中国夏季热浪持续天数的年际变化及环流异常分析

摘要

利用NCEP/NCAR再分析大气资料和中国台站观测温度资料,本文分析了1960-2015年中国夏季6-8月热浪持续天数的年际变率及其环流异常.研究发现,中国的热浪主要集中发生于东南地区和新疆地区.通过对不同区域热浪持续天数进行经验正交分解,分析了东南地区和新疆地区热浪的年际变化的空间模态,并进一步研究了不同模态对应的同期大气环流异常的空间特征.为了揭示热浪不同模态的可能预报源,本文进一步分析了热浪发生前期春季海温的异常特征.诊断分析表明,春季赤道印度洋的一致偏暖,有利于夏季西太平洋副热带高压偏强偏西,引起我国东南地区夏季容易出现高温异常.春季北太平洋中部、里海、黑海的海温偏暖有利于夏季对流层高层大陆高压的增强,使得新疆地区夏季易出现热浪.%Using the NCEP/NCAR reanalysis data and observation data,the variation of the heat wave frequency over China in summer during 1960-2015 is investigated.It is found that the most frequent heat wave in China is located in southeastern China and Xinjiang.Through the empirical orthogonal function analysis,the dominant modes of heat wave frequency over the above two regions are further analyzed.Examination on the atmospheric circulation anomaly and the sea surface temperature in the previous season shows that prevalence of the heat wave over southeastern China is attributed to the warming in Indian Ocean during previous months.The heat wave over Xinjiang is mainly due to the strong mid-latitude warming over Pacific,Black Sea and Caspian Sea.