1961—2017年基于地面观测的新疆积雪时空变化研究

选取新疆89个气象站1961—2017年逐日积雪深度观测资料， 分析近60 a新疆冬季最大积雪深度及积雪日数的时空变化特征。结果表明： 新疆冬季最大积雪深度以天山为界， 天山以北多于南部， 北疆北部和伊犁河谷最大达60 ~ 100 cm， 天山山区及天山北坡30 ~ 60 cm， 南疆大部地区不足20 cm； 新疆北部最大雪深多出现在1996年以后， 也是新疆气候由暖干转为暖湿的阶段。近60 a新疆区域尤其是北疆、 天山山区冬季最大积雪深度呈显著增加趋势， 南疆略有增加； 89个气象站中87.6%呈增加趋势， 20个显著增加， 主要分布在天山以北地区。分析不同积雪深度出现的日数， 新疆区域、 北疆地区、 天山山区≤10 cm积雪约占积雪总日数的48% ~ 58%， 10 ~ 20 cm积雪占24% ~ 32%， 20 ~ 30 cm积雪占12% ~ 15%， >30 cm积雪约占5%左右； 南疆地区以≤5 cm积雪为主。新疆区域、 北疆地区以及天山山区积雪日数总体呈减少趋势， 其中≤10 cm积雪日数减少， 尤其北疆显著减少， >20 cm积雪日数显著增加， 南疆变化不明显； 空间变化趋势分布基本与区域变化一致。

Spatial-temporal variation of snow cover in Xinjiang based on surface observation from 1961 to 2017

Based on the daily data of snow cover depth from 89 meteorological stations in Xinjiang over the period of 1961-2017， the spatial-temporal change of the maximum snow cover depth and days with snow cover were analyzed by the methods of stastics and diagnose. It was found that： （1） The maximum snow cover depth in winter in the north was more than in the south. The maximum snow cover depth was 60-100 cm in Altay and Ili Valley， and 30-60 cm in north slopes of the Tianshan Mountains， and under 20 cm in Southern Xinjiang. The maximum snow cover depth in Northern Xinjiang mostly occurred after 1996， which was also the period when the climate of Xinjiang changed from warm-dry to warm-wet； （2） The maximum snow cover depth increased significantly in winter in Xinjiang region， Northern Xinjiang and Tianshan Mountains， and slightly in Southern Xinjiang. About 87.6% of the 89 meteorological stations showed an increasing trend， while 20 stations increased significantly， mainly in the Northern Xingjiang； （3） 48%-58% of the total number of days with snow cover was in snow cover depth less than 10 cm， 24%-32% of that was in snow cover depth between 10 and 20 cm， 12%-15% of that was in snow cover depth between 20 and 30 cm， and 5% of that was in snow cover depth greater than 30 cm in Xinjiang region， Northern Xinjiang and Tianshan Mountains； （4） In these regions， the number of days with snow cover showed slightly decreasing trend， the number of days in snow cover depth less than 10 cm decreased， especially in Northern Xinjiang， and the number of days in snow cover depth more than 20 cm increased significantly； （5） In Southern Xinjiang， the snow depth was mainly less than 5 cm and the change trend of the duration of snow cover was not obvious in southern Xinjiang； （6） The spatial change trend distribution was basically consistent with the regional change.