东江中上游流域日照变化特征及其影响因素

Characteristics of Sunshine Duration Variation in the Middle and Upper Reaches of Dongjiang River and Their Influencing Factors

利用东江中上游8个气象站1965—2017年的日照、降水、云量等资料,采用统计学等方法,分析东江中上游年、季日照时数的时空特征及其影响因素。结果表明:东江中上游日照时数在时序变化上,年和夏秋季减少显著;春冬季减少不显著。空间分布上,年和季呈自西向东递增分布,夏季差异最显著,冬季差异最小;空间变化趋势上,年除寻乌、新丰、龙川减少不显著外,其余地区减少显著。春夏季除东源、龙门、连平减少显著外,其余地区变化不显著;秋季除新丰、寻乌减少不显著外,其余地区减少显著;冬季增加或减少均不显著。年日照时数存在2~3、18~20年的周期变化。日照时数与平均低云量、平均总云量、降水日数、降水量、平均相对湿度、雾日数等气象要素大多呈显著的负相关。

Using the data of sunshine duration, rainfall amount and cloudage from eight meteorological stations in the middle and upper reaches of Dongjiang River from 1965 to 2017, this paper statistically studies the spatiotemporal characteristics of sunshine hours and their influencing factors. The result is shown as follows. In the middle and upper reaches of the river, the time series of sunshine duration decreases significantly on the annual scale and the summer and autumn scales but insignificantly on the spring and winter scales. On the spatial distribution, the annual and seasonal sunshine duration increase from the west to the east, with the most remarkable difference in summer and minimum difference in winter. On the trend of spatial variation, the sunshine duration decreases significantly in all regions but Xunwu, Xinfeng and Longchuan on the annual scale, decreases insignificantly in all regions but Dongyuan, Longmen and Lianping on the spring and summer scales, decreases significantly in all regions but Xinfeng and Xunwu on the autumn scale, and increases or decreases all insignificantly on the winter scale. For the annual number of sunshine hours, there exist periodic variations of 2-3 and 18-20 years. Mostly, the sunshine hours are negatively correlated with average low-cloud amount, mean total cloudage, rain days, rainfall amount, mean relative humidity and foggy days.