A5083391049- Meteorological Phenomena and Simulations
- Climate variability and models
- Atmospheric aerosols and clouds
- Tropical and Extratropical Cyclones Research
- Atmospheric chemistry and aerosols
- Climate change and permafrost
- Atmospheric and Environmental Gas Dynamics
- Icing and De-icing Technologies
- Atmospheric Ozone and Climate
- Cryospheric studies and observations
- Belt Conveyor Systems Engineering
- Aeolian processes and effects
- Ionosphere and magnetosphere dynamics
- Methane Hydrates and Related Phenomena
- Peatlands and Wetlands Ecology
- Wind and Air Flow Studies
- Oceanographic and Atmospheric Processes
- Distributed and Parallel Computing Systems
- Climate change impacts on agriculture
- Geological Studies and Exploration
- Advanced Data Storage Technologies
- Computational Physics and Python Applications
- Meta-analysis and systematic reviews
- Academic Writing and Publishing
- Scientific Computing and Data Management
ETH Zurich
2014-2024
European Centre for Medium-Range Weather Forecasts
2019
Oeschger Centre for Climate Change Research
2014
University of Bern
2014
Johannes Gutenberg University Mainz
2014
Max Planck Institute for Meteorology
2009
Abstract A global climatology of warm conveyor belts (WCBs) is presented for the years 1979–2010, based on trajectories calculated with Interim ECMWF Re-Analysis (ERA-Interim) data. WCB are identified as strongly ascending air parcels (600 hPa in 2 days) near extratropical cyclones. Corroborating earlier studies, WCBs more frequent during winter than summer and they ascend preferentially western ocean basins between 25° 50° latitude. Before ascending, typically approach from subtropics...
Abstract The role of moisture for extratropical atmospheric dynamics is particularly pronounced within warm conveyor belts (WCBs), which are characterized by intense latent heat release and precipitation formation. Based on the WCB climatology period 1979–2010 presented in Part I, two important aspects cycle investigated: evaporative sources relevance WCBs total extreme precipitation. most source regions western North Atlantic Pacific boreal winter South summer. strongest continental...
Abstract The role of warm conveyor belts (WCBs) and their associated positive low-level potential vorticity (PV) anomalies are investigated for extratropical cyclones in Northern Hemisphere winter, using ERA-Interim composite techniques. Spearman correlation coefficient 0.68 implies a moderate to strong between cyclone intensification WCB strength. Hereby, is quantified by the normalized maximum 24-h central sea level pressure deepening strength air mass with cyclone’s period strongest...
Abstract The potential vorticity (PV) in warm conveyor belts (WCBs) is strongly influenced by the latent heating associated with various microphysical processes occurring during formation of clouds. first‐order effect that PV increases below level maximum diabatic and decreases above. Thus, WCB reaches upper troposphere low values has to influence large‐scale dynamics. In order quantify different on rates (DHRs) development ascent, a Lagrangian analysis used applied regional model simulation...
In July and August 2010 floods of unprecedented impact afflicted Pakistan. The resulted from a series intense multi-day precipitation events in early August. At the same time blocking anticyclones dominated upper-level flow over western Russia breaking waves i.e. equatorward extrusions stratospheric high potential vorticity (PV) air formed along downstream flank blocks. Previous studies suggested that these extratropical were crucial for instigating Here detailed analysis is provided forcing...
Abstract Extratropical cyclones are responsible for many extreme precipitation events in the midlatitudes. Warm conveyor belts (WCBs) and fronts known to be related uplift hence within cyclones. The authors have investigated link between WCBs how such a impacts occurrence of events. WCB trajectories been calculated from ERA-Interim dataset, low-level (below 790 hPa) midlevel (790–600 considered. These matched with objectively identified (i.e., characterized by an overlap front somewhere...
