Job vacancy: Researcher (closed)

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The European Severe Storms Laboratory (ESSL, is looking for a

Researcher (75 – 100 %)
for two years initially

based in Germany, to support its work in the research project CHECC on severe thunderstorms and climate change (see below) at 75% of a full position.

Optionally, other tasks involving programming work in support of the ESSL Testbeds may be taken over. In this case, the researcher can be hired full-time. We are looking for someone who can start in the coming months, or at the latest by September 2021.


We are looking for support of the project “Convective Hazard Evolution under Climate Change” (CHECC, see:, part of the German research programme ClimXtreme (see: which includes several research groups at various universities. The primary goal of CHECC is to find out if effects of climate change on the occurrence of (severe) thunderstorms in Europe can be detected in reanalyses and climate models. This is done by developing and applying statistical methods with a strong basis in physics. Tasks of the researcher will include:

  • Evaluating the role of changes in synoptic scale weather patterns on severe thunderstorm probability
  • Evaluating changes in the variability of weather conditions supportive of severe thunderstorms
  • Reporting on the research in peer-reviewed scientific journals

ESSL Testbed

The ESSL Testbed is a collection of one-week events, which (in non-corona times) takes place in person at ESSL premises in Wiener Neustadt, Austria. There, forecasters and developers work together to evaluate novel products developed to support the forecasting and warning process. They do this by using these products based on satellite, radar, and numerical weather prediction data to make forecasts in a quasi-operational setting. ESSL seeks someone to help develop and maintain the ESSL Weather Data Displayer, which is an interactive web page for displaying meteorological data.


The employee needs to be a resident in or moving to Germany as this is a prerequisite by the funder of the CHECC project. The current ESSL team is spread across many European countries including Germany, Austria, the Netherlands, Romania, and Croatia and often works remotely. The employee do their work through teleworking from Germany. In collaboration with the Institute of Meteorology of the Freie Universität Berlin, we offer a workplace at the Institute, which is the location of the other current ESSL CHECC researcher. It is expected that the new employee will coordinate with him and with other ESSL colleagues in weekly video meetings and will meet in person approximately every two to three months, in Berlin, Wiener Neustadt, or another agreed location. In case work in support of the ESSL Testbed is done, it is expected that the employee will take part in person in the Testbed in Wiener Neustadt for at least one week in June and/or July.

ESSL offers this position for a two-year period, limited by the duration of the funding for the CHECC project. Provided that subsequent funding is found, the employment may be continued beyond the two-year period, and could be made permanent. As a researcher at ESSL, you will be part of a small international team of ESSL which has become an important centre of competence in Europe with regard to severe convection. You will be able to contribute to the various other activities carried out and take part in ESSL courses taught by experts in the field.

We are looking for a person who has a Master or Ph.D. degree or equivalent in meteorology, physics, or a related discipline, who is enthusiastic about severe weather research. A well-organized, reliable, and communicative character is expected. For graduates of a Master’s degree, the work done for the CHECC project can be part of a Ph.D. degree (dr. rer. nat.) pursued at the Freie Universität Berlin or another university.

We require:

  • Good command of the English language in speaking and writing
  • An M.Sc. or Ph.D. degree in physics, meteorology, geophysics, mathematics or similar
  • An interest in (severe) convective storms
  • Experience with programming using languages such as Python, R, or similar

Beneficial, but not essential, are:

  • Having published in peer-reviewed literature
  • Having done prior research work related to atmospheric circulation patterns
  • Knowledge of the German language or willingness to learn German
  • Some knowledge of web-programming (HTML, PHP, JavaScript)
  • An interest in weather forecasting

The salary level is oriented at the German TvöD salary table, level E 13. In case the employee with carry out the research work (at 75%), an indicative net salary is around € 2000/month, depending on the applicable tax class according to German law and other factors.  In case the employee will also contribute to the Testbed and work full time (100%), an indicative net salary is € 2500/month.

