青海高原1961-2013年积雪日数变化特征分析

应用1961-2013年逐日积雪深度及气象要素资料，采用REOF、多元线性回归等方法，分析了青海高原积雪日数时空分布特征，探讨了各季节积雪日数与气温和降水的关系.结果表明：（1）青海高原积雪日数呈先增加再减少的变化趋势，1961年至20世纪90年代末呈增加趋势，其中1982年达到峰值为44天，2000-2012年呈减少趋势.（2）青海高原积雪时空分布不均，地域差异大，分为六个积雪气候区，主要特点为高原南部积雪日数最多且呈显著增加趋势；东部农业区、西部柴达木盆地积雪少且呈下降趋势.（3）冬、春季积雪日数有上升趋势，冬季较显著；秋季积雪日数有下降趋势.（4）各季节平均气温均呈上升趋势，是影响秋、春季积雪的关键因子；冬、春季降水量呈上升趋势，是影响冬季积雪的关键因子.青海高原冬、春季有暖湿化趋势.

Changes of the days with snow cover on the Qinghai Plateau during 1961-2013

Base on the snow cover data, meteorology data of the Qinghai Plateau from 1961 through 2013, the spatiotemporal change of the days with snow cover was analyzed by REOF method and multiple regression to explore the seasonal relationships between the days with snow cover and temperature and precipitation. The following main conclusions are drawn:(1) During the 53 years the days with snow cover in the Qinghai Plateau had first increased and then decreased; from 1961 to the end of the 1990s an increasing tendency had presented, with a peak of 44-d in 1982, then from 2000 to 2012 a decreasing tendency had presented. (2) Spatially, snow cover distribution in the Qinghai Plateau was uneven, which can be divided into six climate zones. In the southern highlands the duration of snow cover was longest with an increasing tendency; in the eastern agricultural district and west (Qaidam basin), snow cover lacked with a decreasing tendency. (3) Temporally, the duration of snow cover had increased in winter and spring, especially in winter, but decreased in autumn. (4) Seasonal mean temperatures had increased, which was the key factors impacting the snow cover in autumn and spring. It is found that winter and spring precipitation had increased, thus the plateau in winter and spring had more moisture.