Some statistical characteristics of “Geothermal Vortex” in China from 1980 to 2017

Climate prediction is of great significance to the prevention of drought and flood. “Ground-synoptic” map is a method for short-term climate prediction. The main content of this method is “Geothermal Vortex“(GV). Therefore, some characteristics of 3.2 m soil temperature anomaly (hereinafter abbreviated as T′ 3.2 m) and GV are analyzed by using the data of monthly soil temperature at the depth of 3.2 m from 1980 to 2017 in China. Results show that there are regional differences in the frequency of positive anomaly. Overall, there are more positive anomalies in southern China and fewer in Western China. Soil temperature anomaly has good memory, the shortest being 5 months and the longest being nearly 2 years. Moreover, results show the nonuniform distribution of memory duration and decreases from northwest to southeast as a whole. Statistical analysis of GV shows that the average life cycle of each GV is 9.7 months, with an average horizontal scale of 604 km and a characteristic scale of 2.4 cm/s. Spatially, the GV scale is largest in Northwest, with a horizontal scale of 1087 km, and the GV appear most frequently in North China. The central location of GV is uneven, mainly in the central area with strong crustal activity and large absolute vertical deformation rate or in the high value area of soil heat flow.