With reference to ESSL’s diversity policy, we especially encourage women and minorities to apply. We are looking forward to receiving your application including a motivation letter and a curriculum vitae until February 28th 2021 by e-mail to Pieter Groenemeijer:

UPDATE – ESSL events in 2020 online

ESSL has decided to carry out all its events in 2020 online. We have collected experience with organizing such events and have received mostly positive feedback. That being said, we aim to organize event on site in Wiener Neustadt in 2021 as soon as the virus situation allows it. We are looking forward to welcoming participants personally to our expanded facilities.

Frequency rise of future European thunderstorm hazards

Researchers at the European Severe Storms Laboratory (ESSL), Munich Re, the Ludwig-Maximilians University Munich (LMU) and the German Aerospace Centre (DLR) could show that damaging convective weather events including lightning, hail and severe wind gusts are likely to become more common across Europe until the end of this century. An increase in convective instability as a result of rising humidity near the earth’s surface was identified as main reason for the increase in hazard frequency.

They applied a set of additive logistic regression models (AR-CHaMo) to an ensemble of 14 regional climate simulations to predict the frequency of severe thunderstorms and its associated hazards in Europe under projected anthropogenic climate conditions.

Simulated annual 6-hourly periods with (a), (b) and (c) hail ≥ 2cm (d), (e) and (f) wind (g), (h) and (i) with hail ≥ 5 cm. The first column (a, d and g) represent the historical period (1971-2000) while the second and third column show the percent change at the end of the century (2071-2100) for the (b, e and h) RCP4.5 and (c, f and i) RCP8.5 scenarios. Trends are called (very) robust where the change is larger than (twice) the initial standard deviation of the model ensemble. (Very) robust changes are indicated by (large) black dots in (b, c, e, f, h and i). Areas where models already diverge greatly for the historical period are displayed in gray in (a, d and g). From Rädler et al. (2019).

They projected a slight decrease in thunderstorm occurrence in southwestern and southeastern Europe, but an increase in the probability of severe weather. Large hail (≥ 2 cm) is projected to become 40%-80% more likely across central Europe in the RCP8.5 scenario by the end of the 21st century (Figure c ) while very large hail is projected to become more likely across most of Europe, with a doubling possible in parts of central and northeastern Europe (Figure i).  As a consequence of the rising hazard probabilities, risk models will need to be adapted and public warnings and precautionary measures should be issued as storms approach.

More information on this study can be found in this open access article: 
Anja T. Rädler, P.H. Groenemeijer, E. Faust, R. Sausen and T. Púčik, 2019: Frequency of severe thunderstorms across Europe expected to increase in the 21st century due to rising instability, npj Climate and Atmospheric Science, DOI:10.1038/s41612-019-0083-7

The severe convective weather season of 2018 has started

During recent days, pronounced severe convective storm activity has occurred across Europe, reports of which have been collected into the ESWD with help of ESSL’s partners. In total, we have received over 360 reports in the past 7 days. A majority of them were of large hail (184 reports), followed by severe wind gusts (79 reports) and heavy rainfall (66 reports). The first notable event was 29th April, where a tornadic supercell tracked more than 500 km from central France to Belgium. Wind damage caused by this supercell is still being investigated to confirm possible occurrence of several tornadoes along its path. On 1 May, a long-lived supercell over eastern Poland produced a hail swath 300 km long with hail up to 5 cm in diameter. And one day later, series of severe storms struck Croatia, Slovenia, Hungary and Austria. Hail up to 6 cm in diameter was observed over northeastern Slovenia, damaging houses and numerous flash floods were reported from Vienna, where storms persisted for several hours.

New statistical method shows increases in European hail and lightning

Researchers at ESSL, Munich Re, the Ludwig-Maximilians University Munich (LMU) and the German Aerospace Centre DLR have developed a new statistical method to investigate trends in thunderstorm and severe weather activity. Anja Rädler, the main developer of this method, called AR-CHaMo, will defend her Ph.D. thesis on this topic at LMU.

