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Univ.-Prof. Stephan Pfahl

Image Credit: Petra Grasse

Freie Universität Berlin

Institut für Meteorologie


Carl-Heinrich-Becker-Weg 6-10
Room 185
12165 Berlin

Since April 2018: Professor of Weather and Climate Processes, Institute of Meteorology, Freie Universität Berlin

2012 - 2018: Senior Scientist and Lecturer, Institute for Atmospheric and Climate Science, ETH Zurich

2009 - 2012: PostDoc, Institute for Atmospheric and Climate Science, ETH Zurich

2006 - 2009: PhD, Institute for Atmospheric Physics, University of Mainz

2000 - 2005: Diploma in Physics, University of Göttingen

Summer semester 2022

Winter semester 2021/22

Researcher-ID: G-4194-2014

Peer reviewed journals


  • Dolores-Tesillos, E., Pfahl, S., 2024: Future changes in North Atlantic winter cyclones in CESM-LE – Part 2: A Lagrangian analysis, Weather Clim. Dynam., 5, 163-179, doi:10.5194/wcd-5-163-2024.

  • Quinting, J. F., Grams, C. M., Chang, E. K., Pfahl, S., Wernli, H.,2024: Warm conveyor belt activity over the Pacific: modulation by the Madden–Julian Oscillation and impact on tropical–extratropical teleconnections, Weather Clim. Dynam., 5, 65-85, doi:10.5194/wcd-5-65-2024.


  • Pacey, G., Pfahl, S., Schielicke, L., Wapler, K., 2023: The climatology and nature of warm-season convective cells in cold-frontal environments over Germany, Nat. Hazards Earth Syst. Sci. 23, 3703-3721, doi:10.5194/nhess-23-3703-2023.
  • Villiger, L., Dütsch, M., Bony, S., Lothon, M., Pfahl, S., Wernli, H., Brilouet, P., Chazette, P., Coutris, P., Delanoë, J., Flamant, C., Schwarzenboeck, A., Werner, M., Aemisegger, F., 2023: Water isotopic characterisation of the cloud–circulation coupling in the North Atlantic trades – Part 1: A process-oriented evaluation of COSMOiso simulations with EUREC4A observations, Atmospheric Chem. Phys, 23, 14643-14672, doi:10.5194/acp-23-14643-2023.
  • Dahinden, F., Aemisegger, F., Wernli, H., Pfahl, S., 2023: Unravelling the transport of moisture into the Saharan Air Layer using passive tracers and isotopes, Atmos. Sci. Lett., 24, doi:10.1002/asl.1187.
  • Gertler, C. G., O'Gorman, P. A., Pfahl, S., 2023: Moist available potential energy of the mean state of the atmosphere and the thermodynamic potential for warm conveyor belts and convection, Weather Clim. Dynam., 4, 361-379, doi:10.5194/wcd-4-361-2023.

  • Ruff, F., Pfahl, S., 2023: What distinguishes 100-year precipitation extremes over central European river catchments from more moderate extreme events?, Weather Clim. Dynam., 4, 427-447, doi:10.5194/wcd-4-427-2023.


