DOI: 10.1002/2013JD020553
论文题名: Characteristics of low clouds over the Arabian Sea
作者: Sathiyamoorthy V. ; Mahesh C. ; Gopalan K. ; Prakash S. ; Shukla B.P. ; Mathur A.K.
刊名: Journal of Geophysical Research Atmospheres
ISSN: 21698996
出版年: 2013
卷: 118, 期: 24 起始页码: 13489
结束页码: 13503
语种: 英语
英文关键词: Arabian Sea
; cloud radiative forcing
; Indian summer monsoon
; low clouds
Scopus关键词: Atmospheric radiation
; Atmospheric thermodynamics
; Moisture
; Wind
; Arabian sea
; Cloud radiative forcing
; Clouds and the Earth's radiant energy systems
; Indian summer monsoon
; International satellite cloud climatology projects
; Moisture convergence
; Possible mechanisms
; Tropospheric circulation
; Troposphere
; acceleration
; atmospheric forcing
; cloud cover
; cooling
; satellite data
; seasonal variation
; temperature effect
; troposphere
; Arabian Sea
; Indian Ocean
英文摘要: This paper studies climatically important low clouds (with cloud top below 680 hPa) over the Arabian Sea using the Kalpana-1 satellite data and International Satellite Cloud Climatology Project cloud data. Characteristics and possible mechanisms behind low-cloud formation in the summer monsoon season are presented. The dominant lower tropospheric circulation over the Arabian Sea during the summer season is the monsoon low-level jet (LLJ). Low clouds are predominantly found on the exit portion of the LLJ with decelerating winds. We postulate that the moisture carried by the LLJ from the entrance region with accelerating winds converge at the exit region with decelerating winds. This low-level convergence (observed ~925 hPa level) may be conducive for moisture convergence, parcel uplifting, and low-cloud formation. These clouds are unable to grow vertically due to the presence of lower tropospheric thermal inversion. Change in the spatial extent of low-level convergence is found to influence the spatial coverage of the low clouds. It is found that low cloud cover is inversely related to the Indian summer monsoon activity. It is speculated that the changes in the strength of the lower tropospheric stability and spatial extent of convergence may be possible causes behind the observed inverse relation between low cloud cover and monsoon activity. Based on Clouds and the Earth's Radiant Energy System data, we find that these low clouds exert a peak cooling of about -55 Wm-2. Key Points Characteristics of the Arabian Sea low clouds are studied Month-to-month and year-to-year variability of the low clouds are studied Radiative forcing of the Arabian Sea low clouds are studied ©2013. American Geophysical Union. All Rights Reserved. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/63074
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: Atmospheric and Oceanic Sciences Group, Space Applications Centre, Indian Space Research Organisation, Ahmedabad 380015, India
Recommended Citation:
Sathiyamoorthy V.,Mahesh C.,Gopalan K.,et al. Characteristics of low clouds over the Arabian Sea[J]. Journal of Geophysical Research Atmospheres,2013-01-01,118(24)