Orographic Cirrus and Its Radiative Forcing ...
Document type :
Article dans une revue scientifique: Article original
DOI :
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Title :
Orographic Cirrus and Its Radiative Forcing in NCAR CAM6
Author(s) :
Lyu, Kai [Auteur]
Texas A&M University [College Station]
Liu, Xiaohong [Auteur]
Texas A&M University [College Station]
Bacmeister, Julio [Auteur]
National Center for Atmospheric Research [Boulder] [NCAR]
Zhao, Xi [Auteur]
Texas A&M University [College Station]
Lin, Lin [Auteur]
Texas A&M University [College Station]
Shi, Yang [Auteur]
Texas A&M University [College Station]
Sourdeval, Odran [Auteur]
Laboratoire d'Optique Atmosphérique (LOA) - UMR 8518
Texas A&M University [College Station]
Liu, Xiaohong [Auteur]
Texas A&M University [College Station]
Bacmeister, Julio [Auteur]
National Center for Atmospheric Research [Boulder] [NCAR]
Zhao, Xi [Auteur]
Texas A&M University [College Station]
Lin, Lin [Auteur]
Texas A&M University [College Station]
Shi, Yang [Auteur]
Texas A&M University [College Station]
Sourdeval, Odran [Auteur]

Laboratoire d'Optique Atmosphérique (LOA) - UMR 8518
Journal title :
Journal of Geophysical Research: Atmospheres
Abbreviated title :
JGR Atmospheres
Volume number :
128
Publisher :
American Geophysical Union (AGU)
Publication date :
2023-05-11
ISSN :
2169-897X
HAL domain(s) :
Planète et Univers [physics]/Océan, Atmosphère
English abstract : [en]
Cirrus clouds play an important role in the Earth's radiative energy budget, thereby affecting the climate state and climate change. Orographic gravity wave (OGW)-induced sub-grid scale vertical velocity (i.e., cooling ...
Show more >Cirrus clouds play an important role in the Earth's radiative energy budget, thereby affecting the climate state and climate change. Orographic gravity wave (OGW)-induced sub-grid scale vertical velocity (i.e., cooling rate) is not resolved by large-scale models and its impact on ice formation in cirrus clouds is not well quantified. In this study, one sub-grid scale OGW scheme (e.g., McFarlane) is used in the Community Atmosphere Model version 6 (CAM6) to generate vertical velocity variance (σw) for cirrus formation. Results from the default model and simulations with the OGW-induced σw are evaluated against the DOE ARM Small Particles in Cirrus (SPARTICUS) campaign observations. The OGW based on the McFarlane scheme increases the sub-grid scale σw over mountains compared to the default model and improves the model agreement with the SPARTICUS observations. Larger σw due to OGWs can trigger more frequent homogeneous nucleation in orographic cirrus and generates a higher number concentration of ice crystals observed during the SPARTICUS campaign. Moreover, our evaluation of the model simulations against satellite observations indicates that the McFarlane scheme generates high in-cloud ice number concentrations (>200 L−1) in the upper troposphere over mountains and high plateaus at mid- and high-latitudes of the winter hemisphere as shown in the observations. More ice crystals with smaller sizes absorb more infrared radiation (+0.523 ± 0.125 W m−2). The net radiative cloud forcing change at the top of the atmosphere is +0.330 W m−2 due to the orographic cirrus.Show less >
Show more >Cirrus clouds play an important role in the Earth's radiative energy budget, thereby affecting the climate state and climate change. Orographic gravity wave (OGW)-induced sub-grid scale vertical velocity (i.e., cooling rate) is not resolved by large-scale models and its impact on ice formation in cirrus clouds is not well quantified. In this study, one sub-grid scale OGW scheme (e.g., McFarlane) is used in the Community Atmosphere Model version 6 (CAM6) to generate vertical velocity variance (σw) for cirrus formation. Results from the default model and simulations with the OGW-induced σw are evaluated against the DOE ARM Small Particles in Cirrus (SPARTICUS) campaign observations. The OGW based on the McFarlane scheme increases the sub-grid scale σw over mountains compared to the default model and improves the model agreement with the SPARTICUS observations. Larger σw due to OGWs can trigger more frequent homogeneous nucleation in orographic cirrus and generates a higher number concentration of ice crystals observed during the SPARTICUS campaign. Moreover, our evaluation of the model simulations against satellite observations indicates that the McFarlane scheme generates high in-cloud ice number concentrations (>200 L−1) in the upper troposphere over mountains and high plateaus at mid- and high-latitudes of the winter hemisphere as shown in the observations. More ice crystals with smaller sizes absorb more infrared radiation (+0.523 ± 0.125 W m−2). The net radiative cloud forcing change at the top of the atmosphere is +0.330 W m−2 due to the orographic cirrus.Show less >
Language :
Anglais
Peer reviewed article :
Oui
Audience :
Internationale
Popular science :
Non
Administrative institution(s) :
Université de Lille
CNRS
CNRS
Collections :
Research team(s) :
Interactions Rayonnement Nuages (IRN)
Submission date :
2023-06-08T09:26:40Z
2023-10-27T07:35:03Z
2023-10-27T07:35:03Z
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