Characteristics of Temperature in Spatial and Temporal Variation in China During Recent 40 Years

Based on the decadely mean temperature at 336 stations in China from 1951 to 1990, the statistical methods of empirical orthogonal function (EOF) and periodogram are used to analysed the characteristics of temperature in spatial and temporal variation. The facts that the interannual change and change trend of temperature have significant differences among different districts and seasons are revealed. It can be drawn that the temperature decreases in the first 20 years and increases in the last 20 years. And temperature decreases in summer, increases in winter. The periodic oscillation in temperature trend is also analysed in the paper.