1981~2018年青海夏季极端降水时空演变及成因分析  

Comprehensive Analysis of Summer Extreme Precipitation in Qinghai from 1981 to 2018

作　　者：杨雪 张渝杰 孙俊[1,3] 张敏 李信[2] 张玲[2] YANG Xue;ZHANG Yujie;SUN Jun;ZHANG Min;LI Xin;ZHANG Ling(Heavy Rain and Drought-Flood Disasters in Plateau and Basin Key Laboratory of Sichuan Province,Chengdu 610072,China;Suining Meteorological Bureau,Suinig 627000,China;Sichuan Branch of China Meteorological Administration Training Centre,Chengdu 610072,China)

机构地区：[1]高原与盆地暴雨旱涝灾害四川省重点实验室,成都610072 [2]四川省遂宁市气象局,遂宁627000 [3]中国气象局气象干部培训学院四川分院,成都610072

出　　处：《高原山地气象研究》2021年第3期33-41,共9页Plateau and Mountain Meteorology Research

基　　金：遂宁市青年科技人才托举工程项目(遂科协发[2021]6号);青藏高原第二次综合科学考察研究项目(2019QZKK0105)。

摘　　要：采用青海省41个国家地面气象站6~8月逐日降水资料和ERA-Interim0.5°×0.5°逐月再分析资料,分析了1981~2018年青海夏季极端降水的时空变化特征及天气学成因。结果表明:8月和夏季极端降水频次均呈显著增加趋势,75%以上站次的最大日降水量、极端降水阈值和极端降水频次均呈增加趋势;极端降水频次与海拔高度之间、最大日降水量与500hPa比湿、500hPa位势高度、近地面温度之间均存在显著的正相关;以极端降水高发年8月的大气环流场为例,200hPa高空急流扩展到70°~100°E,100hPa高度正距平超过3.2hPa,高层冷高压发展异常偏强,500hPa青藏高原温度和高度距平异常偏高,上游区域扰动能量辐合强度达−1×10^(−6)m/s^(2),高发年水汽异常增强,比湿最大正距平超过0.4g/kg,上升运动异常扰动和正涡度异常扰动强度均明显偏强,其特征有利于极端降水的产生。Based on the daily precipitation data of 41 national surface meteorological stations in Qinghai Province from June to August and the monthly reanalysis data of ERA-Interim 0.5° × 0.5°, the temporal and spatial variation characteristics and synoptic causes of summer extreme precipitation in Qinghai Province from 1981 to 2018 were analyzed. The results show that the frequency of extreme precipitation in August and summer has a significant increasing trend, and the maximum daily precipitation, extreme precipitation threshold and extreme precipitation frequency of more than 75 % stations have an increasing trend. There is a significant positive correlation between extreme precipitation frequency and altitude, between maximum daily precipitation and 500 hPa specific humidity, 500 hPa geopotential height, and near-surface temperature. Taking the atmospheric circulation field in August in the year with high incidence of extreme precipitation as an example, the 200 hPa upper-level jet extended to 70°~100°E, and the positive height anomaly at 100 hPa exceeded3.2 hPa. The development of high-level cold high was abnormally strong, and the temperature and height anomaly of the Tibetan Plateau at500 hPa were abnormally high. The convergence intensity of disturbance energy in the upstream region reached-1 ×10^(−6)m/s^(2). The water vapor anomaly in the year with high incidence was enhanced, and the maximum positive specific humidity anomaly exceeded 0.4 g/kg. The disturbance intensity of ascending motion anomaly and positive vorticity anomaly was abnormally strong, and its characteristics were conducive to the generation of extreme precipitation.

关 键 词：青海 日极端降水 大气环流 扰动波能辐合 

分 类 号：P467[天文地球—大气科学及气象学]