Mainly based on the method of Mann-Kendall test,both annual and seasonal air temperature in Jinan are analyzed by using observational data from 1951 to 2007.The results show that the mean annual air temperature increases very significantly with a speed of 0.24℃/10a,among which the average annual air temperature in 50′s and 80′s increases rapidly,is relatively stable in 60′s and 70′s,rises again obviously after 1983,and becomes stabilized and even shows a slight downward trend after 2000.Two abrupt changes i...