Abstract:Based on the ERA-interim reanalysis data from 1979 to 2013, the interdecadal variations of the extra-tropical cyclones and land surface thermal anomaly and their possible relationship are investigated with statistical methods. Results show that there exists a distinct cyclogenesis area in the mid-latitude region of East Asia, and the frequency of cyclogenesis over this area exhibits significant interdecadal changes. Before 1990, the frequency of cyclogenesis was relatively high; however, from the 1990s to the present, it is relatively weak. Meanwhile, the land surface thermal anomaly shows a decadal increasing trend. Further analysis suggests that there is a close linkage between the decadal warming of the land surface in the mid-latitude of East Asia and the decadal weakening of the cyclone activity. Due to the heterogeneity of the land surface warming, it is a key region in the north of that has a significant effect on the cyclone activity over the cyclogenesis area. The decadal warming of the key region tends to decrease the meridional gradient of the surface soil temperature over the cyclongenesis source region, leading to the weakening atmospheric baroclinicity, and the decreasing frequency of the cyclogenesis.