DOI: 10.1175/JCLI-D-13-00701.1
Scopus记录号: 2-s2.0-84919696659
论文题名: Role of convective entrainment in spatial distributions of and temporal variations in precipitation over tropical oceans
作者: Hirota N. ; Takayabu Y.N. ; Watanabe M. ; Kimoto M. ; Chikira M.
刊名: Journal of Climate
ISSN: 8948755
出版年: 2014
卷: 27, 期: 23 起始页码: 8707
结束页码: 8723
语种: 英语
Scopus关键词: Experiments
; Humidity control
; Spatial distribution
; Troposphere
; Control experiments
; Intertropical convergence zone
; Large-scale circulation
; Numerical experiments
; Precipitation events
; Spatial and temporal variation
; Tropospheric humidity
; Tropospheric moistening
; Atmospheric humidity
; atmospheric convection
; atmospheric modeling
; entrainment
; humidity
; intertropical convergence zone
; precipitation assessment
; spatial distribution
; spatial variation
; temporal variation
; tropical region
; troposphere
英文摘要: The authors demonstrate that an appropriate treatment of convective entrainment is essential for determining spatial distributions of and temporal variations in precipitation. Four numerical experiments are performed using atmospheric models with different entrainment characteristics: a control experiment (Ctl), a no-entrainment experiment (NoEnt), an original Arakawa-Schubert experiment (AS), and an AS experiment with a simple empirical suppression of convection depending on cloud-layer humidity (ASRH). The fractional entrainment rates of AS and ASRH are constant for each cloud type and are very small in the lower troposphere compared with those in the Ctl, in which half of the buoyancy-generated energy is consumed by entrainment. Spatial and temporal variations in the observed precipitation are satisfactorily reproduced in the Ctl, but their amplitudes are underestimated with a so-called double intertropical convergence zone bias in the NoEnt and AS. The spatial variation is larger in the Ctl because convection is more active over humid ascending regions and more suppressed over dry subsidence regions. Feedback processes involving convection, the large-scale circulation, free tropospheric moistening by congestus, and radiation enhance the variations. The temporal evolution of precipitation events is also more realistic in the Ctl, because congestus moistens the midtroposphere, and large precipitation events occur once sufficient moisture is available. The large entrainment in the lower troposphere, increasing free tropospheric moistening by congestus and enhancing the coupling of convection to free tropospheric humidity, is suggested to be important for the realistic spatial and temporal variations. © 2014 American Meteorological Society. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/51273
Appears in Collections: 气候变化事实与影响
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作者单位: National Institute of Polar Research, University of Tokyo, Tokyo, Japan; Atmosphere and Ocean Research Institute, University of Tokyo, Tokyo, Japan; Japan Agency for Marine-Earth Science and Technology, Yokohama, Japan
Recommended Citation:
Hirota N.,Takayabu Y.N.,Watanabe M.,et al. Role of convective entrainment in spatial distributions of and temporal variations in precipitation over tropical oceans[J]. Journal of Climate,2014-01-01,27(23)