南海北部历史水文调查资料揭示的上升流现象及形成机制  

The upwelling phenomena revealed by the historic hydrologic survey data in the northern South China Sea and their formation mechanisms

作　　者：夏华永 李锐祥 Xia Huayong;Li Ruixiang(South China Sea Marine Forecasting and Hazard Mitigation Center,Ministry of Natural Resources,Guangzhou 510300,China;South China Sea Marine Survey Center,Ministry of Natural Resources,Guangzhou 510300,China;Key Laboratory of Marine Environmental Survey Technology and Application,Ministry of Natural Resources,Guangzhou 510300,China)

机构地区：[1]自然资源部南海预报减灾中心,广东广州510300 [2]自然资源部南海调查技术中心,广东广州510300 [3]自然资源部海洋环境探测技术与应用重点实验室,广东广州510300

出　　处：《海洋学报》2024年第8期1-18,共18页

基　　金：国家重点研发计划“海洋环境安全保障与岛礁可持续发展”重点专项(2021YFC3101800);广东省平台基地及科技基础条件建设项目(2021B1212050025);自然资源部南海局科技发展基金(202205)。

摘　　要：南海夏季盛行西南季风,琼东、雷州半岛东部及粤东沿岸海域季节性上升流经常发生,且受到广泛的关注。本文在处理了南海北部的历史水文调查资料时发现,除了直达海面的上升流频发区域外,还存在次表层上升流分布形态:强西南季风下,贯穿琼东、粤西、粤东沿岸的次表层上升流;粤西陆架大区域次表层上升流;珠江口外冲淡水驱动的上升流;粤东海湾陆架底层水入侵及湾内气旋环流。这些分布形态在已有文献中未见报道,或关注不多。除了夏季强西南季风的Ekman输送、风应力旋度产生的Ekman泵吸,南海海盆尺度环流的底边界层Ekman效应可能是次表层贯穿上升流不能忽略的驱动机制。上升流同期的大气环流形态表明,南海北部正风应力旋度Ekman泵吸似乎是粤西陆架次表层上升流的主要驱动机制。正风应力旋度与珠江冲淡水联合驱动了粤西陆架气旋型环流。气旋型环流的辐散利于粤西陆架次表层上升流的形成与维持。在粤东海湾,西南季风驱动的湾内垂向环流,及水平气旋型环流是陆架底层水入侵海湾的主要驱动机制。大亚湾内核电温排水热力羽流利于湾内气旋环流的加强。海湾岬角利于红海湾气旋环流的形成。除了Ekman效应,上升流形成机制还需关注更多的动力因素。It prevails southwesterly monsoon in summer in the northern South China Sea.Consequently,the seasonal coastal upwellings are frequently driven up in summer off the southeastern coast of the Hainan Island,the eastern coast of the Leizhou Peninsula and the eastern coast of Guangdong Province,and these upwellings have attracted common research attention.The present paper revisits the historic hydrologic survey data in the northern South China Sea.It is found that,besides the coastal upwellings frequently reaching the sea surface in the above-mentioned zones,there are more subsurface upwelling patterns in the northern South China Sea:namely,(1)the subsurface upwelling throughout the eastern coastal zones of Hainan Province and all the western and eastern coastal zones of Guangdong Province under strong overlying southwesterly monsoon;(2)the subsurface one over the wide continental shelf off the western coast of Guangdong Province;(3)the subsurface one driven by the diluted Pearl River runoff off the river mouth;and(4)the bottom continental water invasion into the bays of eastern Guangdong Province and the cyclonic eddies in the bays.These four upwelling patterns have not been reported in the existing research papers,or little attention has been paid to them.Besides the Ekman’s transport due to strong summer southwesterly monsoon and Ekman’s pumping due to overlying wind stress curl,the bottom Ekman’s effect due to the basin-scale South China Sea circulation is possibly the non-negligible driving mechanism for the subsurface upwelling throughout all the coastal zones.In the light of the simultaneous atmospheric circulation over the northern South China Sea,Ekman’s pumping due to positive wind stress curl seems to be the major driving force for the subsurface upwelling over the continental shelf off western Guangdong coast.The positive wind stress curl as well as the diluted Pearl River runoff drives a cyclonic circulation off western Guangdong coast.The seawater divengence in the cyclonic circulation is favora

关 键 词：南海北部 上升流 珠江冲淡水 风应力旋度 垂向环流 

分 类 号：P731.21[天文地球—海洋科学]