Seasonal climate change characteristics of the Mu Us Sandy Land based on long time scale

The study of seasonal-scale climate-vegetation coupling mechanisms is important for coordinating desertification control and climate adaptation. Taking the Mu Us Sandy Land (MUSL) as a case study, we gathered meteorological data from 1959 to 2019 (including maximum temperature, minimum temperature, and precipitation) for seasonal analysis. We conducted M-K significance and mutation analysis, Morlet wavelet periodicity analysis and correlation analysis and investigated the effects of various seasonal and annual climate factors on NDVI using NDVI values collected from 1999 to 2019. The results indicate the following: (1) Both the maximum and minimum temperatures in the MUSL exhibit an upward trend across all four seasons. Precipitation in autumn shows a decreasing trend, while in spring, summer, and winter, it increases, leading to an overall rise in precipitation. (2) The maximum and minimum temperatures in MUSL experienced a mutation in the 1980 and 2000, respectively, while precipitation underwent a mutation in the 1980 and 2019. After these mutations, both temperature and precipitation exhibited an overall upward trend. (3) The first primary cycle for both the maximum and minimum temperatures is 18 years, while the first primary cycle for precipitation is 8 years. (4) The impact of the climate in MUSL on vegetation is as follows: precipitation > temperature.