基于不同标准的四川强降温时空分布和区域特征

Spatial-temporal Distribution and Regional Characteristics of Strong Cooling in Sichuan Based on Different Standards

采用近56 a四川省156县(市)逐日平均气温和最低气温资料,按照不同的强降温标准,研究四川强降温过程的时空分布和区域特征。结果表明:强降温频次距平的逐年时间序列基本呈“增加—减少”的年代际变化特征,年际波动较大,整体呈弱减少趋势。强降温频次的突变点在1990年,且自2005年后单站强降温频次的减少十分显著。盆地、攀西和川西高原的区域性强降温过程发生时间存在不同步性,主要原因是冷空气路径、影响系统及四川特殊地形和气候特征存在差异。区域性强降温频次盆地最多,攀西和川西高原少,单站强降温频次川西高原北部最多。

Based on the daily average temperature and minimum temperature data of 156 counties(cities)in Sichuan in recent 56 years,th spatial and temporal distribution and regional characteristics of strong cooling process in Sichuan were studied according to different strong cooling standards.The statistical results show that the annual time series of strong cooling frequency basically shows the interdecadal variation characteristics of'increase-decrease',and the interannual fluctuation is large,and the overall trend is weak.The sudden change in the frequency of strong cooling was in 1990,and the strong cooling frequency of single stationhas decreased significantly since 2005.The occurrence time of the regional strong cooling events in the Basin,Panxi and Western Sichuan Plateau was not synchronized,mainly due to differences in cold air paths,influence systems,and special topography and climate characteristics in Sichuan.The frequency of regional strong cooling events was the most in Basin,less in Panxi and Western Sichuan Plateau,and the strong cooling frequency of single station was the highest in the northern part of the Western Sichuan Plateau.