Characteristics of air temperature change in Dandong during recent 100 years

Based on air temperature data in Dandong from 1906 to 2005,the characteristics of air temperature changes were analyzed.The results indicate that monthly mean air temperatures in July and August are linearly increasing,while those in other months are linearly decreasing.The linear ratio of mean air temperature at inter-decadal level is about 1.13 ℃/100 a,and that at inter-annual level is about 0.12 ℃/10 a.The warming trend is the most obvious in winter(from December to February) with 0.30 ℃/10 a,followed in spring(from March to May) with 0.12 ℃/10 a and in autumn(from September to November) with 0.06 ℃/10 a.In summer,mean air temperature changes are small in June,while decrease in July and August.The trend ratio of summer is about 0.03 ℃/10 a.The warming trend is abnormally significant during recent 20 years,and the trend ratio is about 0.36 ℃/10 a.