湖北省积雪时空特征分析

摘要

利用湖北省77个测站1961-2007年气象资料,分析了积雪的时空特征。结果表明,湖北省积雪年际变化振幅明显,20世纪60年代到70年代中期缓慢增加,为积雪多发期;80年代年波动较大;90年代开始明显减少。月积雪日数呈准正态分布,1月最多,2月、12月次之。积雪空间分布表现为西部多,中东部少;山地多,丘陵平原少;沿江多,内陆少。有利于湖北大范围出现积雪的大尺度背景的环流类型主要有纬向型和两槽一脊型。出现积雪时24h变压Δp24为正,24h变温Δt24和水汽压变化Δe24为负,地面气象要素的异常变化,也可以作为积雪预报的着眼点之一。%Based on the meteorological data from 77 stations in Hubei Province from 1961 to 2007,the spatial and temporal distribution characteristics of snowcover were analyzed.Results show that the duration of annual snowcover days varies obviously.It increased from 1960s to the mid 1970s,which was the peak time of snowcover days.It fluctuated apparently in 1980s and decreased gradually from 1990s.The number of mensal snowcover days shows a quasi-normal distribution with a maximum value in January and then in February and December.Snowcover is more likely to occur in the west parts than in the middle and east,more likely to occur in mountains than on plains,and more likely to occur along the river than in midland.The two types of circulation background that is the most propitious for snowcover are zonal circulation or trough-ridge-trough.When snowcover occurs,Δp24 is positive and Δt24 and Δe24 are negative,which can be used to forecast snowcover by unwonted changes of meteorological factors.