DOI: 10.1002/jgrd.50683
论文题名: Diurnal variability of low clouds in the Southeast Pacific simulated by a multiscale modeling framework model
作者: Cheng A. ; Xu K.-M.
刊名: Journal of Geophysical Research Atmospheres
ISSN: 21698996
出版年: 2013
卷: 118, 期: 16 起始页码: 9191
结束页码: 9208
语种: 英语
Scopus关键词: Atmospheric thermodynamics
; Boundary layers
; Clouds
; Models
; Sun
; Turbulence
; Boundary layer turbulence
; Cloud radiative effects
; Cloud resolving model
; Diurnal variability
; Multi-scale Modeling
; Spatial variability
; Stratocumulus clouds
; Turbulence closures
; Computer simulation
; boundary layer
; cloud
; diurnal variation
; fractionation
; numerical model
; open ocean
; stratocumulus
; topography
; turbulence
; Pacific Ocean
; Pacific Ocean (Southeast)
英文摘要: This study analyzes the diurnal variations of austral-spring stratocumulus clouds in the Southeast Pacific and their physical mechanisms from a global multiscale modeling framework (MMF) simulation. This MMF contains an advanced third-order turbulence closure in its cloud-resolving model component, helping it to realistically simulate boundary layer turbulence and low-level clouds. The main finding is that the MMF simulation can reproduce the spatial pattern of the diurnal variations of low clouds within the region, with the day-night cloud fraction (CF) differences ranging from 0.10 at 30° off the shore to 0.40 near the shore. The diurnal phases and ranges of simulated liquid water path, CF, and surface cloud radiative effects agree well with available observations. The maximum CF occurs in the early morning and the minimum in the late afternoon over the open ocean. However, near the shore, the maximum/minimum CF anomalies are more variable. The spatial variability of the diurnal variations is attributed to the modulation of solar-forced variation by the orographically induced circulation. The solar radiation makes the lower cloud layer dissipated during the day, and clouds recover first there in the early evening, with the upper cloud layer changing relatively less in cloudiness. The southwestward propagating upsidence wave that is related to the orographical forcing modulates the CF anomalies near the shore. The orographically induced subsidence, however, extends too deeply into the boundary layer because of the model's unrealistically smooth topography, and it dissipates rather than enhances the stratocumulus near the shore between the late night and the following noon. © 2013. Her Majesty the Queen in Right of Canada. American Geophysical Union. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/63407
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Climate Science Branch, NASA Langley Research Center, Mail Stop 420, Hampton, VA 23681, United States; Science Systems and Applications, Inc., Hampton, VA, United States
Recommended Citation:
Cheng A.,Xu K.-M.. Diurnal variability of low clouds in the Southeast Pacific simulated by a multiscale modeling framework model[J]. Journal of Geophysical Research Atmospheres,2013-01-01,118(16)