ENSO及其组合模态对中国东部各季节降水的影响

发布时间：2018-05-03 07:06

本文选题：ENSO模态 + ENSO组合模态　；参考：《气象学报》2016年03期

【摘要】：近期的研究发现,热带太平洋低层大气存在两种主要模态,即经向对称ENSO模态和ENSO与海表温度(SST)年循环相互作用产生的经向反对称组合模态。主要探讨了这两种不同ENSO模态对中国东部各季节降水的影响。结果表明,厄尔尼诺年秋季,中国西南、长江及华南大部分区域呈现显著正降水异常;冬季,正降水异常范围扩大,覆盖华南、华东及华北东南部地区。这两个季节的异常降水都主要受ENSO模态的影响。与ENSO模态相关的正异常海温局地强迫导致120°E以西出现反气旋性环流,其西北侧增强的西南暖湿气流使得中国东部地区降水增多。次年春季,从中国华南延伸到东北出现正的异常降水,主要是ENSO组合模态的贡献。因为次年春季热带太平洋地区ENSO模态信号只局限于赤道地区,并没有对中国东部降水有显著的影响,而ENSO与海温年循环相互作用的组合模态使得与ENSO相关的赤道大气异常可以扩展到赤道以外地区。ENSO组合模态对中国降水异常有重要影响,在今后的研究和短期预测中需引起重视。
[Abstract]:Recent studies show that there are two main modes in the lower tropical Pacific atmosphere: meridional symmetric ENSO mode and meridional antisymmetric combined mode produced by the annual cycle interaction between ENSO and sea surface temperature (SST). The effects of these two different ENSO modes on the precipitation in different seasons in eastern China are discussed. The results show that there are significant positive precipitation anomalies in most areas of Southwest China, Yangtze River and South China in the autumn of El Nino year, and the range of positive precipitation anomalies in winter is enlarged to cover South China, East China and Southeast North China. The anomalous precipitation in both seasons is mainly affected by the ENSO mode. The local forcing of positive anomalous SST associated with the ENSO mode results in an anticyclonic circulation west of 120 掳E, and the increased southwest warm and humid air flow in the north and west makes the precipitation increase in the eastern part of China. In the spring of the following year, positive anomalous precipitation occurred from South China to northeast China, mainly contributed by ENSO combined mode. Because the ENSO modal signal in the tropical Pacific region is confined to the equatorial region in the following spring, it has no significant effect on the precipitation in eastern China. The combined mode of ENSO and SST annual cycle interaction makes the equatorial atmospheric anomaly associated with ENSO can be extended beyond the equator to influence the precipitation anomaly in China, which should be paid more attention to in the future research and short-term prediction.
【作者单位】：南京信息工程大学气象灾害预报预警与评估协同创新中心气象灾害教育部重点实验室;
【基金】：国家重点基础研究发展计划973项目(2012CB417403) 公益性行业(气象)科研专项(GYHY201506013,GYHY201406022) 江苏省研究生培养创新工程项目(CXZZ13_0505) 江苏省高校“青蓝工程”项目
【分类号】：P426.6;P732

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