摘要
利用湖南省97个气象站点逐日气温和降水观测资料,结合再分析资料,分析了2013年夏季湖南省持续高温干旱的变化特征及其可能成因。结果表明:2013年夏季湖南省平均高温日数为44 d,主要高温时段为6月15—25日、6月29日至8月18日、8月21—30日,97个气象站中有32个气象站高温日数刷新历史同期最高记录。2013年夏季湖南全省大范围的气象干旱自6月15日前后开始,7月28日至8月20日重度以上干旱范围超过50%以上。西太平洋副热带高压的持续异常偏强、偏西,控制中国江南地区,是2013年夏季湖南省高温干旱最重要最直接的原因。在对流层高层,南亚高压持续偏强、偏东且偏北,有利于西太平洋副热带高压偏强和偏西的维持,从而导致江南地区持续受异常下沉运动控制,对流活动明显受到抑制,江南西部和华南北部地区为水汽通量的辐散中心,不利于水汽的堆积。
Based on observational data of daily temperature and precipitation at 97 meteorological stations in Hu＇nan province and the National Centers for Environmental Prediction/National Center for Atmospheric Research（ NCEP/NCAR） reanalysis data, the characteristics and formation of a persistent high temperature and drought event during summer season in 2013 in Hu＇nan province were analyzed. The results show that the mean number of days with high temperature in Hu＇nan province is 44 d,and these high temperature days occur mostly in the periods of June 15-25,f rom June 29 to August 18,and August 21-30. The numbers of days with high temperature at 32 stations in 2013 are larger than the historical records in the same period. The large-scale meteorological drought in Hu＇nan province begins in the mid-June of 2013,and the area of severe and even heavier drought is over half area of the province from July 28 to August 20. The Subtropical High over the western Pacific that is abnormally and persistently strong and locates westward controls the Jiangnan region,which is the most important and direct influencing factor of this high temperature and drought event in Hu＇nan province. In the upper troposphere, the South Asian High is persistently strong and moves eastward or northward,which is favorable to the maintenance of the western Pacific Subtropical High. This leads to the continuous subsidence motions of air flows over the Jiangnan region and the significant suppression of convective activity. Meanwhile, the divergence center of water vapor flux is located at the western of Jiangnan region and the northern part of South China,which is unfavorable to the accumulation of water vapor.
作者
张剑明
段丽洁
ZHANG Jian-ming DUAN Li-jie(Hu＇ nan Climate Center, Changsha 410118, China)
出处
《气象与环境学报》
2018年第4期45-51,共7页
Journal of Meteorology and Environment
基金
湖南省气象局气象预报业务能力建设专项(YBNL16-10
YBNL16-07
YBNL16-08
YBNL16-09
YBNL16-11)
湖南省地方标准项目(201500676)共同资助
关键词
高温日数
干旱范围
副热带高压
环流异常
水汽
Day number with high temperature
Drought area
Subtropical High
Abnormal circulation
Water vapor
