Abstract

Using monthly precipitation and temperatures from 160 stations in China and monthly characteristic indices of the Western Pacific subtropical high from 1951 to 2000, a new method of multivariate analysis, i.e., “transfer entropy”, was adopted to study the impacts of the Western Pacific subtropical high on precipitation and temperature in summer. The subtropical high is a system that occupies two roles in precipitation: necessary condition and sufficient condition. The results show that the indices of the western ridge point, north boundary and ridge line that represent subtropical high positions are necessary conditions, and the intensity index and region index that represent subtropical high strength are sufficient conditions based on the former three indices, which initially reveals the global behavior characteristics of the subtropical high system influencing weather. In short, the effect of the subtropical high on meteorological elements is a process of energy release. Weather phenomena are generated due to energy release (e.g., precipitation phenomenon is an energy release process), resulting in the weakening or intensifying of the subtropical high system, i.e., feedback action.