extratropical cyclones; diabatic processes; field experiments; atmospheric dynamics; numerical weather prediction; potential vorticity; atmospheric blocking
Gehring Josué, Oertel Annika, Vignon Étienne, Jullien Nicolas, Besic Nikola, Berne Alexis (2020), Microphysics and dynamics of snowfall associated with a warm conveyor belt over Korea, in Atmospheric Chemistry and Physics
, 20(12), 7373-7392.
Attinger Roman, Spreitzer Elisa, Boettcher Maxi, Forbes Richard, Wernli Heini, Joos Hanna (2019), Quantifying the role of individual diabatic processes for the formation of PV anomalies in a North Pacific cyclone, in Quarterly Journal of the Royal Meteorological Society
, 145(723), 2454-2476.
Spreitzer Elisa, Attinger Roman, Boettcher Maxi, Forbes Richard, Wernli Heini, Joos Hanna (2019), Modification of Potential Vorticity near the Tropopause by Nonconservative Processes in the ECMWF Model, in Journal of the Atmospheric Sciences
, 76(6), 1709-1726.
Oertel Annika, Boettcher Maxi, Joos Hanna, Sprenger Michael, Konow Heike, Hagen Martin, Wernli Heini (2019), Convective activity in an extratropical cyclone and its warm conveyor belt – a case‐study combining observations and a convection‐permitting model simulation, in Quarterly Journal of the Royal Meteorological Society
, 145, 1406-1426.
Brunamonti Simone, Jorge Teresa, Oelsner Peter, Hanumanthu Sreeharsha, Singh Bhupendra B., Kumar K. Ravi, Sonbawne Sunil, Meier Susanne, Singh Deepak, Wienhold Frank G., Luo Bei Ping, Boettcher Maxi, Poltera Yann, Jauhiainen Hannu, Kayastha Rijan, Karmacharya Jagadishwor, Dirksen Ruud, Naja Manish, Rex Markus, Fadnavis Suvarna, Peter Thomas (2018), Balloon-borne measurements of temperature, water vapor, ozone and aerosol backscatter on the southern slopes of the Himalayas during StratoClim 2016–2017, in Atmospheric Chemistry and Physics
, 18(21), 15937-15957.
Schäfler Andreas, Craig George, Wernli Heini, Arbogast Philippe, Doyle James D., McTaggart-Cowan Ron, Methven John, Rivière Gwendal, Ament Felix, Boettcher Maxi, Bramberger Martina, Cazenave Quitterie, Cotton Richard, Crewell Susanne, Delanoë Julien, Dörnbrack Andreas, Ehrlich André, Ewald Florian, Fix Andreas, Grams Christian M., Gray Suzanne L., Grob Hans, Groß Silke, Hagen Martin, et al. (2018), The North Atlantic Waveguide and Downstream Impact Experiment, in Bulletin of the American Meteorological Society
, 99(8), 1607-1637.
Rodwell Mark, Forbes Richard, Wernli Heini (2018), Why warm conveyor belts matter in NWP, in ECMWF Newsletter
, 154, 21-28.
Binder Hanin, Boettcher Maxi, Grams Christian M., Joos Hanna, Pfahl Stephan, Wernli Heini (2017), Exceptional airmass transport and dynamical drivers of an extreme wintertime Arctic warm event, in Geophys. Res. Lett.
, 44, 12028-12036.
Wernli Heini, Boettcher Maxi, Joos Hanna, Miltenberger Annette K., Spichtinger Peter (2016), A trajectory-based classification of ERA-Interim ice clouds in the region of the North Atlantic storm trach, in Geophysical Research Letters
, 43(12), 6657-6664.
Atmospheric research during the last decade emphasized the important role of diabatic processes for extratropical weather systems, including cyclones, blockings and tropopause-level Rossby waves. These processes include surface fluxes mainly over the ocean, latent heating and cooling in and below clouds, and cloud-related radiation mainly in the upper troposphere. It has become generally accepted that quantifying these processes and how they interact with the atmospheric flow is essential for obtaining a more holistic understanding of the dynamics of weather systems and for further improving numerical weather prediction models. Also the climate community recently emphasized the importance of studying the linkage between clouds and dynamics in the extratropical storm track regions and its representation in climate models. In our previous SNF projects and in accompanying group activities, we contributed to this research area by studying the climatology of so-called warm conveyor belts (WCBs, strongly precipitation producing airstream in extratropical cyclones), and their important role in (i) inducing and amplifying upper-level ridges, (ii) generating and maintaining atmospheric blockings, and (iii) contributing to the explosive development of cyclones via the diabatic generation of low-level potential vorticity (PV) anomalies. Unique aircraft measurements of thermodynamic characteristics in WCBs have been obtained through collaboration with partners in Germany. A particular category of extratropical cyclones whose dynamics is essentially tied to in-cloud latent heating, so-called diabatic Rossby waves, have been investigated in terms of their dynamics and global climatology. And on the mesoscale, our research has shown that also below-cloud microphysical processes (e.g., the evaporation of rain) can be important for the formation of PV anomalies and that significant uncertainties exist related to the model representation of the coupling between cloud microphysics and dynamics. In this three-part continuation project we plan to continue and extend this research by addressing novel aspects of the complex interaction of diabatic processes and the evolution of extratropical weather systems. The main objectives are to (i) co-lead the German/Swiss activities during the international aircraft experiment NAWDEX in autumn 2016; (ii) climatologically quantify the occurrence of different cloud types (liquid, mixed-phase, ice), and the associated microphysical and radiative heating rates along the life-cycle of extratropical weather systems (cyclones, blockings), (iii) assess the potential role of embedded convection in WCBs on the formation of mesoscale low-level PV anomalies and on the location and dynamical impact of the WCB outflow, and (iv) continue shaping this research field on an international level also by collaborating with our key partners (ECMWF, University of Reading, DLR Oberpfaffenhofen, LMU Munich, LMD Paris). Complementary state-of-the-art techniques will be applied in order to reach these challenging objectives, including global and regional model simulations, specifically designed diagnostic tools, observational data and, for the first time, online trajectories that allow unprecedented details. This ambitious project will thereby contribute to an improved understanding of the important role of diabatic processes for the structure and evolution of weather systems and their potential societal impact.