The experiments of transseasonal prediction by combining together the dynamical and statistical methods of the geopotential height fields on the blocking high in the Eurasia mid-high latitudes

Abstract

The blocking high in Eurasia mid-high latitudes (EMHBH) is one of the leading members of East Asian summer monsoon circulation system, which also has a crucial influence on the summer flood/drought in China, especially in the region of Yangtze River. However, the objective quantitative prediction of EMHBH is an urgent issue we are facing and also a complicated problem in the current short-term climate prediction. This paper, by using the dynamical and statistical prediction (DSP) methods and based on the forecast data of the numerical modal(CGCM) and the abundant historical observations, has carried out prediction experiments of the above three blocking high regions in the summer averaged 500 hPa geopotential height fields. The results show that the DSP methods can diminish the prediction errors to some extent, which is also suitable for operational application. In addition, sensitivity tests show that the selection of the number of similar targets or similar yeas has significant influences on the prediction results.