近50年福建省日照时数的变化特征及其影响因素

采用气候倾向率方法,对福建省64个站1961-2008年逐月日照时数以及对日照有影响的总云量、低云量、水汽压和相对湿度等资料进行了统计分析。结果表明：近50a福建省的年日照时数呈现出显著的减少趋势,平均减速为71.7h/10a,闽南地区减速最大。四季日照时数也表现出明显的减少趋势,减速为13.8～26.5h/10a,以夏季减速最大,秋季减速最小;最近30a夏季日照时数的减幅更大,春、秋季则呈增加趋势。从年代际变化看,20世纪60-70年代四季日照充足,均为正距平;80年代夏季偏多,其它三季为负距平;90年代春季正常,其它季节偏少。年日照时数异常偏多出现在1963、1971年,但从未出现过异常偏少年。年、季日照时数减少与低云量增加关系密切,而冬季日照时数的减少还与水汽压的增加有关。

Variation of Sunshine Hours and Its Influence Factors in Last 50 Years in Fujian Province

The meteorological data including monthly sunshine hours and total cloud amount,low-level cloud amount,vapor pressure and relative humidity,from 64 observational stations in Fujian province from 1961 to 2008 was analyzed,based on climate tendency rate method.The results showed that annual sunshine hours decreased in Fujian province at the rate of 71.7 h/10y in last 50 years,in southern Fujian particularly.The sunshine hours in four seasons decreased at the rate between 13.8 h/10y to 26.5 h/10y,of which the maximum was in summer and the minimum was in autumn,in latest 30 years particularly.From decadal variation,four seasons had sufficient sunshine during 1960s to 1970s,with positive anomaly.But only summer sunshine hours had positive anomaly in 1980s,while negative anomaly for the other three seasons.In 1990s,three seasons had more sunshine except spring.The annual sunshine hours were extremely excessive in 1963 or 1971,but never extremely deficient.Annual and seasonal sunshine hours decreased with the increasing of low-level cloud amount,and the reduction of sunshine hours increased along with vapor pressure in winter.