Warm conveyor belts (WCBs) are important Lagrangian features in extratropical cyclones for the evolution of clouds, precipitation and flow dynamics. According to classical concept, WCBs rise continuously from boundary layer upper troposphere with ascent rates less than 50 hPa/hr. Recent studies identified embedded convection exceeding hPa/hr, however, its significance characteristics have not yet been analysed systematically. This study presents a detailed analysis frontal wave cyclone that...
Abstract. This study investigates how warm conveyor belts (WCBs) will change in a future climate. WCBs are strongly ascending airstreams extratropical cyclones that responsible for most of their precipitation. In conjunction with the cloud formation, latent heat is released, which has an impact on potential vorticity distribution and therefore atmospheric circulation middle upper troposphere. Because these other impacts WCBs, it great importance to investigate changes frequencies, regions...
Abstract Between 15 and 19 March 2022, East Antarctica experienced an exceptional heat wave with widespread 30°–40°C temperature anomalies across the ice sheet. This record-shattering event saw numerous monthly records being broken including a new all-time record of −9.4°C on 18 at Concordia Station despite typically transition month to Antarctic coreless winter. The driver for these extremes was intense atmospheric river advecting subtropical/midlatitude moisture deep into interior. scope...
Abstract Between 15 and 19 March 2022, East Antarctica experienced an exceptional heat wave with widespread 30°–40°C temperature anomalies across the ice sheet. In Part I, we assessed meteorological drivers that generated intense atmospheric river (AR) caused these record-shattering anomalies. Here, continue our large collaborative study by analyzing diverse impacts driven AR landfall. These included rain surface melt was recorded along coastal areas, but this outweighed high snowfall...
Abstract A two‐type classification of ice clouds (cirrus) is introduced, based on the liquid and water content, LWC IWC, along air parcel backward trajectories from clouds. In situ cirrus has no trajectory segment containing IWC; it forms via nucleation gas phase. contrast, liquid‐origin both IWC their trajectories; lifting lower troposphere freezing mixed‐phase This applied to 12 years ERA‐Interim in North Atlantic region. Between 400 500 hPa more than 50% are cirrus, whereas this frequency...
The influence of microphysical processes on the upper‐level flow features associated with an extratropical cyclone is investigated ECMWF global atmospheric model. A control simulation model version operational at during 2014/early 2015 and a new parametrizations rain autoconversion/accretion, evaporation snow riming since May are compared in detail. In order to investigate impact each process separately, diabatic heating rate for change potential vorticity (PV) calculated two simulations....
Abstract The upper-level potential vorticity (PV) structure plays a key role in the evolution of extratropical weather systems. PV is modified by nonconservative processes, such as cloud latent heating, radiative transfer, and turbulence. Using Lagrangian method, material modification near tropopause attributed to specific parameterized processes global model European Centre for Medium-Range Weather Forecasts (ECMWF). In case study, several flow features identified vertical section across an...
Abstract. Warm conveyor belts (WCBs) are important airstreams in extratropical cyclones. They can influence large-scale flow evolution by modifying the potential vorticity (PV) distribution during their cross-isentropic ascent. Although WCBs typically described as slantwise-ascending and stratiform-cloud-producing airstreams, recent studies identified convective activity embedded within WCB cloud band. However, impacts of this WCB-embedded convection have not been investigated detail. In...
Abstract At the turn of years 2015/2016, maximum surface temperature in Arctic reached record‐high values, exceeding melting point, which led to a strong reduction sea ice extent middle cold season. Here we show, using Lagrangian method, that combination very different airstreams contributed this event: (i) warm low‐level air subtropical origin, (ii) initially polar origin heated by fluxes, and (iii) strongly descending adiabatic compression. The poleward transport these occurred along an...
Abstract. This study presents a systematic investigation of the characteristics and meteorological impacts warm conveyor belts (WCBs). For this purpose, we compile new WCB climatology (1980–2022) trajectories calculated with most recent reanalysis dataset ERA5 from European Centre for Medium-Range Weather Forecasts (ECMWF). Based on climatology, two-dimensional masks are defined that represent inflow, ascent, outflow locations WCBs. These then used to objectively quantify key (intensity,...
