关键词: 日照时数, 气候倾向率, Mann-Kendall检验, 小波分析

Abstract: Based the monthly sunshine duration, total cloud cover,low cloud cover,relative humidity,precipitation days and precipitation at 6 meteorological observation stations in Xianning from 1960 to 2016,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 and Mann-Kendall test methods. The results indicated that the annual sunshine duration was high in the middle and low on the north and south in Xianning. The change of annual sunshine duration showed a decreasing tendency in whole area in Xianning from 1960 to 2016 and the decreasing tendency had slowed down in the past 30 years.The sunshine duration in summer,autumn and winter showed a decreasing trend,especially in August. In the 1960s and 1970s annual sunshine hours were unusually high. In the 1980s-1990s and 2000 years later annual sunshine hours were abnormal too few. The mutation of sunshine duration with the obvious decrease occurred in 1977,and the oscillation periods of 3-year and 7-year were significant. The seasonal and annual sunshine hours and meteorological elements were mostly negative correlation. The reduction in sunshine hours was closely related to low cloud cover,precipitation days and precipitation in Xianning during 1960-2016. But in contrast to the changes of the past 30 years,the significant reduction trend of these influencing factors contributes more to the increasing trend of sunshine hours.

Key words: sunshine hours, climatic tendency rate, Mann-Kendall test, Morlet wavelet analysis