  • Schielicke, L., Pfahl, S., 2022: European heatwaves in present and future climate simulations: a Lagrangian analysis, Weather Clim. Dynam., 3, 1439-1459, doi:10.5194/wcd-3-1439-2022.
  • Caldas-Alvarez, A., Augenstein, M., Ayzel, G., Barfus, K., Cherian, R., Dillenardt, L., Fauer, F., Feldmann, H., / Heistermann, M., Karwat, A., Kaspar, F., Kreibich, H., Lucio-Eceiza, E. E., Meredith, E. P., Mohr, S., Niermann, D., Pfahl, S., Ruff, F., Rust, H. W., Schoppa, L., Schwitalla, T., Steidl, S., Thieken, A. H., Tradowsky, J. S., Wulfmeyer, V., Quaas, J., 2022: Meteorological, impact and climate perspectives of the 29 June 2017 heavy precipitation event in the Berlin metropolitan area, Nat. Hazards Earth Syst. Sci., 22, 3701-3724, doi:10.5194/nhess-22-3701-2022.
  • Geppert, M., Hartmann, K., Kirchner, I., Pfahl, S., Struck, U., Riedel, F., 2022: Precipitation Over Southern Africa: Moisture Sources and Isotopic Composition, J. Geophys. Res. Atmos., 127, doi:10.1029/2022jd037005.
  • Steinfeld, D., Sprenger, M., Beyerle, U., Pfahl, S., 2022: Response of moist and dry processes in atmospheric blocking to climate change, Environ. Res. Lett., 17, 084020, doi:10.1088/1748-9326/ac81af.
  • de Vries, A. J., Aemisegger, F., Pfahl, S., Wernli, H., 2022: Stable water isotope signals in tropical ice clouds in the West African monsoon simulated with a regional convection-permitting model, Atmos. Chem. Phys., 22, 8863-8895, doi:10.5194/acp-22-8863-2022.
  • Klein, R., Schielicke, L., Pfahl, S. and Khouider, B. (2022): QG–DL–Ekman: Dynamics of a Diabatic Layer in the Quasi-Geostrophic Framework, Journal of the Atmospheric Sciences, 79(3), 887-905, doi:10.1175/JAS-D-21-0110.1.
  • Kautz, L.-A., Martius, O., Pfahl, S., Pinto, J. G., Ramos, A. M., Sousa, P. M., and Woollings, T. (2022): Atmospheric blocking and weather extremes over the Euro-Atlantic sector – a review, Weather Clim. Dynam., 3, 305–336, doi:10.5194/wcd-3-305-2022.
  • Dolores-Tesillos, E., Teubler, F., and Pfahl, S. (2022): Future changes in North Atlantic winter cyclones in CESM-LE – Part 1: Cyclone intensity, potential vorticity anomalies, and horizontal wind speed, Weather Clim. Dynam., 3, 429–448, doi:10.5194/wcd-3-429-2022.


  • Dahinden, F. and Aemisegger, F. and Wernli, H. and Schneider, M. and Diekmann, C. J. and Ertl, B. and Knippertz, P. and Werner, M. and Pfahl, S. (2021) - Disentangling different moisture transport pathways over the eastern subtropical North Atlantic using multi-platform isotope observations and high-resolution numerical modelling, Atmospheric Chemistry and Physics, 21, 16319-16347, doi:10.5194/acp-21-16319-2021.
  • Diekmann, C.J., Schneider, M., Knippertz, P., de Vries, A.J., Pfahl, S., Aemisegger, F., Dahinden, F., Ertl, B., Khosrawi, F., Wernli, H., Braesicke, P. (2021) - A Lagrangian Perspective on Stable Water Isotopes During the West African Monsoon, Journal of Geophysical Research: Atmospheres, 126, e2021JD034895, doi:10.1029/2021JD034895.
  • Zhuo, Z., Kirchner, I., Pfahl, S., and Cubasch, U., 2021 -  Climate impact of volcanic eruptions: the sensitivity to eruption season and latitude in MPI-ESM ensemble experiments, Atmos. Chem. Phys., 21, 13425–13442, doi:10.5194/acp-21-13425-2021.


  • Steinfeld, D., et al, Boettcher, M., Forbes, R., Pfahl, S., 2020:  The sensitivity of atmospheric blocking to upstream latent heating – numerical experiments, EGU, Weather Clim. Dynam., 1, 405–426, doi:10.5194/wcd-1-405-2020.
  • Thurnherr, I., Kozachek A., Graf., Weng,Y., Bolshiyanov, D., Landwehr, S., Pfahl, S., Schmale, J., Sodemann, H., Steen-Larsen, H. C.,  Toffoli, A., Wernli, H. and Aemisegger, F.2020: Meridional and vertical variations of the water vapour isotopic composition in the marine boundary layer over the Atlantic and Southern Ocean, EGU, Atmos. Chem. Phys., 20, 5811–5835. doi:10.5194/acp-20-5811-2020.
  • Zschenderlein, P., Pfahl, S., Wernli, H., and Fink, A. H., 2020: A Lagrangian analysis of upper-tropospheric anticyclones associated with heat waves in Europe, Weather Clim. Dynam., 1, 191–206, doi:10.5194/wcd-1-191-2020.


