沿海省份夏旱特征及典型旱涝年的水汽差异研究

Characteristics of Summer Drought and Water Vapor Differences in Typical Drought and Flood Years in the Coastal Provinces

选择山东和江苏省代表沿海省份,采用128个气象站点1962—2015年的月降水资料和同期的ERA5再分析资料,分析研究区夏季SPI指数时空变化特征,进一步筛选旱涝典型年份分析环流背景,最后从水汽输送和大气水分平衡的角度,揭示典型旱涝年水汽输送和水汽收支差异。主要结论如下:(1)2000年后,研究区干旱趋缓,山东和江苏省中部SPI指数多为上升趋势;(2)夏旱年水汽含量和水汽利用效率均小于夏涝年,且研究区内水汽输送量与西南急流位置密切相关;(3)不同于总水汽和平均水汽,瞬变水汽主要源自东南方向的西太平洋,夏旱年瞬变水汽对总水汽的贡献为负;(4)研究区旱涝年均有水汽盈余。

The monthly precipitation data of 128 stations in Shandong and Jiangsu provinces(typical coastal provinces)from 1962 to 2015 and the ERA5 reanalysis data were used in this paper.The paper first analyzed the spatial and temporal variation characteristics summer SPI index in the study area,further investigated the typical drought and flood years and circulation background,finally explored the differences of water vapor transport and budget in the typical drought and flood years from the perspective of atmospheric water vapor transmission and moisture balance.The main conclusions are as follows:(1)The study area tended to flood since 2000s.The SPI index in the middle of Shandong and Jiangsu Provinces mostly showed an upward trend.(2)The water vapor content and the water vapor utilization efficiency in the drought years were smaller than those in the flood years.The amount of water vapor in the study area was related to the location of the Southwest Jet Water Vapor Conveyor Belt.(3)Different from the total and average water vapor,the transient water vapor mainly originated from the western Pacific Ocean in the southeast direction.The contribution of transient water vapor to total water vapor in summer drought year was negative.(4)The water vapor budget is surplus during both the drought and flood years in the study area.