The upwelling phenomena revealed by the historic hydrologic survey data in the northern South China Sea and their formation mechanisms
-
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。Abstract: 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 favorable to the formation and maintenance of the subsurface upwelling. The vertical circulations driven by southwesterly monsoon and horizontal cyclonic ones in the coastal bays of eastern Guangdong Province are the major driving forces for the bottom continental water intruding into the bays. In the Daya Bay, the thermal plume due to the unclear power plants is favorable to strengthen the horizontal cyclonic circulations. The western and eastern capes of the Honghai Bay are favorable to the formation of horizontal cyclonic circulations in the bay. So we need attach more importance to the other driving mechanisms of the upwelling but to surface Ekman’s effect in the northern South China Sea.
-
表 1 南海北部夏季断面调查航次日期
Tab. 1 The date of summer sectional survey cruises in the northern South China Sea
1978年 1979年 1980年 1981年 1982年 1983年 1984年 1985年 1986年 1987年 1988年 6月 13−16日 15−22日 10−19日 16−20日 5−10日 11−24日 11−15日 7−12日 6−16日 20−29日 12−17日 7月 14−17日 14−19日 15−30日 15−27日 8月 10−13日 19−23日 10−16日 14−16日 19−24日 10−16日 7−12日 7−12日 6−13日 15−20日 19−24日 -
[1] Wyrtki K. Scientific results of marine investigations of the South China Sea and the Gulf of Thailand 1959−1961: physical oceanography of the Southeast Asian waters (NAGA Report 2)[R]. La Jolla, Calif: Scripps Inst of Oceanogr, 1961: 138−143. [2] Niino H, Emery K O. Sediments of shallow portions of East China Sea and South China Sea[J]. GSA Bulletin, 1961, 72(5): 731−762. doi: 10.1130/0016-7606(1961)72[731:SOSPOE]2.0.CO;2 [3] 管秉贤, 陈上及. 中国近海的海流系统[R]. 青岛: 中国科学院海洋研究所, 1964.Guan Bingxian, Chen Shangji. Report on nearshore current systems in China’s Coastal Waters[R]. Qingdao: Institute of Oceanography, Chinese Academy of Sciences, 1964. [4] 马应良. 南海北部陆架邻近水域十年水文断面调查报告[R]. 北京: 海洋出版社, 1990: 1−7.Ma Yingliang. Report on the 10-year sectional hydrologic surveys in the shelf waters of the northern South China Sea[R]. Beijing: China Ocean Press, 1990: 1−4. [5] 曾流明. 粤东沿岸上升流迹象的初步分析[J]. 热带海洋, 1986, 5(1): 68−73.Zeng Liuming. A preliminary analysis of indicators of offshore upwelling off eastern Guangdong[J]. Tropic Oceanology, 1986, 5(1): 68−73. [6] 于文泉. 南海北部上升流的初步探讨[J]. 海洋科学, 1987(6): 7−10.Yu Wenquan. A preliminary approach of the upwelling for the northern South China Sea[J]. Marine Sciences, 1987(6): 7−10. [7] 李立. 珠江口以西陆架夏季上升流的研究[J]. 台湾海峡, 1990, 9(4): 338−346.Li Li. A study on the summer upwellings in shelf waters west to Zhujiang River mouth[J]. Journal of Oceanography in Taiwan Strait, 1990, 9(4): 338−346. [8] 伍伯瑜. 珠江口以西陆架海域环流研究Ⅱ.[J]. 台湾海峡, 1990, 9(1): 14−21.Wu Boyu. A study on the circulation in shelf waters west to Zhujiang River mouthⅡ. Upwelling[J]. Journal of Oceanography in Taiwan Strait, 1990, 9(1): 14−21. [9] 洪启明, 李立. 