A5012391076- Meteorological Phenomena and Simulations
- Climate variability and models
- Tropical and Extratropical Cyclones Research
- Atmospheric and Environmental Gas Dynamics
- Precipitation Measurement and Analysis
- demographic modeling and climate adaptation
- Atmospheric Ozone and Climate
- Oceanographic and Atmospheric Processes
- Atmospheric aerosols and clouds
- Hydrology and Watershed Management Studies
ETH Zurich
2019-2025
Currently major efforts are underway toward refining the horizontal resolution (or grid spacing) of climate models to about 1 km, using both global and regional (GCMs RCMs). Several groups have succeeded in conducting kilometer-scale multiweek GCM simulations decadelong continental-scale RCM simulations. There is well-founded hope that this increase represents a quantum jump modeling, as it enables replacing parameterization moist convection by an explicit treatment. It expected will improve...
Abstract. This study presents a detailed analysis of the climatological distribution precipitation in relation to cyclones and fronts over Europe for 9-year period 2000–2008. The uses hourly output COSMO (Consortium Small-scale Modeling) model simulation with 2.2 km grid spacing resolved deep convection. Cyclones are identified as two-dimensional features 850 hPa geopotential, equivalent potential temperature, wind fields subsequently tracked time based on feature overlap size. Thermal heat...
Abstract. The jet stream is a hemisphere-wide midlatitude band of westerly wind. Jet streaks, which are regions enhanced wind speed within the stream, characterize it locally. streaks frequent upper-tropospheric flow features that accompany troughs and ridges form in tandem with surface cyclones. Upper-level divergence their equatorward entrance poleward exit couples them to weather via vertical motion, these prone precipitation formation, feeds back into strength upper level diabatic heat...
The jet stream — the hemispheric-wide band of westerly winds that circles mid-latitudes and shapes day-to-day weather by guiding large-scale flow features has been a long-standing area interest in atmospheric dynamics. Within this stream, streaks are regions enhanced wind speed. These important frequently accompanied clear-air-turbulence, affecting air travel flight times, comfort, safety. Moreover, upper level divergence equatorward entrance poleward exit couples to...
Abstract The influence of adiabatic and diabatic processes on the midlatitude circulation is a formidable research question, especially considering their projected changes under global warming. This study presents prospects, merits, caveats potential vorticity (PV) gradient perspective as means to disentangle contributions affecting circulation. Theoretical considerations reassess link between PV jet stream. They reveal that maximum isentropic consistently located stratospheric side jet,...
Abstract. The use of single precision in floating-point representation has become increasingly common operational weather prediction. Meanwhile, climate simulations are still typically run double precision. reasons for this likely manifold and range from concerns about compliance conservation laws to the unknown effect on slow processes or simply less frequent opportunity higher computational costs validation. Using an ensemble-based statistical methodology, Zeman Schär (2022) could detect...
Abstract. The jet stream is a hemispheric-wide mid-latitude band of westerly wind. Jet streaks, which are regions enhanced wind speed within the stream, characterize it locally. streaks frequent upper-tropospheric flow features that accompany troughs and ridges form in tandem with surface cyclones. Upper level divergence their right entrance left exit couples them to weather via vertical motion prone precipitation formation, feeds back on strength upper diabatic heat release. This...
Abstract. A novel method is introduced to identify and track the life cycle of upper-level troughs ridges. The aim close existing gap between methods that detect initiation phase Rossby wave development breaking decaying waves. presented quantifies horizontal trough ridge orientation identifies corresponding axes. These allow us study dynamics pre- post-trough–ridge regions separately. based on curvature geopotential height at a given isobaric surface computationally efficient....
This paper continues the exploration of Machine Learning (ML) parameterization for radiative transfer ICOsahedral Nonhydrostatic weather and climate model (ICON). Three ML models, developed in Part I this study, are coupled to ICON. More specifically, a UNet bidirectional recurrent neural network (RNN) with long short-term memory (LSTM) compared against random forest. The parameterizations ICON code that includes OpenACC compiler directives enable GPUs support. coupling is done through...
Abstract. This study presents a detailed analysis of the climatological distribution precipitation in relation to cyclones and fronts over Europe for nine-year period 2000–2008. The uses hourly output COSMO (Consortium Small-scale Modeling) model simulation with 2.2 km grid spacing resolved deep convection. Cyclones are identified as two-dimensional features 850 hPa geopotential, equivalent potential temperature, wind fields, subsequently tracked time based on feature overlap size. Thermal...
This paper continues the exploration of \gls{ml} parameterization for radiative transfer \gls{icon}. Three models, developed in Part I this study, are coupled to More specifically, a UNet model and bidirectional \gls{rnn} with \gls{lstm} compared against random forest. The parameterizations \gls{icon} code that includes OpenACC compiler directives enable \glspl{gpu} support. coupling is done through Infero, by ECMWF, PyTorch-Fortran. most accurate physics-informed normalization strategy...
The jet stream is a circumpolar global band of high wind speeds in the upper troposphere. Meridional meanders lead to high-impact weather events and may synchronize them over thousands kilometres. As Rossby waveguide, influences paths synoptic-scale eddies, which turn alter dynamics. Coherent regions enhanced speed, so-called streaks, typify locally anomalously strong streaks often coincide with extreme precipitation events.Despite their relevance, process understanding remains...
Abstract. The use of single precision in floating-point representation has become increasingly common operational weather prediction. Meanwhile, climate simulations are still typically run double precision. reasons for this likely manifold and range from concerns about compliance to conservation laws the unknown effect on slow processes, or simply less frequent opportunity higher computational costs validation. Using an ensemble-based statistical methodology, Zeman Schär (2022) could detect...
<p> </p><p><span> </span>The jet stream is a circumpolar global band of high wind speeds in the upper troposphere. Meridional meanders lead to high-impact weather events and synchronize them over thousands kilometres. Locally, can be typified by concentrations extreme so-called streaks, whose formation mechanisms are largely...