云南省近44年日照时数时空变化及其影响因素分析

An analysis on the temporal and spatial variations in sunshine duration and its influencing factors in recent 44 years of Yunnan Province

利用云南省28个气象站1969—2012年逐月日照时数、风速、气温和降水资料,采用气候倾向率、趋势线法和Kriging空间插值法,分析了该省日照时数时空变化及其影响因素.结果表明:①近44年,云南年日照时数整体呈波动减少趋势,减少速率为14.95 h/10a;②年日照时数空间分布大体表现为一高两低:以华坪为单峰中心的西南高值区,以屏边为中心的东部边缘低值区,和以贡山为中心的西北低值区,即自南向北呈纬向增大型分布;③年日照时数空间变化差异明显,以大理—景东—元江—江城为界,以西呈明显增加趋势,以东的滇西北—滇中—滇东南地区呈减少趋势,即自西向东呈经向减少型分布;④四季日照时数变化趋势与年日照变化趋势基本一致(减少),但秋季较为特殊,呈上升趋势(4.15 h/10a);⑤四季日照时数空间变化特征主要表现为,滇西南和滇东北南部地区增多,其他各地减少;⑥云南省年日照时数与平均风速、气温和降水量均有一定的相关性.其中,降水量对年日照时数的影响最为密切,风速与日照时数变化的相关性最弱.

Based on the data of sunshine duration, wind speed, temperature, and precipitation collected at 28 stations from 1969 to 2012 in Yunnan Province, the sunshine temporal -spatial distribution and its influencing factors have been analyzed by applying the methods of linear regression, and the Kriging. The results show that firstly in recent 44 years, the sunshine duration have displayed a marked decreasing tendency with the rate of 14.95 h/10a. Secondly,the sunshine duration spatial distribution has showed a single peak in Huaping which is the south - west high areas, a low center in Pingbian which is the eastern edge of the low sunshine duration areas, and a low areas center in Gongshan which lies in the northwest of Yunnan Province. Thirdly the annual sunshine duration in the west of Dali--Jingdong--Yuanjiang--Jiangcheng has increased significantly, and the east has showed a decreasing trend,which is to reduce the distribution from the west to the east. In addition, the sunshine duration of spring, summer and winter showed a different decreasing trend, besides the autumn. Meanwhile it shows that an increasing tendency in the southwest and the south of northeast Yunnan＇ s seasonal sunshine dura- tion, elsewhere decreased. Finally it has been found that the annual sunshine duration shows a significant correla- tion with the wind speed,temperature, and precipitation,while the precipitation＇ s influence is stronger;the wind speed is the weaker.