气候变化领域集成服务门户(CCPortal): Asymmetry in the tropical Indian Ocean subsurface temperature variability

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DOI	10.1016/j.dynatmoce.2020.101142
	Asymmetry in the tropical Indian Ocean subsurface temperature variability
	Kakatkar R.; Gnanaseelan C.; Chowdary J.S.
发表日期	2020
ISSN	03770265
卷号	90
英文摘要	The empirical orthogonal function (EOF) analysis of subsurface temperature shows a dominant north-south mode of interannual variability in the Tropical Indian Ocean (TIO) at around 100 m depth (thermocline). This subsurface mode (SSM) of variability evolves in September-November (SON) as a response to Indian Ocean Dipole and intensifies during December-February (DJF) reinforced by El Niño and Southern Oscillation (ENSO) forcing. The asymmetry in the evolution of positive and negative phases of SSM and its impacts on the modulation of surface features are studied. The asymmetry in the representation of anomalous surface winds along the equator and off-equatorial wind stress curl anomalies are primarily responsible for maintaining the asymmetry in the subsurface temperature through positive and negative phases of the SSM. During the positive phase of SSM, downwelling Rossby waves generated by anticyclonic wind stress curl propagate towards the southwestern TIO (SWTIO), the thermocline ridge region of mean upwelling. The warmer subsurface water associated with the downwelling Rossby waves upwells in the region of mean upwelling and warms the surface resulting in strong subsurface-surface coupling. Such interaction processes are however weak during the negative phase of SSM. The asymmetry in the subsurface-surface interaction during the two phases of SSM and its impact on the modulation of surface features of TIO are also reported. In addition to the ENSO forcing, self-maintenance of SSM during DJF season is evident in the positive SSM (PSSM) years through modulation of subsurface surface coupling and air-sea coupling. This positive feedback during PSSM years is maintained by the deepening thermocline, warm SSTs and convection. The asymmetry in the thermocline evolution is more evident in the SWTIO and southern TIO. © 2020 Elsevier B.V.
英文关键词	Asymmetry; Subsurface mode; Tropical Indian Ocean variability
语种	英语
scopus关键词	Atmospheric pressure; Climatology; Mechanical waves; Modulation; Orthogonal functions; Stream flow; Tropics; Wind stress; Empirical orthogonal function analysis; Indian Ocean dipole; Interaction process; Interannual variability; Southern oscillation; Subsurface temperature; Surface interactions; Tropical Indian ocean; Oceanography; annual variation; El Nino-Southern Oscillation; Indian Ocean Dipole; Rossby wave; sea surface temperature; thermocline; upwelling; wind stress; Indian Ocean; Indian Ocean (Tropical)
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/178317
作者单位	Indian Institute of Tropical Meteorology, Pune, 411008, India
推荐引用方式 GB/T 7714	Kakatkar R.,Gnanaseelan C.,Chowdary J.S.. Asymmetry in the tropical Indian Ocean subsurface temperature variability[J],2020,90.
APA	Kakatkar R.,Gnanaseelan C.,&Chowdary J.S..(2020).Asymmetry in the tropical Indian Ocean subsurface temperature variability.Dynamics of Atmospheres and Oceans,90.
MLA	Kakatkar R.,et al."Asymmetry in the tropical Indian Ocean subsurface temperature variability".Dynamics of Atmospheres and Oceans 90(2020).