doi:  10.3878/j.issn.1006-9895.1805.17305
青藏高原西侧地区冬季降水的年际变率及其影响因子

The Interannual Variability of Winter Precipitation over the West Side of Tibetan Plateau and its Impact Factors
摘要点击 301  全文点击 58  投稿时间:2017-12-25  修订日期:2018-05-03
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基金:  国家自然科学基金 91637208、41605038; Funded by National Natural Science Foundation of China (Grants 91637208 and 41605038)
中文关键词:  青藏高原  冬季降水  水汽输送  海温异常
英文关键词:  Tibetan Plateau  winter precipitation  moisture transport  sea surface temperature anomaly
        
作者中文名作者英文名单位
孙畅Sun Chang中山大学大气科学学院
王子谦Wang Ziqian中山大学大气科学学院; 广东省气候变化与自然灾害研究重点实验室
杨崧中山大学大气科学学院; 广东省气候变化与自然灾害研究重点实验室
引用:孙畅,王子谦,杨崧.2018.青藏高原西侧地区冬季降水的年际变率及其影响因子[J].大气科学
Citation:Sun Chang,Wang Ziqian.2018.The Interannual Variability of Winter Precipitation over the West Side of Tibetan Plateau and its Impact Factors[J].Chinese Journal of Atmospheric Sciences (in Chinese)
中文摘要:
      基于全球降水气候中心(GPCC)和全球降水气候计划(GPCP)降水数据及ERA-interim再分析资料,分析了1979-2012年冬季青藏高原西侧地区降水的基本特征及影响其年际变率的潜在因子。结果表明青藏高原冬季降水主要发生在其西侧地区且为全区变化一致型,降水所需的水汽主要来自上游地区,从该区域的西边界输入。然而,青藏高原西侧地区冬季降水的年际变率主要由水汽输送的动力过程所决定,表现为高原西侧的西南风异常。此外,高原西侧冬季降水的年际变率与其上游典型的大气内部变率北大西洋涛动和北极涛动相关性不强,而与赤道西印度洋和热带中东太平洋的海温显著相关。热带中东太平洋海温异常通过影响大气环流变化,在印度洋北部激发一个反气旋式的环流异常,使得高原西侧地区出现异常西南风,从而加强了水汽通量输送的动力作用。同时在赤道异常东风的作用下,暖水也向印度洋西部输送堆积。赤道中东太平洋海温的异常可进一步导致西风急流发生南北移动,从而也在一定程度上影响了高原西侧冬季水汽输送以及降水的年际变率。
Abstract:
      Based on the monthly precipitation datasets of the Global Precipitation Climatology Centre (GPCC) and the Global Precipitation Climatology Project (GPCP) and the daily ERA-Interim reanalysis data, the characteristics of winter precipitation over the west side of Tibetan Plateau (TP) from 1979 to 2012 and the impact factors of its interannual variability are investigated in this study. Results indicate that the winter precipitation over the TP is mainly occurred over the west side region and its principal spatial pattern is uniform. The moisture source for the precipitation is mainly from upstream areas and enters into TP from the western boundary. However, the interannual variability of winter precipitation over the west side of TP is mainly explained by the dynamic component of the moisture transport, which is featured by an anomaly of southwesterly circulation over the west side of TP. Besides, the interannual variability of winter precipitation over the TP west side is related more to the sea surface temperature (SST) in the equatorial oceans than the North Atlantic Oscillation (NAO) and the Arctic Oscillation (AO) over upstream regions. The anomalous SST over the central and eastern tropical Pacific Ocean can affect the atmospheric circulation and stimulates an anticyclonic anomaly over the northern Indian Ocean, inducing an anomaly of southwesterly wind over the west side of TP, and further enhancing the dynamic process of moisture transport. Besides, under the influence of the tropical easterly anomalies, the warm water transports to the western Indian Ocean and accumulates there. The anomaly of the equatorial SST also regulates the meridional location of westerly jet, which further affects the winter moisture transport and the interannual variability of precipitation over the west side region of TP.
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