贵州冻雨时空分布变化特征及其影响因素浅析

Analyses on the Space-Time Distribution Characteristics and Their Influence Factors of Freezing Rain in Guizhou Province

利用贵州84个测站冻雨日数资料和NCEP/NCAR再分析资料,借助EOF展开、小波分析及其它诊断技术,分析了贵州冻雨的空间分布特征、时间演变规律及其影响因素。结果表明:贵州冻雨的地区分布特点是西部多、东部少,中部多、南北少;冻雨日数变化梯度较大的区域主要集中在贵州省的中、西部,尤其是西北部地区;GIS反演的贵州冬季雨凇空间分布更接近实际分布特征,即一般海拔较高处凝冻重,而一般气象观测站大多分布在海拔相对较低的城镇附近,导致其观测结果比实际凝冻强度要弱;贵州冻雨存在较大的年际变化,具有非常明显的12年和32年的周期振荡,在4年的时间尺度上,周期振荡也比较明显;贵州冬季冻雨空间分布特征和时间演变规律主要受海拔高度、相对高度、迎风坡和背风坡、静止锋区、冷空气厚度和不同高度冷空气活动等多种因素的综合影响。

Using the data of the freezing rain days at 84 stations in Guizhou and the NCEP/NCAR reanalysis data, the space-time distribution characteristics and time change discipline and the influence factors are firstly studied with EOF and wavelet analysis, and other ways. It is found that the characteristic of freezing rain distribution is that it happened more in the west of Guizhou and middle than the east, north and south. The big gradient change of freezing rain day＇s area is middle-west of Guizhou, especially northwest. The results of the GIS refutations are similar as the real distributions, namely the freezing is severe in common height, but the most of stations locate nearby low height cities and towns lead to the observation results weaker than the real freezing intensity. There is big change of interannual timescale of Guizhou freezing rain. It has obviously 12-year and 32-year oscillation periods. In the four year timescales, the oscillation period is also obviously. The influence factors of the winter freezing rain distribution and spacetime change are the height above sea level, relative height, windward side and lee slope, stationary front area, cold air thickness and activities in different heights.