中国东南春季降水异常特征及其与ENSO关系的年代际变化

发布时间：2018-06-17 19:05

本文选题：中国东南春季降水 + ENSO　；参考：《中国海洋大学学报(自然科学版)》2016年09期

【摘要】：利用中国160站观测降水资料和美国NOAA ERSST海温资料以及NCEP/NCAR再分析资料,研究了中国东南地区春季降水异常特征及其与ENSO关系的年代际变化。结果表明:东南春季降水异常具有全区一致性,在1950年代末之前有不显著的上升趋势,之后一直呈现下降趋势,其中在1960年代初至1970年代初下降趋势显著,1980、1990年代趋势较为平稳,1999年之后下降趋势增加。在过去64年中,中国东南春季降水与ENSO有显著的相关关系,即在El Nis豱o事件发生的次年春季,东南地区一般降水偏多,其主要机制为ENSO通过影响西北太平洋异常反气旋进而影响中国东南地区春季降水,并且利用前冬季Nis豱o3区海温指数可提前4个月较好地预测东南地区春季降水。进一步分析表明,东南春季降水与ENSO的相关关系具有年代际差异:在1969—1990年间两者相关性较好;而在1951—1968年和1991—2014年间,两者相关性较弱。在不同时间段内,与东南春季降水相应的春季环流系统有较大差异,ENSO作为影响因子的重要性也发生变化。在1951—1968年,影响降水的环流系统主要位于中高纬度,而西北太平洋反气旋位置较为偏东,难以影响到中国东部地区;在1969—1990年,副高和西北太平洋异常反气旋是影响东南春季降水的主要环流系统,反气旋西侧气流是提供水汽的主要来源;在1991—2014年,东南春季降水受到高低纬环流系统共同影响,来自印度洋西风气流和西北太平洋反气旋西侧气流共同为降水提供水汽,ENSO的作用减弱。因此,在中国东南春季降水预测中必须根据不同年代际背景考虑ENSO作为预报因子的可靠性。
[Abstract]:Based on the observational precipitation data of 160 stations in China, the NOAA ERSST SST data and the NCEP / NCAR reanalysis data, the characteristics of spring precipitation anomaly and the decadal variation of its relationship with ENSO in southeastern China are studied. The results show that the anomalous spring precipitation in Southeast China is consistent with the whole region, and there was no significant upward trend before the end of 1950's, and then it has been decreasing. During the early 1960s to the early 1970s, the downward trend was more stable than that in the 1980s and 1990s, and the downward trend increased after 1999. In the past 64 years, there was a significant correlation between spring precipitation and ENSO in southeast China. The main mechanism is that ENSO affects the spring precipitation in southeast China by influencing the anomalous anticyclone in the Northwest Pacific Ocean, and the SST index of the Niszao _ 3 region in the previous winter can better predict the spring precipitation in southeast China by 4 months ahead of schedule. Further analysis shows that the correlation between spring precipitation and ENSO in Southeast China has Interdecadal differences: the correlation between them is better in 1969-1990, but the correlation between them is weak in 1951-1968 and 1991-2014. In different time periods, the importance of ENSO as an influential factor also varies greatly with the spring circulation system corresponding to the precipitation in southeastern China. From 1951 to 1968, the circulation system affecting precipitation was mainly located in the middle and high latitudes, while the anticyclonic position in the Northwest Pacific Ocean was relatively easterly, and it was difficult to affect the eastern part of China; in 1969-1990, The subtropical high and the anomalous anticyclone in the Northwest Pacific Ocean are the main circulation systems which affect the precipitation in the southeast spring, and the westward flow of the anticyclone is the main source of water vapor. In 1991-2014, the precipitation in the southeast spring was affected by the circulation system of high and low latitudes. The effects of the westerly flow from the Indian Ocean and the western side of the anticyclone in the Northwest Pacific Ocean on the supply of water vapor to the precipitation are weakened. Therefore, the reliability of ENSO as a forecast factor must be considered according to the different decadal background in the spring precipitation prediction in southeastern China.
【作者单位】：中国海洋大学物理海洋实验室海洋-大气相互作用与气候实验室;南京信息工程大学气象灾害教育部重点实验室;
【基金】：国家自然科学基金项目(41276002,41130859) 国家重大研究计划项目(2012CB955603,2013CB956201) 气象灾害教育部重点实验室(南京信息工程大学)开放课题项目(KLME1301)资助~~
【分类号】：P426.6;P732

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