The double westerly jet(DWJ) in the austral winter is studied by using the NCEP/NCAR reanalysis data.

Based on a new climate variability theory “Energy complement each other and balance between westerly jet in winter and subtropical high in summer ”presented by the author in this paper, the flood and drought prediction in China from 1997 to 2001 had been completed.

The significant impact of heating fields on the upper-tropospheric westerly jet has been revealed in much previous research,but little effort has been paid on differentiating the relative contribution of various heating fields over tropical and subtropical regions.

In this paper, westerly jet, storm track and baroclinic wave packets of upper troposphere in the Northern Hemisphere at summer of 1980?1998 are analyzed by using NCEP/NC.

In this study,the monthly wind and temperature fields from ECMWF(European Center for Medium-Range Weather Forecasts) reanalysis dataset ERA40 are used to investigate the characteristics and variabilities of the East Asian-western Pacific westerly jet stream(WJS) in winter seasons.

Results are as follows:(1)The cold air and the shortwave trough disrupted from the westly jet at the level of 500 hPa which moved from the Ural Mountain to the Balkhash Lake,moved along the bottom of the jet to the Hexi Corridor of Gansu and the middle part of Qinghai,which provided energy for the ra.

Sensitive experiments were performed by using a regional climate model with p-σ incorporated coordinate to investigate the impacts of the uplift of the Tibetan Plateau on the East Asian subtropical westerly jet(EAWJ).

They are (1) preparation stage of Subtropical westerly jet (from May to September); (2) Development stage of jet from October to March; (3) the jet disappearing and replacing by west pacific subtropical high from May to September.