1961-2016年新疆单站不同等级冷空气过程气候特征及变化

利用新疆1961年1月-2016年12月资料完整的89个国家气象观测站的日最低气温资料，根据中国气象局2017年发布的行业标准《冷空气过程监测指标》（QX/393-2017）的单站冷空气等级，计算近56 a来新疆各单站不同等级冷空气过程的发生频次、降温幅度、持续天数，应用线性趋势、EOF分解等分析方法，对新疆各单站不同等级冷空气过程的时空分布特征进行分析。结果表明：新疆单站不同等级冷空气年平均频次和年累计天数均表现为中等强度冷空气最多、寒潮次多、强冷空气最少，空间分布都呈现为北疆多、南疆少的分布特征；中等强度冷空气和强冷空气区域平均的年平均频次和年累计天数的年际变化均呈不显著减少趋势，寒潮均呈显著减少趋势，而空间分布上不是整体呈减少趋势，甚至个别地区呈显著增加趋势；中等强度冷空气和强冷空气在秋季前期和春季后期发生较多，寒潮则在冬季发生较多；中等强度以上冷空气年累计降温呈现北疆大、南疆小的分布特征，区域平均的年累计降温呈显著减小趋势；新疆年寒潮频次和年累计降温第一模态的方差贡献率分别为33%、39%，远远大于其它模态，第一模态（即主模态）的空间分布二者均表现为整个新疆为一致的正值，说明其变化趋势在全疆具有一致性的特征，另外北疆特征值较大，南疆特征值较小，说明北疆更容易出现异常，南疆不易出现异常。

Various levels of cold air in Xinjiang Region from 1961 through 2016: climatic characteristics and variation

Based on the daily minimum temperature data of 89 national meteorological stations from January 1961 to February 2017, within the single station cold air rate according to the Cold Wave Level (GB/T 21987-2008) and Cold Air Grade (GB/T 20484-2006) in the National Standard of the People's Republic of China and the Cold Air Process Monitoring Index (QT/T 21987-2008) in the People's Republic of China Meteorological Industry Standard, we applied of linear trend, EOF decomposition and other analytical methods, and calculated the occurrence frequency, temperature drop and continuous days of the cold wave process of Xinjiang in the past 56 years, and the temporal and spatial distribution characteristics of the single-station cold wave in Xinjiang were analyzed. The results show, 1) Xinjiang single station different levels of cold air annual average frequency and the cumulative number of days are the medium cold air up, the second most cold wave, strong cold air at least, spatial distribution characteristics were presented in northern Xinjiang more, southern Xinjiang less. 2) The annual mean frequency and annual cumulative number of medium strength and strong cold air showed no significant decrease trend, interannual fluctuations are more obvious. 3) Medium strength and strong cold air in the early fall and late spring occurred more, cold wave occurred in the winter more. 4) The cumulative temperature drop of the cold air above the medium strength are showing the distribution characteristics of the northern Xinjiang more, southern Xinjiang less, and the distribution of the regional average is significantly reduced. 5) The first mode of annual cold wave frequency and accumulative temperature drop were 33% and 39%, far more than other mode, and their spatial distribution of the first mode were expressed as a positive value for the whole of Xinjiang, and the characteristic value of northern Xinjiang is larger than southern Xinjiang, indicating that their trends are consistent with the characteristics of the trend, while the northern Xinjiang is more prone to abnormal, southern Xinjiang is not easy to abnormal. Prior to the 1980s, their coherence interannual variability was mainly for positive phase, indicating that there is much more likely to be consistent, since 2000, the time coefficient is mainly in the negative phase, indicating that there is less coincidence.