气候变化领域集成服务门户(CCPortal): South Asian monsoon precipitation in CMIP5: a link between inter-model spread and the representations of tropical convection

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DOI	10.1007/s00382-018-4177-4
	South Asian monsoon precipitation in CMIP5: a link between inter-model spread and the representations of tropical convection
	Hagos S.; Leung L.R.; Ashfaq M.; Balaguru K.
发表日期	2019
ISSN	0930-7575
起始页码	1049
结束页码	1061
卷号	52 期号:2020-01-02
英文摘要	CMIP5 models exhibit a mean dry bias and a large inter-model spread in simulating South Asian monsoon precipitation but the origins of the bias and spread are not well understood. Using moisture and energy budget analysis that exploits the weak temperature gradients in the tropics, we derived a non-linear relationship between the normalized precipitation and normalized precipitable water that is similar to the non-linear relationship between precipitation and precipitable water found in previous observational studies. About half of the 21 models analyzed fall in the steep gradient of the non-linear relationship where small differences in the normalized precipitable water in the equatorial Indian Ocean (EIO) manifest in large differences in normalized precipitation in the region. Models with larger normalized precipitable water in the EIO during spring contribute disproportionately to the large inter-model spread and multi-model mean dry bias in monsoon precipitation through perturbations of the large-scale winds. Thus the intermodel spread in precipitable water over EIO leads to the dry bias in the multi-model mean South Asian monsoon precipitation. The models with high normalized precipitable water over EIO also project larger response to warming and dominate the inter-model spread in the multi-model projections of monsoon rainfall. Conversely, models on the flat side of the relationship between normalized precipitation and precipitable water are in better agreement with each other and with observations. On average these models project a smaller increase in the projected monsoon precipitation than that from multi-model mean. This study identified the normalized precipitable water over EIO, which is determined by the relationship between the profiles of convergence and moisture and therefore is an essential outcome of the treatment of convection, as a key metric for understanding model biases and differentiating model skill in simulating South Asian monsoon precipitation. © 2018, The Author(s).
语种	英语
scopus关键词	atmospheric convection; atmospheric moisture; CMIP; energy budget; monsoon; nonlinearity; precipitable water; precipitation (climatology); Indian Ocean; Indian Ocean (Equatorial)
来源期刊	Climate Dynamics
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/146582
作者单位	Atmospheric Sciences and Global Change Division, Pacific Northwest National Laboratory, 902 Battelle Boulevard, Richland, WA 99352, United States; Oak Ridge National Laboratory, Oak Ridge, TN, United States
推荐引用方式 GB/T 7714	Hagos S.,Leung L.R.,Ashfaq M.,et al. South Asian monsoon precipitation in CMIP5: a link between inter-model spread and the representations of tropical convection[J],2019,52(2020-01-02).
APA	Hagos S.,Leung L.R.,Ashfaq M.,&Balaguru K..(2019).South Asian monsoon precipitation in CMIP5: a link between inter-model spread and the representations of tropical convection.Climate Dynamics,52(2020-01-02).
MLA	Hagos S.,et al."South Asian monsoon precipitation in CMIP5: a link between inter-model spread and the representations of tropical convection".Climate Dynamics 52.2020-01-02(2019).