Abstract:Based on the objectively analyzed data of T213 model,the strong consecutive rainfall in Shaanxi province,which happened from August 24 to September 7,2003,has been analyzed.The results show that,this consecutive rainfall occurred in the stable zonal circulation of eastern Asian,with great longitudinal circles and blocked high at its upside,which made the latitudinal circle sustain in the mid-latitude areas of eastern Asian and west Pacific Ocean.The study on vertical structure of synthetic circle in eastern Asian displays that,during the consecutive rainfall,the area of Qinling Mountains was under the control of front,with vertical structure of convergence in the low air but divergence in high air.The vertical section displays rainfall progress happened with the flimsy cold air cushion in the low air,but warm air flow climbing by the cold air cushion.Additionally ,the analyses on vapor condition explore that during the rainy time,the moisture was transported mainly in the bottom of troposphere and the water almost derived from the East Sea and the South Sea by the easterly or southerly great and stable airflow around the subtropical high.In the end,study of thermodynamics uncovers that Northwest China always was in the area of high potential,and the southerly airflow was closely related with the transmission of energy and the maintenance of high potential,at the same,time the strengthening of easterly air flow in the low air impelled the release of potential and resulted in the strong rainfall in Qinling Mountains.