Influences of the Great Whirl on surface chlorophyll a concentra-tion off the Somali Coast in 2017

• 作者: Lingxing Dai Bing Han Shilin Tang Chuqun Chen Yan Du
• 来源期刊: 海洋学报（英文版）
• 年，卷（期）: 2021,（11）
• 所属期刊栏目: Physical Oceanography, Marine Meteorology and Marine Physics
• 页码范围: 79-86
• 页数: 8页
• 语种: 英文

摘要

The general features of the Great Whirl (GW) off the Somali Coast in 2017 and its influences on chlorophyll a (Chl a) concentration were studied by using satellite data and model outputs. Results show that GW, which initiated at 7°N, 53°E on June 13, had a lifetime of 153 d with an average amplitude of 16 cm and an average radius of 205 km. After the formation of GW, the concentration of Chl a in the interior of GW showed a downward trend throughout its life cycle, except in early July and mid-October. In early July, the Chl a blooms in the interior of GW were attributed to the combined effect of three processes. They are eddy horizontal transportation, the deepening of the mixed layer caused by the monsoon and eddy pumping, and the upward transportation of nutrients caused by eddy-induced Ekman pumping. In October, the Chl a blooms were probably due to the weakening of GW. During the period, water exchange occurred more frequently across the eddy, thus phytoplanktons were imported into the interior of GW.