Atmospheric Physics

Our interest in atmospheric physics has a focus on interactions of atmospheric composition and dynamics from weather to climate scales. We seek answers to questions on the role of aerosols and circulation for the regional climate, including links to the hydrological cycle, interactions with land processes, and impacts on renewable power production. A strength in our works is the fusion of the physical understanding of weather processes with climatological assessments from the geological past to modern climate changes. We give an impression of our research themes in the following that jointly aim to contribute to the physical science basis of climate change.

 

Research themes

Past and modern climate
We perform and inter-compare climate model experiments to better understand how the Earth system responds to perturbations under modern conditions, and in warmer worlds of the past and the future. A focus is the influence of changes in atmospheric composition and irradiance on the radiative forcing and the associated climate responses, e.g., responses of the atmosphere-ocean circulation. We further assess the role of circulation for extreme weather, e.g., sea-surface temperature effects on heat waves and synoptic weather influences on extremes in power production from renewables in Europe. Another example is our research on quantifying model differences in aerosols and rain, and contributing to understand model differences in the aerosol radiative forcing from experiments like used in assessment reports of the Intergovernmental Panel on Climate Change.

 

Desert-dust storms
Natural dust aerosols contribute most to the aerosol mass on Earth, but both weather forecasts and climate models have considerable differences in simulating dust storms. We contribute to a better understanding of the dust storm dynamics, their climatology and trends. Specifically, we compile benchmark climatologies for different dust-emitting processes, e.g., nocturnal low-level jets, mobile cyclones and the post-frontal strengthening of trade winds. Such benchmarks are helpful for evaluating weather and climate models at a process level. We also perform kilometre-scale experiments for dust outbreaks, collect land- and ship-based measurements with our atmospheric observatory, apply machine learning techniques to satellite images, and develop own automated detection algorithms for process-based assessments in data. These methods allow us to gain insights into storm dynamics from the meso- to the synoptic scale and to quantify dust effects on weather, climate and impacts on photovoltaic power production.

Methods

Our research methods are diverse and are tailored for the question that we want to address. Our tool box includes conducting atmospheric model experiments with different process-complexity and for different regions, applying machine learning techniques and theoretical approaches, using space- and ground-based observational data, and collecting new measurements at land and sea.

 

  • FOCI Earth system model
    The FOCI Earth system model is used for studying climate variability and change in some of our projects. More information on the model components is accessible is accessible here.
     
  • Simple-plumes parameterisation MACv2-SP
    The magnitude of the radiative forcing of anthropogenic aerosols remains one of the key uncertainties in our understanding of climate change. To better understand the climate model spread in aerosol radiative forcing, the simple plumes parameterisation MACv2.0-SP for optical properties of anthropogenic aerosols and an associated effect on clouds was developed. The parameterisation MACv2-SP was implemented in several CMIP6 models for representing anthropogenic aerosols for contributing experiments on past and potential future climate changes for AR6.
    The code of MACv2-SP and the historical data is available as supplement of Stevens et al. (2017). We published the future scenarios for MACv2-SP based on CMIP6 emission data in the supplement of Fiedler et al. (2019) and provide updated future scenarios to account for the effects of the Covid-19 pandemic in support of CovidMIP in the supplement of Fiedler et al. (2021).

Team members

Prof. Dr. Stephanie Fiedler (Team lead)

Science support:
Dr. Sebastian Wahl

Scientists:
Dr. Sabine Bischof 
Dr. Wenjuan Huo
Dr. Franz Kanngießer
Feifei Mu (Scholarship student)
Tabea Rahm
Dr. Natalia Sudarchikova
Dr. Vidya Varma
Yamoula, Dametoti (Scholarship student)

 

Students:
Samuel Kuthe (Master Thesis)
Christiane Lösel  (Master Thesis)
Lisa Weber (Master Thesis Universität zu Köln)

Current Projects

Latest publications

  • Fiedler, S., Naik, V., O'Connor, F. M., Smith, C. J., Griffiths, P., Kramer, R. J., Takemura, T., Allen, R. J., Im, U., Kasoar, M., Modak, A., Turnock, S., Voulgarakis, A., Watson-Parris, D., Westervelt, D. M., Wilcox, L. J., Zhao, A., Collins, W. J., Schulz, M., Myhre, G., and Forster, P. M. (2024) Interactions between atmospheric composition and climate change – progress in understanding and future opportunities from AerChemMIP, PDRMIP, and RFMIP, Geosci. Model Dev., 17, 2387–2417, https://doi.org/10.5194/gmd-17-2387-2024
  • Huo, W., Drews, A., Martin, T., & Wahl, S. (2024). Impacts of North Atlantic model biases on natural decadal climate variability. Journal of Geophysical Research: Atmospheres, 129, e2023JD039778. https://doi.org/10.1029/2023JD039778
  • K. Bechir Ferchichi, T. Böhnert, B. Ritter, D. Harpke, A. Stoll, P. Morales, S. Fiedler, F. Mu, J. Bechteler, C. Münker, M.A. Koch, T. Wiehe, D. Quandt (2024) Genetic diversity of the Atacama Desert shrub Huidobria chilensis in the context of geography and climate, Global and Planetary Change, 104385, https://doi.org/10.1016/j.gloplacha.2024.104385
  • Ho-Tran, L., Fiedler, S. A climatology of weather-driven anomalies in European photovoltaic and wind power production. Commun Earth Environ 5, 63 (2024). https://doi.org/10.1038/s43247-024-01224-x
  • Kanngießer, F., & Fiedler, S. (2024): “Seeing” beneath the clouds—Machine-learning-based reconstruction of North African dust plumes. AGU Advances, 5, e2023AV001042. https://doi.org/10.1029/2023AV001042
  • Scheele, R., and Fiedler, S. (2024): What drives historical and future changes in photovoltaic power production from the perspective of global warming? Environ. Res. Lett. 19 (1), DOI 10.1088/1748-9326/ad10d6
  • Hohenegger, C. et al. incl. Fiedler, S. (2023) FESSTVaL: the Field Experiment on Submesoscale Spatio-Temporal Variability in Lindenberg. Bulletin of the American Meteorological Society, 104 (10). E1875-E1892. DOI 10.1175/BAMS-D-21-0330.1.
  • Richardson, K. et al. incl. Fiedler, S. (2023) Earth beyond six of nine planetary boundaries. Sci. Adv., 9 (37), https://doi.org/10.1126/sciadv.adh2458
  • Fiedler, S.,  van Noije, T., Smith, C.J.,  Boucher, O., Dufresne, J., Kirkevåg, A.,  Olivié, D., Pinto, R., Reerink, T.,  Sima, A.,  Schulz, M. (2023) Historical Changes and Reasons for Model Differences in Anthropogenic Aerosol Forcing in CMIP6. Geophysical Research Letters, 50 (15), https://doi.org/10.1029/2023GL104848
  • Boroughani, M., Mirchooli, F., Hadavifar, M. and Fiedler, S. (2023) Mapping land degradation risk due to land susceptibility to dust emission and water erosion. SOIL, 9 (2), 411–423, https://doi.org/10.5194/soil-9-411-2023
     
  • Access to full publication list

Events

CACTI Workshop 2023: 13. - 15. June 2023 at GEOMAR in Kiel