| 西南季风期间斯里兰卡降水的年代际、年际变化及其与热带印度洋的联系 |
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| 引用本文： | W. A. E. LAKSHANI,张广隶,王鑫.西南季风期间斯里兰卡降水的年代际、年际变化及其与热带印度洋的联系[J].南京气象学院学报,2018,10(3):282-289. |
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| 作者姓名： | W. A. E. LAKSHANI 张广隶 王鑫 |
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| 作者单位： | 中国科学院南海海洋研究所 热带海洋环境国家重点实验室, 广州, 510301;中国科学院大学, 北京, 100049,中国科学院大学, 北京, 100049;中国科学院深海科学与工程研究所, 三亚, 572000,中国科学院南海海洋研究所 热带海洋环境国家重点实验室, 广州, 510301;青岛海洋科学与技术国家实验室区域海洋动力学与数值模拟功能实验室, 青岛, 266000 |
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| 基金项目： | 中国科学院国际合作局对外合作重点项目（131551KYSB20160002） |
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| 摘 要： | 本文主要研究了1979—2016期间斯里兰卡在西南季风期间降水的年代际、年际变化以及与印度洋海温的联系.首先用经验正交的方法分析了斯里兰卡以及周边地区降水的时空分布，发现前两个模态能够解释超过70%的方差.其中第一模态为均一模态，且其PC1以及斯里兰卡7 a滑动平均降水序列都有年代际变化，降水异常在2000年前后异常偏多和偏少.通过合成分析发现2000年之后降水的异常减少与热带西部、中部印度洋的暖海温异常有关.暖海温异常通过调整经向环流引起了斯里兰卡上空的下沉运动，抑制了降水.在第二模态中，负的信号出现在斯里兰卡大部分地区，只有在斯里兰卡北部海角很小地区出现了正的信号.PC2表现出了年际变化，且与热带东南印度洋海温异常有显著的关系.通过Gill-Matsuno响应，热带东南印度洋海温异常造成热带北印度洋上空的气旋性环流异常，引起了水汽的辐合，从而利于降水.
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| 关 键 词： | 降水 斯里兰卡 西南季风 热带印度洋 |
| 收稿时间： | 2018/6/10 0:00:00 |
The interdecadal and interannual variations of Sri Lankan precipitation during southwest monsoon and their connections with the tropical Indian Ocean SST |
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| W. A. E. LAKSHANI,ZHANG Guangli and WANG Xin.The interdecadal and interannual variations of Sri Lankan precipitation during southwest monsoon and their connections with the tropical Indian Ocean SST[J].Journal of Nanjing Institute of Meteorology,2018,10(3):282-289. |
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| Authors: | W A E LAKSHANI ZHANG Guangli and WANG Xin |
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| Affiliation: | State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;University of Chinese Academy of Sciences, Beijing 100049, China,University of Chinese Academy of Sciences, Beijing 100049, China;Institute of Deep-sea Science and Engineering, Chinese Academy of Sciences, Sanya 572000, China and State Key Laboratory of Tropical Oceanography, South China Sea Institute of Oceanology, Chinese Academy of Sciences, Guangzhou 510301, China;Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology, Qingdao 266000, China |
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| Abstract: | The present study investigates the interdecadal and interannual variations of Sri Lankan precipitation during Southwest Monsoon (SWM) and their connections with the Indian Ocean Sea Surface Temperature (SST) over 38 years (1979-2016).Empirical orthogonal function (EOF) analysis is applied to examine the spatial-temporal variations of precipitation in Sri Lanka and surrounding region.The first two leading EOF modes explain exceeding 70% of the total variance.EOF1 shows a monotonous mode.Both PC1 and 7-yr running mean of precipitation in Sri Lanka show clear interdecadal variations with more and less precipitation before and after 2000.The interdecadal variation of precipitation is associated with the warmer SST in the western and central tropical Indian Ocean during 2000-2014,which induces the anomalous downward motion over Sri Lanka through enhancing the meridional circulation,and thus depresses the precipitation over there.For EOF2 mode,negative signals are in most regions of Sri Lanka except in cape of northern Sri Lanka with positive signals.PC2 shows an interannual variation,and is significantly positively related to the SST anomalies in the southeast Indian Ocean.These warm SST anomalies could induce anomalous cyclonic circulation in the north tropical Indian Ocean due to Gill response,which is favourable for convergences of moisture flux and more precipitation in Sri Lanka.This study suggests that the interdecadal variation of precipitation in Sri Lanka is greatly associated with western and central tropical Indian Ocean SST,while the interannual variation is significantly influenced by the anomalous SST in the southeast tropical Indian Ocean. |
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| Keywords: | precipitation Sri Lanka southwest monsoon tropical Indian Ocean |
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