1971-2016年塔里木盆地冷空气过程频数变化特征

利用南疆塔里木盆地周边50个气象站1971年1月1日-2016年12月31日的最低气温资料,依据《冷空气等级标准》（GB/T20484-2006）,整理出塔里木盆地近46a来冷空气过程数据,采用合成、线性倾向估计、Morlet小波、Mann-kendall、滑动平均和累积距平检验等方法分析了单站及整个塔里木盆地冷空气频数的空间、时间变化特征。结果发现:（1）中等及以上等级冷空气高发地多分布于盆地西部的高原、北部的山区和东部的风口地带,单站各等级冷空气总体上呈线性减少趋势,整个塔里木盆地冷空气、寒潮减少趋势明显,递减率均为0.19次/10a,其余等级变化趋势不明显;（2）塔里木盆地冷空气年均103.2次,弱冷空气86.3次占总次数的83.6%,中等强度冷空气10.4次占10.1%,较强、强、寒潮分别为2.5、2.3、2.2次,合计占冷空气总次数的6.8%;（3）各等级冷空气持续1～3d的频率高达87.4～95.4%,弱冷空气持续1d的频率最高,其余等级持续2d的频率最高,3d及以上的频率随着持续时间的增加明显下降;（4）各等级冷空气的年代际频次变化不大,1970年代较强、强及寒潮频次最多,分别为2.8、2.4、2.9次,1980年代弱冷空气最多,达86.6次,近6a(2011-2016年)中等强度冷空气最多,达10.8次;（5）不同等级冷空气的出现具有较强的季节性,中等、较强冷空气夏季频率最高,分别占30.1%和57.9%,强冷空气春季最高,占到40.1%,寒潮冬季最高,占38.9%;（6）各等级冷空气均有8～10a的年际尺度周期,年代际周期却不一致,寒潮在1979年发生显著的减少突变。

The Characteristics of Frequency Variation of Cold Air Process in Tarim Basin Xinjiang During 1971-2016

Based on the daily minimum temperature of 50 weather stations in Tarim basin of Southern Xinjiang during 1971-2016,,The temporal-spatial frequency distribution of the cold air process in single station and the whole area were analyzed by means of synthesis,linear propensity estimation,Morlet wavelet,Mann-kendall and Moving average and Cumulative anomaly according to "Cold Air Grate Standards"(GB/T20484-2006).The results showed that: (1) the cold air process which grade is medium and above was mostly distributed in the western plateau the basin,the northern mountainous area and the eastern windy area.the cold air process of each grade in single station showed a linear decrease trend and not obvious in the most stations,the cold air and cold wave process decreased significantly in the whole Tarim basin which the decreasing rates were 0.19 times/10a.however,the remaining grade have a little change.(2)The occurrence of cold air process was 103.2 times a year in the area,among them the weak and medium process occupied for 86.3 and 10.4times,which amount to 83.6% and 10.1% respectively.the grade above strong cold air was totally 7.0 times,accounted for 6.8% of the total number.(3) The frequency percent of each cold air grade with 1 ~ 3d was 87.4 ~ 95.4%,weak cold air with 1d duration and other process grade with 2d duration has the highest frequency.The frequency with 3d or above decreased significantly with the increase of duration.(4) The interdecadal frequency of different cold air process grades has little change.In 1970s,the stronger,strong cold air and cold wave frequency was 2.8,2.4 and 2.9 times respectively.In 1980s,the weak cold air reached 86.6 times.In the nearly 6a (2011-2016) had the most moderate cold air,up to 10.8 times.(5) The occurrence of cold air in different grades has a strong seasonality.The frequency of medium and strong cold air grades was the highest in summer,accounting for 30.1% and 57.9% respectively.In spring strong cold air was the highest,accounting for 40.1%,and the cold wave was the highest in winter,accounting for 38.9%.(6) The cold air in all grades has 8 to 10a interannual period that was not consistent,but the cold wave dramatically decreased obviously in 1979. Keywords: Cold air process; frequcency; trend; period ; sudden change;Tarim basin