气候变化领域集成服务门户(CCPortal): Signatures of monsoon intra-seasonal oscillation and stratiform process in rain isotope variability in northern Bay of Bengal and their simulation by isotope enabled general circulation model

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DOI	10.1007/s00382-020-05344-w
	Signatures of monsoon intra-seasonal oscillation and stratiform process in rain isotope variability in northern Bay of Bengal and their simulation by isotope enabled general circulation model
	Sengupta S.; Bhattacharya S.K.; Parekh A.; Nimya S.S.; Yoshimura K.; Sarkar A.
发表日期	2020
ISSN	0930-7575
起始页码	1649
结束页码	1663
卷号	55
英文摘要	Monsoon intra-seasonal oscillation (MISO) represents a quasi-periodic occurrence of rainfall spells over India during summer monsoon (June–September) associated with large-scale circulation and convection. The connection of MISO with the hydrological cycle has been explored in this study through stable oxygen (δ18O) and hydrogen isotope ratios (δD) in rainwater samples collected from two stations located near the north coast of the Bay of Bengal during 2004–2014. The δ18O and δD values of the samples (total 202) have wide ranges: − 18.2 to 2.8‰ and − 132 to 28‰ (rel. to VSMOW) respectively. Based on northward propagation of negative anomaly in Outgoing Longwave Radiation, 16 convective MISO phases were identified during this period. Out of 69 samples associated with these MISO phases, 46 samples have isotope ratios depleted in heavier isotopes. These ratios are well correlated (R = 0.81) with the MISO propagation speed and enhanced rainfall (R = − 0.71) over the Bay of Bengal. In addition, the isotope ratios also show a significant anti-correlation (R = − 0.94) with satellite-derived stratiform rain fraction. The observed isotopic ratios were compared with the results obtained from an Isotope Enabled Global Spectral Model (IsoGSM). The model simulation reproduces the amplitude of variation in the observed values reasonably well, but on average, the model values are higher in δ18O and δD by about 2‰ and 11‰ respectively. In contrast, the model d-excess values are much lower (by 4.5‰ on average). We speculate that the discrepancies in δ18O, δD and d-excess may arise due to an overestimation of raindrop evaporation effect in the model. Our study thus identifies two major physical processes controlling rain isotope variability in northern Bay of Bengal, namely, the effect of MISO propagation characteristics in inducing isotope depletion through rain out over the ocean and contribution from the stratiform rains. © 2020, Springer-Verlag GmbH Germany, part of Springer Nature.
英文关键词	Bay of Bengal; MISO; Rain isotope; Stratiform
语种	英语
scopus关键词	atmospheric circulation; atmospheric convection; climate oscillation; computer simulation; general circulation model; hydrogen isotope; hydrological cycle; isotopic composition; longwave radiation; monsoon; oxygen isotope; rainfall; rainwater; stratiform cloud; summer; Bay of Bengal; India; Indian Ocean
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/145345
作者单位	Indian Institute of Tropical Meteorology, Pune, 411008, India; Institute of Earth Science, Academia Sinica, Taipei, 11529, Taiwan; Department of Geology and Geophysics, Indian Institute of Technology, Kharagpur, 721302, India; Atmosphere and Ocean Research Institute, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8568, Japan
推荐引用方式 GB/T 7714	Sengupta S.,Bhattacharya S.K.,Parekh A.,et al. Signatures of monsoon intra-seasonal oscillation and stratiform process in rain isotope variability in northern Bay of Bengal and their simulation by isotope enabled general circulation model[J],2020,55.
APA	Sengupta S.,Bhattacharya S.K.,Parekh A.,Nimya S.S.,Yoshimura K.,&Sarkar A..(2020).Signatures of monsoon intra-seasonal oscillation and stratiform process in rain isotope variability in northern Bay of Bengal and their simulation by isotope enabled general circulation model.Climate Dynamics,55.
MLA	Sengupta S.,et al."Signatures of monsoon intra-seasonal oscillation and stratiform process in rain isotope variability in northern Bay of Bengal and their simulation by isotope enabled general circulation model".Climate Dynamics 55(2020).