粤东陆架区夏季的上升流[J]. 台湾海峡, 1991, 10(3): 271−277.Hong Qiming, Li Li. A study of upwelling over continental shelf off eastern Guangdong[J]. Journal of Oceanography in Taiwan Strait, 1991, 10(3): 271−277. [10] 邓松, 钟欢良, 王名文. 琼海沿岸上升流及其与渔场的关系[J]. 台湾海峡, 1995, 14(1): 51−56.Deng Song, Zhong Huanliang, Wang Mingwen. On relation between upwelling off Qionghai and fishery[J]. Journal of Oceanography in Taiwan Strait, 1995, 14(1): 51−56. [11] 韩舞鹰, 马克美. 粤东沿岸上升流的研究[J]. 海洋学报, 1988, 10(1): 52−59.Han Wuying, Ma Kemei. A study on the upwelling off the coast of eastern Guangdong[J]. Haiyang Xuebao, 1988, 10(1): 52−59. [12] 韩舞鹰, 王明彪, 马克美. 我国夏季最低表层水温海区—琼东沿岸上升流区的研究[J]. 海洋与湖沼, 1990, 21(3): 267−275.Han Wuying, Wang Mingbiao, Ma Kemei. On the lowest surface water temperature area of China Sea in summer—the upwelling along the east coast of Hainan Island[J]. Oceanologia et Limnologia Sinica, 1990, 21(3): 267−275. [13] 吴林兴, 林洪瑛. 粤东陆架边缘水域夏季上升流初析[J]. 热带海洋, 1990, 9(4): 16−23.Wu Linxing, Lin Hongying. Preliminary analysis for the summer upwelling in the continental shelf margin waters of east Guangdong[J]. Tropical Oceanology, 1990, 9(4): 16−23. [14] 吴日升, 李立. 南海上升流研究概述[J]. 台湾海峡, 2003, 22(2): 269−277.Wu Risheng, Li Li. Summarization of study on upwelling system in the South China Sea[J]. Journal of Oceanography in Taiwan Strait, 2003, 22(2): 269−277. [15] 朱佳, 胡建宇, 陈照章, 等. 珠江口以外海域温、盐度的断面分布特征—2001年5月与2002年11月航次[J]. 厦门大学学报, 2005, 44(5): 680−683.Zhu Jia, Hu Jianyu, Chen Zhaozhang, et al. Analysis on sectional characteristics of temperature and salinity off the Zhujiang River estuary―during the cruises of May 2001 and November 2002[J]. Journal of Xiamen University (Natural Science), 2005, 44(5): 680−683. [16] 曾淦宁, 胡建宇, 洪华生, 等. 西南季风不同阶段南海北部珠江口外断面水文调查分析[J]. 热带海洋学报, 2005, 24(3): 10−17. doi: 10.3969/j.issn.1009-5470.2005.03.002Zeng Ganning, Hu Jianyu, Hong Huasheng, et al. Analysis of hydrologic section off Zhujiang River Estuary in northern South China Sea during various southwest monsoon phases[J]. Journal of Tropical Oceanography, 2005, 24(3): 10−17. doi: 10.3969/j.issn.1009-5470.2005.03.002 [17] Wang Dongxiao, Zhuang Wei, Xie Shangping, et al. Coastal upwelling in summer 2000 in the northeastern South China Sea[J]. Journal of Geophysical Research: Oceans, 2012, 117(C4): C04009. [18] 许金电, 蔡尚湛, 宣莉莉, 等. 粤东至闽南沿岸海域夏季上升流的调查研究[J]. 热带海洋学报, 2014, 33(2): 1−9. doi: 10.3969/j.issn.1009-5470.2014.02.001Xu Jindian, Cai Shangzhan, Xuan Lili, et al. Observational study on summertime upwelling in coastal seas between eastern Guangdong and southern Fujian[J]. Journal of Tropical Oceanography, 2014, 33(2): 1−9. doi: 10.3969/j.issn.1009-5470.2014.02.001 [19] Jing Zhiyou, Qi Yiquan, Du Yan. Upwelling in the continental shelf of northern South China Sea associated with 1997−1998 El Niño[J]. Journal of Geophysical Research: Oceans, 2011, 116(C2): C02033. [20] 潘爱军, 郭小钢, 许金电, 等. 粤东沿岸上升流对2006年夏季台风响应[J]. 