DOI: 10.1002/2016JD025262
论文题名: Variability of oceanic deep convective system vertical structures observed by CloudSat in Indo-Pacific regions associated with the Madden-Julian oscillation
作者: Yuan J.
刊名: Journal of Geophysical Research: Atmospheres
ISSN: 2169897X
出版年: 2016
卷: 121, 期: 18 起始页码: 10761
结束页码: 10785
语种: 英语
英文关键词: anvil clouds
; cloud structures
; CloudSat
; deep convection
; mesoscale convective systems
; MJO
Scopus关键词: cloud cover
; CloudSat
; convective system
; deep sea
; humidity
; Madden-Julian oscillation
; mesoscale motion
; radar interferometry
; reflectivity
; troposphere
; Indian Ocean
; Pacific Ocean
英文摘要: Vertical structures of deep convective systems during the Madden-Julian oscillation (MJO) are investigated using CloudSat radar measurements in Indo-Pacific oceanic areas. In active phases of the MJO, relatively more large systems and connected mesoscale convective systems (CMCSs) occur. The occurrence frequency of CMCSs peaks in the onset phase, a phase earlier than separated mesoscale convective systems (SMCSs). Compared with SMCSs, CMCSs of all sizes have weaker reflectivity above 8 km in their deep precipitating portions and thick anvil clouds closely linked to them, suggesting more “stratiform” physics associated with them. SMCSs and CMCSs together produce relatively the least anvil clouds in the onset phase, while their deep precipitating portions show stronger/weaker reflectivity above 8 km before/after the onset phase. Thus, after the onset phase of the MJO, mesoscale convective systems shift toward a more “convective” organization because SMCSs maximize after the onset, while their internal structures appear more stratiform because internally they have weaker reflectivity above 8 km. CMCSs coincide with a more humid middle troposphere spatially, even at the same locations a few days before they occur. Middle-tropospheric moistening peaks in the onset phase. Moistening of the free troposphere around deep convective systems shows relatively stronger moistening/drying below 700 hPa before/after the onset phase than domain-mean averages. Low-topped clouds occur most frequently around CMCSs and in active phases, consistent with the presence of a moister free troposphere. Coexistence of these phenomena suggests that the role of middle troposphere moisture in the formation of CMCSs should be better understood. ©2016. 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/62850
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: Institute of Climate and Global Change Research & School of Atmospheric Sciences, Nanjing University, Nanjing, China; Collaborative Innovation Center for Climate Change, Nanjing, China
Recommended Citation:
Yuan J.. Variability of oceanic deep convective system vertical structures observed by CloudSat in Indo-Pacific regions associated with the Madden-Julian oscillation[J]. Journal of Geophysical Research: Atmospheres,2016-01-01,121(18)