Variation Characteristics of Sunshine Duration and Wind Velocity in Naqu,Xizang for Recent 40 Years
Based on the conventional statistic methods and Mexican hat wavelet, the geographical distribution of sunshine duration and wind velocity and their annually, and interdecadal changes in recent 40 years are analyzed using daily sunshine duration and wind velocity data of 6 stations in Naqu from 1961 to 2000. The main results are as follows: (1) In the most of places of Naqu, the annual sunshine duration are more than 2550 hours and average wind velocity are higher than 4m·s-1. (2) The sunshine duration in spring, summer, autumn, winter, growing season (from May to September) and a year all decreased in recent 40 years. (3) The wind velocity in winter decreased and the wind velocity in other 5 periods all increased. (4) The sunshine duration and wind velocity in 1990′s were smaller than that in 1980′s for all 6 periods. (5) The sunshine duration and wind velocity from 2000 to 2005 could continue to decrease.