Spatiotemporal variation in air temperature in Shuozhou of Shanxi Province

【Objective】 Shuozhou, located North of Shanxi province, has been significantly influenced by climate change. Since temperature is one of the most important factors influencing plant growth and evaporation of surface water and subsurface water, this paper analyses its spatiotemporal variation in this region. 【Method】 Using air temperature data measured from 1972 to 2023 at weather stations in six counties, districts, and cities in the region, we calculated both mean and extreme temperatures using statistical method, linear analysis, moving average method, Mann-Kendall test, and Morlet wavelet analysis. 【Result】 ① From 1972 to 2023, the average temperature, annual mean maximum temperature, and annual mean minimum temperature exhibited significant upward trends, increasing at rates of 0.4 ℃/decade, 0.39 ℃/decade and 0.53 ℃/decade, respectively. Nighttime temperature increases contributed most to this warming trend; daily average temperature had been decreasing. The warming trend was most pronounced in spring and winter; temperature increases were more significant from 1991 to 2020 than in other years. ② Extreme annual maximum and minimum temperatures did not show significant increases, with a change in 0.26 ℃/decade and 0.08 ℃/decade respectively. ③ Extreme maximum temperatures occurred mainly from late May to early August, peaking in late July. Extreme minimum temperatures typically appeared from late December to early February, with the highest frequency in January. ④ A marked temperature shift occurred in 1997, with a significant warming trend after 1998. Cold winters were more common before the 1990s, while warmer winters predominated after the 20th century. ⑤ Both mean and extreme temperatures in showed significant oscillations with periods of 2 to 4 years. 【Conclusion】 Our results could help improve irrigation and drainage management under the influence of climate change.