  • Schuster, M., Grieger, J., Richling, A., Schartner, T., Illing, S., Kadow, C.,  Müller, W. A., Pohlmann, H., Pfahl, S., Ulbrich, U., 2019: Improvement in the decadal prediction skill of the North Atlantic extratropical winter circulation through increased model resolution, Earth System Dynamics, 10, 901-917, doi:10.5194/esd-10-901-2019.
  • Zschenderlein, P., Fink, A.H., Pfahl, S. and Wernli, H., 2019: Processes determining heat waves across different European climates, Q.J.R. Meteorol. Soc., 145, 0035-9009, doi:10.1002/qj.3599.

  • Catto, J.L., Ackerley, D., Booth, J.F., Champion, A.J., Colle, B.A., Pfahl, S., Pinto, J.G., Quinting, J.F., Seiler, C., 2019: The Future of Midlatitude Cyclones, Curr. Clim. Change Rep., 5, 407-420, doi:10.1007/s40641-019-00149-4.

  • Russo, E., Kirchner, I., Pfahl, S., Schaap, M. and Cubasch, U., 2019: Sensitivity studies with the regional climate model COSMO-CLM 5.0 over the CORDEX Central Asia Domain, Geoscientific Model Development, 12, 5229-5249, doi:10.5194/gmd-12-5229-2019.

  • Steinfeld, D. and Pfahl, S., 2019: The role of latent heating in atmospheric blocking dynamics: A global climatology, Climate Dynamics, 53, 6159-6180, doi:10.1007/s00382-019-04919-6.

  • Sprenger M., Stumpp C., Weiler M., Aeschbach W., Allen S.T., Benettin P., Dubbert M., Hartmann A., Hrachowitz M., Kirchner J.W., McDonnell J.J., Orlowski N., Penna D., Pfahl S., Rinderer M., Rodriguez N., Schmidt M., Werner C. 2019: The demographics of water: A review of water ages in the critical zone, Rev. of Geophysics, 57, 800-834, doi:10.1029/2018RG000633.
  • Büeler, D. and Pfahl, S., 2019: Potential vorticity diagnostics to quantify effects of latent heating in extratropical cyclones. Part II: Application to idealized climate change simulations, J. Atmos. Sci., 76, 1885-1901, doi:10.1175/JAS-D-18-0342.1.

  • Lee, K.-O., Aemisegger, F., Pfahl, S., Flamant, C., Lacour, J.-L., and Chaboureau, J.-P., 2019: Contrasting stable water isotope signals from convective and large-scale precipitation phases of a heavy precipitation event in southern Italy during HyMeX IOP 13: A modelling perspective, Atmos. Chem. Phys., 19, 7487-7506, doi:10.5194/acp-19-7487-2019.

  • Škerlak, B., Pfahl, S., Sprenger, M., and Wernli, H., 2019: A numerical process study on the rapid transport of stratospheric air down to the surface over western North America and the Tibetan Plateau, Atmos. Chem. Phys., 19, 6535-6549, doi:10.5194/acp-19-6535-2019.

  • Pasquier, J.T., Pfahl, S., Grams, C.M., 2019: Modulation of atmospheric river occurrence and associated precipitation extremes in the North Atlantic region by European weather regimes, Geophys. Res. Lett., 46, 1014-1023, doi:10.1029/2018GL081194.

  • Graf, P., Wernli, H., Pfahl, S., Sodemann, H., 2019: A new interpretative framework for below-cloud effects on stable water isotopes in vapour and rain, Atmos. Chem. Phys., 19, 747-765, doi:10.5194/acp-19-747-2019.


  • Eckstein J., Ruhnke R., Pfahl S., Christner E., Dyroff C., Reinert D., Rieger D., Schneider S., Schröter S., Zahn A., and Braesicke P., 2018. From climatological to small-scale applications: simulating water isotopologues with ICON-ART-Iso (version 2.3). Geosci. Model Dev., 11, 5113-5133, doi:10.5194/gmd-2017-280.

  • Christner E., Aemisegger F., Pfahl S., Werner M., Cauquoin A., Schneider M., Hase F., Barthlott S., and Schädler G., 2018. The climatological impacts of continental surface evaporation, rainout, and subcloud processes on δD of water vapor and precipitation in Europe. J. Geophys. Res. 123, 4390-4409, doi:10.1002/2017JD027260.

