over the equatorial Pacific may have played a pivotal role in the global warming episode of the early twentieth century. A new paper in "Nature Geoscience" presents a coral-based wind proxy and relates westerly wind strength over the Pacific to warming. In the accompanying News & Views, Stefan Brönnimann from the climatology group tries to fit the new piece of evidence to the puzzle of explanations surrounding episodes of accelerated or slowed warming, including the ongoing hiatus. Fitting together the pieces also means fitting together two communities with very different science cultures - palaeoclimatology and dynamical climatology.

Read more

Merry Christmas

The Climatology Group wishes you a merry Christmas and a happy 2015.

Maps of wind storm risk in Switzerland

Together with Meteotest and the Climate Impacts group of the Institute of Geography, Peter Stucki from the climatology group has contributed to generating maps of wind storm risk in Switzerland. The maps are based on downscaling of 83 wind storms since 1871. They provide wind gust speeds with return periods of 30, 50, 100 and 300 years.

Read more

Mountains and Climate Change

Today (11 Dec 2014) is the International Mountain Day. At this occasion, the publication "Mountains and Climate Change" is launched at a side event in the Mountain Pavilion at COP 20 Lima. The publication was coordinated by Thomas Kohler from the University of Bern and encompasses several chapters authored by scientists from the Institute of Geography, including the opening chapter on climate.

Download Publication (pdf, 18.6 MB)

New HORIZON2020 project funded

The climatology group of the Institute of Geography participates in the HORIZON2020 project "EUSTACE", led by the UK Met Office. The project, which starts in January 2015 and last for 3.5 years, aims at producing global gridded data products of daily surface air temperature from combining satellite-derived skin temperatures with conventional meterological stations. At the climatology group, Yuri Brugnara and Renate Auchmann will carry out the work.

Projects in the Tropical Andes

Last week Stefan Hunziker, Martìn Jacques Coper und Stefan Brönnimann attended the project meetings of CLIMANDES in Lima and of DECADE in La Paz. The goal of the two projects, funded by the Swiss Agency for Development and Cooperation (SDC), is to improve climate services in the tropical Andes and to build up research capabilities in the region through links with the Universidad Nacional Agraria La Molina (Lima), the Universidad Mayor de San Andrés (La Paz), and the weather services of the two countries. The CLIMANDES project is led by MeteoSwiss (http://www.meteoschweiz.admin.ch/web/de/meteoschweiz/internationales/Internationale_Projekte/CLIMANDES.html) under the umbrella of WMO. The DECADE project was funded under an SDC/SNF "Research for Development" project. The goal is to compile meteorological data and metadata for the Altiplano region, to perform quality assessment (and, if possible, homogenisation), and to produce climatological maps of extreme indices. The DECADE meeting ended with a visit at of the high-altitude research station Chacaltaya (Photo: S. Hunziker).

Synergies, not conflicts between air quality and climate policy

Air quality in Switzerland has improved over the past decade. This success should not be jeopardized by climate policy measures. Wood burning in small installations, for instance, has a positive effect on greenhouse gases, but leads to emissions of particulate matter. However, synergies between air quality and climate policy are obvious as many sources of pollutants and greenhouse gases are the same, writes the commission of Atmospheric Chemistry and Physics (ACP) of the Swiss Academy of Sciences (SCNAT). The fact sheet «Energiepolitik und Klimaschutz mit Luftreinhaltung verbinden» can be downloaded here: http://www.akademien-schweiz.ch/factsheets

Homogenisation expert visits Climatology Group

The Oeschger Centre regularly hosts visiting scientists. Victor Venema from the University of Bonn, Germany, is visiting us in August and September. He works on the removal of non-climatic changes from the raw climate station records, typically called data homogenisation.

Improvements in our understanding of measurement errors and economic, societal and technological changes over the centuries have produced non-climatic changes in the climate record. For example, an important change for temperature observations was the transition to double-Louvre Stevenson screens that protect the thermometer well against influences of solar and heat radiation. Before the time, observations were often performed at the window of North facing walls or half-open screens, such as the French screen or the Wild screen. These half-open screens provide more ventilation, but were found to be affected too much by radiation errors.

