南海东北部中尺度涡对海表叶绿素a浓度的影响规律研究

EFFECT OF MESOSCALE EDDIES ON SEA SURFACE CHLOROPHYLL A CONCENTRATION IN NORTHEASTERN SOUTH CHINA SEA

基于南海东北部1998~2019年的多源卫星遥感数据和风场再分析数据,较系统地分析了南海东北部涡旋内部叶绿素a浓度的分布特征,通过量化统计和涡心坐标系参数合成等方法探究了中尺度涡对叶绿素a浓度变化的影响规律及潜在机制。结果表明:(1)南海东北部约有60%的中尺度涡旋内部存在叶绿素a浓度增加和减少的现象。(2)南海东北部中尺度涡内部叶绿素a扰动受到涡旋抽吸和涡致Ekman抽吸机制的共同调控,其中约有38%(39%)的暖(冷)涡内涡旋抽吸的贡献更大, 21%(24%)的暖(冷)涡内涡致Ekman抽吸的贡献更大。(3)南海东北部中尺度涡生命周期内的海表叶绿素a浓度变化存在显著的阶段性差异,在冷暖涡的生成期,涡旋抽吸的作用更为显著,而在冷暖涡的顶峰和消亡期,涡致Ekman抽吸的作用更为明显。上述研究结果有助于理解南海东北部初级生产力对中尺度涡的响应过程与机理,对认识海洋物理-生物耦合过程具有一定的参考价值和研究意义。

Based on multi-source satellite remote sensing data and wind field reanalysis data from 1998 to 2019 in the northeastern South China Sea(nSCS),the distribution characteristics of chlorophyll a concentration inside the mesoscale eddies in the area were analyzed systematically,and the influence and mechanism of mesoscale eddies on chlorophyll a concentration variation were explored by quantitative statistics and parameter synthesis of eddy center coordinate system.The results show that(1)about 60%of the mesoscale eddies increased or decreased chlorophyll a concentrations in nSCS;(2)chlorophyll a concentration variation within mesoscale eddies in nSCS was regulated by both eddy pumping and eddy-Ekman pumping,of which about 38%(39%)of the anticyclonic(cyclonic)eddies had a greater contribution from eddy pumping and 21%(24%)of the anticyclonic(cyclonic)eddies had a greater contribution from eddy-Ekman pumping;(3)variation in sea surface chlorophyll a concentration showed obvious phased differences over the life cycle of the mesoscale eddies.The role of eddy pumping was more significant during the generation phase of mesoscale eddies,while the role of eddy-Ekman pumping was more significant during the peak and extinction phases of mesoscale eddies.The above findings help to understand the process and mechanism of primary productivity response to mesoscale eddies in the nSCS,and provided a reference for the research into the coupling between oceanic physical and biological processes.