天山山区近40a夏季降水变化及与南北疆的比较

利用新疆1959-1998年的降水资料,分析了天山山区近40a来夏季降水变化特征,并与南疆、北疆进行了比较.结果表明:天山山区近40a来的夏季降水在干湿阶段、最干最湿年份、降水变化的周期方面均与南北疆有别;天山山区夏季降水空间上的同步性变化比南疆及北疆弱一些;天山山区近40a来夏季降水年代际变化与北疆较为相近.新疆近40a来夏季降水最多的年代是90年代,天山山区偏多12%,南疆偏多25%,北疆偏多21%.

Summer Precipitation Change for Recent 40 Years in the Tianshan Mountains and Compared with Southern and Northern Xinjiang Regions

Precipitation in mountainous of arid Xinjiang Region is ultimate source of runoff and lifeline for maintaining and developing environment and society economy in Xinjiang Region; therefore, researching precipitation changing in mountains has very important significance. But, there is less research on precipitation change before in mountains and less comparison of precipitation changing features between mountains and plain areas. The researches were mainly done in the southern or northern Xinjiang regions. In the paper, using the summer precipitation data for each 8 meteorological stations in the Tianshan Mountains, the southern and northern Xinjiang regions during 1959～1998, the mean series of summer precipitation for the three regions are built separately. Using the 30-year mean of summer precipitation during 1961～1990 as standard of anomaly comparison, the basic features of summer precipitation change in the recent 40 years are analyzed in the Tianshan Mountains, and then the features are compared with those in the southern and northern Xinjiang regions. The main results obtained are as follows: 1)There are different in wet-dry stage, driest year and wettest year, changing period of summer precipitation among the Tianshan Mountains, the southern and northern Xinjiang regions. The dry-wet variation is wet-dry-wet pattern in the Tianshan Mountains, three-dry-wet pattern in the southern Xinjiang region and wet-dry-wet-dry-wet pattern in the northern Xinjiang region. The maximum summer precipitation occurred in 1998 and the minimum in 1977 for the Tianshan Mountains, the maximum summer precipitation occurred in 1981 and the minimum in 1985 for the southern Xinjiang region and the maximum summer precipitation occurred in 1993 and the minimum in 1974 for the northern Xinjiang region. The summer precipitation change has significant periods of 3.1 years, 5.7, 2.2 years and greater than 40 years in the Tianshan Mountains, significant periods of 8,5,3.1 years in the southern Xinjiang region and significant periods of 3.1 and greater than 40 years in the northern Xinjiang region. Thus the common period is 3.1 years for the three regions. 2)The spatial synchronization change of summer precipitation in the Tianshan Mountains is weaker than those in the southern and northern Xinjiang regions. 3)The decadal change of summer precipitation in the Tianshan Mountains is similar to that in the northern Xinjiang region. 4)The maximum decade of summer precipitation in the recent 40 years occurred in the 1990s, summer precipitation is 12% more in the Tianshan Mountains, 25% in the southern Xinjiang region and 21% in the northern Xinjiang region.