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Ice Supersaturation Variability in Cirrus Clouds: Role of Vertical Wind Speeds and Deposition Coefficients

Kärcher, Bernd and Jensen, Eric and Pokrifka, Gwenore and Harrington, Jerry Y. (2023) Ice Supersaturation Variability in Cirrus Clouds: Role of Vertical Wind Speeds and Deposition Coefficients. Journal of Geophysical Research: Atmospheres, pp. 1-25. Wiley. doi: 10.1029/2023JD039324. ISSN 2169-897X.

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Official URL: https://doi. org/10.1029/2023JD039324


Aircraft measurements reveal ice supersaturation statistics in cirrus (ISSs) with broad maxima around ice saturation and pronounced variance. In this study, processes shaping ISSs in midlatitude and tropical upper tropospheric conditions are systematically investigated. Water vapor deposition and sublimation of size-resolved ice crystal populations are simulated in an air parcel framework. Mesoscale temperature fluctuations (MTFs) due to gravity waves force the temporal evolution of supersaturation. Various levels of background wave forcing and cirrus thickness are distinguished in stochastic ensemble simulations. Kinetic limitations to ice mass growth are brought about by supersaturation-dependent deposition coefficients that represent efficient and inefficient growth modes as a function of ice crystal size. The simulations identify a wide range of deposition coefficients in cirrus, but most values stay above 0.01 such that kinetic limitations to water uptake remain moderate. Supersaturation quenching times are long, typically 0.5–2 hr. The wave forcing thus causes a remarkably large variability in ISSs and cirrus microphysical properties except in the thickest cirrus, producing ensemble-mean ISSs in line with in-situ measurements. ISS variance is controlled by MTFs and increases with decreasing cirrus integral radii. In comparison, the impact of ice crystal growth rates on ISSs is small. These results contribute to efforts directed at identifying and solving issues associated with ice-supersaturated areas and non-equilibrium cirrus physics in global models.

Item URL in elib:https://elib.dlr.de/199082/
Document Type:Article
Title:Ice Supersaturation Variability in Cirrus Clouds: Role of Vertical Wind Speeds and Deposition Coefficients
AuthorsInstitution or Email of AuthorsAuthor's ORCID iDORCID Put Code
Kärcher, BerndDLR, IPAhttps://orcid.org/0000-0003-0278-4980UNSPECIFIED
Jensen, EricNASA Ames Research Center, Moffet Field, CA, USAUNSPECIFIEDUNSPECIFIED
Pokrifka, GwenoreThe Pennsylvania State University, University Park, PA, USAUNSPECIFIEDUNSPECIFIED
Harrington, Jerry Y.The Pennsylvania State University, University Park, PA, USAUNSPECIFIEDUNSPECIFIED
Date:10 November 2023
Journal or Publication Title:Journal of Geophysical Research: Atmospheres
Refereed publication:Yes
Open Access:Yes
Gold Open Access:No
In ISI Web of Science:Yes
Page Range:pp. 1-25
Keywords:ice supersaturation, cirrus clouds, gravity waves, deposition growth
HGF - Research field:Aeronautics, Space and Transport
HGF - Program:Aeronautics
HGF - Program Themes:Air Transportation and Impact
DLR - Research area:Aeronautics
DLR - Program:L AI - Air Transportation and Impact
DLR - Research theme (Project):L - Climate, Weather and Environment
Location: Oberpfaffenhofen
Institutes and Institutions:Institute of Atmospheric Physics > Atmospheric Trace Species
Deposited By: Kärcher, Prof. Bernd
Deposited On:13 Nov 2023 09:39
Last Modified:20 Nov 2023 10:21

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