Abstract:Based on the daily maximum and minimum temperature data from 45 weather stations in Jilin Province for the period of 1970 to 2014, the temporal and spatial evolution characteristics of the asymmetric changes in the maximum and minimum temperature at the annual and seasonal scales are analyzed. At the same time, the Empirical Mode Decomposition (EMD) is adopted to decompose and analyze the trends of the annual and seasonal maximum and minimum temperature sequences. The results show that the average maximum and minimum temperature in the last 45 years has been on the rise, and the increase of the minimum temperature was twice as high as that of the maximum temperature. Besides, the maximum and minimum temperature changes at the seasonal scale were consistent with those at the annual scale; there was little difference in the increase in the maximum temperature between different regions, but a certain difference between the minimum temperature increases of different regions. The increase of the minimum temperature in the eastern region was smaller than those of the central and the western regions. In addition, regions with relatively stable temperature rise appeared to be the central and the western regions, where different increases in amounts were found in different seasons, referring to that temperature rise in spring and summer was larger than in autumn and winter. The EMD (Empirical Mode Decomposition) results indicate that the annual average maximum and minimum temperature in Jilin Province were on the rise, while the inclination rates of the maximum temperature trend component in spring and winter were different from that of the primary sequence. The inclination rates of the maximum temperature trend component in summer and autumn and the minimum temperature trend component for four seasons were all in accordance with the primary sequence, which were positive, but different in size.