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Ice Nucleation in the Tropical Tropopause Layer: Implications for Cirrus Occurrence, Cirrus Microphysical Properties, and Dehydration of Air Entering the StratosphereRecent laboratory experiments have advanced our understanding of the physical properties and ice nucleating abilities of aerosol particles atlow temperatures. In particular, aerosols containing organics will transition to a glassy state at low temperatures, and these glassy aerosols are moderately effective as ice nuclei. These results have implications for ice nucleation in the cold Tropical Tropopause Layer (TTL; 13-19 km). We have developed a detailed cloud microphysical model that includes heterogeneous nucleation on a variety of aerosol types and homogeneous freezing of aqueous aerosols. This model has been incorporated into one-dimensional simulations of cirrus and water vapor driven by meteorological analysis temperature and wind fields. The model includes scavenging of ice nuclei by sedimenting ice crystals. The model is evaluated by comparing the simulated cloud properties and water vapor concentrations with aircraft and satellite measurements. In this presentation, I will discuss the relative importance of homogeneous and heterogeneous ice nucleation, the impact of ice nuclei scavenging as air slowly ascends through the TTL, and the implications for the final dehydration of air parcels crossing the tropical cold-point tropopause and entering the tropical stratosphere.
Document ID
20170004663
Acquisition Source
Ames Research Center
Document Type
Abstract
Authors
Jensen, Eric
(NASA Ames Research Center Moffett Field, CA United States)
Kaercher, Bernd
(Deutsches Zentrum fuer Luft- und Raumfahrt (DLR) Bonn, Germany)
Ueyama, Rei
(Bay Area Environmental Research Inst. Moffett Field, CA, United States)
Pfister, Leonhard
(NASA Ames Research Center Moffett Field, CA United States)
Date Acquired
May 23, 2017
Publication Date
May 20, 2017
Subject Category
Meteorology And Climatology
Report/Patent Number
ARC-E-DAA-TN39211
Meeting Information
Meeting: Japanese Geophysical Union (JPGU) / American Geophysical Union (AGU) Joint Meeting 2017
Location: Chiba City
Country: Japan
Start Date: May 20, 2017
End Date: May 25, 2017
Sponsors: American Geophysical Union, Japan Geoscience Union
Funding Number(s)
CONTRACT_GRANT: NNX12AD05A
Distribution Limits
Public
Copyright
Public Use Permitted.
Keywords
tropopause
aerosol
vapor
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