DOI: 10.1175/JCLI-D-14-00776.1
Scopus记录号: 2-s2.0-84934448553
论文题名: Improved low-cloud simulation from the community atmosphere model with an advanced third-order turbulence closure
作者: Cheng A. ; Xu K.-M.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2015
卷: 28, 期: 14 起始页码: 5737
结束页码: 5762
语种: 英语
Scopus关键词: Atmospheric humidity
; Atmospheric radiation
; Atmospheric turbulence
; Boundary layers
; Climate models
; Clouds
; Liquids
; Parameterization
; Turbulence
; Turbulent flow
; Atmospheric circulation
; Cloud cover
; Cloud radiative forcing
; Cloud resolving model
; Community atmosphere model
; Model evaluation/performance
; Planetary boundary layers
; South pacific convergence zones
; Atmospheric thermodynamics
; air temperature
; atmospheric circulation
; atmospheric convection
; atmospheric modeling
; atmospheric moisture
; boundary layer
; climate modeling
; cloud cover
; turbulence
英文摘要: In this study, a simplified intermediately prognostic higher-order turbulence closure (IPHOC) is implemented in the Community Atmosphere Model, version 5 (CAM5), to provide a consistent treatment of subgrid-scale cloud processes, except for deep convection. The planetary boundary layer (PBL) height is prognosticated to better resolve the discontinuity of temperature and moisture above the PBL top. Single-column model tests show that fluxes of liquid water potential temperature and total water, cloud fraction, and liquid water content are improved with this approach. The simplified IPHOC package replaces the boundary layer dry and moist turbulence parameterizations, the shallow convection parameterization, and the liquid-phase part of the cloud macrophysics parameterization in CAM5. CAM5-IPHOC improves the simulation of the low-level clouds off the west coasts of continents and the storm track region in the Southern Hemisphere (SH). The transition from stratocumulus to cumulus clouds is more gradual. There are also improvements on the cloud radiative forcing, especially shortwave, in the subsidence regime. The improvements in the relationships among low cloud amount, surface relative humidity, lower tropospheric stability, and PBL depth are seen in some stratocumulus regions. CAM5-IPHOC, however, produces weaker precipitation at the South Pacific convergence zone than CAM5 because of less energy flux into the SH atmosphere. The more downward surface shortwave radiative cooling and the less top-of-the-atmosphere longwave cloud radiative heating in the SH relative to the Northern Hemisphere explains the anomalous cooling and the lesser energy flux into the SH, which is related to the underestimate of extratropical middle/high clouds in the SH. © 2015 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/50816
Appears in Collections: 气候变化事实与影响
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作者单位: Science Systems and Applications, Inc., Climate Science Branch, NASA Langley Research Center, Hampton, VA, United States; Climate Science Branch, NASA Langley Research Center, Hampton, VA, United States
Recommended Citation:
Cheng A.,Xu K.-M.. Improved low-cloud simulation from the community atmosphere model with an advanced third-order turbulence closure[J]. Journal of Climate,2015-01-01,28(14)