四川省日照时数时空变化特征及影响因子分析
Temporal and Spatial Variation Characteristics and Influencing Factors Analysis of Sunshine Hours in Sichuan Province

基于四川省1961~2017年31个气象站点实测的日照时数和同步观测的气压、气温、相对湿度和风速等资料，采用气候倾向率、Mann-Kendall (M-K)突变检验和Morlet小波分析等方法，本文研究了四川省日照时数的时空变化特征及其影响因子，结果表明：1) 四川省年平均日照时数为1795.5 h，呈显著下降趋势，约为每10年下降29.4 h。年代际尺度上，自20世纪90年代起，日照时数从相对较高的时期逐渐过渡到相对较低的时期。2) 日照时数在1985年发生了明显突变：从偏多期骤然转变为偏少期。就周期性特征而言，日照时数主要包含了3个不同周期，分别为5年(第三周期)、11年(首要周期)和23年(次要周期)。3) 四川省日照时数在空间上自东向西递增，呈现出“西多东少”的分布格局。4) 平均风速对日照时数影响最大，二者呈显著正相关；云量和相对湿度对日照时数的影响次之，呈显著负相关关系；降水量与日照时数呈负相关关系，但不是很显著；气压对日照时数影响较小。
Based on the sunshine hours measured by 31 meteorological stations in Sichuan Province from 1961 to 2017 and the data of air pressure, temperature, relative humidity and wind speed observed simultaneously, this paper studies the temporal and spatial variation characteristics and influencing factors of sunshine hours in Sichuan Province by using climatic inclination rate, Mann-Kendall (M-K) mutation test and Morlet wavelet analysis. The results showed that: 1) The annual average sunshine hours in Sichuan Province were 1795.5 h, showing a significant downward trend, about 29.4 h per 10 years. From the perspective of interdecadal change, since the 90s of the 20th century, the sunshine hours have gradually transitioned from a relatively high period to a relatively low period. 2) In 1985, there was an obvious abrupt change in the number of sunshine hours: it changed from a period of more than one period to one period of less. In terms of cyclical characteristics, the number of sunshine hours mainly includes three different cycles, namely 5 years (the third cycle), 11 years (the primary cycle) and 23 years (the secondary cycle). 3) The sunshine hours in Sichuan Province increased spatially from east to west, showing a distribution pattern of “more in the west and less in the east”. 4) The average wind speed had the greatest impact on the number of sunshine hours, and there was a significant positive correlation between the two. The effects of cloud cover and relative humidity on sunshine hours were the second, showing a significant negative correlation. There was a negative correlation between precipitation and sunshine hours, but it was not very significant. Barometric pressure has little effect on the number of hours of sunshine.