关键词: 夏季, 降水, 小波变换

Abstract: Based on the monthly rainfall data of the 19 stations in Shaanxi province from 1959 to 2004 and by the wavelet transform method, the climate characteristics and the variations of summer rainfall during the previous 46 years in Shaanxi province has been investigated, and meanwhile, the change trend is estimated. The results show that: ①the summer rainfall of the three different climate belts is all concentrated in July, August and September, and the total precipitation is 60.9%, 51.2% and 51.5% of the annual precipitation in the northern Shaanxi, Guanzhong and southern Shaanxi province, respectively. ② In the three different climate belts, the characteristics of summer rainfall variation are similar in Guanzhong and in the southern Shaanxi, both have the significant time-scale change of the 12-year, 6-year and 2-year. But it is different in the northern Shaanxi plateau, in which the significant time-scale is 21.1-year and 2.3-year. ③ According to the significant time-scale of the summer rainfall, it can be estimated that the summer precipitation in the near future will be more in Guangzhong, normal in southern Shaanxi and less in northern Shaanxi.

Key words: summer rainfall, Shaanxi province, wavelet transform