DOI: 10.1007/s00382-016-3413-z
Scopus记录号: 2-s2.0-84992736532
论文题名: Mechanisms of improved rainfall simulation over the Maritime Continent due to increased horizontal resolution in an AGCM
作者: Rashid H.A. ; Hirst A.C.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2017
卷: 49, 期: 2017-05-06 起始页码: 1747
结束页码: 1764
语种: 英语
英文关键词: GCMs
; Maritime Continent
; Orographic lifting
; Rainfall bias
; Tropical convection
英文摘要: The General Circulation Models experience a significant challenge in realistically simulating rainfall over the tropical Maritime Continent (hereafter, MC). Here, we investigate the mechanisms of an improvement in monthly rainfall simulation over the MC region in the UK Met Office Unified Model (version Global Atmosphere 6.0), which occurs when the horizontal resolution is increased from N96 (grid spacing ~135 km) to N216 (~60 km). The increased resolution enhances the area-averaged rainfall rate over the MC, thereby reducing the dry rainfall bias seen in the model at the N96 resolution. We find that the enhanced area-averaged rainfall is mostly due to an increase in the medium rainfall rates that occurs over the MC islands in the N216 experiment. The rainfall change is predominantly associated with changes in the atmospheric convective circulation and the related horizontal moisture flux convergence. The vertical profiles of convective circulation show a strong sensitivity to the increased horizontal resolution over the MC islands, but not over the surrounding oceans. It is shown that a significant underestimation of the deep convection (as opposed to the shallow convection) in the N96 experiment is primarily responsible for the stronger dry bias in this experiment. We present evidence that the dry bias, and the associated weaker deep convection, are in part caused by the strongly smoothed orography used in the N96 experiment, which provides a weaker orographic lifting of the moist surface air (in a conditionally unstable atmosphere) than that in the N216 experiment. © 2016, Springer-Verlag Berlin Heidelberg. Citation statistics:
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/53071
Appears in Collections: 过去全球变化的重建
There are no files associated with this item.
作者单位: CSIRO Oceans and Atmosphere, 107-121 Station Street, Aspendale, Melbourne, VIC, Australia
Recommended Citation:
Rashid H.A.,Hirst A.C.. Mechanisms of improved rainfall simulation over the Maritime Continent due to increased horizontal resolution in an AGCM[J]. Climate Dynamics,2017-01-01,49(2017-05-06)