LEI Yang1,2, WANG Hongbin1, LU Tongsuo1,3, LIU Lile4, FU Wenxue1, WEI Dong5
（1.School of Science, Tibet University, Lhasa 850000, China;
2.Institute for Plasma Physics Chinese Academy of Sciences, Hefei 230031, China;
3.Shanghai Institute of Applied Physics Chinese Academy of Sciences, Shanghai 201800, China;
4.College of Water Resources and Architectural, Northwest A & F University, Yangling 712100, China;
5.Lhasa Meteorological Service, Lhasa 850000, China）
Abstract: On June 24, 2019, a record high air temperature of 30.8℃ appeared in Lhasa. In order to better understand the mechanism of climate warming in Lhasa and evaluate the future climate change in this region, the temporal and spatial evolution characteristics of temperature on multiple time scales was deeply studied by using the linear trend method, Mann-Kendall (M-K) mutation test, wavelet analysis, R/S analysis and other methods based on the observation data in Lhasa for the past 49 years. The results showed that: (a) The annual mean temperature (AMT) is increasing at a rate of 0.5℃/10a, and the average temperature for different seasons also increased significantly, especially in winter. (b) Although there was an intersection of two statistical lines in M-K test in 1995, we found the difference of AMT did not pass the reliability test at a significance level α=0.05, this means there hasn’t an abrupt change in AMT before and after the intersection point. While, the seasonal mean temperatures (SMT) are contrary to AMT after the intersection point (near 1995), that means SMT is rising significantly. (c) The results of wavelet analysis show that AMT has 8-year and 28 year time scale characteristics; the periodic variation of temperature in spring, summer and autumn is similar to the annual average temperature, but the periodic variation of temperature in winter is relatively complex. (d) The Hurst index of AMT and different seasons indicates that the temperature is likely to continue to rise in the future in Lhasa.
Key word: global warming; the Tibetan plateau; an abrupt change of temperature; high altitude zone; the correlation coefficient; wavelet analysis
EARTH AND ENVIRONMENT Vol.49, No.5, Tot No.343, 2021, Page 492-503
