The increase of temperature and precipitation in the different regions of Tarim River Basin has spatial and temporal heterogeneity over 1961-2021.

Abstract

Based on the monthly temperature and precipitation observation data of 42 national meteorological stations in the Tarim River Basin (TRB) from 1961 to 2021, the spatiotemporal variation characteristics and differences of temperature and precipitation in the whole basin and its sub-basin were explored and quantified. The results showed that: 1) The average annual temperature and annual precipitation increase rate were 0.2 ℃/10a and 7.1 mm/10a during 1961 to 2021, respectively, with significant spatial and temporal distribution differences. 2) The first mode of the Empirical Orthogonal Function (EOF1) for both temperature and precipitation showed a consistent pattern, while EOF2 showed an opposite pattern. 3) In the TRB sub-basin, the difference between the highest and lowest annual average temperature increase rates was 0.1 ℃/10a. Similarly, the difference between the highest annual precipitation increase rates (in the Aksu River Basin) and lowest (in the Cherchen River Basin and Tarim River Mainstream Region) was 0.9 mm/10a. 4) The Kaidu River Basin had a significantly lower winter mean temperature of -9.69 ℃ compared to other sub-basins. Additionally, seasonal precipitation varied greatly among sub-basins, particularly in summer. 5) The annual mean temperature showed a strong positive correlation with the global mean temperature (coefficients over 0.5 for most sites), while the correlation for annual precipitation was weaker but still positive, ranging from 0.2 to 0.5. Significant positive correlations were observed for seasonal mean temperatures, especially in summer and autumn. Seasonal precipitation correlations were generally lower but had notable impacts in summer and autumn, particularly in sub-basins like Hotan River Basin and Aksu River Basin.