基于探空资料的1961-2018年新疆高空大气比湿气候特征分析

Climatic Characteristics of Atmosphere Specific Humidity in Xinjiang from 1961 to 2018 Based on Radiosonde Observation Data

利用1961-2018年新疆12个探空气象站逐日观测资料,分析新疆对流层850、700和500 hPa比湿的气候特征,结果表明:新疆大气比湿自西向东、自南向北递减,且随高度增加而减小,新疆比湿远小于东亚季风区;夏季比湿最大,其次为秋季、春季,冬季最小,850和500 hPa各站之间比湿差异较大,而700 hPa各站比湿差异较小;850、700和500 hPa比湿均表现为线性增加趋势,并表现为1967-1986年偏干、1987-2005年偏湿,1987年为突变点;850、700和500 h Pa比湿与降水均呈显著正相关关系;夏季暴雨天气对流层中低层比湿最大,发生暴雨时比湿约为气候平均1~2倍,夏季暴雨的动力和不稳定条件更关键,新疆暴雨天气时比湿比东亚季风区显著偏小;冬季暴雪天气比湿是一年中最小的,春、秋季强降水比湿介于夏、冬季之间,但可达气候平均的2~3倍,春、秋季需要更多的水汽产生强降水。

Based on the daily observation data of 12 radiosonde weather stations in Xinjiang from 1961 to 2018,the climate characteristics of specific humidity(SH)in the 850,700 and 500 hPa were analyzed.The results showed that the SH of atmosphere in Xinjiang decreased from west to east and from south to north,and decreased with the increasing of altitude.The SH in Xinjiang was far less than that in East Asian monsoon region,and the largest in summer,followed by autumn and spring,and the minimum in winter.The SH of 850 hPa and 500 hPa stations had a great difference,while the SH of 700 hPa stations had a little difference,all appeared a linear increasing trend and positively correlated with precipitation.The SH was drier during 1967-1986,wetter during 1987-2005,and had a abrupt point in 1987.The SH in the middle and lower troposphere was the largest during rainstorm weather in summer and 1-2 times of the climatic average during the rainstorm.The dynamic and unstable conditions of rainstorm were more critical.The SH of rainstorm in Xinjiang was significantly smaller than that in East Asia monsoon region.The SH of snowstorm in winter was the smallest in the year,and the SH of heavy rainfall in spring and autumn was between summer and winter,but it could reach 2-3 times of the average climatic.In spring and autumn,more water vapor was needed to produce heavy precipitation.