  • Dütsch M., Pfahl S., Meyer M., and Wernli H., 2018. Lagrangian process attribution of isotopic variations in near-surface water vapour in a 30-year regional climate simulation over Europe. Atmos. Chem. Phys. 18, 1653-1669, doi:10.5194/acp-18-1653-2018.


  • Dütsch M., Pfahl S., and Sodemann H., 2017. The impact of rainout and mixing on two different deuterium excess definitions. J. Geophys. Res. 122, 12732-12746, doi:10.1002/2017JD027085.

  • Booth J.F., Dunn-Sigouin E., and Pfahl S., 2017. The relationship between extratropical cyclone steering and blocking along the North American East coast. Geophys. Res. Lett. 44, 11976-11984, doi:10.1002/2017GL075941.

  • Binder H., Boettcher M., Grams C.M., Joos H., Pfahl S., and Wernli H., 2017. Exceptional airmass transport and dynamical drivers of an extreme wintertime Arctic warm event. Geophys. Res. Lett. 44, 12028-12036, doi:10.1002/2017GL075841.

  • Büeler D. and Pfahl S., 2017. Potential vorticity diagnostics to quantify effects of latent heating in extratropical cyclones. Part I: Methodology. J. Atmos. Sci. 74, 3567-3590, doi:10.1175/JAS-D-17-0041.1.

  • Pfahl S., O'Gorman P.A., and Fischer E.M., 2017. Understanding the regional pattern of projected future changes in extreme precipitation. Nature Clim. Change 7, 423-427, doi:10.1038/nclimate3287.

  • Sodemann H., Aemisegger F., Pfahl S., Bitter M., Corsmeier U., Feuerle T., Graf P., Hankers R., Hsiao G., Schulz H., Wieser A., and Wernli H., 2017. The stable isotopic composition of water vapour above Corsica during the HyMeX SOP1 campaign: insight into vertical mixing processes from lower-tropospheric survey flights. Atmos. Chem. Phys. 17, 6125-6151, doi:10.5194/acp-17-6125-2017.


  • Röthlisberger M., Pfahl S., and Martius O., 2016. Regional-scale jet waviness modulates the occurrence of mid-latitude weather extremes. Geophys. Res. Lett. 43, 10989-10997, doi:10.1002/2016GL070944.

  • Martius O., Pfahl S., and Chevalier C., 2016. A global quantification of compound precipitation and wind extremes. Geophys. Res. Lett. 43, 7709-7717, doi:10.1002/2016GL070017.

  • Dütsch M., Pfahl S. and Wernli H., 2016. Variations of δ2H in an idealized extratropical cyclone. Geophys. Res. Lett. 43, 5401-5408, doi:10.1002/2016GL068600.

  • Pfahl S. and Sprenger M., 2016. On the relationship between extratropical cyclone precipitation and intensity. Geophys. Res. Lett. 43, 1752-1758, doi:10.1002/2016GL068018.

  • Papritz L. and Pfahl S., 2016. Importance of latent heating in mesocyclones for the decay of cold air outbreaks: A numerical process study from the Pacific sector of the Southern Ocean. Mon. Weather Rev. 144, 315-336, doi:10.1175/MWR-D-15-0268.1.

  • Barton Y., Giannakaki P., von Waldow H., Chevalier C, Pfahl S., and Martius O., 2016. Clustering of regional-scale extreme precipitation events in southern Switzerland. Mon. Weather Rev. 144, 347-369, doi:10.1175/MWR-D-15-0205.1.


  • Pfahl S., O'Gorman P.A., and Singh M.S., 2015. Extratropical cyclones in idealized simulations of changed climates. J. Climate 28, 9373-9392, doi:10.1175/JCLI-D-14-00816.1.

  • Pfahl S., Schwierz C., Croci-Maspoli M., Grams C.M., and Wernli H., 2015. Importance of latent heat release in ascending air streams for atmospheric blocking. Nature Geosci. 8, 610-614, doi:10.1038/ngeo2487.

  • Aemisegger F., Spiegel J.K., Pfahl S., Sodemann H., Eugster W., and Wernli H., 2015. Isotope meteorology of cold front passages: a case study combining observations and modeling. Geophys. Res. Lett. 42, 5652-5660, doi:10.1002/2015GL063988.

