气候变化领域集成服务门户(CCPortal): NWP perspective of the extreme precipitation and flood event in Kerala (India) during August 2018

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DOI	10.1016/j.dynatmoce.2020.101158
	NWP perspective of the extreme precipitation and flood event in Kerala (India) during August 2018
	Mohandas S.; Francis T.; Singh V.; Jayakumar A.; George J.P.; Sandeep A.; Xavier P.; Rajagopal E.N.
发表日期	2020
ISSN	03770265
卷号	91
英文摘要	In depth examination of the extreme precipitation over Kerala during 15–17th August 2018 – triggering major flood episode in the peninsular Indian state - have been made via the National Centre for Medium Range Weather Forecasting (NCMRWF) Unified Model. A rare alignment of an intense low pressure area (LPA) over head Bay of Bengal (BoB) and a couple of typhoons over South China Sea and West Pacific, driven by anomalous sea surface conditions along the south-east Asian coastal belts, kept the low level jet meander from central Arabian Sea to West North Pacific (WNP) and remain relentless throughout the episode. Positive velocity potentials (VP, at 850 hPa) were seen prevailing for the region and some of these VP fringes unevenly crossed over to Kerala - suggestive of an uneven wind convergence – and associated rainfall necessarily not dictated by orography alone. A single system of negative stream functions (SF) suggested the prevalence of a conveyor belt like flow – termed, the ‘Remotely Aligned Intense Tropical Circulations’ (RAITC) – helping bring ‘an additional supply of moisture’ from WNP to Kerala; the cyclones over the WNP provided large amounts of moisture to the upper air and while some of these cyclones were weakening, a part of this moisture got injected to the south-westward flow and was then propelled further by the BoB LPA. While the NCUM global forecasts could capture the general circulation pattern for the intense precipitation over Kerala in the medium range, the spatial distribution of the heavy spells couldn't be captured well in day-7 forecast; the strength and movement of the BoB LPA as well as the alignment and intensity modulation of the multiple tropical circulations showed some deviations. The convection permitting regional version of the model, NCUM-R (4 km grid length), exhibited lesser frequency for the light rainfall events, while over-predicting the frequency for the extreme precipitations. © 2020 Elsevier B.V.
英文关键词	Kerala floods; Low pressure area; NCUM; RAITC; Western Ghats
语种	英语
scopus关键词	Alignment; Atmospheric movements; Belt conveyors; Floods; Moisture; Rain; Storms; Surface waters; Tropics; Extreme precipitation; General circulation; Intense precipitation; Intensity modulations; Low-pressure area; Sea-surface conditions; Unified Modeling; Velocity potentials; Weather forecasting; extreme event; flood; numerical method; precipitation (climatology); rainfall; typhoon; weather forecasting; Arabian Sea; Bay of Bengal; India; Indian Ocean; Kerala; Pacific Ocean; Pacific Ocean (North); South China Sea
来源期刊	Dynamics of Atmospheres and Oceans
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/178300
作者单位	National Centre for Medium Range Weather Forecasting, A-50, Sector-62, Noida, UP, India; School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, United Kingdom; Met Office, Exeter, EX1 3PB, United Kingdom
推荐引用方式 GB/T 7714	Mohandas S.,Francis T.,Singh V.,et al. NWP perspective of the extreme precipitation and flood event in Kerala (India) during August 2018[J],2020,91.
APA	Mohandas S..,Francis T..,Singh V..,Jayakumar A..,George J.P..,...&Rajagopal E.N..(2020).NWP perspective of the extreme precipitation and flood event in Kerala (India) during August 2018.Dynamics of Atmospheres and Oceans,91.
MLA	Mohandas S.,et al."NWP perspective of the extreme precipitation and flood event in Kerala (India) during August 2018".Dynamics of Atmospheres and Oceans 91(2020).