DOI: 10.1007/s00382-014-2379-y
Scopus记录号: 2-s2.0-84925515675
论文题名: Tropical Indian Ocean subsurface temperature variability and the forcing mechanisms
作者: Sayantani O. ; Gnanaseelan C.
刊名: Climate Dynamics
ISSN: 9307575
出版年: 2015
卷: 44, 期: 2017-09-10 起始页码: 2447
结束页码: 2462
语种: 英语
英文关键词: El Nino
; Indian Ocean
; Interannual variability
; IOD
; Subsurface variability
英文摘要: The first two leading modes of interannual variability of sea surface temperature in the Tropical Indian Ocean (TIO) are governed by El Niño Southern Oscillation and Indian Ocean Dipole (IOD) respectively. TIO subsurface however does not co-vary with the surface. The patterns of the first mode of TIO subsurface temperature variability and their vertical structure are found to closely resemble the patterns of IOD and El Niño co-occurrence years. These co-occurrence years are characterized by a north–south subsurface dipole rather than a conventional IOD forced east–west dipole. This subsurface dipole is forced by wind stress curl anomalies, driven mainly by meridional shear in the zonal wind anomalies. A new subsurface dipole index (SDI) has been defined in this study to quantify the intensity of the north–south dipole mode. The SDI peaks during December to February (DJF), a season after the dipole mode index peaks. It is found that this subsurface north–south dipole is a manifestation of the internal mode of variability of the Indian Ocean forced by IOD but modulated by Pacific forcing. The seasonal evolution of thermocline, subsurface temperature and the corresponding leading modes of variability further support this hypothesis. Positive wind stress curl anomalies in the south and negative wind stress curl anomalies in the north of 5°S force (or intensify) downwelling and upwelling waves respectively during DJF. These waves induce strong subsurface warming in the south and cooling in the north (especially during DJF) and assist the formation and/or maintenance of the north–south subsurface dipole. A thick barrier layer forms in the southern TIO, supporting the long persistence of anomalous subsurface warming. To the best of our knowledge the existence of such north–south subsurface dipole in TIO is being reported for the first time. © 2014, Springer-Verlag Berlin Heidelberg. 资助项目: CSIR, Council of Scientific and Industrial Research
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/54196
Appears in Collections: 过去全球变化的重建
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作者单位: Indian Institute of Tropical Meteorology, Pune, India
Recommended Citation:
Sayantani O.,Gnanaseelan C.. Tropical Indian Ocean subsurface temperature variability and the forcing mechanisms[J]. Climate Dynamics,2015-01-01,44(2017-09-10)