  • Skerlak B., Sprenger M., Pfahl S., Tyrlis E., and Wernli H., 2015. Tropopause folds in ERA-Interim: global climatology and relation to extreme weather events. J. Geophys. Res. 120, 4860-4877, doi:10.1002/2014JD022787.

  • Santos J.A., Pfahl S., Pinto J.G., and Wernli H., 2015. Mechanisms underlying temperature extremes in Iberia: a Lagrangian perspective. Tellus A 67, 26032, doi:10.3402/tellusa.v67.26032.

  • Bieli M., Pfahl S., and Wernli H., 2015. A Lagrangian investigation of hot and cold temperature extremes in Europe. Q. J. R. Meteorol. Soc. 141, 98-108, doi:10.1002/qj.2339.

  • Papritz L., Pfahl S., Sodemann H., and Wernli H., 2015. A climatology of cold air outbreaks and their impact on air-sea heat fluxes in the high-latitude South Pacific. J. Climate 28, 342–364, doi:10.1175/JCLI-D-14-00482.1.


  • Papritz L., Pfahl S., Rudeva I., Simmonds I., Sodemann H., and Wernli H., 2014. The role of extratropical cyclones and fronts for Southern Ocean freshwater fluxes. J. Climate 27, 6205-6224, doi:10.1175/JCLI-D-13-00409.1.

  • Grams C.M., Binder H., Pfahl S., Piaget N., and Wernli H., 2014. Atmospheric processes triggering the central European floods in June 2013. Nat. Hazards Earth Syst. Sci. 14, 1691-1702, doi:10.5194/nhess-14-1691-2014.

  • Pfahl S., 2014. Characterising the relationship between weather extremes in Europe and synoptic circulation features. Nat. Hazards Earth Syst. Sci. 14, 1461-1475, doi:10.5194/nhess-14-1461-2014.

  • Winschall A., Pfahl S., Sodemann H., and Wernli H., 2014. Comparison of Eulerian and Lagrangian moisture source diagnostics - the flood event in eastern Europe in May 2010. Atmos. Chem. Phys. 14, 6605–6619, doi:10.5194/acp-14-6605-2014.

  • Winschall A., Sodemann H., Pfahl S., and Wernli H., 2014. How important is intensified evaporation for Mediterranean precipitation extremes? J. Geophys. Res. 119, 5240–5256, doi:10.1002/2013JD021175.

  • Aemisegger F., Pfahl S., Sodemann H., Lehner I., Seneviratne S., and Wernli H., 2014. Deuterium excess as a proxy for continental moisture recycling and plant transpiration. Atmos. Chem. Phys. 14, 4029-4054, doi:10.5194/acp-14-4029-2014.

  • Pfahl S. and Sodemann H., 2014. What controls deuterium excess in global precipitation? Clim. Past, 10, 771-781, doi:10.5194/cp-10-771-2014.

  • Pfahl S., Madonna E., Boettcher M., Joos H., and Wernli H., 2014. Warm conveyor belts in the ERA-Interim data set (1979-2010). Part II: Moisture origin and relevance for precipitation. J. Climate 27, 27-40, doi:10.1175/JCLI-D-13-00223.1.


  • Miltenberger A. K., Pfahl S. and Wernli H., 2013. An online trajectory module (version 1.0) for the nonhydrostatic numerical weather prediction model COSMO. Geosci. Model Dev. 6, 1989-2004 doi:10.5194/gmd-6-1989-2013.

  • Catto J.L. and Pfahl S., 2013. The importance of fronts for extreme precipitation. J. Geophys. Res. 118, 10791–10801, doi:10.1002/jgrd.50852.

  • Martius O., Sodemann H., Joos H., Pfahl S., Winschall A., Croci-Maspoli M., Graf M., Madonna E., Mueller B., Schemm S., Sedlacek J., Sprenger M. and Wernli H., 2013. The role of upper-level dynamics and surface processes for the Pakistan flood in July 2010. Q. J. R. Meteorol. Soc. 139, 1780–1797, doi:10.1002/qj.2082.


  • Pfahl S. and Wernli H., 2012. Quantifying the relevance of cyclones for precipitation extremes. J. Climate 25, 6770-6780, doi:10.1175/JCLI-D-11-00705.1.