中国科学: 地球科学, 2012, 55(3): 495−506Pan Aijun, Guo Xiaogang, Xu Jindian, et al. Responses of Guangdong coastal upwelling to the summertim typhoons of 2006[J]. Science China Earth Sciences, 2012, 55(3): 495−506 [21] 许金电, 蔡尚湛, 宣莉莉, 等. 2006年夏季琼东、粤西沿岸上升流研究[J]. 海洋学报, 2013, 35(4): 11−18. doi: 10.3969/j.issn.0253-4193.2013.04.002Xu Jindian, Cai Shangzhan, Xuan Lili, et al. Study on coastal upwelling in eastern Hainan Island and western Guangdong in summer, 2006[J]. Haiyang Xuebao, 2013, 35(4): 11−18. doi: 10.3969/j.issn.0253-4193.2013.04.002 [22] 夏华永, 刘长建, 王东晓. 2006年夏季珠江冲淡水驱动的上升流[J]. 海洋学报, 2018, 40(7): 43−54. doi: 10.3969/j.issn.0253-4193.2018.07.004Xia Huayong, Liu Changjian, Wang Dongxiao. The upwelling driven by the Zhujiang River runoff in 2006 summer[J]. Haiyang Xuebao, 2018, 40(7): 43−54. doi: 10.3969/j.issn.0253-4193.2018.07.004 [23] 谢玲玲, 宗晓龙, 伊小飞, 等. 琼东上升流的年际变化及长期变化趋势[J]. 海洋与湖沼, 2016, 47(1): 43−51.Xie Lingling, Zong Xiaolong, Yi Xiaofei, et al. The interannual variation and long-term trend of Qiongdong upwelling[J]. Oceanologia et Limnologia Sinica, 2016, 47(1): 43−51. [24] 蔡尚湛, 靖春生, 许金电, 等. 粤东及闽南近岸上升流对局地风场变化的响应[J]. 海洋学报, 2016, 38(9): 1−12. doi: 10.3969/j.issn.0253-4193.2016.09.001Cai Shangzhan, Jing Chunsheng, Xu Jindian, et al. Response of upwelling in eastern Guangdong and southern Fujian coastal seas to the local wind variation[J]. HaiyangXuebao, 2016, 38(9): 1−12. doi: 10.3969/j.issn.0253-4193.2016.09.001 [25] Su Jian, Pohlmann T. Wind and topography influence on an upwelling system at the eastern Hainan coast[J]. Journal of Geophysical Research: Oceans, 2009, 114: C06017. [26] Jing Zhiyou, Qi Yiquan, Hua Zulin, et al. Numerical study on the summer upwelling system in the northern continental shelf of the South China Sea[J]. Continental Shelf Research, 2009, 29(2): 467−478. doi: 10.1016/j.csr.2008.11.008 [27] Gan Jianping, Li Li, Wang Dongxiao, et al. Interaction of a river plume with coastal upwelling in the northeastern South China Sea[J]. Continental Shelf Research, 2009, 29(4): 728−740. doi: 10.1016/j.csr.2008.12.002 [28] Gan Jianping, Cheung A, Guo Xiaogang, et al. Intensified upwelling over a widened shelf in the northeastern South China Sea[J]. Journal of Geophysical Research: Oceans, 2009, 114(C9): C09019, doi: 10.1029/2007JC004660 [29] Shu Yeqiang, Wang Dongxiao, Zhu Jiang, et al. The 4-D structure of upwelling and Pearl River plume in the northern South China Sea during summer 2008 revealed by a data assimilation model[J]. Ocean Modelling, 2011, 36(3/4): 228−241. [30] Wang Dongxiao, Shu Yeqiang, Xue Huijie, et al. Relative contributions of local wind and topography to the coastal upwelling intensity in the northern South China Sea[J]. Journal of Geophysical Research: Oceans, 2014, 119(4): 2550−2567. doi: 10.1002/2013JC009172 [31] 舒业强, 王强, 俎婷婷. 南海北部陆架陆坡流系研究进展[J]. 