贵州省近30a秋风的气候特征分析

Climatic Characteristics of the Low Temperature in autumn in Guizhou during the past 30 years

利用1981—2010年30 a贵州省78站逐日日平均气温数据和NCEP/NCAR逐日的再分析资料,采用合成、EOF分解、傅立叶滤波等方法,分析了贵州省秋风的气候特征。结果表明:贵州省秋风天气强度有自西向东部或向东南部、东北部递减的分布规律。贵州省异常秋风过程次数的空间分布表现为全省各站呈同位相变化,进入2000年后,秋风过程次数由全省秋风偏弱偏少型转为全省秋风偏多偏强型。在环流场上,纬向西风在不断东移的过程中不断分裂出短波槽引导冷空气南下影响贵州,形成秋风天气过程,因而造成的秋风过程时间较长,强度较大。对秋风过程的环流场进行滤波表明:1波对于秋风过程有着十分显著的影响,而1波、2波在时间上的配合对于秋风过程也非常重要。

Using daily averaged temperature data of 78 meteorological observational stations in Guizhou and the NCEP/NCAR reanalysis data during the period from 1981 to 2010, the climatic characteristics of the low temperature in autumn are analyzed with the methods of composite analysis and Fourier filtering and EOF decomposition. Analysis showed that the intensity of the low temperature in autumn is decreasing from west to the east or to the south- east and northeast. The distribution of abnormal number of the low temperature course in autumn showed that all the stations are in the same phase change. And after entered in 2000, the number of the low temperature course in au- tumn is increasing and the intensity is intensified. In the circulation field, zonal westerly splits the shortwave trough which guides cold air get to the north influencing ＇Guizhou and causes longer and stronger low temperature course in autumn. The Fourier filtering shows that wave-number 1 has significant impact on the low temperature in autumn. It is very important for the low temperature in autumn when they have a greater coordination in time between wavenumbers 1 and 2.