  • Winschall A., Pfahl S., Sodemann H. and Wernli H., 2012. Impact of North Atlantic evaporation hot spots on southern Alpine heavy precipitation events. Q. J. R. Meteorol. Soc. 138, 1245-1258, doi:10.1002/qj.987.

  • Pfahl S. and Wernli H., 2012. Quantifying the relevance of atmospheric blocking for co-located temperature extremes in the Northern Hemisphere on (sub-)daily time scales. Geophys. Res. Lett. 39, L12807, doi:10.1029/2012GL052261.

  • Aemisegger F., Sturm P., Graf P., Sodemann H., Pfahl S., Knohl A. and Wernli H., 2012. Measuring variations of δ18O and δ2H in atmospheric water vapour using two commercial laser-based spectrometers: an instrument characterisation study. Atmos. Meas. Tech. 5, 1491-1511, doi:10.5194/amt-5-1491-2012.

  • Sirocko F., Brunck H. and Pfahl S., 2012. Solar influence on winter severity in central Europe. Geophys. Res. Lett. 39, L16704, doi:10.1029/2012GL052412.

  • Pfahl S., Wernli H. and Yoshimura K., 2012. The isotopic composition of precipitation from a winter storm - a case study with the limited-area model COSMOiso. Atmos. Chem. Phys. 12, 1629-1648, doi:10.5194/acp-12-1629-2012.

  • Pfahl S. and Wernli H., 2012. Spatial coherency of extreme weather events in Germany and Switzerland. Int. J. Climatol. 32, 1863–1874, doi:10.1002/joc.2401.


  • Pfahl S. and Niedermann N., 2011. Daily co-variations in near-surface relative humidity and temperature over the ocean. J. Geophys. Res. 116, D19104, doi:10.1029/2011JD015792.

  • Schäfler A., Dörnbrack A., Wernli H., Kiemle C. and Pfahl S., 2011. Airborne lidar observations in the inflow region of a warm conveyor belt. Q. J. R. Meteorol. Soc. 137, 1257-1272, doi:10.1002/qj.827.

  • Leimer S., Pohlert T., Pfahl S. and Wilcke W., 2011. Towards a new generation of high-resolution meteorological input data for small-scale hydrologic modeling. J. Hydrol. 402 (3-4), 317-332, doi:10.1016/j.jhydrol.2011.03.026.


  • Wernli H., Pfahl S., Trentmann J. and Zimmer M., 2010. How representative were the meteorological conditions during the COPS field experiment in summer 2007? Meteorol. Z. 19 (6), 619-630, doi:10.1127/0941-2948/2010/0483.

  • Pfahl S. and Wernli H., 2009. Lagrangian simulations of stable isotopes in water vapor - an evaluation of non-equilibrium fractionation in the Craig-Gordon model. J. Geophys. Res. 114, D20108, doi:10.1029/2009JD012054.

  • Pfahl S., Sirocko F., Seelos K., Dietrich S., Walter A. and Wernli H., 2009. A new windstorm proxy from lake sediments - a comparison of geological and meteorological data from western Germany for the period 1965-2001. J. Geophys. Res. 114, D18106, doi:10.1029/2008JD011643.

  • Pfahl S. and Wernli H., 2008. Air parcel trajectory analysis of stable isotopes in water vapor in the eastern Mediterranean. J. Geophys. Res. 113, D20104, doi:10.1029/2008JD009839.

  • Xing X., Pfahl S., Mukhopadhyay S., Goldbart P.M. and Zippelius A., 2008. Nematic elastomers: From a microscopic model to macroscopic elasticity theory. Phys. Rev. E 77, 051802, doi:10.1103/PhysRevE.77.051802.


  • Pfahl S., 2009. Exploring physical processes related to past climate proxies: lake sediments and stable water isotopes, PhD thesis, University of Mainz.

  • Wernli H. and Pfahl S., 2009. Grundlagen des Klimas und extremer Wettersituationen, in Wetter, Klima, Menschheitsentwicklung: Von der Eiszeit bis ins 21. Jahrhundert, edited by F. Sirocko, Wissenschaftliche Buchgesellschaft, Darmstadt, Germany.

  • Pfahl S., 2005. Nematische Elastomere - ein mikroskopisches Modell, Diploma thesis, University of Göttingen.