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Lagrangian analysis of ice cloud formation pathways and their isotopic signals in high-resolution COSMO-iso simulations of the African and Asian monsoon

English title Lagrangian analysis of ice cloud formation pathways and their isotopic signals in high-resolution COSMO-iso simulations of the African and Asian monsoon
Applicant Wernli Heini
Number 177996
Funding scheme PIRE
Research institution Institut für Atmosphäre und Klima ETH Zürich
Institution of higher education ETH Zurich - ETHZ
Main discipline Meteorology
Start/End 01.07.2018 - 31.12.2020
Approved amount 227'255.00
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All Disciplines (2)

Discipline
Meteorology
Climatology. Atmospherical Chemistry, Aeronomy

Keywords (7)

trajectories; high-resolution numerical modelling; stable water isotopes; ice clouds; monsoon; convection; meteorology

Lay Summary (German)

Lead
Eiswolken in den Tropen spielen eine zentrale Rolle für den Energiehaushalt der Erde. Die komplexen Prozesse bei der Bildung dieser Wolken sind jedoch erst teilweise verstanden und in Klimamodellen nur näherungsweise repräsentiert. Die detaillierte Untersuchung der Eiswolken in Simulationen tropischer Monsunsysteme in diesem Projekt soll helfen, ihre Bildungsprozesse in Modellen besser zu verstehen. Als Werkzeug verwenden wir dafür auch die Simulation stabiler Wasserisotope.
Lay summary

Inhalt und Ziel des Forschungsprojekts

Unser übergeordnetes Ziel ist es, zu einem verbesserten Verständnis der Wolkenbildungsprozesse im afrikanischen und asiatischen Monsun beizutragen. Dazu werden wir hochauflösende Simulationen der Monsunsysteme durchführen und mit Hilfe von Trajektorien unterschiedliche Bildungsprozesse identifizieren und ihre Signatur im Isotopengehalt des Eis quantifizieren.

Dafür verwenden wir eine spezielle, von uns entwickelte, Version des Wettervorhersagemodells COSMO. Die Auswertung dieser Simulationen, in Kombination mit Messungen von den Feldmesskampagnen DACCIWA und STRATOclim, wird einen neuartigen Einblick in die vielfältigen Bildungsmechanismen von Eiswolken in Monsunsystemen erlauben.

 

Wissenschaftlicher und gesellschaftlicher Kontext des Forschungsprojekts

Unsere Arbeit wird neue Informationen liefern zu den physikalischen Prozessen, die für den globalen Energiehaushalt und damit für globale Klimasimulationen essentiell sind. Der Fokus des Projekts liegt auf Wolken im afrikanischen und asiatischen Monsun, d.h. in Wettersystemen, die für die Bevölkerung und Ökonomie dieser Regionen prägend sind.

Direct link to Lay Summary Last update: 22.09.2017

Responsible applicant and co-applicants

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Project partner

Scientific events

Active participation

Title Type of contribution Title of article or contribution Date Place Persons involved
Seminar, NCAR Individual talk Extreme precipitation events in subtropical regions and their meteorological drivers 04.10.2019 Boulder CO, United States of America De Vries Andries-Jan;
US CLIVAR Water Isotopes and Climate Workshop Talk given at a conference Ice cloud formation pathways and their isotopic signals in high-resolution COSMOiso simulations of the African monsoon 01.10.2019 Boulder CO, United States of America De Vries Andries-Jan;
Seminar, University of Washington WA Individual talk Extreme precipitation events in subtropical regions and their meteorological drivers 23.09.2019 Seattle, United States of America De Vries Andries-Jan;
PIRE summer school Talk given at a conference Ice cloud formation pathways and their isotopic signals in high-resolution COSMOiso simulations of the African monsoon 16.09.2019 Seattle, United States of America De Vries Andries-Jan;


Associated projects

Number Title Start Funding scheme
188731 Large-scale circulation drivers and stable water isotope characteristics of low-level clouds over the tropical North Atlantic 01.11.2019 Project funding (Div. I-III)
154486 Cloud-resolving climate modeling on future supercomputing platforms 01.05.2015 Sinergia
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)
164721 MOisture Transport pathways and Isotopologues in water Vapour (MOTIV) 01.01.2017 Project funding (Div. I-III)

Abstract

The representation of tropical cirrus clouds in climate models is uncertain, and an improved understanding is required of their structure, formation mechanisms, and variability. We contribute to the U.S. PIRE project on tropical cirrus clouds by combining our expertise in the high-resolution regional modeling of stable water isotopes and in the detailed Lagrangian analysis of microphysical processes leading to cloud formation. These models and diagnostic techniques have been developed during the last years for studying aspects of the atmospheric water cycle in the extratropics - here they will be, for the first time, combined and applied to the complex processes associated with ice cloud formation in the African and Asian monsoon systems, as simulated with high-resolution convection-permitting simulations. We will distinguish three main cirrus formation pathways: (i) from convective clouds (rapid ascent, ice formation mainly via freezing of liquid cloud particles), (ii) from slantwise ascent in baroclinic regions (slow ascent, ice formation again via the liquid phase), and (iii) from in situ cloud formation (directly from the gas phase). Our methodological approach will ideally complement the research activities from the U.S. project partners, and allow addressing the following main scientific objectives: (1) quantify the relative role of the three formation pathways for cirrus clouds in the monsoon regions; (2) assess the potential differences in the spectrum of the isotopic signature of the three types of cirrus clouds; (3) achieve an improved understanding of the microphysical processes that determine the isotopic composition of cirrus clouds; and (4) investigate whether the isotopic composition of cirrus clouds reflects information about the temporal variability of the intensity of the monsoon systems.
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