气候变化领域集成服务门户(CCPortal): Moisture flux adjustments in RegCM4 for improved simulation of Indian summer monsoon precipitation

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DOI	10.1007/s00382-018-4564-x
	Moisture flux adjustments in RegCM4 for improved simulation of Indian summer monsoon precipitation
	Mohanty M.R.; Sinha P.; Maurya R.K.S.; Mohanty U.C.
发表日期	2019
ISSN	0930-7575
起始页码	7049
结束页码	7069
卷号	52 期号:11
英文摘要	The complexity of the Indian summer monsoon precipitation makes it’s prediction a challenging task as it is not only influenced by the large-scale flows but also by the micro-scale features. In a dynamical model, precipitation is resulted from the formation of clouds. The cloud formation and its processes occur at a micro scale. Current state-of-the-art dynamical models lack proper representation of the cloud processes, particularly at high resolutions for which the cloud processes are parameterized, thereby poorly resolving the precipitation. This study aims at examining the impact of the cloud parameters on the simulation of Indian summer monsoon precipitation in Regional Climate Model version 4 (RegCM4). The autoconversion coefficient which determines the conversion of cloud water into precipitation in the Explicit Moisture Convergence scheme is adjusted in the RegCM4. The impact of autoconversion is experimented with ten different values and it is found that it has a significant effect on the simulation of precipitation during summer monsoon season. The experiments are conducted by changing autoconversion from 1.5 × 10−4 to 7.5 × 10−4/s along with the default value of 2.5 × 10−4/s. On changing the autoconversion values from 60 to 300% of the default value, the precipitation pattern improves over most parts of India. The model simulates the rainfall better when the autoconversion coefficient is changed to 7.5 × 10−4/s. With the best outcome with the adjusted autoconversion and control configuration, the model is simulated for seventeen monsoon seasons and the analyses of RegCM4 simulated vertically integrated moisture transport, convective available potential energy and atmospheric moisture budget suggest that the model efficacy is enhanced in higher autoconversion value than the control one. Statistical evaluations using bias, correlation coefficients, comprehensive rating matrices and skill score confirm the suitability of higher autoconversion rate for summer monsoon simulations. The model with adjusted autoconversion coefficient (at 7.5 × 10−4/s) has improved the representation of seasonal precipitation distribution and its year-to-year variation including other derived features. The rainfall pattern is improved over North West India and North East India especially, the monsoon core regions. The mean seasonal rainfall is in phase 94% of the time with the modeler-adjusted moisture as compared to 82% in the control in the long term simulation. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Auto conversion coefficient; Explicit moisture convergence scheme; Indian summer monsoon rainfall; RegCM4
语种	英语
scopus关键词	atmospheric moisture; climate modeling; computer simulation; moisture flux; monsoon; precipitation (climatology); regional climate; summer
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/146232
作者单位	School of Earth, Ocean and Climate Sciences (SEOCS), Indian Institute of Technology (IIT), SIF Building, Bhubaneswar, Odisha 752050, India
推荐引用方式 GB/T 7714	Mohanty M.R.,Sinha P.,Maurya R.K.S.,et al. Moisture flux adjustments in RegCM4 for improved simulation of Indian summer monsoon precipitation[J],2019,52(11).
APA	Mohanty M.R.,Sinha P.,Maurya R.K.S.,&Mohanty U.C..(2019).Moisture flux adjustments in RegCM4 for improved simulation of Indian summer monsoon precipitation.Climate Dynamics,52(11).
MLA	Mohanty M.R.,et al."Moisture flux adjustments in RegCM4 for improved simulation of Indian summer monsoon precipitation".Climate Dynamics 52.11(2019).