Momentum flux spectrum of convectively forced internal gravity waves and its application to gravity wave drag parameterization. Part II

Impacts in a GCM (WACCM)

In Sun Song, Hye-Yeong Chun, Rolando R. Garcia, Byron A. Boville

Research output: Contribution to journalArticle

33 Citations (Scopus)

Abstract

Impacts of a spectral parameterization of gravity wave drag (GWD) induced by cumulus convection (GWDC) in the NCAR Whole Atmosphere Community Climate Model (WACCM1b) are investigated. In the spectral GWDC parameterization, reference wave momentum flux spectrum is launched at cloud top and analytically calculated based on the physical properties of convection and the large-scale flow. The cloud-top wave momentum flux is strong mainly in the Tropics and midlatitude storm-track regions, and exhibits anisotropy and spatiotemporal variability. The anisotropy and variability are determined by the distributions and variations of convective activities, the moving speed of convection, and horizontal wind and stability in convection regions. Zonal-mean zonal GWDC has a maximum of 13-27 (37-50) m s-1 day-1 in the mesosphere in January (July). Impacts of GWDC on zonal wind appear mainly in the low to midlatitudes of the upper stratosphere and mesosphere. In these regions, biases of zonal wind with respect to observation are reduced more than 50% through the GWDC process. In contrast to zonal wind, impacts of GWDC on temperature occur mainly in the mid- to high latitudes. Through the analysis of forcing terms in the zonal wind and temperature equations, it is found that impacts of GWDC result from interaction among wave forcing terms (resolved wave forcing, parameterized background GWD, and GWDC) and meridional circulations induced by the wave forcing terms. With regard to tropical variability, when GWDC is included, the model produces the stratospheric semiannual oscillation with more realistic amplitude and structure and stronger interannual variabilities in the lower stratosphere. These enhanced variabilities are caused by resolved wave forcing and meridional circulations.

Original languageEnglish
Pages (from-to)2286-2308
Number of pages23
JournalJournal of the Atmospheric Sciences
Volume64
Issue number7
DOIs
Publication statusPublished - 2007 Jul 1

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internal wave
gravity wave
drag
general circulation model
parameterization
momentum
zonal wind
convection
meridional circulation
mesosphere
stratosphere
anisotropy
semiannual oscillation
storm track
cumulus
climate modeling
physical property
temperature
atmosphere

All Science Journal Classification (ASJC) codes

  • Atmospheric Science

Cite this

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title = "Momentum flux spectrum of convectively forced internal gravity waves and its application to gravity wave drag parameterization. Part II: Impacts in a GCM (WACCM)",
abstract = "Impacts of a spectral parameterization of gravity wave drag (GWD) induced by cumulus convection (GWDC) in the NCAR Whole Atmosphere Community Climate Model (WACCM1b) are investigated. In the spectral GWDC parameterization, reference wave momentum flux spectrum is launched at cloud top and analytically calculated based on the physical properties of convection and the large-scale flow. The cloud-top wave momentum flux is strong mainly in the Tropics and midlatitude storm-track regions, and exhibits anisotropy and spatiotemporal variability. The anisotropy and variability are determined by the distributions and variations of convective activities, the moving speed of convection, and horizontal wind and stability in convection regions. Zonal-mean zonal GWDC has a maximum of 13-27 (37-50) m s-1 day-1 in the mesosphere in January (July). Impacts of GWDC on zonal wind appear mainly in the low to midlatitudes of the upper stratosphere and mesosphere. In these regions, biases of zonal wind with respect to observation are reduced more than 50{\%} through the GWDC process. In contrast to zonal wind, impacts of GWDC on temperature occur mainly in the mid- to high latitudes. Through the analysis of forcing terms in the zonal wind and temperature equations, it is found that impacts of GWDC result from interaction among wave forcing terms (resolved wave forcing, parameterized background GWD, and GWDC) and meridional circulations induced by the wave forcing terms. With regard to tropical variability, when GWDC is included, the model produces the stratospheric semiannual oscillation with more realistic amplitude and structure and stronger interannual variabilities in the lower stratosphere. These enhanced variabilities are caused by resolved wave forcing and meridional circulations.",
author = "Song, {In Sun} and Hye-Yeong Chun and Garcia, {Rolando R.} and Boville, {Byron A.}",
year = "2007",
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Momentum flux spectrum of convectively forced internal gravity waves and its application to gravity wave drag parameterization. Part II : Impacts in a GCM (WACCM). / Song, In Sun; Chun, Hye-Yeong; Garcia, Rolando R.; Boville, Byron A.

