全球变暖背景下陕西省夏季极端降水及其大尺度环流特征  

Characteristics of Extreme Summer Precipitation and Large-Scale Circulation in Shaanxi Province under Global Warming

作　　者：杜一博 李双双 冯典 肖贻青 陈小婷[1] 黄少妮[1] 杜莉丽[1] DU Yibo;LI Shuangshuang;FENG Dian;XIAO Yiqing;CHEN Xiaoting;HUANG Shaoni;DU Lili(Meteorological observatory of Shaanxi province,Xi’an 710014,Shaanxi,China)

机构地区：[1]陕西省气象台,陕西西安710014

出　　处：《高原气象》2024年第2期342-352,共11页Plateau Meteorology

基　　金：秦岭和黄土高原生态环境气象重点实验室青年基金项目(2022Y-3)和面上基金项目(2022G-3);中国气象局创新发展专项(CXFZ2023J031);陕西省自然科学基础研究计划项目(2023-JC-YB-283)。

摘　　要：基于陕西省99个国家站1979-2021年夏季逐日降水资料和ERA5再分析数据,研究了陕西省夏季极端降水的时空变化以及相应的大尺度环流特征,并对全省典型地区进行水汽追踪分析。结果表明,陕西省夏季极端降水总体呈现出南多北少的空间分布,陕北中部、关中中东部极端降水为增加的趋势,通过REOF分析并计算得到陕北、关中极端降水变化趋势分别为0.36 mm·a^(-1),0.35 mm·a^(-1),陕南极端降水变化趋势最小为0.11 mm·a^(-1)。夏季影响陕西省的水汽来源主要有三支路径,北支水汽来自欧亚中高纬地区,东支水汽主要来自内陆的江河流域,南支水汽主要来自南海和孟加拉湾。此外,陕西省夏季极端降水在2005年后增多是大气高、中、低层大气环流共同作用的结果,大气高层辐散增强有利于上升运动,大气中层西太平洋副热带高压(以下简称,西太副高)西伸北抬造成外围水汽更容易进入内陆,蒙古反气旋南侧的异常东风和低层的异常东南风更有利于水汽进一步向西北地区输送。Based on the daily summer precipitation data of 99 national stations in Shaanxi Province and the ERA5 reanalysis data from 1979 to 2021,the temporal and spatial variations of extreme summer precipitation and the corresponding large-scale circulation characteristics in Shaanxi Province were studied,and the water vapor tracking analysis was conducted on the typical regions.The results showed that the extreme summer precipitation in shannxi Province exhibits more in the south and less in the north,with increasing trend in the central part of northern shannxi and the eastern part of Guanzhong.The variation trend of extreme precipitation in northern Shaanxi,Guanzhong and southern Shannxi is 0.36 mm·a^(-1),0.35 mm·a^(-1) and 0.11 mm·a^(-1) respectively based on REOF analysis.In summer,there are three main paths for water vapor sources that affect Shaanxi Province.The northern branch comes from the high latitude region of Eurasia,the eastern branch comes from inland river basins,and the southern branch comes from the South China Sea and the Bay of Bengal.In addition,the increase of extreme summer precipitation in Shaanxi Province after 2005 was the result of the combined effects of the high,middle,and low-level atmospheric circulation.The enhanced divergence in the high atmosphere is conducive to the upward movement,and the water vapor is more likely to enter the inland due to the westward extension of the west Pacific subtropical high in the middle atmosphere.The anomalous easterly wind in the south side of the Mongolian anticyclone and the anomalous southeast wind in the lower atmosphere are more conducive to the transport of water vapor to the northwest region.

关 键 词：极端降水 西太平洋副热带高压 水汽追踪 

分 类 号：P426.6[天文地球—大气科学及气象学]