热带印度洋-西太平洋海表温度异常对斯里兰卡夏季季风降水的影响
文献类型：学位论文
| 作者 | ERANDANI LAKSHANI WIDANA ARACHCHIGE |
| 答辩日期 | 2019 |
| 授予单位 | 南海海洋研究所 |
| 导师 | 王鑫 |
| 关键词 | 夏季降水，斯里兰卡， 西南季风， 印度洋，太平洋 |
| 学位名称 | 硕士 |
| 学位专业 | 物理海洋学 |
| 其他题名 | Impact of anomalous sea surface temperature in the tropical Indian Ocean-western Pacific on precipitation in Sri Lanka during summer monsoon |
| 英文摘要 | The interdecadal and interannual variations of Sri Lankan precipitation during summer monsoon (May-September) and their associations with the tropical Indian and Pacific Oceans sea surface temperature (SST) are investigated. The present study involves the use of Empirical Orthogonal Function (EOF) analysis to identify the dominant rainfall patterns over Sri Lanka during 38 years (1979–2016). The first principal component (PC) of rainfall data shows high negative values, which are dispersed all over Sri Lanka. EOF1 accounts for 57.3% of the total variance in monotonous mode while EOF2 explains 15% of the total variance with negative values except for the northern part of Sri Lanka. PC2 exhibits an interannual variation of summer precipitation which is positively associated with the anomalous SST in the southeastern tropical Indian Ocean and western tropical Pacific. Those warm SST anomalies can influence the strong cyclonic circulation over the southern India and Bay of Bengal which supports for advance precipitation over the country.PC1 showed that clear interdecadal variation which is identical to the change of the 7-year moving average of Sri Lankan precipitation Index (SLPI) with more and fewer precipitation before and after the year 2000 respectively. The composite analysis indicates that the SSTs in western and central tropical Indian Ocean are considerably warmer during 2000–2014 than 1979–1998.Thus, influence the anomalous downward motion and less summer precipitation into Sri Lanka.The community atmospheric model (CAM 5) simulated consequences are noticeably in phase with the observation. Further, it confirmed that, the tropical Indian Ocean and western Pacific Ocean SST play an important role in summer rainfall of Sri Lanka. The standardized precipitation index (SPI) is used to identify the extreme wet and dry events for each selected meteorological stations based on their climatic zone (wet, Intermediate, dry).Observed SPI indicates a conspicuous, extreme wet period occurred in the year 2011 all over the country. It is noted that, if dry events in first inter-monsoon (FIM; March-April) are continuing in the (SWM; May-September), that year create an extremely dry condition in the wet zone. Further analysis exhibit a strong correlation between SPI values in FIM and SWM in the wet zone. Hence, this study suggests the importance of investigating the variations of extreme rainfall events over Sri Lanka on seasonal, interannual and long-term timescales and the possible mechanism. |
| 源URL | [http://ir.scsio.ac.cn/handle/344004/18115]  |
| 专题 | 南海海洋研究所_学位论文（硕士） |
| 推荐引用方式 GB/T 7714 | ERANDANI LAKSHANI WIDANA ARACHCHIGE. 热带印度洋-西太平洋海表温度异常对斯里兰卡夏季季风降水的影响[D]. 南海海洋研究所. 2019. |
入库方式： OAI收割
来源：南海海洋研究所
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