Past work on homogenisation was often focussed on the removal of mean shifts from monthly climate data (especially temperature and precipitation). The next important step is the homogenisation of the probability distribution of daily climate data. This is important for research on climatic changes in weather variability and extremes. The inherent reduction in the amount of data when considering extremes and the concurrent stochastic and deterministic nature of the non-climatic changes make this problem much more challenging.

Thus the current trend is to study the nature of these non-climatic changes using parallel measurements, where classical measurements are performed alongside modern ones. With such parallel measurements the statistical changes and their physical causes can be studied directly.

Read more

The group of Stefan Brönnimann at the Oeschger Centre has two beautiful datasets with parallel measurements with a frequently used Wild screen and a Stevenson screen (see photo), which Venema together with Renate Auchmann will analyse during this visit.

40 years of BernClim pheno data available

More than 40 years ago, the Institute of Geography started a network with phenological observations in the canton of Bern. Some of the observes are still actively reporting their observations, contributing to a long time series of climatically relevant data. Part of the data set, which offers a unique archive of seasonal climatic proxy data, is now available from the "Amt für Geoinformation" of the Canton of Bern. The data set includes the data of four standard plants (hazel, dandelion, apple, beech), snow and fog. Decadally aggregated maps of the phenophases complete the unique seasonal and regional information.

Downscaled historical wind storms for Switzerland

Wind storms are among the most costly natural disasters. However, good statistics of the wind storm hazard on a local scale are usually not available. In a collaborative project of the groups of Climatology and Climate Risks of the Institute of Geography and Meteotest, Bern, supported by the Bafu, MeteoSwiss and the Bretscher Fonds, approximately 100 historical storms have been downscaled to a 3 km resolution. The downscaling is based on the Twentieth Century Reanalysis.

Read article in 'Physik in unserer Zeit'

Northern and Southern Hemisphere Climate Change

Over the last 1000 years, temperature differences between the Northern and Southern Hemispheres were larger than previously thought. Using new data from the Southern Hemisphere, Raphael Neukom, Heinz Wanner and co- authors have shown that climate model simulations overestimate the links between the climate variations across the Earth with implications for regional predictions.

Read article

"Years Without a Summer" caused by weakening monsoon?

Historical records provide evidence that strong volcanic eruptions in the tropics are often followed by a cold and rainy summer in Central Europe. These «years without a summer» often lead to catastrophic famines; the last time in 1816 after the eruption of the Tambora volcano in Indonesia. Martin Wegmann and collaborators from the climatology group now found a possible cause for the rainy summers: the volcano-induced weakening of the African monsoon.

Read article

Climate Change 2013: The Physical Science Basis

The contribution of Working Group I of the IPCC to the Fifth Assessment Report is published in full today. It was jointly written by 259 authors over a period of almost 4 years. The authors had to reply to 54,677 review comments. The climatology group contributed to this report: Stefan Brönnimann was Lead Author, Heinz Wanner was Review Editor, and former group member and guest professor Jürg Luterbacher was also Lead Author. The full report can be donwloaded here: http://www.climatechange2013.org

Weather Extremes in the Twentieth Century Reanalysis

Winterstorms, floodings, heatwave, hurricanes - extreme weather events may cause tremendous damage. The "Twentieth Century Reanalysis", which provides six-hourly, global data back to 1871, allows studying more extreme events than hitherto possible. However, is this data set suitable for that purpose? In the framework of a seminar, students of the University of Bern analysed extreme weather events in the "Twentieth Century Reanalysis". Eleven papers are now published open access in "Geographica Bernensia".

Merry Christmas

The Climatology Group wishes you a merry Christmas and a happy 2014.

One hundred fifty years of Swiss climate monitoring

This weekend the Swiss meteorological network celebrates its 150th anniversary. On 1 December 1863, 88 stations started standardised measurements. Parts of these data were digitised by the climatology group in the DIGIHOM project.

Kick-off of DECADE project

The climatology group is leading the project "DECADE" (Data on climate and Extreme weather for the Central AnDEs), funded by the Swiss National Science Foundation. Together with MeteoSwiss and partners in Peru (SENAMHI-Peru) and Bolivia (SENAMHI-Bolivia, Universidad Mayor de San Andrés, La Paz), the project aims to produce climate data products for stakeholders in the region. Last week, a Pre-Kick-Off meeting took place in Lima, Peru. Official project start is February 2014.

