On the Mechanism of the Seasonal Variability of SST in the Tropical Indian Ocean

• Published in: Advances in atmospheric sciences Vol. 22; no. 3; pp. 451 - 462
• Main Author: 胡瑞金 刘秦玉 孟祥风 J.StuartGODFREY
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Nature B.V 01.05.2005; Physical Oceanography Laboratory and Ocean-Atmosphere Interaction and Climate Laboratory,Ocean University of China, Qingdao 266003%CSIRO, Division of Marine Research, GPO Box 1538, Hobart, Tasmania, Australia
• Subjects: Advection; Annual variations; Atmospheric circulation; Coastal zone; Entrainment; Equator; Equatorial regions; General circulation models; Heat flux; Heat transfer; Horizontal advection; Marine; Meteorology; Ocean circulation; Ocean-atmosphere interaction; Oceanic general circulation model; Oceans; Sea surface; Seasonal variability; Seasonal variation; Seasonal variations; SST; 东亚季风; 季节变化; 海平面温度; 热带印度洋; Indian Ocean; Bay of Bengal; Arabian Sea; ISW, Africa, East; ISW, Indian Ocean, Bengal Bay; ISW, Arabian Sea; ISW, Saudi Arabia; ISW, Bangladesh, Bengal Bay; ISW, Tropical Indian Ocean; new equation; seasonal variation; mechanism; SST; tropical Indian Ocean
• ISSN: 0256-1530; 1861-9533
• DOI: 10.1007/BF02918758

A general form of an equation that “explicitly” diagnoses SST change is derived. All other equations in wide use are its special case. Combining with the data from an ocean general circulation model (MOM2) with an integration of 10 years (1987-1996), the relative importances of various processes that determine seasonal variations of SST in the tropical Indian Ocean are compared mainly for January, April, July and October. The main results are as follows. (1) The net surface heat flux is the most important factor affecting SST over the Arabian Sea, the Bay of Bengal and the region south of the equator in January; in April, its influence covers ahnost the whole region studied; whereas in July and October, this term shows significance only in the regions south of 10°S and north of the equator, respectively. (2) The horizontal advection dominates in the East African-Arabian coast and the region around the equator in January and July; in October, the region is located south of 10°S. (3) The entrainment is significant only in a narrow band centered on 10~S in April and the coastal region around the Arabian Sea and the equator in July. (4) As for SST, it decreases in January and July but increases in April and October in the Arabian Sea and the Bay of Bengal, showing a (asymmetrical) semiannual variability; by contrast, the SST in the region south of the equator has an annual variability, decreasing in April and July and increasing in October and January.