Project

Back to overview

Understanding the influence of warm conveyor belts in extratropical cyclones on tropopause dynamics: analysis with observations, reanalyses and global climate simulations

Applicant Wernli Heini
Number 185049
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 01.01.2020 - 30.06.2023
Approved amount 780'443.00
Show all

All Disciplines (2)

Discipline
Meteorology
Climatology. Atmospherical Chemistry, Aeronomy

Keywords (9)

field experiments; climate modeling; atmospheric dynamics; potential vorticity; diabatic processes; tropopause; extratropical cyclones; warm conveyor belt; cloud microphysics

Lay Summary (German)

Lead
Warm Conveyor Belts (WCBs) sind kohärente Luftströmungen in Tiefdruckgebieten, die sowohl die Entwicklung des Tiefdruckgebiets selbst wie auch die Wellendynamik an der Tropopause beeinflussen können. WCBs sind damit ein zentrales Element im Klimasystem und dieses Projekt untersucht die möglichen Veränderungen von WCBs im sich ändernden Klima, die unterschiedlichen Mechanismen der Wechselwirkung von WCBs mit dem Jetstream, sowie die Rolle von WCBs für Austauschprozesse an der Tropopause.
Lay summary

Inhalt und Ziel des Forschungsprojekts

Unser übergeordnetes Ziel ist es, zu einem verbesserten Verständnis der Rolle von sogenannt diabatischen Prozessen in der Atmosphäre (z.B. Kondensation von Wasserdampf in Wolken, Turbulenz, Strahlung) auf die Entwicklung aussertropischer Wettersysteme beizutragen. Diese Prozesse sind in WCBs und ihrer Umgebung besonders wirksam. Deshalb werden wir spezifisch untersuchen (i) wie gut Klimamodelle WCBs repräsentieren und wie sich ihre Eigenschaften durch die Klimaänderung wandeln, (ii) welche Prozesse massgeblich sind für die unterschiedlichen Wechselwirkungen von WCBs mit dem Jetstream, und (iii) wie die Eiswolkenbildung in WCBs den Massentransport durch die Tropopause beeinflusst. Diese Untersuchungen benutzen eine Kombination von Daten aus Messkampagnen, ERA5 Reanalysen, idealisierte Modelle sowie umfangreiche Klimasimulationen.

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: 29.03.2019

Responsible applicant and co-applicants

Employees

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
ECMWF Workshop on “Warm conveyor belts – a challenge for forecasting” Poster Vertical cloud structure of warm conveyor belts – a comparison and evaluation of ECMWF operational analyses, CloudSat and CALIPSO data 10.03.2020 Reading, Great Britain and Northern Ireland Wernli Heini; Binder Hanin Verena; Joos Hanna;
ECMWF Workshop on “Warm conveyor belts – a challenge for forecasting” Talk given at a conference An overview on the concept of warm conveyor belts 10.03.2020 Reading, Great Britain and Northern Ireland Wernli Heini; Binder Hanin Verena; Joos Hanna;
ECMWF Workshop on “Warm conveyor belts – a challenge for forecasting” Talk given at a conference Warm conveyor belts and their role for cloud radiative forcing in the extratropical storm tracks 10.03.2020 Reading, Great Britain and Northern Ireland Joos Hanna;
ECMWF Workshop on “Warm conveyor belts – a challenge for forecasting” Poster PV and warm conveyor belt analysis of a North Atlantic cyclone 10.03.2020 Reading, Great Britain and Northern Ireland Rausch Christopher;
ECMWF Workshop on “Warm conveyor belts – a challenge for forecasting” Poster The origin and lifecycle of diabatically modified PV anomalies in atmospheric blocks: A case study 10.03.2020 Reading, Great Britain and Northern Ireland Joos Hanna; Heitmann Katharina;
ECMWF Workshop on “Warm conveyor belts – a challenge for forecasting” Talk given at a conference The effect of clouds, radiation and turbulence on upper-level PV 10.03.2020 Reading, Great Britain and Northern Ireland Wernli Heini; Joos Hanna;
ECMWF Workshop on “Warm conveyor belts – a challenge for forecasting” Talk given at a conference Exceptional air mass transport and dynamical drivers of an extreme wintertime Arctic warm event 10.03.2020 Reading, Great Britain and Northern Ireland Binder Hanin Verena; Joos Hanna; Wernli Heini;
ECMWF Workshop on “Warm conveyor belts – a challenge for forecasting” Talk given at a conference Embedded convection in the warm conveyor belt of a North Atlantic cyclone and its relevance for large-scale dynamics 10.03.2020 Reading, Great Britain and Northern Ireland Joos Hanna; Wernli Heini;