Anja Rädler says: “the strength of our approach is that we are now able to assess changes in severe weather frequency using climate models that are themselves too coarse to simulate each and every thunderstorm”. To do this, the probability of lightning and severe weather is determined as a function of parameters such as instability, moisture and wind shear, using severe weather observations from ESSL’s European Severe Weather Database.

Annual number of 6-hourly periods with hail of 2 cm or larger in Europe (1979 - 2016), modelled using AR-CHaMo. From: Rädler et al, 2018.

Annual number of 6-hourly periods with hail of 2 cm or larger in Europe (1979 – 2016), modelled using AR-CHaMo. From: Rädler et al, 2018.

In a new article in the Journal of Applied Meteorology and Climatology, the development of AR-CHaMo is explained in detail, and trends of lightning and severe weather frequency since 1979 are presented. The basis of these projections are a numerical model (ERA-Interim), that simulates the past weather since 1979. The annual average predicted number of large hail events (see map below) conforms quite well to what we know: the Alpine forelands are the Europe’s hailfall hotbed.

The number of simulated hail events was not constant during the last three decades. When considering hail activity over Central Europe, significant increases are detected.

Simulated number of 6-hourly periods with hail > 2 cm across Germany and the Alps (blue) and Western and Central Europe (green), 1979-2016.

Simulated number of 6-hourly periods with hail > 2 cm across Germany and the Alps (blue) and Western and Central Europe (green), 1979-2016. From: Rädler et al, 2018.

Of course, it is of interest to know what the reason for the increase is. Anja Rädler: “we found that the driving factor is the increasing humidity close to the earth’s surface. This is something we expect to happen when temperatures increase, because warmer air can contain more moisture.” Indeed, temperature has increased since 1979, at least partly, because of the rising CO2 content of the atmosphere.

The map below shows which areas have seen the strongest increase, according to ERA-Interim and the AR-CHaMo model.

Trend of number of 6-hourly periods with severe hail (1979-2016). Dots denote where a ignificant trend was found.

Trend of number of 6-hourly periods with severe hail of 2cm or larger (1979-2016). Dots denote where a ignificant trend was found. From: Rädler et al, 2018.

The next question Anja and her team will address is what will happen in the future. First results that were published by the ESSL team in 2017 suggest that the moisture increase will continue and create more situations favorable for severe thunderstorms during the 21st century. Using the new AR-CHaMo method, the team will soon be able to give an estimate of how much more hail, tornadoes, severe winds and lightning we should count on in different climate change scenarios.

New study shows: severe thunderstorms more frequent if Europe warms and moistens

A new study led by ESSL researcher Dr. Tomáš Púčik shows how climate change will affect weather conditions responsible for severe thunderstorms. In the study, which has appeared in the Journal of Climate, no fewer that 14 regional climate models were studied. Because climate models are still too coarse to simulate convective storms directly, the researchers looked how often the three necessary ingredients for severe storms occur: unstable conditions, a strong change of wind with height, and a mechanism to trigger the storms.

The climate models predict that strongly unstable situations will occur more frequently, because the water vapour content in the lowest air layers will increase. At the same time, the wind shear, a factor important for the development of well-organized supercells, will not change much. As a result, severe convective storms are forecast to occur more frequently, with the strongest increases scenario with higher greenhouse gas emissions.

The increase is not geographically uniform and considerable uncertainty remains about the future changes in severe convective storm frequency over southwestern and southern Europe, due to a drying in the summer season.

The full open-access article can be downloaded here:

Tomáš Púčik, Pieter Groenemeijer, Anja T. Rädler, Lars Tijssen, Grigory Nikulin, Andreas F. Prein, Erik van Meijgaard, Rowan Fealy, Daniela Jacob, and Claas Teichmann, 2017: Future Changes in European Severe Convection Environments in a Regional Climate Model Ensemble, J. Climate, in press.

Present annual number of 6-hourly periods with high instability, strong wind shear and precipitation in the period 1971-2000 (a) and the changes expected in two future periods according to a scenario of moderate climate change (rcp4.5, b. and c.) and strong climate change (rcp8.5, d. and e.).