IPCC-AR5: Summary for Policymakers of WG1 published

Today, the 12th Session of the Intergovernmental Panel on Climate Change Working Group I formally approved the Summary for Policymakers of the WG1 contribution to the Fifth Assessment Report of the IPCC. Over the last three years, several hundred scientists have worked on this report, including climatology group members Stefan Brönnimann (lead author), Jürg Luterbacher (lead author) and Heinz Wanner (review editor). The full text of the Summary for Policymakers can be downloaded from www.climatechange2013.org.

Data Assimilation in Paleoclimatology

The field of paleoclimatology is undergoing profound changes of its methodological toolbox. Numerical models are increasingly used, and scientists think about methods to combine models with proxy data in order to obtain reconstructions of past climate or to estimate parameters. These methods are termed data assimilation. The climatology group is contributing actively to this process. A series of short papers in the latest PAGES newsletter now summarizes the state of research on data assimilation methods in paleoclimatology.

Climate Column of Heinz Wanner

The climate column of Heinz Wanner appeared in the latest issue of 'klimafreundlich', the annual for sustainability, ecology and lifestyle.

Read column (pdf, 168KB, in German)

Interview with Stefan Brönnimann on solar and anthropogenic climate forcing

Read interview (in German)

Sunspot cycle affects atmospheric circulation over Europe

A study by Yuri Brugnara and colleagues from the Climatology Group finds a significant effect of solar variability changes during the sunspot cycle on atmospheric circulation over Europe. This study confirms earlier studies, which however were relying only on few sunspot cycles. Using the recently published Twentieth Century Reanalysis, circulation reconstructions based on historical upper-air data, and reconstructions of sea-level pressure, the study shows that circulation over Europe was more zonal during solar maxima winters, but more meridional (northerly over central Europe) during solar minimum winters. Recent solar minimum winters (which were not included in the study) exhibited a similar circulation anomaly.

Read article

Group excursion to Fribourg

Last Thursday, the climatology, climate risks and remote sensing groups went for a hike in the Gottéron Canyon near Fribourg (photo), followed by a geological city tour. We discovered amber on the pavement, shark teeth on the stairs to the city hall and heard many other fascinating stories.

Meteorology Field Course

Last week 15 highly motivated students attended a field course on micrometeorology and boundary layer meteorology led by Werner Eugster (ETH) and Stefan Brönnimann. The course took place at the farm Chamau near the Lake of Zug; an ETH research station. In small groups, the students had the tasks to compare parallel meteorological measurements, perform a radiosonde ascent, perform carbon dioxide flux measurements with eddy covariance and with flux chambers, build a psychrometer, and measure methane along a transect with a specially equipped car. The generally fair weather allowed efficient work and kept the spirits high. One of the highlights was an ascent with a helium-filled balloon reaching an altitude of 28 km.

First 2000-year-long temperature reconstructions for individual continents

Past climate change varied remarkably between regions. This is demonstrated in a new study coordinated by the international Past Global Changes (PAGES) project, which reconstructed temperature over the past 1000 to 2000 years. It is the first comprehensive temperature reconstruction on a continental scale. One of its main findings is that a general cooling trend, caused by different factors (e.g. orbital-driven insolation and changes in solar and volcanic activity), was ubiquitous across all continental-scale regions and was reversed by a distinct warm trend beginning at the end of the 19th century. Some 80 researchers from all over the world, including former climatology group leader Heinz Wanner, collaborated on the study, which has just been published in the scientific journal "Nature Geoscience".

Read more (pdf, 95KB)

Physics-based homogenisation of temperature records

Most temperature series are affected by inhomogeneities such as artificial breaks. Statistical methods are mostly used to correct such breaks, but the error may well have physical causes such as the change of the shelter. A new project in the climatology group (in collaboration with MeteoSwiss) aims at finding a physics-based correction for one, frequent cause of breaks: The change from a Wild Screen to a Stevenson screen. The project is funded by the Swiss National Science Foundation.