Associated projects

Number Title Start Funding scheme
164721 MOisture Transport pathways and Isotopologues in water Vapour (MOTIV) 01.01.2017 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)
177996 Lagrangian analysis of ice cloud formation pathways and their isotopic signals in high-resolution COSMO-iso simulations of the African and Asian monsoon 01.07.2018 PIRE
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)
146834 Diabatic processes in North Atlantic weather systems: dynamics and impact on forecast errors 01.06.2013 Project funding (Div. I-III)

Abstract

Atmospheric research during the last decade found increasing evidence for the important role of diabatic processes for extratropical weather systems, including cyclones, blocks 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 widely acknowledged that quantitatively identifying these processes and their interactions with the atmospheric flow is fundamental for increasing the understanding of weather system dynamics, for further improving numerical weather prediction models, and most likely also for better assessing extratropical climate variability and trends. The climate community recently emphasized the importance of studying the linkage between clouds and dynamics in the extratropics and the ability of different types of climate models in representing these processes and linkages. In our previous SNF projects and in accompanying group research activities, we aimed at contributing to this research area by studying so-called warm conveyor belts (WCBs, i.e., ascending airstreams in extratropical cyclones characterized by intense diabatic processes), and their important role in (i) inducing and amplifying upper-level ridges, atmospheric blocks, and Arctic anticyclones, (ii) contributing to the explosive development of cyclones via the diabatic production of low-level cyclonic potential vorticity, and (iii) creating important mesoscale sub-structures in particular along surface fronts due to embedded convection and locally intense below-cloud latent cooling processes (from, e.g., rain evaporation). We also contributed strongly to the international field experiment NAWDEX in autumn 2016, which collect-ed a unique set of airborne in situ and remote sensing observations of WCBs and their interaction with the tropopause-level flow. Collaboration with our key partners (ECMWF, DLR Oberpfaffenhofen, LMU Munich, LMD Paris, University of Reading) has been essential for the success of our research and will be extended in the coming years thanks also to additional new collaborations with the Weizmann Institute, KIT Karlsruhe and FU Berlin. In this three-part continuation project, we plan to extend our WCB-related research by addressing important novel aspects of the complex role of these flow features for cloud-dynamics interactions mainly at the tropopause level, both in the current and future climate. The main objectives are to (i) obtain an up-dated and more detailed climatology of WCBs based upon the new ERA5 reanalyses; (ii) investigate the representation of WCBs in present day global climate simulations and quantify potential implications of global warming for the future WCB climatology; (iii) improve the understanding of the puzzling variability of the effect of WCBs on Rossby wave dynamics; (iv) quantify the importance of cirrus clouds in WCB outflows for cross-tropopause transport; and (v) contribute to the flight planning of WCB related field experiments (e.g., the high-latitude cirrus campaign planned in spring 2021). Research in this ambitious project will make use of sophisticated diagnostic tools, observational datasets (from NAWDEX and other field experiments), new ERA5 reanalyses, and, for the first time, global climate simulations, which allow applying our detailed weather-system expertise also to broader research questions in the framework of global climate change.
-