午夜欧美大片免费观看,欧美激情综合五月色丁香,亚洲日本在线视频观看,午夜精品福利在线

The climate changes and their characteristics over the northern Shaanxi plateau in recent 42 years are comprehensively analyzed on the basis of the data of mean air temperature, precipitation, relative humidity and wind speed of 16 stations from 1961 to 2002. The results show that the precipitation in recent 42 years decreased by －25.31 mm per 10 years, especially in autumn. The tempera ture increased by 0.26 ℃ per 10 years, and it was remarkably higher in winter. It was relatively cold and wet in the 1980s, and became worm and dry from the 1990s.