News and Events
A treasure much bigger than previously thought
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.
Two types of North American droughts related to different atmospheric circulation patterns
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”.
Happy Holiday Season!
Surface and satellite observations combined back to 1850
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).
Climate Data Rescue Supports Climate Services In Africa
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.
Project on long Swiss meteorological series started
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.
Welcome back Noemi
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.
Quantifying the role of the Tambora eruption in the 1816 ‘year without a summer’
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
Humboldt born 250 years ago
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.
Erfahren in Politik und Wirtschaft, eher überfordert in Klimafragen
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.
Grape harvest date of the last half millennium
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!
Causes of 19th century flood peak
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.
Fastest warming in the last 2,000 years
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.
Volcanoes shaped the climate before humankind
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.
e-learning: From historical climate data to hazard maps
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.
Urban climate and micrometeorology field course
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.
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.
GeoAgenda Themenheft zu Humboldt
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.
Das Berner Stadtklima vor 40 Jahren
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.
Klimawandel erkannt – aber wer kann und wer muss was tun?
Heinz Wanner äussert sich auf INFOsperber zur Klimadebatte und erläutert die unterschiedlichen Sichtweisen in der Diskussion.
PALAEO-RA website is online
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.
Was Klimaforscher zu den häufigsten Argumenten von Skeptikern sagen
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.
Welche Motive stecken hinter den Klimastreiks?
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).
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 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.
Two Copernicus Climate Change Services projects
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.
50 Jahre "Physik in unserer Zeit"
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.
Wieviel Schnee im zukünftigen Klima?
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
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.
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.
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).
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.
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.
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 (email@example.com).
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.
Effect of quality control on climate trends
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.
Climate Reanalyses and Services for Society
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!
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.
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.
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.
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.
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.
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: firstname.lastname@example.org
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
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
The study (in English, German, and Italian) can be downloaded here:
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:
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.
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)
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.
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.