Structure and mechanisms of the Arabian Sea variability during the winter monsoon |
| |
| Institution: | 1. Department of Oceanography, Naval Postgraduate School, Monterey, California 93943, USA;2. Graduate School of Environmental Earth Science, Hokkaido University, Sapporo, Japan;1. Institute of Low Temperature Science, Hokkaido University, N19W8, Kita-ku, Sapporo 060-0819, Japan;2. Department of Natural History Sciences, Faculty of Science, Hokkaido University, N10W8, Kita-ku, Sapporo 060-0810, Japan;1. Department of Environmental Chemistry, Institute of Environmental Assessment and Water Research (IDAEA-CSIC), Jordi Girona 18, E-08034 Barcelona, Spain;2. Barcelona Center for Subsurface Imaging (Barcelona-CSI-CSIC), Passeig Marítim de la Barceloneta 37, E-08003 Barcelona, Spain;1. Department of Biochemistry and Molecular Biology, LSU Health Sciences Center, New Orleans, LA;2. Department of Medicine, University of Massachusetts Medical School, Worcester, MA;1. Department of Pathology, Chicago, IL;2. Department of Hematology and Oncology, Chicago, IL;3. Department of Biochemistry and Molecular Genetics, Northwestern University Feinberg School of Medicine, Chicago, IL;4. Department of Medicine, Gainesville, FL;5. Department of Biochemistry and Molecular Biology, University of Florida Health Cancer Center, Gainesville, FL;1. Key Laboratory of Ocean and Marginal Sea Geology, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;2. State Key Laboratory of Marine Geology, Tongji University, Shanghai 200092, China;3. Innovation Academy of South China Sea Ecology and Environmental Engineering, Chinese Academy of Sciences, Guangzhou 510301, China;4. Key Laboratory of Gas Hydrate, Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, China;5. Institute of Environmental and Biogeochemistry (eBig), School of Earth Sciences, Zhejiang University, Hangzhou 310027, China;6. Key Laboratory of Gas Hydrate, Ministry of Land and Resources, Qingdao Institute of Marine Geology, Qingdao 266071, China;7. Laboratory for Marine Mineral Resources, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266071, China;8. University of Chinese Academy of Sciences, Beijing 100049, China |
| |
| Abstract: | In the southern Arabian Sea (between the Equator and 10°N), the shoaling of isotherms at subsurface levels (20 °C isotherm depth is located at ～90 m) leads to cooling at 100 m by 2–3 °C relative to surrounding waters during the winter monsoon. The annual and interannual variations of this upwelling zone, which we call the Arabian Sea dome (ASD), are studied using results from an eddy-permitting ocean general circulation model in conjunction with hydrography and TOPEX/ERS altimeter data. The ASD first appears in the southeastern Arabian Sea during September–October, maturing during November–December to extend across the entire southern Arabian Sea (along ～5°N). It begins to weaken in January and dissipates by March in the southwestern Arabian Sea. From the analysis of heat-budget balance terms and a pair of model control experiments, it is shown that the local Ekman upwelling induced by the positive wind-stress curl of the winter monsoon generates the ASD in the southeastern Arabian Sea. The ASD decays due to the weakening of the cyclonic curl of the wind and the westward penetration of warm water from the east (Southern Arabian Sea High). The interannual variation of the ASD is governed by variations in the Ekman upwelling induced by the cyclonic wind-stress curl. Associated with the unusual winds during 1994–1995 and 1997–1998 Indian Ocean dipole (IOD) periods, the ASD failed to develop. In the absence of the ASD during the IOD events, the 20 °C isotherm depth was 20–30 m deeper than normal in the southern Arabian Sea resulting in a temperature increase at 97 m of 4–5 °C. An implication is that the SST evolution in the southern Arabian Sea during the winter monsoon is primarily controlled by advective cooling: the shoaling of isotherms associated with the ASD leads to SST cooling. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