The warm conveyor belt (WCB) of an extratropical cyclone generally splits into two branches. One branch (WCB1) turns anticyclonically the downstream upper-level tropospheric ridge, while second (WCB2) wraps cyclonically around centre. Here, WCB split in a typical North Atlantic cold-season is analysed using numerical models: Met Office Unified Model and COSMO model. flow defined off-line trajectory analysis. models represent consistently. occurs early evolution with WCB1 experiencing maximum...
Recent work has shown that both the amplitude of upper‐level Rossby waves and tropopause sharpness decrease with forecast lead time for several days in some operational weather systems. In this contribution, evolution error growth a case‐study type is diagnosed through analysis forecasts hindcast simulations. Potential vorticity (PV) on 320 K isentropic surface used to diagnose waves. The Rossby‐wave ECMWF high‐resolution be associated errors warm conveyor belt (WCB) trajectory an metric WCB...
Abstract Diabatically generated low-level potential vorticity (PV) anomalies in extratropical cyclones enhance near-surface winds and influence the cyclone’s development. Positive negative PV warm-frontal region of an cyclone, simulated with idealized moist baroclinic channel model, are investigated to identify microphysical processes that produce them. Using a novel method based on backward trajectories from anomalies, contribution different formation is quantified. It found that, for each...
Abstract. Warm conveyor belts (WCBs) are dynamically important, strongly ascending and mostly stratiform cloud-forming airstreams in extratropical cyclones. Despite the predominantly character of WCB's large-scale cloud band, convective clouds can be embedded it. This convection leads to a heterogeneously structured band with locally enhanced hydrometeor content, intense surface precipitation substantial amounts graupel middle troposphere. Recent studies showed that forms relevant...
Abstract. Warm conveyor belts (WCBs) are strongly ascending, cloud- and precipitation-forming airstreams in extratropical cyclones. The intense cloud-diabatic processes produce low-level cyclonic potential vorticity (PV) along the ascending airstreams, which often contribute to intensification of associated cyclone. This study investigates how climate change affects cyclones' WCB strength importance WCB-related diabatic PV production for cyclone intensification, based on present-day...
A comparison of satellite data with simulations from global circulation models shows that there is a lack cirrus cloud amount in large‐scale above and the lee mountains. The formation orographic clouds due to gravity waves usually not parameterized models. To improve simulation such orographically excited coupling wave dynamics microphysics has been implemented climate model European Centre/Hamburg 5 (ECHAM5). As homogeneous freezing solution droplets strongly depends on vertical velocity,...
Abstract The link between cloud radiative forcing (CRF) and warm conveyor belts (WCBs), which are strongly ascending airstreams in extratropical cyclones, is investigated based on ERA-Interim reanalysis from 1979 to 2011. Clouds associated with WCBs can be liquid, mixed phase, or ice clouds. They interact the longwave shortwave radiation different ways thus influence Earth’s budget storm tracks a complex way. In this study, identified Lagrangian method, where represented by trajectories that...
Abstract. The influence of heterogeneous freezing on the microphysical and optical properties orographic cirrus clouds has been simulated with large eddy simulation model EULAG. Idealised simulations different concentrations ice nuclei (IN) in a dynamically dominated regime high vertical velocities have performed. Furthermore temperature at cloud formation as well critical supersaturation for initiation heterogenous varied. shortwave, longwave net forcing calculated under assumption that...
Processes that do not conserve potential vorticity (PV) have a profound impact on the intensity, evolution, and mesoscale details of extratropical weather systems. This study aims at quantifying improving understanding how when physical processes modify PV in cyclones. To this end, 6‐day forecast North Pacific cyclone is performed using recent operational version ECMWF global numerical prediction model. Hourly instantaneous temperature momentum tendencies each parametrized process are used...