Abstract: In this study,data from the China meteorological forcing dataset (CMFD) and Global Land Data Assimilation System (GLDAS),including air temperature (2m),precipitation,specific humidity,wind speed (10m) and solar radiation,were used to study the modern climate characteristics of the Selin Co Basin,as well as its spatial-temporal variations throughout 39 years from 1979 to 2017 using linear tendency estimation,the Mann-Kendall mutation test,five-year moving average,and cumulative anomaly methods. Results showed that the multi-year annual average temperature,specific humidity,solar radiation,and wind speed were -1.8℃,3.2g·kg^-1,236.2 W·m^-2,and 3.7m·s^-1,respectively. The multi-year average annual precipitation was 389.4 mm. For all years,monthly average temperatures were above 0℃ from May to September and generally lower than 0℃ in the other months. Between 1979 and 2017,the annual average temperature in the Selin Co Basin increased significantly at a rate of 0.049℃·a^-1. 80% of the annual precipitation occurred between June and September. The annual average precipitation in the basin for the same period also increased significantly at a rate of 4.65mm·a-1. Together,increased temperature and precipitation demonstrates an obvious changing climate characterized by a tendency toward warmer and wetter conditions during the last 20 years. During the same period,wind speed showed an increasing trend in the southern region and a decreasing trend in northern region,with the largest rate of decrease occurring in northeast of the basin. From east to west,the multi-year annual average solar radiation gradually increased. Solar radiation showed a significant decrease at a rate of -0.29 W·m^-2·a^-1 throughout the last 39 years,especially from the mid-1980s until the mid-2000s. Moreover,while specific humidity did not show a significant change,it exhibited a significant decreasing trend since 2006. Results of this study are indicative for delineating the mechanism of lake expansion,the response of ecosystems to climate change,and phenological changes.

Key words: Tibetan Plateau, Selin Co Basin, climate characteristics, climate change, trend analysis