西天山小流域动态融雪过程及其与气温的关系

利用西天山阿热都拜小流域积雪、融雪和气象观测场2017-2018年每30 min的同步降雪、融雪和气温观测数据,对全年积雪期较短时间尺度上的融雪动态过程及其与气温的关系进行了对比分析。结果表明:山区降雪表现为"先升后降"的总体特征。稳定积雪期集中在2017年12月27日至2018年3月8日,最大降雪速率高达9. 6mm·h^-1(雪水当量值,转化成新鲜雪深值为96. 5 mm·h^-1)。山区融雪过程的变化规律与降雪变化正好相反,呈现出"先降后升"的变化特征。融雪变化分为3个阶段,第一阶段:随着气温的下降,融雪速率下降,融雪速率由3. 24 mm·h^-1逐渐下降至0 mm·h^-1;第二阶段:当气温低于融雪的临界温度(-13. 5-12. 0℃)时,不产生融雪;第三阶段:随着气温的回升,融雪速率从0 mm·h^-1逐渐上升至3. 87 mm·h^-1。在全年融雪与气温的大数据关系中,融雪量与气温的相关性系数不是很显著,其相关性系数为0. 708;在无降水干扰下,7 d平均同步融雪量与气温的相关性系数处于显著水平,Pearson相关性系数为0. 907,R^2=0. 823;当进一步考虑滞后效应后,融雪量与气温的相关性系数提升至极显著的线性关系,相关性系数高达0. 943,R^2=0. 889,均通过了0. 01显著性水平的双尾检验。在西天山阿热都拜小流域融雪量的变化过程与气温的变化过程有着密切的相关性。这种融雪量对气温变化的响应关系及其分析方法,对于提高应对未来气候变化的能力和预防洪灾及水资源管理具有一定的参考价值。

Dynamic Snowmelt Process and Its Relationship with Air Temperature in a Small Watershed in the West Tianshan Mountains

Snowfall,snowmelt and air temperature in a small watershed named as Aredubai in the west Tianshan Mountains were synchronously observed every 30 minutes from 2017 to 2018,and the relationship between snowmelt and air temperature was analyzed. The results showed that the snowfall in the mountainous area increased at first and then decreased. The duration of snow cover accumulation was from December 27,2017 to March 8,2018,and the maximum snowfall intensity was as high as 9. 6 mm·h^-1 (when the value of snow water was converted into fresh snow depth,it was 96. 5 mm·h^-1). The rule of snowmelt in the mountainous area was opposite to that of snowfall,that is,the snowmelt was decreased at first and then increased. The snowmelt was divided into three stages. The snowmelt rate was gradually decreased from 3. 24 mm·h^-1 to 0 mm·h^-1 with the decrease of air temperature at the first stage. The snowmelt did not occur when the air temperature was lower than the critical temperature of snowmelt(-13. 5--12. 0 ℃) at the second stage. The snowmelt rate was gradually increased from 0 mm·h^-1 to 3. 87 mm·h^-1 with the increase of air temperature at the third stage. In the big data relation between snowmelt and air temperature,the correlation coefficient between snowmelt and air temperature was not so significant,and the correlation was 0. 708. Under the conditions without precipitation,the correlation coefficient between the 7-day average snowmelt and air temperature was significant,the Pearson correlation coefficient was 0. 907,and R^2= 0. 823.When the hysteresis was further considered,the correlation coefficient between snowmelt and air temperature was increased significantly,the correlation coefficient was as high as 0. 943,and R^2= 0. 889,which all passed the twotailed test at significance level 0. 01. There was a close correlation between the dynamic change of snowmelt and air temperature in the small watershed named as Aredubai in the west Tianshan Mountains. The response relationship and analysis method of snowmelt to temperature change have certain reference value for improving the ability to cope with future climate change and preventing flood and water resources management.