News and Events


New colloquium program now available

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.


New Topics for Bachelor and Master Theses

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


Portrait Laura Hövel

New People

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.


Portrait Duncan Pappert

New People

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.


Stefan Brönnimann with headphones

Climate data mirror world history

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.


Winter Landscape

Merry Christmas

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


Portrait Martin Wegmann

New People

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.


Portrait Moritz Burger

New People

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.


Portrait Lucas Pfister

New People

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.


50 Jahre Klimaforschung in der Geographie

50 Jahre Klimaforschung am GIUB

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.


Blooming flowers and leaves covered with ice

«Klimawandel und Jahreszeiten»

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.


Open Access ist ganz einfach ein Muss

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.


New Topics for Bachelor and Master Theses

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 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.


Moritz Gubler with a temperature logger

SRF-Beitrag zum Stadthitzemessnetz

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. 


data sheet for snow fall amounts in Einigen

Shifts in springs seasons after record low snow observations

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“.


Left: Temperature Sensor on the Bubenberplatz. Right: Mounting a logger on the train track of Bern main station.

Stadthitze Messnetz wieder in Betrieb

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!


Portrait Stefan Brönnimann

Historical weather diaries as a basis for climate research

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.


Portrait Andrew Friedman

Marie Curie Fellow: Andrew Friedman

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.


Painting of frozen lake

New Project "Weather Reconstruction"

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.


Weltkarte der WHO welche die Ausbreitung von COVID-19 zeigt

Cancelled: Colloquium in Climatology, Climate Impact and Remote Sensing

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.


Swiss historical meteorological records

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.


Hefte "Informationen und Beiträge zur Klimaforschung"

"Beiträge zur Klimatologischen Grundlagenforschung" neu veröffentlicht

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.


Screenshot of the new C3S Data Resue Portal

New C3S Data Rescue Portal

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:


map showing locations of the inventories around the world

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.

Media Information.pdf (PDF, 256KB)


two maps showing dust bowl-type drought and 1950s-type drought in North America

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”.


Merry Christmas and a Happy New Year from the Climatology Group, University of Bern (picture of an inversion situation in a snowy landscape)

Happy Holiday Season!


Four maps of the world showing the number of stations in 1850, 1900, 1950 and 2000

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).


Program of Copernicus Climate Change Services (C3S) General Assembly in Warsaw (October 2019)

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.


Image of historical weather measurements overlayed with a red line displaying the change of a variable

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.



Portrait of Noemi Imfeld

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!


Portrait of Mussie Fessehaye

New PostDoc

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.


eruption of Pinatubo 1991

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


street sign in Bern: "Humboldtstrasse - Alexander von Humboldt, 1783-1859, Naturforscher"

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.


Portrait picture of Heinz Wanner

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.

Blog Heinz Wanner.pdf (PDF, 92KB)


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.


Group members prepare pizzas

Group excursion

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!


flooded street on 22 June 1876

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.


Graph of the global warming / cooling rates over the past 2000 years

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.


painting of Rosenlaui Glacier

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.


detail from the website of

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, 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.


two students carry out field experiments

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.


advertising poster of "keineismeehr" of Kunsthaus Interlaken


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.


front page picture of GeoAgenda with a drawing of Alexander von Humboldt showing four mountain peaks

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.


Stefan Brönnimann in Swiss television "Schweiz Aktuell"


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.


heat map of Bern

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.


portrait of Heinz Wanner

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.


screenshot of the website of PALAEO-RA

PALAEO-RA website is online

A comprehensive overview of the PALAEO-RA-project is now accessible online. On, 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: 


portrait of Elin Lundstad

New People

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”.


portrait of Ralf Hand

New People

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.


deviation of summer temperature in Switzerland from 1981-2010 in °C

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 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.



a person holds a weather balloon for Copernicus

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. 


portrait of Eric Samakinva

New People

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.


cover page of "Physik in unserer Zeit" from January 2019

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.


portrait of Fernando Jaume Santero

Visiting Scientist

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.


Stefan Brönnimann giving an interview for

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

On Friday and Saturday, 30 Nov to 1 Dec, the Institutes of Geology and Geography of the University of Bern hosted the 16th Swiss Geoscience Meeting under the umbrella theme "A Habitable Planet". Around 850 scientists attended numerous talks in 23 individual Sessions. Members of the climatology group were involved as local organisers, helped during the meeting, convened or co-convened three sessions and gave four talks. Thanks to all of you for making this meeting such a great success!   


New People

Angela-Maria Burgdorf recently finished her MA studies at the GIUB, specializing in climatology. She is currently working as a research assistant in the climatology group. In January, she will start a PhD in Climate Science at the Graduate School of Climate Sciences of the Oeschger Centre supervised by Prof. Stefan Brönnimann. She wrote her master thesis at Monash University in Melbourne (Australia) where she focused on the influence of stratospheric ozone depletion on precipitation in the Southern Hemisphere. In her PhD project, she will be focusing on monsoon variability in the past 500 years based on phenological data with a special focus on the influence of volcanic eruptions.


Climate Data Empathy

Information on weather and climate data affects many decisions. Providing this information used to be the task of experts, but today we find such information conveniently on web portals. Globally complete, highly processed weather and climate data products are available freely, in a ready-to-use form, donwloadable via web-interfaces. This is first of all a commendable achievement. By providing information on extremes, these data also contribute to increase the resilience of society towards climatic changes. However, the ease-of-use changes our relation to climate data. We tend to forget how the climate information was generated. Writing in WIREs Climate Change, Stefan Brönnimann and Jeannine Wintzer recall the diverse origins of climate data and demonstrate that historical and present-day context imprints on the data (


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:


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.


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).


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.


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 (


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 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

When downloading climate data from existing data bases, we usually assume that they have undergone some quality screening. While this may be true, there may still be quality issues that are not easily detected with automatic quality control algorithms. In the SNF-funded R4D-project DECADE, Stefan Hunziker discovered many such issues in data from Bolivia and Peru. Once detected, some of them could be corrected, others led to the exclusion of stations from the data set. The resulting trend maps show substantial differences to those without applying this additional quality control. Besides generating a new, high-quality data set of meteorological measurements in the Altiplano, Stefan Hunziker packed his quality control experience into an R-code that can be used in other parts of the world. His paper just appeared in "Climate of the Past".


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.


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!


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" (, 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.

Link to paper
Link to press release


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.

Model-aided climate reconstructions


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): Want to observe plant phenological phases as well? Use our portal 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.

Brochure ERA-CLIM2 (PDF, 7.5 MB)


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:

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:


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 (


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.



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.