A Daily Soil Temperature Dataset and Soil Temperature Climatology of the Contiguous United States

3Although affected by atmospheric circulation, variations in soil temperature result primarily from the radiation and sensible and latent heat exchanges at the surface and heat transfer in the soils of different thermal properties. Thus soil temperature and its variation at various depths are unique parameters useful in understanding both the surface energy processes and regional environmental and climate conditions. Yet, despite the importance, long-term quality data of soil temperatures are not available for the United States. The goal of this study is to fill this data gap and develop a soil temperature dataset from the historical data of U.S. cooperative stations. Cooperative stations ’ soil temperatures at various depths from 1967 to 2002 are collected and examined by a set of quality checks, and erroneous data of extended periods are estimated using methods constructed in this study. After the quality control, the data are used to describe the soil temperature climatology as well as soil temperature change in the continuous United States. The 35-year climatology shows that the annual soil temperature at 10cm depth, where most stations have soil temperature measurements, decreases gradually from 297<K in the coastal areas along the Gulf of Mexico to below 281<K in the U.S.-Canadian boarder. In seasonal variation, the largest seasonal change occurs from spring to summer when soil temperatures are