2001-2013年中亚干旱区季节性积雪监测及时空变异分析

Spatial and temporal characteristics of snow cover in arid area of Central Asia from 2001 to 2013

以中亚干旱区为研究区,利用2001-2013年的遥感积雪产品MOD10A2、反射率数据MOD09A1,分析了积雪分布时空分布特征、年内和年际变化趋势、随纬度的变化趋势。结果表明：在13 a间,中亚干旱区的积雪覆盖率最大值范围为51.40%~76.40%,最小范围为0.86%~1.5%,最大积雪覆盖率波动较为剧烈,冬季积雪覆盖具有从高纬度向低纬度推进的趋势,而山区主要表现为从高海拔到低海拔上的增加,整体上冬季积雪日呈增加趋势,整体平均积雪日变化率为0.06;平原区的积雪覆盖年际变化率呈增加趋势,随着纬度的增加变化幅度减小,山区的积雪覆盖年际变化率基本上呈稳定状态。低纬度的昆仑山和帕米尔高原的积雪覆盖年际波动较大,中高纬度的天山山区和阿尔泰山山区的积雪覆盖年际波动较小。佐证了中亚干旱区气候由暖干向暖湿转变。

Based on the remote sensing cover data MOD10A2 and reflectance data MOD09A1 from 2001 to2013 over the arid area of Central Asia,the temporal and spatial variation of snow cover,the annual and inter-annual change trend of snow distribution,and the snow distribution change with latitude were studied to understand the historical change of snow coverage in the arid area of Central Asia. Results show as follows：（1）The largest snow-covered year was 2008 and the smallest one occurred in 2004 in the arid area of Central Asia;the maximum range of snow coverage was from 51.40% to 76.40% and the minimum range was from 0.86% to 1.5%;the fluctuation of maximum snow coverage was more intense than that of minimum snow coverage.（2）Plain areas were the main distribution areas of snow cover. The increase of snow cover is presented from high latitude to low in winter,while from high altitude to low altitude in the mountain area.（3）The snow cover duration has a universal increasing trend in the arid area of Central Asia from 2001 to 2013. Taking the arid area of Central Asia as a whole,the slope of average change rate of snow covering duration was 0.06,and the increased,invariant and decreased area proportions were respectively 62.9%,3.1% and 34.0%.（4）The inter-annual rate of snow coverage change showed an increasing trend in low-altitude region and the change range became smaller with the increasing of latitude;the inter-annual rate of snow coverage change showed a decreasing trend as a whole,and the snow coverage of Kunlun Mountains and Pamirs located in low-latitudes showed a relatively larger fluctuation than that of Tianshan Mountains and Altai Mountains located in mid-latitudes and high-latitudes,respectively. Snow cover is a very important physical factor for climate prediction in arid area of Central Asia and it is the most important way of water resource supply. It is of great significance to strengthen research in this field for improving the accuracy of climate forecasting in the arid area of Central Asia,and the climate changing from warm-dry to warm-humid is proved in the arid area of Central Asia.