In: Journal of the Atmospheric Sciences, Vol. 64, No. 7, 01.07.2007, p. 2286-2308.

Research output: Contribution to journalArticle

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T1 - Momentum flux spectrum of convectively forced internal gravity waves and its application to gravity wave drag parameterization. Part II

T2 - Impacts in a GCM (WACCM)

AU - Song, In Sun

AU - Chun, Hye-Yeong

AU - Garcia, Rolando R.

AU - Boville, Byron A.

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N2 - Impacts of a spectral parameterization of gravity wave drag (GWD) induced by cumulus convection (GWDC) in the NCAR Whole Atmosphere Community Climate Model (WACCM1b) are investigated. In the spectral GWDC parameterization, reference wave momentum flux spectrum is launched at cloud top and analytically calculated based on the physical properties of convection and the large-scale flow. The cloud-top wave momentum flux is strong mainly in the Tropics and midlatitude storm-track regions, and exhibits anisotropy and spatiotemporal variability. The anisotropy and variability are determined by the distributions and variations of convective activities, the moving speed of convection, and horizontal wind and stability in convection regions. Zonal-mean zonal GWDC has a maximum of 13-27 (37-50) m s-1 day-1 in the mesosphere in January (July). Impacts of GWDC on zonal wind appear mainly in the low to midlatitudes of the upper stratosphere and mesosphere. In these regions, biases of zonal wind with respect to observation are reduced more than 50% through the GWDC process. In contrast to zonal wind, impacts of GWDC on temperature occur mainly in the mid- to high latitudes. Through the analysis of forcing terms in the zonal wind and temperature equations, it is found that impacts of GWDC result from interaction among wave forcing terms (resolved wave forcing, parameterized background GWD, and GWDC) and meridional circulations induced by the wave forcing terms. With regard to tropical variability, when GWDC is included, the model produces the stratospheric semiannual oscillation with more realistic amplitude and structure and stronger interannual variabilities in the lower stratosphere. These enhanced variabilities are caused by resolved wave forcing and meridional circulations.

AB - Impacts of a spectral parameterization of gravity wave drag (GWD) induced by cumulus convection (GWDC) in the NCAR Whole Atmosphere Community Climate Model (WACCM1b) are investigated. In the spectral GWDC parameterization, reference wave momentum flux spectrum is launched at cloud top and analytically calculated based on the physical properties of convection and the large-scale flow. The cloud-top wave momentum flux is strong mainly in the Tropics and midlatitude storm-track regions, and exhibits anisotropy and spatiotemporal variability. The anisotropy and variability are determined by the distributions and variations of convective activities, the moving speed of convection, and horizontal wind and stability in convection regions. Zonal-mean zonal GWDC has a maximum of 13-27 (37-50) m s-1 day-1 in the mesosphere in January (July). Impacts of GWDC on zonal wind appear mainly in the low to midlatitudes of the upper stratosphere and mesosphere. In these regions, biases of zonal wind with respect to observation are reduced more than 50% through the GWDC process. In contrast to zonal wind, impacts of GWDC on temperature occur mainly in the mid- to high latitudes. Through the analysis of forcing terms in the zonal wind and temperature equations, it is found that impacts of GWDC result from interaction among wave forcing terms (resolved wave forcing, parameterized background GWD, and GWDC) and meridional circulations induced by the wave forcing terms. With regard to tropical variability, when GWDC is included, the model produces the stratospheric semiannual oscillation with more realistic amplitude and structure and stronger interannual variabilities in the lower stratosphere. These enhanced variabilities are caused by resolved wave forcing and meridional circulations.

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