华南春季降水的年代际变化及其与大气环流和海温的关系

发布时间：2018-02-21 08:34

本文关键词： 华南春季降水年代际变化大气环流海温　出处：《大气科学学报》2017年04期 　论文类型：期刊论文

【摘要】：利用1960—2010年中国降水资料、NCEP/NCAR再分析资料、NOAA提供的海表温度资料以及太平洋年代际振荡(Pacific Decadal Oscillation,PDO)指数,分析了华南春季降水的年代际变化特征及其与大气环流和海温的关系。结果表明:华南春季降水经历了偏少(1960—1971年)—偏多(1972—1992年)—次偏少(1993—2010年)三个阶段。第一阶段少雨期,500 hPa上西风气流较平直,不利于北方冷空气南下,华南地区的暖气团也不活跃,对应的水汽通量散度为异常辐散。第二阶段多雨期,500 hPa高度上,高原北部脊偏强,利于冷空气南下,与华南地区活跃的暖湿气团汇合,对应的水汽场上为水汽异常辐合。第三阶段少雨期,500 hPa西风气流上的槽脊系统偏强,利于北方强冷空气南下,孟加拉湾地区的南支槽填塞,南方暖湿空气向华南的输送减弱。华南春季降水与PDO指数存在正相关关系,从不同季节来看,在年代际时间尺度上,前期秋季的PDO指数与华南春季降水的正相关显著,PDO处于负位相时,华南春季降水偏少,反之亦然;从华南春季降水年代际变化的不同阶段来看,PDO指数与华南春季降水的正相关在1960—1971年少雨期较显著。
[Abstract]:Using the NCEP / NCAR reanalysis data from 1960 to 2010, the sea surface temperature data provided by NOAA and the Pacific Decadal Oscillation- PDO index of the Pacific Interdecadal Oscillation are used. The characteristics of decadal variation of spring precipitation in South China and its relationship with atmospheric circulation and sea surface temperature are analyzed. The results show that the spring precipitation in South China has experienced three stages: from 1960-1971 to 1972-1992 and from 1993 to 2010. During the rainy season, the westerly air flow over 500 hPa is relatively flat, It is unfavorable for the northern cold air to go south, and the warm air mass in South China is not active, and the corresponding water vapor flux divergence is abnormal divergence. In the second stage, the ridge of the northern plateau is stronger at the height of 500 hPa, which is favorable to the south of the cold air. The water vapor field corresponds to abnormal convergence of water vapor with the active warm and wet air mass in South China. In the third stage, the trough ridge system on the westerly air flow of 500 hPa is stronger, which is favorable for the strong cold air in the north and the southern branch channel in the Bay of Bengal area. The transport of warm and wet air from southern China to South China is weakened. There is a positive correlation between spring precipitation and PDO index in South China, and in different seasons, on the Interdecadal time scale, There is a significant positive correlation between the early autumn PDO index and the precipitation in spring in South China. When the PDO index is in the negative phase, the precipitation in spring in South China is less, and vice versa. According to the different stages of interdecadal variation of spring precipitation in South China, the positive correlation between PDO index and spring precipitation in South China was significant in the young rain period of 1960-1971.
【作者单位】：南京信息工程大学气象灾害教育部重点实验室/气候与环境变化国际合作联合实验室/气象灾害预报预警与评估协同创新中心;南京信息工程大学大气科学学院;
【基金】：国家重点基础研究发展计划(973计划)项目(2013CB430202) 国家自然科学基金资助项目(41575085;41430528)
【分类号】：P426.6;P434;P731.11

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