南海东北部上层海洋对台风“莲花”的响应  

Response of the upper northeastern South China Sea to the Typhoon Linfa

作　　者：杨军 宏波 YANG Jun;HONG Bo(School of Civil Engineering&Transportation,South China University of Technology,Guangzhou 510641,China;Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai),Zhuhai 519000,China)

机构地区：[1]华南理工大学土木与交通学院,广东广州510641 [2]南方海洋科学与工程广东省实验室(珠海),广东珠海519000

出　　处：《海洋通报》2021年第2期161-171,共11页Marine Science Bulletin

基　　金：国家自然科学基金(41976014,51761135021);中国科学院前沿科学重点研究项目(QYZDJ-SSW-DQC022)。

摘　　要：台风过境会引起所经海域海洋环境要素场剧烈响应。本文通过分析南海东北部上层海域各要素对2015年第10号台风“莲花”的响应过程,发现以下规律:台风过境期间,海表温度(SST)影响台风的移动路径和强度,两次显著的台风移动方向偏转均发生在台风下垫面温度发生显著改变的条件下。台风吸收海表热量引起SST降低0~1.5℃,而这种热量(以短波辐射和潜热通量为主的海表净热通量)吸收引起的海表失热每秒可达60 W/m^(2),对台风移动过程产生影响。同时,台风过境时(7月6—9日)的SST降低与失热变化都存在一定的“左偏性”。台风引起的Ekman抽吸速率最高可达1.6×10^(-3) m/s,引起台风过后(7月9日之后)SST的降低。通过对海面10 m风场、海表温度、降雨量进行EOF分析发现:风场在南海东北部海域呈东西反位相分布,风场增强持续时间约5天,具有显著“右偏性”且近岸的局部风场特征明显;降雨量在台风期间呈全域一致性的增加,持续时长约4天,具有显著“左偏性”且在吕宋岛北部局部降雨特征明显;SST在南海东北部绝大部分海域呈降温态势,时长超过8天,降温时间滞后风场约2~3天。整个降温过程(7月5—15日)受Ekman抽吸作用较海表失热作用更大,表现为在台风右侧降温更为显著。同时,台风移动速度越慢,降温效果越明显。台风过境时,粤东离岸流显著增强,上升流区的垂直温度降幅可达2.5℃且滞后流场响应约1~2天;垂直盐度降幅可达1.3 psu且滞后流场响应约2~3天。总体上看,温度在台风响应过程中起着重要的联结作用。The passage of typhoon maycan usually cause remarkable responses of marine environment.By analyzing the response of the upper northeastern South China Sea(NESCS)to the Typhoon Linfa(1510),the following results were found in our study:During the passage of typhoon(from July 5th to 15th,2015),sea surface temperature(SST)affected the path and intensity of typhoon.Two obvious deflectionsof typhoon moving direction happened while the obvious temperature changes occurred at the underling surface of typhoon.The SST decreasedby 0~1.5℃due to the absorption of sea surface heat by typhoon and the heat loss caused by the heat absorption(net sea surface heat flux mainly resulted from short wave radiation and latent heat flux)could reach 60 W/m^(2) per second,which had impacts on the moving of typhoon.At the same time,the decrease of SST was related to the changes of heat loss and both of them showed more tendency of decrease to the left of typhoon track.The maximum Ekman pumping velocity(EPV)could reach 1.6×10^(-3) m/s,which was more significant on the right of the typhoon track,resulting in the decrease of SST after typhoon(after July 9th).The EOF analyseson the wind 10 m above the sea surface,SST and precipitation were conducted to study the temporal and spatial distribution characteristics of these variables.It was found that the wind field in the NESCS showed a pattern with opposite spatial pattern in eastern and western areas and the wind enhancement lasted for about 5 days,which showed more tendency of increase to the right of typhoon track and showed obvious local characteristics near the shore.The precipitation increased consistently in the entire NESCS and the increase lasted for about 4 days,which showed a stronger increase to the left of the typhoon track and obvious local variation near the northern Luzon Island.The SST decreased in most part of the NESCS and the decrease lasted for more than 8 days which lagged behind the wind field for about 2~3 days.The whole cooling process from July 5th to 15th was more af

关 键 词：台风 南海东北部 EKMAN抽吸 海表净热通量 

分 类 号：P732.6[天文地球—海洋科学]