Limitations of tree-rings and other proxies

Information on climate variability during the past millennium comes to a considerable extent from tree rings. Tree growth is sensitive to temperature and moisture (i.e., precipitation), among other things, and climate scientists usually try to isolate these effects for reconstructing temperature or precipitation. Writing in "Nature Climate Change", Joerg Franke from the climatology group and his co-authors find significant limitations in the way tree rings and other climate proxies capture the variability spectrum of climate. Tree ring proxies are deficient in high frequency variability (year-to-year changes) relative to low frequency variability (multidecadal or centennial changes). This is specifically true for precipitation-sensitive tree rings. Compared to long instrumental observations of precipitation and model simulations, they overemphasize centennial changes and suppress interannual variability. This spectral bias seems to translate into climate field reconstructions, highlighting that particular care must be taken when working with climate proxies.

Read more

IPCC WG1 Fourth Lead Author Meeting

The Fourth Lead Author Meeting of IPCC's Working Group I contribution to the Fifth Assessment Report (AR5) took place this month in Hobart, Tasmania. The climatology group is well represented in AR5 with Stefan Brönnimann and former group member Jürg Luterbacher as lead authors and Heinz Wanner as review editor. The picture shows Tasmanian's minister of Climate Change Cassy O’Connor addressing the scientists.

Merry Christmas

The Climatology Group wishes you a merry Christmas and a happy 2013.

Tree rings and volcanic cooling

A few months ago, a paper by Mann et al. triggered a discussion on whether or not tree rings are able to adequately capture the effects of volcanic eruptions on climate. Writing in "Nature Geoscience", Anchukaitis an co-authors, including Petra Breitenmoser from the Climatology Group, challenge the study and demonstrate that volcanic eruptions are well imprinted in tree ring records, in agreement with growth models.

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Swiss Geoscience Meeting 2012

The University of Bern hosted the 10th Swiss Geoscience Meeting on 16 and 17 November 2012. The meeting of attracted around 700 scientists from various fields within geosciences. The 18 topical sessions on Saturday were preceded by a plenary session on Friday afternoon on "Mountains - up and down", followed by the traditional "Geo party" on Friday night. Céline Dizerens of the Climatology Group was a key person behind the organisation of this large event.

Swiss Geoscience Meeting Homepage

CLIMANDES Project

The project CLIMANDES (Servicios climáticos con énfasis en los Andes en apoyo a las decisiones) is a pilot project under the umbrella of the WMO-led Global Framework for Climate Services (GFCS). The GFCS Twinning activities between Switzerland and Peru seek to improve climate services for the Peruvian region. In addition, the project aims at increasing the number of professionals and students trained in meteorology and climatology in support of the newly established WMO Regional Training Center in Lima hosted by the National Agrarian University La Molina (UNALM).
The project coordinated by WMO and implemented by the Peruvian National Service for Meteorology and Hydrology (SENAMHI) and the Federal Office of Meteorology and Climatology MeteoSwiss in collaboration with UNALM (Peru), the University of Bern (Switzerland), and Meteodat GmbH (Switzerland). CLIMANDES is financed by the Swiss Agency for Development and Cooperation (SDC) and runs from August 2012 to July 2015. The climatology group develops e-learning modules for the Regional Training Center.

Record sea ice minimum in the Arctic

The area of the Arctic Sea covered by ice has reached a record minimum this September. Only 25% of the area is ice covered. The reduced sea ice has consequences for the Arctic climate and water cycle. Read Blog by Stefan Brönnimann on ETH Klimablog.

Interview with Stefan Brönnimann in the "Berner Zeitung"

Are the recent droughts and other extremes due to climate change? What do we know about solar effects on climate? Will climate change also lead to a change of our preception of climate? In an interview with the "Berner Zeitung", Stefan Brönnimann answers these and other questions...

BZ article (pdf, 590KB)

New PhD project funded by the Bretscher Fonds

In the framework of a PhD project funded by the Bretscher Fonds, Peter Stucki will analyse wind storms in Switzerland during the past 140 years. The goals of the project are to compile a catalogoue of past wind storms events in Switzerland, to analyse each storm using the newly available "Twentieth Century Reanalysis" data set together with historical observations, and to explore relations between wind storm occurrence and synoptic weather types (including trends). Dynamical downscaling (in collaboration with Meteotest) will allow spatio-temporally detailed studies of the development of the storms; information that can be used for impact modeling and it will contribute towards the CH2014 Climate Impacts initiative.

Climate Blog of Heinz Wanner

Heinz Wanner has written a Blog on the influence of the sun on climate for the "ProClim Klimaportal". You can download the text and the figures via the Klimaportal.

