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DOI	10.1007/s00382-018-4396-8
	Modulations of the Indian summer monsoon by the hot subtropical deserts: insights from coupled sensitivity experiments
	Sooraj K.P.; Terray P.; Masson S.; Crétat J.
发表日期	2019
ISSN	0930-7575
起始页码	4527
结束页码	4555
卷号	52 期号:2020-07-08
英文摘要	This study revisits the role of subtropical deserts in the Indian Summer Monsoon (ISM) system by perturbing surface albedo over the subtropical deserts, to the west of the ISM domain in different ways, using a state-of-the-art coupled model. The analysis of up-to-date satellite datasets, atmospheric re-analyses and our control coupled simulation suggests that the model broadly reproduces the radiation budgets close to re-analyses and observed datasets. However, there are large uncertainties in the top-of-atmosphere radiation budget over the Northern Hemishere (NH) subtropical desert region during boreal summer; while the model has a rather neutral radiation budget during boreal summer over the Sahara Desert, the European Centre for Medium Range Weather Forecasts Interim reanalysis show in contrast a radiative excess throughout the NH desert region and the up-to-date satellite dataset has a clear negative radiation budget over north-eastern Sahara region and over Arabian Peninsula. Taking into account these incertitudes, our key finding is that by darkening the deserts and arid regions to the west of ISM through a negative albedo perturbation in our coupled model, the length and intensity of the rainy season over the Indian region are both significantly increased with two well-defined rainfall anomaly maxima in May–June and September–October. The ISM onset is advanced by 1 month and is characterized by a rapid northward propagation of the rainfall band over the Indian domain. Reversing the sign of our artificial albedo perturbation over the deserts in the model gives an opposite response, highlighting the robust role of the subtropical deserts in the ISM system, but the amplitude of the ISM response is also significantly larger, demonstrating nonlinearity in the monsoon-desert relationship. Additional albedo perturbation experiments further demonstrate that the whole hot subtropical deserts extending across Afro-Asian continents, and including the Sahara, plays a key-role in the ISM response. Finally, the modulations of the meridional tropospheric temperature gradient along with stronger equatorial asymmetry of mean easterly shear and moisture distribution over the Indian domain are key-factors for explaining the ISM response and its nonlinearity to the albedo perturbations over the NH subtropical deserts. Further insights from moisture budget show that the nonlinearity in advection moisture tendencies manifests in nonlinearity of the ISM response. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Abrupt monsoon transition; Indian summer monsoon; Land albedo perturbations; Monsoon seasonality; Radiation energy budget; Subtropical deserts
语种	英语
scopus关键词	albedo; desert; energy budget; monsoon; Northern Hemisphere; satellite data; seasonality; subtropical region; summer; temperature gradient; troposphere; Arabian Peninsula; India; Sahara
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/146405
作者单位	Centre for Climate Change Research, Indian Institute of Tropical Meteorology, Pune, 411008, India; Sorbonne Universites (UPMC, Univ Paris 06)-CNRS-IRD-MNHN, LOCEAN Laboratory, 4 Place Jussieu, Paris, France; Indo-French Cell for Water Sciences, IISc-IITM-NIO–IRD Joint International Laboratory, IITM, Pune, 411008, India
推荐引用方式 GB/T 7714	Sooraj K.P.,Terray P.,Masson S.,et al. Modulations of the Indian summer monsoon by the hot subtropical deserts: insights from coupled sensitivity experiments[J],2019,52(2020-07-08).
APA	Sooraj K.P.,Terray P.,Masson S.,&Crétat J..(2019).Modulations of the Indian summer monsoon by the hot subtropical deserts: insights from coupled sensitivity experiments.Climate Dynamics,52(2020-07-08).
MLA	Sooraj K.P.,et al."Modulations of the Indian summer monsoon by the hot subtropical deserts: insights from coupled sensitivity experiments".Climate Dynamics 52.2020-07-08(2019).