Detecting the causal interaction between Siberian High and Winter Surface Air Temperature over Northeast Asia

Past Results indicate that there is a significant negative correlation between the Siberian High (SH) and winter surface air temperature (SAT) over Eurasian continent and East Asia. However, correlation does not mean causation, especially in nonlinear dynamic systems. Here, we apply a recently developed method, Convergent Cross Mapping (CCM), to detect the causal connection between SH and winter SAT over Northeast Asia. It suggests the winter SAT variability in Northeast Asia and SH shows two-way causation, SH <-> winter SAT. Meanwhile, the influence of SH characteristic variables on wintertime SAT is in order of area, longitude of east edge, intensity and latitude of south edge of SH, respectively. What's more, the impact of wintertime SAT on SH characteristic variables is in order of area, intensity, longitude of east edge, and latitude of south edge of SH. Besides, we apply the CCM to analyze the causality between the Northern Hemisphere Annular Mode (NAM) and the intensity of SH. It indicates that the NAM forces the intensity of SH, but not vise versa. Hence, we suggest that the NAM can influence winter SAT through the SH. The mechanism of the causality is presented preliminarily. These causal relationships and feedback effects in dynamic systems have opened up the possibility to improve the seasonal prediction of winter SAT over Northeast Asia by using the external factors of the SH.