New Arctic Climate project funded

The climatology group is leading a consortium of five partners in a new European research project "Arctic Climate Processes Linked Through the Circulation of the Atmosphere".

The project is one of the successful proposals in the "ERAnet.RUS" programme within FP7, which aims at intensifying and strengthening science and technology cooperation between Russia and Europe. The project will deal with decadal variability and trends in Arctic and subarctic climate.

The climate of the Arctic is the product of a range of processes, involving not only the atmosphere but also the ocean, sea ice, land-surface conditions, and snow cover. These processes are linked through the atmospheric circulation. The circulation moves weather systems across the Arctic and controls surface climate and snow cover. It transports heat, water vapour, and aerosol particles from the midlatitudes into the Arctic, it distributes these quantities within the Arctic, and it affects sea ice through wind stress. At the same time, atmospheric circulation is affected by the energy balance of the Arctic surface and thus by sea-ice and snow cover as well as by factors outside the Arctic. The goal of the project is to study the role of these interactions for decadal variability and trends in Arctic climate. The five partners University of Bern (Switzerland), RIHMI (Russia), University of Vigo (Spain), Alfred Wegener Institute, Potsdam (Germany) and NILU (Norway) will use newly available observation based data sets, long reanalyses, numerical techniques such as trajectory modeling or nudging, and different climate models that allow addressing effects of sea-ice and snow cover. The knowledge gained from better understanding the processes governing decadal climate variability in the Arctic may eventually lead to a better assessment of climate models, supporting an increased accuracy of seasonal predictions, projections, and adaptation plans.

Phenological observations are underestimated

Climatology group member This Rutishauser commented the plant phenology study «Warming experiments underpredict plant phenological responses to climate change» for BBC Science and Environment News. The study lead by Elizabeth Wolkovich found that experiments with electrict heaters or open top chambers cannot replicate advances in the timing of flowering and leafing by 8.5-fold and 4.0-fold, respectively, compared with long-term observations. The comment was written together with Reto Stöckli, MeteoSwiss, and published in the «News & Views» forum of the journal «Nature».

Read article

BernClim : Seasonality-Monitoring – Jura, Plateau, Alps - Vernissage of a report on a topoclimatic long-term project

On 5 May, five leading personalities of the research project BernClim - This Rutishauser, Bruno Messerli, Heinz Wanner, Stefan Brönnimann and François Jeanneret - presented the newly published report on the activities from 1970 to 2011 of an original observing programme. Observations on plant phenology in summer and on snow cover duration and fog frequency in winter were designed for a mapping of tococlimatic conditions in a cross-section through Switzerland and ended up as a long-time survey of regional variations on topoclimate change in different landscape settings. The programme will carry on with both new methods and traditional observations, results will be presented in a the on-line atlas of geo-information of the Canton of Berne.

Details G 87

Science communication project funded

The climatology group will lead a «citizen science» project focusing on phenology and seasonality observations. The project aims to create a stage for interaction between scientists and citizens in order to raise awareness and understanding of the impacts of climate and environmental change. Under the auspices of the SCNAT, the project presently has 11 collaborating partner institutions and three communication expert teams. The project is lead by Stefan Brönnimann, Werner Eugster (ETHZ), Martine Rebetez (UniNE) and managed by This Rutishauser and runs from 2012–2015. It is mainly supported by the Swiss National Science Foundation through its AGORA program.

Happy Holidays

The Climatology Group wishes you a merry Christmas and a happy 2012.

Researchers' Night

Jörg Franke and Stefan Brönnimann from the climatology group participated in the Oeschger Centre project the Great Climate Poker at this year's "Researchers' Night". In a Casino ambiance with a large dice table the audience was invited to dice global climate, each of the five dices representing one climate factor. But the anthropogenic influence was a loaded dice, so that the temperature got hotter and hotter.....

Skeptische Forscher bestätigen globale Temperaturkurve

Vor zwei Jahren wurde führenden Klimawissenschaftlern die Manipulation von Daten vorgeworfen. Gefördert von Organisationen, die den Klimaskeptikern nahe stehen, erstellten Wissenschaftler der Universität Berkeley inzwischen eine neue, unabhängige globale Temperaturkurve. Von den mit Spannung erwarteten Ergebnissen berichtet Stefan Brönnimann, Professor für Klimatologie an der Universität Bern.

