增温增湿环境下天山山区降雪量变化

基于APHRO’s气温和降水数据集,运用气温阈值模型,分析了1961~2015年间天山山区降雪量变化特征。研究表明,自1961年以来,天山山区升温趋势显著,速率为0.027℃/a,且冬半年的升温速度大于夏半年。同时,3 000 m海拔以上区域的平均气温上升到0℃左右。冬季降水的增加速率为0.42 mm/a（P<0.01）,春季和夏季的降水量呈减少趋势。降雪量变化时空差异显著,3 000 m海拔以上区域降雪随气温的升高而增加,而3 000 m以下区域降雪随气温的升高而减少。最大降雪量气温是控制降雪变化的关键因子,当平均气温低于最大降雪量气温时,随气温升高降雪量呈增加趋势;当平均气温高于最大降雪量气温时,随气温升高降雪量呈减少趋势。

Changes of Snowfall Under Warmer and Wetter in the Tianshan Mountains

Snow as a land-cover type that is mainly distributed at the high latitude and high altitude regions. Snowfall, as are main precipitation type in mountainous areas, presents significant temporal and spatial difference which was affected by climate change. In this study, based on APHRO’s dataset and temperature threshold model to analyze snowfall changes in the Tianshan Mountains during 1961-2015. Results indicated that: 1) Temperature showed increasing trend in the Tianshan Mountains since 1961, with a rate of 0.027℃/a. And temperature increase rate in winter was higher than that in summer. Meanwhile, the average air temperature of elevation above 3 000 m is rise to around 0℃ during 1961-2015. 2) Precipitation exhibited significant increasing with a rate of 0.42 mm/a (P<0.01) in winter, while decrease in spring and summer. 3) Snowfall changes were characterized by temporal and spatial variations. Snowfall presented positive relationship with air temperature in the regions with elevation over 3 000 m, while negative relationship in regions with elevation below 3 000 m. 4) Maximum snowfall temperature is a key factor to understanding changes of snowfall under warming. When mean temperature is below/above maximum snowfall temperature, snowfall usually increases/decreases with increased warming. Therefore, study on the snowfall variations in mountainous areas can be very helpful to understand the effects of climate change on hydrology process in mountainous areas.