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Diabatic processes in North Atlantic weather systems: dynamics and impact on forecast errors

Applicant Wernli Heini
Number 146834
Funding scheme Project funding (Div. I-III)
Research institution Institut für Atmosphäre und Klima ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Meteorology
Start/End 01.06.2013 - 31.05.2016
Approved amount 582'375.00
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All Disciplines (2)

Discipline
Meteorology
Climatology. Atmospherical Chemistry, Aeronomy

Keywords (9)

potential vorticity; diabatic processes; atmospheric dynamics; field experiments; numerical weather prediction; climatology; extratropical cyclone; cloud microphysics; warm conveyor belt

Lay Summary (German)

Lead
Die latente Wärmefreisetzung bei der Kondensation von Wasserdampf in Wolken ist ein zentraler Prozess in der Atmosphäre, der besonders bei intensiven Tiefdruckgebieten von grosser Bedeutung ist. In diesem Projekt untersuchen wir mit Modellstudien und Beobachtungsdaten, wie das latente Heizen in frontalen Wolkenbändern (sogenannten “warm conveyor belts”, WCBs) die Intensität von Zyklonen beeinflusst und wie gut die aktuellen Wettervorhersagemodelle diesen Prozess darstellen können.
Lay summary

Inhalt und Ziel des Forschungsprojekts

Unser übergeordnetes Ziel ist es, zu einem verbesserten Verständnis der Rolle der Wolkenprozesse in WCBs (z.B. Kondensation von Wasserdampf, Gefrieren von Wolkentröpfchen) auf die Dynamik von Tiefdruckgebieten beizutragen. Im Detail werden wir (i) existierende Klimatologien von WCBs und Zyklonen benutzen, um ihren Zusammenhang physikalisch besser zu verstehen, (ii) detaillierte numerische Modellstudien zu den mikrophysikalischen Prozessen in WCBs durchführen und (iii) Daten von Flugzeugmesskampagnen auswerten, um die Modellresultate mit Beobachtungen in WCBs zu vergleichen. Dieser Vergleich wird mögliche Defizite bei der Modellierung der komplexen Prozesse in WCBs und ihren Auswirkungen auf die Entwicklung von Wettersystemen aufzeigen.

Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojekts

Unsere Arbeit wird neue und wichtige Informationen zu den physikalischen und dynamischen Prozessen liefern, die für eine korrekte Vorhersagen des Wettergeschehens in Europa essentiell sind. Die Ergebnisse werden sowohl für die Grundlagenwissenschaft relevant sein, wie auch für die operationelle Wettervorhersage wichtige Hinweise liefern.

Direct link to Lay Summary Last update: 29.04.2013

Responsible applicant and co-applicants

Employees

Publications

Publication
The complex life cycles of two long-lived potential vorticity cut-offs over Europe
Portmann Raphael, Crezee Bas, Quinting Julian, Wernli Heini (2018), The complex life cycles of two long-lived potential vorticity cut-offs over Europe, in Quarterly Journal of the Royal Meteorological Society, 144(712), 701-719.
Exceptional Air Mass Transport and Dynamical Drivers of an Extreme Wintertime Arctic Warm Event
Binder Hanin, Boettcher Maxi, Grams Christian M., Joos Hanna, Pfahl Stephan, Wernli Heini (2017), Exceptional Air Mass Transport and Dynamical Drivers of an Extreme Wintertime Arctic Warm Event, in Geophysical Research Letters, 44(23), 12,028-12,036.
Global climatologies of Eulerian and Lagrangian flow features based on ERA-Interim
Sprenger Michael, Fragkoulidis Georgios, Binder Hanin, Croci-Maspoli Mischa, Graf Pascal, Grams Christian, Knippertz Peter, Madonna Erica, Schemm Sebastian, Skerlak Bojan, Wernli Heini (2017), Global climatologies of Eulerian and Lagrangian flow features based on ERA-Interim, in Bull. Amer. Meteor. Soc., 98, 1739-1748.
The microphysical building blocks of low-level potential vorticity anomalies in an idealized extratropical cyclone
Crezee Bas, Joos Hanna, Wernli Heini (2017), The microphysical building blocks of low-level potential vorticity anomalies in an idealized extratropical cyclone, in J. Atmos. Sci., 74, 1403-1416.
A route to systematic error in forecasts of Rossby waves.
Martinez-Alvarado O. E. Madonna S. L. Gray and H. Joos (2016), A route to systematic error in forecasts of Rossby waves., in Quart. J. Roy. Meteorol. Soc., 142, 196-210.
The role of warm conveyor belts for the intensification of extratropical cyclones in Northern Hemisphere winter
Binder Hanin, Boettcher Maxi, Joos Hanna, Wernli Heini (2016), The role of warm conveyor belts for the intensification of extratropical cyclones in Northern Hemisphere winter, in J. Atmos. Sci., 73, 3997-4020.
Diabatic Rossby waves in the Southern Hemisphere.
Boettcher M. and H. Wernli (2015), Diabatic Rossby waves in the Southern Hemisphere., in Quart. J. Roy. Meteorol. Soc., 141, 3106-3117.
Atmospheric processes triggering the central European floods in June 2013.
Grams C. M. H. Binder S. Pfahl N. Piaget and H. Wernli (2014), Atmospheric processes triggering the central European floods in June 2013., in Nat. Hazards Earth Syst. Sci., 14, 1691-1702.
The dichotomous structure of the warm conveyor belt.
Martinez-Alvarado O. H. Joos J. Chagnon M. Boettcher S. L. Gray R. S. Plant J. Methven and H. (2014), The dichotomous structure of the warm conveyor belt., in Quart. J. Roy. Meteorol. Soc., 140, 1809-1824.