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Read articles by Antoinette Schwab on Open Science projects in the „Berner Zeitung (pdf, 1.2 MB)” and on the digitisation of ship log books and historical data in the “Coop Zeitung”.

“Mensch Klima!”: New Illustrated Book on Climate Change

Lars Müller publishers have released a new illustrated book on climate change in collaboration with the Department of Environmental Sciences (ETH). Stefan Brönnimann was part of the scientific support team.
The book „Mensch Klima!“ intends to discover the complex climate system, to illustrate findings of climate research understandingly and to analyse the background of climate politics. The book gives an overview of the Earth’s climate history and explains which factors are responsible for climate change. “Mensch Klima!” raises questions and gives answers: Why do we have global warming? What are the consequences? What can be done against it? Who determines the future?

The book will come out on 31.May 2011.

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An article by Holzhauser, Magny and Zumbühl on Glacier and lake-level variations in west-central Europe over the last 3500 years elected as „Emerging Research Front Paper in the field of Geosciences“ of the month of February 2011.

Discussion of the Great Aletsch Galcier by H. Holzhauser

An article in the March issue of the Swiss National Science Foundation magazine "Horizonte" describes the work in the climatology group (in German).

Horizonte, No 88, March 2011 (pdf, 95KB)

A Time Machine for Climate Scientists

The 20th Century Reanalysis Project provides understanding of Earth’s past and future climate.

The picture shows the Tay bridge disaster on the evening of the 28th of December 1879 in the Twentieth Century Reanalysis (left) and in a contemporary drawing (right).

Final QJ_20thCentury (pdf, 74KB)

German summary (pdf, 1.2 MB)

Newspaper article: "Zeitreisen in die Wettergeschichte"Tages-Anzeiger, 31.01.2011 (in German)

Annual-resolved European summer climate has, for the first time ever, been reconstructed over the past 2,500 years. Tree rings reveal possible links between past climate variability and changes in human history. Climate change coincided with periods of socioeconomic, cultural and political turmoil associated with the Barbarian Migrations, the Black Death and Thirty Years’ War.

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The "Forum für Universität und Gesellschaft" of the University of Bern has carried out four workshops on climate change and food security from September to November 2010.
The presentations/podcasts (in German) can be downloaded here (including presentations by Martin Grosjean, Rolf Weingartner, Hans Hurni, Thomas Cottier, Pier Calanca, Urs Wiesmann, Gunther Stephan etc. and an interview with Stefan Brönnimann).

Are the recently experienced autumn storms, the high temperatures in regions with foen and the abrupt temperature drop with snowfall outcomes of climate warming? The radio programme "Treffpunkt" on DRS1 raises the question whether these extreme weather events are new or if they have happened in earlier times. Prof. Brönnimann was interviewed as a climate research expert. The talk was broadcasted on 22.11.2010 at 09.05.

Radio DRS 1 Treffpunkt (in German)

Good bye Apéro for Heinz Wanner

Former Klimet members organised an apéro for Heinz Wanner on 16. November 2010. As a small acknowledgement of our gratitude for all his work, his great team spirit and his cheerful anecdotes about a researcher's life he was given a young apple tree. Thank you very much Heinz!

During the summer of 2010, a new group of climatology has formed in the Institute of Geography. As of 1 October 2010, Prof. Dr. Stefan Brönnimann has officially taken on the position of chair of climatology from Prof. Dr. Heinz Wanner. Please visit our main page and the pages of the individual group members to get to know the new group.

Internet users can help to digitise historical weather data and can thereby account for the research and a better understanding of extreme weather events.

Data rescue at home (German) (pdf, 14KB)

Newspaper article "Klimaforscher setzten auf die Hilfe von Laien", 20 Minuten online, 07.10.2010 (in German)

Stefan Brönnimann speaks about the monsoon and the extreme weather events in Pakistan. The TV programme "Einstein" was broadcasted on 26.08.2010 at 21:00.

SF 1 Einstein (in german)

Prof. Brönnimann was interviewed regarding the latest natural disasters, extreme weather events and his new professorship at the university of Bern. The talk was broadcasted on 17.08.2010 at 13:00 as a DRS 1 "Tagesgespräch".

Radio DRS1 Tagesgespräch (in german)