青藏高原东北部寒潮次数时空变化特征研究

基于青藏高原东北部1961 - 2015年68个国家气象站点的逐日气温观测资料， 统计了各站月、 季、 年不同时间尺度的寒潮次数， 并用气候诊断方法分析了寒潮次数时空变化特征。结果表明： 在时间尺度上， 20世纪60年代至21世纪00年代， 寒潮各年代的年平均次数大致经历了“多 - 多 - 多 - 多 - 少”的变化过程； 1961 - 2015年青藏高原东北部寒潮年次数的平均值为2.6次， 以0.192次·（10a）^-1速率呈显著的减少趋势； 1981年为突变点， 2005 - 2015年为显著的减少时段， 而1961 - 2004年为较弱的减少时段； 春、 秋、 冬三季寒潮次数的平均值分别为0.7、 0.7、 1.2次， 秋季减少趋势通过了显著性检验， 2月和11月减少的趋势最为明显。在空间尺度上， 年度、 春季、 秋季寒潮次数显著减少的站点数量分别达19、 44和21个。寒潮年次数减少的这种变化特征与青藏高原地区20世纪80年代气候变暖以来气温明显升高的趋势基本一致。

Study on variation characteristics of frequency of cold wave processes in the northeastern Qinghai-Tibet Plateau

Based on daily temperature data from 68 national meteorological stations in northeastern Qinghai-Tibet Plateau from 1961 to 2015， the annual， seasonal and yearly frequency sequence of cold waves and the annual， seasonal and yearly mean frequency sequence of cold waves in the region were obtained. Then climate diagnostic method was adopted to analyze the characteristics of spatial and temporal changes of cold wave frequency. The results indicated that in terms of temporal changes， from the 1960s to the 2000s， the annual average frequency sequence of cold waves had presented an evolution process of “more-more-more-more-less”. The average value of annual cold wave frequency in northeastern Qinghai-Tibet Plateau was 2.6 times. Meanwhile， the frequency sequence appeared a significantly declining tendency， with a declining rate of 0.192 times in every ten years； the annual frequency of cold waves presented an obvious point of abrupt in 1981. From 2005 to 2015， the ten years had a significantly decreasing trend， while from 1961 to 2004， the decreasing tendency became insignificant. The average values of cold wave frequency in spring， autumn and winter in the whole region were， respectively， 0.7， 0.7 and 1.2 times， and the sequence in autumn shown an obviously declining tendency； the declining tendencies of average cold wave frequency in the whole region in February and November were more significant than those in other months. Spatially， the frequency sequence of cold waves in the 19 stations in the whole year， 44 stations in spring and 21 stations in autumn had shown significant declining tendency. The characteristics of above periodic changes and decreasing tendencies has been basically consistent with the tendency of temperature rise in the Qinghai-Tibet Plateau since the 1980s.