The Contrast of Structure and Analysis of Cause for China¡¯s Temperature Fields in Two Periods During The Last 100 Years

By using objective and quantitative index and a wealth of data, the spatial and temporal distributions of China°¯s temperature fields in two warming periods (from 1920s to 1940s and by the middle and end of 1970s) are contrasted. The cause of the two warmings is also diagnosed by using BP-CCA method. The results show as follows: (1) There are obvious differences in the spatial distribution and seasonal variation over the two warming periods. The warming before the 1940s is characterized by all seasonable increase over South China, and warming amplitude in summer half year is higher than that in winter half year. However, the warming by the end of 1970s is mainly lies in North China and winter half year. (2) The warming from 1920s to 1940s seems to relate to the greenhouse effect, volcanism and solar activity and that by the end of 1970s may be mainly cause by enhanced greenhouse effect.