青海南部冬季积雪和雪灾变化的特征及其预评估

利用1961-2003年青海南部牧区气象台站观测的气温、降水、积雪资料,用气候诊断方法分析了该地区积雪等气候要素的年代际演变特征以及雪灾变化的成因。结果表明:20世纪60-90年代冬季,青南牧区中雪和大雪出现的站次以及雪灾出现的站次有逐步增多的趋势,降雪量和地表平均积雪量每10 a分别增加1.454 mm、9.861cm,单站积雪量在4 100 m左右的高度上增加比较明显,冬季降雪和积雪增加的趋势和新疆完全一致。典型多(少)雪年500 hPa高度距平场高原西部与中国东部地区为“- ”(“ -”)型。未来10 a冬季积雪增多的趋势仍将维持,雪灾发生的几率仍然偏大。

Character of Snow Cover with Snow Damage Change and Its Prepare Evaluation Research in the South of Qinghai Province

Using the data of air temperature,rainfall,and accumulated snow determined by meteorological observatory stations in herding area in south of Qinghai province from 1961 to 2003,and based on climate diagnosis method we analyzed the evolution character of climate elements for example accumulated snow and the origin of snow disasters.The results indicated that the appearance times of moderate snow,heavy snow and snow disasters presented the tendency with increasing gradually in herding area in the south of Qinghai in 1960's to 1990's;and the rates of climate change tendency of snowfall and surface average accumulated snow were respectively 1.941 mm/(10 years) and 9.861 cm/(10 years);and the accumulation of single station about 4 100 m altitude increased significantly.It is complete consistence in winter that snowfall and surface average accumulated snow increase of the trend with of Xinjiang.The type more(less) snow years of 500 hPa a height anomaly field is "- "(" -") in the west of plateau and the east of China.In the future 10 years it will keep on increasing of accumulated snow in winter,and the probability of snow disasters happened is still big.