中国科学: 地球科学, 2018, 48(3): 276−287.Shu Yeqiang, Wang Qiang, Zu Tingting. Progress on shelf and slope circulation in the northern South China Sea[J]. Science China Earth Sciences, 2018, 61(5): 560−571. [32] Carton J A, Chepurin G, Cao Xianhe, et al. A simple ocean data assimilation analysis of the global upper ocean 1950−95. Part I: methodology[J]. Journal of Physical Oceanography, 2000, 30(2): 294−309. doi: 10.1175/1520-0485(2000)030<0294:ASODAA>2.0.CO;2 [33] Carton J A, Chepurin G, Cao Xianhe, et al. A simple ocean data assimilation analysis of the global upper ocean 1950−95. Part II: results[J]. Journal of Physical Oceanography, 2000, 30(2): 311−326. doi: 10.1175/1520-0485(2000)030<0311:ASODAA>2.0.CO;2 [34] 欧素英. 珠江口冲淡水扩展变化及动力机制研究[D]. 广州: 中国科学院南海海洋研究所, 2005.Ou Suying. On the changes and mechanisms of the diluted water expansion off the Pearl River mouth[D]. Guangzhou: South China Sea Institute of Oceanology, Chinese Academy of Science, 2005. [35] Tang Danling, Kester D R, Wang Zhaoding, et al. AVHRR satellite remote sensing and shipboard measurements of the thermal plume from the Daya Bay, nuclear power station, China[J]. Remote Sensing of Environment, 2003, 84(4): 506−515. doi: 10.1016/S0034-4257(02)00149-9 [36] 张炳楷. 大亚湾1987年与1989年海水特征的差异[J]. 台湾海峡, 1992, 11(1): 35−41.Zhang Bingkai. Difference of seawater characteristics in Daya Bay in 1987 and 1989[J]. Journal of Oceanography in Taiwan Strait, 1992, 11(1): 35−41. [37] 李立, 陈义斌. 大亚湾水温层化的季节性突变[J]. 海洋科学, 1992(6): 61−63.Li Li, Chen Yibin. Sudden change of Daya Bay temperature stratification in September[J]. Marine Sciences, 1992(6): 61−63. [38] 曾刚, 李立, 许金殿, 等. 大亚湾西部和北部浅水区夏半年的温、盐度分析[J]. 台湾海峡, 1992, 11(1): 28−34.Zeng Gang, Li Li, Xu Jindian, et al. Analysis of summer water temperature and salinity in shallow waters of western and northern DayaBay[J]. Journal of Oceanography in Taiwan Strait, 1992, 11(1): 28−34. [39] 殷建平, 王友绍, 徐继荣, 等. 大亚湾温跃层形成及其对有关环境要素的影响[J]. 海洋通报, 2006, 25(4): 1−8. doi: 10.3969/j.issn.1001-6392.2006.04.001Yin Jianping, Wang Youshao, Xu Jirong. Seasonal thermocline in the Daya Bay and its influence on the environmental factors of seawater[J]. Marine Science Bulletin, 2006, 25(4): 1−8. doi: 10.3969/j.issn.1001-6392.2006.04.001 [40] Garvine R W. A dynamical system for classifying buoyant coastal discharges[J]. Continental Shelf Research, 1995, 15(13): 1585−1596. doi: 10.1016/0278-4343(94)00065-U [41] Fong D A, Geyer W R. The alongshore transport of freshwater in a surface-trapped river plume[J]. Journal of Physical Oceanography, 2002, 32(3): 957−972. [42] 杨士瑛, 鲍献文, 陈长胜, 等. 夏季粤西沿岸流特征及其产生机制[J]. 海洋学报, 2003, 25(6): 1−8. doi: 10.3321/j.issn:0253-4193.2003.06.001Yang Shiying, Bao Xianwen, Chen Changsheng, et al. Analysis on characteristics and mechanism of current system in west coast of Guangdong Province in the summer[J]. Haiyang Xuebao, 2003, 25(6): 1−8. doi: 10.3321/j.issn:0253-4193.2003.06.001 [43] Gu Yanzhen, Pan Jiayi, Lin Hui. Remote sensing observation and numerical modeling of an upwelling jet in Guangdong coastal water[J]. Journal of Geophysical Research, 2012, 117(C8): C08019, doi: 10.1029/2012JC007922