Collaboration

Group / person Country
Types of collaboration
MeteoSchweiz Switzerland (Europe)
- Research Infrastructure
ECMWF Reading Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel
University of Mainz Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
DLR Oberpfaffenhofen Germany (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Research Infrastructure
- Exchange of personnel
University of Reading Great Britain and Northern Ireland (Europe)
- in-depth/constructive exchanges on approaches, methods or results
- Publication
- Exchange of personnel

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
EGU General Assembly 2016 Talk given at a conference The relevance of individual microphysical processes for potential vorticity anomalies in extratropical cyclones 18.04.2016 Vienna, Austria Wernli Heini; Crezee Sebastiaan; Joos Hanna;
ECMWF/WWRP Workshop on Model Uncertainty Talk given at a conference A weather-system perspective on forecast errors 11.04.2016 Reading, Great Britain and Northern Ireland Wernli Heini;
DACH Konferenz Talk given at a conference Der Einfluss des latenten Heizens in Wolken auf die Dynamik von Zyklonen, Rossby Wellen und Jetstreams 14.03.2016 Berlin, Germany Wernli Heini;
TAC subgroup on verification measures 2016, ECMWF Talk given at a conference Diabatic processes in extratropical cyclones – relevance for forecast accuracy 02.03.2016 Reading, Great Britain and Northern Ireland Wernli Heini;
CloudSat and CALIPSO data, CALIPSO CloudSat Science Team Meeting Poster Vertical cloud structure of warm conveyor belts – a combined evaluation and intercomparison of ERA-Interim 01.03.2016 Newport News, United States of America Binder Hanin Verena;
Understanding Clouds and Precipitation, HD(CP)2 conference Talk given at a conference Warm conveyor belts – important cloud systems in the extratropical storm track regions 15.02.2016 Berlin, Germany Wernli Heini;
Cyclone Workshop 2015 Talk given at a conference The role of positive PV anomalies in warm conveyor belts for the evolution of extratropical cyclones 26.10.2015 Monterey, United States of America Joos Hanna; Böttcher Maxi; Binder Hanin Verena; Crezee Sebastiaan;
4th Stormex Workshop Poster Diabatic Rossby waves: from “Lothar” to a global climatology 01.09.2015 Bern, Switzerland Wernli Heini; Böttcher Maxi;
26th IUGG General Assembly Talk given at a conference Diabatic PV anomalies related to clouds and precipitation in an idealized extratropical cyclone 24.06.2015 Prag, Czech Republic Crezee Sebastiaan;
Atmospheric Rivers Science Planning Workshop Talk given at a conference Atmospheric rivers, warm conveyor belts, tropical moisture exports - all the same or are there interesting differences? 16.06.2015 San Diego, United States of America Wernli Heini;
PANDOWAE Final Symposium Talk given at a conference The importance of moist-diabatic PV generation for extratropical cyclones: PV towers and diabatic Rossby-waves 20.05.2015 Karlsruhe, Germany Joos Hanna; Binder Hanin Verena; Wernli Heini; Böttcher Maxi; Crezee Sebastiaan;
Seminar Stony Brook University Individual talk Diabatic processes in extratropical cyclones: Dynamics and relevance for forecast accuracy 18.11.2014 New York, United States of America Wernli Heini;
Seminar Princeton University Individual talk The PV perspective of extratropical weather systems – why is it so insightful? 17.11.2014 Princeton, United States of America Wernli Heini;
Seminar Lamont Doherty Earth Observatory Individual talk Warm conveyor belts: concept, dynamical relevance and their role in the climate system 14.11.2014 New York, United States of America Wernli Heini;
AMS Chapter Seminar Individual talk How well do we understand and can we predict extreme weather associated with extratropical cyclones? 13.11.2014 New York, United States of America Wernli Heini;
WWRP Open Science Conference Talk given at a conference Diabatic Rossby waves 20.08.2014 Montreal, Canada Böttcher Maxi;
WWRP Open Science Conference Talk given at a conference Microphysical processes in a WCB: IFS and COSMO simulations 18.08.2014 Montreal, Canada Joos Hanna;
WWRP Open Science Conference Talk given at a conference Diabatic processes in extratropical cyclones: Dynamics and relevance for forecast accuracy 17.08.2014 Montreal, Canada Wernli Heini;
Latsis Symposium Talk given at a conference The PV perspective of extratropical weather systems – why is it so insightful? 18.06.2014 Zürich, Switzerland Wernli Heini;
EGU General Assembly Talk given at a conference Relevance of warm conveyor belts for the dynamics of weather systems and the radiation budget in the extra-tropics 28.04.2014 Vienna, Austria Joos Hanna;
Seminar at ECMWF Individual talk Diabatic processes in extratropical cyclones: Dynamics and relevance for forecast accuracy 12.12.2013 Reading, UK, Great Britain and Northern Ireland Wernli Heini;
RMS Seminar Talk given at a conference Warm conveyor belts and downstream impacts on weather 11.12.2013 Reading, UK, Great Britain and Northern Ireland Wernli Heini;
7th HYMEX Workshop Talk given at a conference The relevance of warm conveyor belts for heavy precipitation events in the Mediterranean 07.10.2013 Cassis, France, France Wernli Heini;
16th Cyclone Workshop Talk given at a conference Numerical study on the downstream impact of warm conveyor belts in extratropical cyclones 23.09.2013 Sainte-Adele, Canada, Canada Böttcher Maxi;
NCCR summer school Talk given at a conference Predictability of weather and climate: theory and processes 01.09.2013 Grindelwald, Schweiz, Switzerland Wernli Heini;
DACA-13 Talk given at a conference Aircraft measurements in warm conveyor belts 08.07.2013 Davos, Schweiz, Switzerland Böttcher Maxi; Wernli Heini;
Heraeus-Seminar WEH535 Water vapour and ice in the atmosphere Talk given at a conference Warm conveyor belts: Concept, dynamical relevance and impact on upper-tropospheric ice cloud formation 10.06.2013 Bad Honnef, Deutschland, Germany Wernli Heini;


