2013-2015年青藏高原玛多地区两次动态融雪过程及其与气温关系对比分析

受自然条件与观测数据的限制,青藏高原腹地高时间频次积雪融雪动态过程的认识与研究十分不足。论文利用玛多地区野外观测试验场2013-2015年冬半年每30 min同步积雪深度和气温数据,对发生在2013年12月和2014年11月的积雪动态融雪过程及其与气温的关系进行了对比分析。结果表明：2013-2014年冬季融雪过程表现为先缓后急的总体特征,每日融雪过程主要发生在13:00 ~ 18:00间,而2014-2015年冬季融雪整体表现为均匀变化的过程,每日融雪过程主要发生在7:00 ~ 16:00间。雪深变化与气温存在紧密联系,玛多地区两次冬季融雪过程日最高气温都低于0 ℃,融雪发生前3 h之内的气温都将显著影响到积雪雪深变化,融雪幅度主要取决于超前半小时和当时的温度条件,雪深与气温间的线性关系与雪的厚度存在密切联系。两次融雪过程的发生与大于0 ℃变温过程关系密切,升温的变化过程可能更有利于促进积雪消融。

A Comparative Analysis of the Two Dynamic Snow-melting Process and Their Relationship with Air Temperature during 2013-2015 in the Area of Maduo,Tibetan Plateau

The recognition and research of high-frequency dynamic snow-melting process in hinterlands of Tibet Plateau are insufficient due to the restriction of natural conditions and observation data. In this paper, every 30-minute snow depth and synchronous air temperature observation data of Maduo area in the winter of 2013-2015 are used to investigate the dynamic snow-melting processes in December, 2013 and November, 2014 and their relationship with air temperature. The results indicate that the snow melted slowly at first and then quickly during the whole snowmelt process in the winter of 2013-2014, and the snow melting process mainly occurred during 13:00-18:00. The snow melted in an uniform process during the winter of 2014-2015, and the snow melting process mainly occurred during 7:00-16:00. There is a close relationship between snow depth and air temperature. The daily maximum temperature during two winter snowmelt process were both lower than 0 ℃. The temperature three hours before the snow melting significantly affected the snow depth change. The snowmelt magnitude is mainly determined by the temperature in half an hour before the melting. There is close linear relationship between snow depth and air temperature. The two snow melting processes were close related to the variation of temperature above 0 ℃, which inferred temperature-rise process can promote snow melting.