Abstract:

Based the monthly sunshine duration, total cloud cover, low cloud cover, fog and haze days, relative humidity and precipitation at 11 meteorological observation stations in Jining of Shandong Province from 1970 to 2014, the temporal and spatial variation characteristics of sunshine duration and their correlation with meteorological factors were studied by using the climate tendency rate, Morlet wavelet analysis, sliding t test and Mann-Kendall test methods. The results indicated that the annual sunshine duration was high in the middle and low on the edge in Jining. The change of annual sunshine duration showed a decreasing tendency in whole area in Jining during 1970-2014, and the maximum of climatic tendency rate occurred in western plain with Jiaxiang as the center and southern lake area with Weishan as the center. The sunshine duration in summer and autumn decreased significantly in the past 45 years, while that in spring and winter hadn’t obviously changed, and the decreasing rate was the maximum in August. Therefore, the significant decrease of sunshine duration in summer and the early autumn had greatly contributed to the decrease of annual sunshine duration. The mutation of sunshine duration with the obvious decrease occurred in 1989, and the oscillation periods of 8-year and 20-year were significant during 1970-2014. The decrease of sunshine duration was closely related with the change of total cloud cover, low cloud cover, relatively humidity, mist days, fog and haze days, precipitation and rainfall days. The total cloud cover, low cloud cover and mist days in Jining increased significantly during 1970-2014, which had greatly contribute to the decrease of sunshine duration in all year and summer. Moreover, the remarkable increase of mist days was conductive to the decrease of sunshine duration in autumn.

Key words:  sunshine duration, temporal and spatial variation, climatic tendency rate, abrupt change test；wavelet analysis

摘要：

利用1970—2014年山东省济宁市11个国家级气象观测站逐月日照时数、总云量、低云量、相对湿度、降水和雾霾等资料，采用气候倾向率、滑动t检验、Mann-Kendall检验及小波分析等方法分析了济宁市日照时数变化特征及其与各气象要素的相关性。结果表明：山东济宁市年日照时数呈“中间高，四周低”的地域分布特征。近45 a，全区年日照时数变化均呈减少趋势，最大降幅位于以嘉祥和微山为中心的西部平原和南部湖区；夏、秋季日照时数减少趋势极为显著，冬、春季变化趋势不明显，其中8月日照时数减少速率最大。可见，夏季和初秋日照时数的显著减少对年日照时数减少的贡献较大。1989年日照时数发生了明显减少的突变，且以8 a和20 a振荡周期最为显著。在气象因子共同作用下，总云量、低云量和轻雾日数的显著增多对济宁地区年、夏季日照时数的显著减少贡献最大，而秋季主要是轻雾日数的极显著增加。

关键词: 日照时数, 时空变化, 气候倾向率, 突变检验, 小波分析