2014年夏季我国气候异常及成因简析

Analysis on Climate Anomalies in China in Summer 2014

2014年夏季,全国平均气温为21.1℃,较常年同期偏高0.2℃。全国平均降水量为320.1 mm,较常年同期偏少1.6%,空间分布呈现北少南多的显著特征,其中黄淮地区平均降水量与1999年并列历史同期最少。进一步对2014年夏季我国降水异常成因分析表明,东亚夏季风偏弱及西北太平洋副热带高压偏强、偏南是造成我国夏季降水北少南多的直接原因;印度洋海温偏暖和厄尔尼诺状态共同作用导致副热带高压持续偏强偏南;两者是造成降水异常的重要外强迫条件。

In summer 2014,the surface air temperature averaged over China was 21.1℃,which is 0.2℃ above normal.The mean precipitation over China was 320.1 mm,which was less than normal by 1.6%,and its spatial distribution shows the significant feature of less in the north but more in the south.The average rainfall over the Huanghe River and Huaihe River region was minimum in historic records tied for the same period in 1999.Further analysis on the summer rainfall anomaly shows that the summer precipitation anomaly in China is because the East Asian summer monsoon was weaker and the Northwest Pacific subtropical high was stronger and further southward than normal.Warm Indian Ocean SST and the El Nino condition jointly resulted in continued stronger and southward Northwest Pacific subtropical high.The two parts were important external forcing conditions for abnormal rainfall.