Abstract:The characteristics of the interdecadal variability in the differences between surface temperature (Ts) and surface air temperature (Ta) are analyzed, using daily-observed surface temperature and surface air temperature data from 1960 to 2006. Analysis results show that there is a clear interdecadal variability in Ts-Ta in Southeast and Northwest China. Before the late 1970s, the Ts-Ta anomalies were mostly positive in Southeast China, but they mostly became negative after this period. In contrast, in Northwest China, the Ts-Ta anomalies were mostly negative in spring and summer before the late 1970s, but became largely positive after this time. The opposite trend can be seen in the variability of Ts-Ta in Northwest China in the winter. However, in the autumn in Northwest China, the interdecadal variability of Ts-Ta was not as clear as during the other seasons. The analyzed results of Ts and Ta over the study period show that their contributions to interdecadal variability of in Ts-Ta differed between different seasons.