Temporal and Spatial Characteristics of Soil Heat Flux in China

The authors used soil heat flux data observed at 17 stations of the Chinese Ecosystem Research Network (CERN) from 2004 to 2007 to analyze the seasonal and spatial variation of the soil surface heat flux. The soil heat flux changed from negative to positive at the beginning of February and became negative again around September. It remained positive from March to August then became negative from December to January. The soil heat flux showed seasonal variation over the northeast and northwest regions of China while it had little seasonal variation over the Yangtze River basin. Over the plateau region, the heat flux was relatively small and varied only slightly throughout the year. The general spatial distribution pattern of the soil heat flux over China was larger in northern China in spring and summer and in southern China during fall and winter. The annual mean soil heat flux was higher over the black land areas of northeast China, the northwest desert region, the north Loess Plateau, and the Sichuan Basin regions, but had negative values over the lower reaches of the Yangtze River and the alluvial regions of the lower reaches of the Yellow River. This study provides good references for further studies of soil climate formation.