Climate Change and Its Impact on the Eco-environment in the Source Regions of the Yangtze and Yellow Rivers in Recent 40 Years
WANG Gen xu, 1, 2 LI Qi 3, CHENG Guo dong 1,SHEN Yong ping 1 (1. State Key Laboratory. of Frozen Soil Engineering, CAREERI, CAS, Lanzhou Gansu, 730000, China; 2. Resource and Environmental College of Lanzhou University, Lanzhou Gansu 7
Based on precipitation and temperature data obtained from the five meteorological stations in the source regions of the Yangtze and Yellow Rivers, the features of climate change in the recent 40 a are studied. The results show that the trend of climate change in the regions, as a whole, is both temperature and precipitation rise. However, precipitation increase mostly results from precipitation rise in spring and winter. Precipitation in summer, which takes an important contribution to vegetation growing, declines in the recent 40 years. In the source regions, the decadal mean temperature in the 1980s was higher than that in the 1950s by 0.12～0.9 ℃, and by 0.3 ℃in most part of the study area. Contrasting to the mean temperature increasing in whole China, 0.2 ℃, the regions are the highest ones with temperature rising, 0.44 ℃ on the average.However, the temperature in April or May and September, which have very important significance to the growth and development of high cold meadow vegetation, decline. The eco environment in the Tibetan Plateau is very vulnerable, which is sensitive to the regional climate change. The climate in the plateau is becoming drier and warmer, resulting in a gradual degradation of permafrost. Both climate change and degradation of permafrost result in degradation of high-cold meadow vegetation.