Abstract: The continuous rise in global temperature and changes in precipitation patterns have profound impacts on the structure and function of grassland ecosystems. Based on the daily temperature and precipitation observation data of Bairin Right Banner Meteorological Station in Horqin grassland from 1959 to 2022, we analyzed climate in time series by using methods such as cumulative anomaly, Mann-Kendall test, Morlet wavelet analysis, and rescaled range analysis. Further, the net primary productivity (NPP) of the grassland was estimated by using the Miami model and Thornthwaite Memorial model. The results showed that: (1) Over the past 64 years, the mean annual temperature in Bairin Right Banner was 5.67 ℃, with increasing rates of 0.32 ℃·10 a^-1 for annual average temperature, 0.24 ℃·10 a^-1 for maximum temperature, and 0.40 ℃·10 a^-1 for minimum temperature. The greatest warming trend was observed in spring. The mean annual precipitation was 349 mm, showing a weak increasing trend. Precipitation distribution was uneven throughout the four seasons, with summer precipitation accounting for 72.39% of the total. Extreme precipitation events became more pronounced after 2000. (2) Regarding climate mutation, there was a shift from low to high temperatures in 1996, and the mutation point for annual precipitation occurred in 2005 and 2010. Regarding climate cycles, there was a significant cyclic variation in mean annual temperature over 14 years, exhibiting multiple fluctuations from low to high and back to low. Annual precipitation showed significant cyclic variations over 48 years, alternating between high and low levels. (3) In terms of future climate prediction, the climate in Bairin Right Banner is projected to follow the trends observed over the past 64 years, overall showing a trend towards aridification. (4) The NPP of grassland was more sensitive to precipitation than temperature, and it will face greater challenges under the trend of aridification in future climates. These results are beneficial to the restoration of the Horqin grassland ecosystem and the protection of grassland resources, providing a scientific basis for its ecological risk assessment and agricultural production management.

Key words: climate change, climate productivity model, rescaled range analysis, net primary productivity, Bairin Right Banner