Communication with the public

Communication Title Media Place Year

Associated projects

Number Title Start Funding scheme
154486 Cloud-resolving climate modeling on future supercomputing platforms 01.05.2015 Sinergia
130079 The dynamics of North Atlantic warm conveyor belts and their impact on downstream wave propagation and European weather systems 01.06.2010 Project funding (Div. I-III)
149140 Quantifying effects of latent heating on midlatitude cyclones under different climate conditions 01.05.2014 Project funding (Div. I-III)
148177 The mutual interaction of individual weather systems and weather regimes 01.07.2014 Ambizione
185049 Understanding the influence of warm conveyor belts in extratropical cyclones on tropopause dynamics: analysis with observations, reanalyses and global climate simulations 01.01.2020 Project funding (Div. I-III)
165941 Diabatic processes in North Atlantic weather systems: synoptic and mesoscale dynamics 01.06.2016 Project funding (Div. I-III)

Abstract

Extratropical cyclones and persistent anticyclones, also referred to as atmospheric blockings, are key synoptic-scale weather systems that strongly determine the evolution of daily weather in Europe. Recent research has quantified that also many extreme events are linked to the passage of these systems; e.g., extreme precipitation and wind co-occur frequently with cyclones. It is therefore of crucial importance to understand the dynamics of cyclones and blockings and the reasons why their prediction at times fails. A central aspect, which has been increasingly considered during the last years, is the interaction of dry dynamical and moist physical processes for the dynamics and forecasting of cyclones and blockings. In our current SNF project and in accompanying group activities, we have been mainly focusing on the role of moist ascending airstreams in extratropical cyclones, so-called warm conveyor belts (WCBs), and could clarify their role for the formation of low-level positive and upper-level negative potential vorticity (PV) anomalies, both in detailed case study simulations and from a climatological point of view. Due to their cross-isentropic transport of low-PV air into the upper-level ridges, WCBs tend to intensify these ridges and modify the downstream flow at the level of the jet stream. The cloud microphysical processes within the ascending WCB air have been investigated, leading to a refined picture of the various phase transitions and the related release of latent heat associated with the cloud and precipitation mechanisms in WCBs. The aircraft field experiment T-NAWDEX-Falcon, to which we will contribute in October 2012, will provide in-situ observations of these complex processes. In this continuation project, novel aspects of the role of diabatic processes for the evolution of cyclones and blockings will be addressed, which extend our current work on WCBs. To further advance the understanding of these fundamental and complex processes, the main objectives of this project are to (i) investigate the role of positive low-level PV anomalies in WCBs for the evolution of the associated cyclones, (ii) identify the impact of various cloud microphysical processes on the mesoscale PV structures within cyclones, (iii) quantify the evolution of cirrus cloud properties and associated radiative impact in the WCB outflow, (iv) utilize observational data from the aircraft field experiment T-NAWDEX-Falcon to better characterize these processes in nature and for assessing the accuracy of their implementation in numerical models, and (v) assess the role of microphysical PV modifications for the quality of weather system predictions. The project will also contribute to the aircraft experiment ML-CIRRUS in 2014 and to the planning of an international T-NAWDEX activity in 2015. Again within three subprojects, complementary state-of-the-art techniques will be applied in order to reach these objectives, including idealized moist baroclinic wave simulations, real case sensitivity experiments, diagnostic investigations based upon (re-) analysis and forecast data sets, and observational data. In this way this ambitious project will contribute to an improved understanding of the fundamental role of diabatic processes for the evolution and prediction of (high-impact) weather systems.
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