| Abstract: | In China and East Asia, the long-term continuous observational data at daily resolution are insufficient, and thus there is a lack of good understanding of the extreme climate variation over the last 100 years plus. In this study, the extreme temperature indices defined by ETCCDI（Expert Team on Climate Change Detection and Indices） and local meteorological administrations were analyzed for Changchun City, Northeast China, by using the daily maximum temperature（Tmax） and daily minimum temperature（Tmin） over 1909-2018. The results showed that extreme cold events, such as cold days, cold nights, frost days, icing days, and low temperature days, decreased significantly at rates of-0.41 d（10 yr）-1,-1.45 d（10 yr）-1,-2.28 d（10 yr）-1,-1.16 d（10 yr）-1 and-1.90 d（10 yr）-1, respectively. Warm nights increased significantly at a rate of1.71 d（10 yr）-1, but warm days decreased slightly and the number of high temperature days decreased at a rate of-0.20 d（10 yr）-1. The frequency of cold surge events increased significantly at a rate of 0.25 d（10 yr）-1, occurring mainly from the mid-1950 s to late-1980 s. The average Tmax, average Tmin and extreme Tmin increased at rates of 0.09°C（10 yr）-1,0.36°C（10 yr）-1 and 0.54°C（10 yr）-1, respectively; and extreme Tmax decreased significantly at a rate of-0.17°C（10 yr）-1. In 1909-2018, 1951-2018 and 1979-2018, the indices related to cold events decreased, while the trends of the indices related to warm events were different for different periods. |
