【摘要】 利用2011年9月河南119个地面气象站逐日降水资料及同期NCEP/NCAR再分析资料数据,分析连阴雨降水特点及大气环流特征。用相关分析法找出中高纬度影响河南连阴雨降水的关键区,采用正斜压大气分解、E-P通量诊断方法从基本气流和扰动气流相互作用的角度分析连阴雨期间关键区的大气环流异常机制。正、斜压涡度的演变特征表明:关键区高压系统的建立和维持主要是由高纬度地区负的正压涡度向关键区输送造成,斜压扰动对关键区的高压系统的发展起抑制作用,基本气流中负的正压涡度起主导作用,大气环流的准正压性及基本气流的正压涡度对扰动气流起发展与维持作用。E-P通量诊断显示,降水时段40—120°E范围中高纬度对流层中上层的E-P通量矢量为辐合状态,导致中西伯利亚地区基本气流减速,使大气环流倾向于径向型;降水减弱或处于间歇期时,中高纬度E-P通量矢量为辐散状态时,基本气流加速,大气环流趋向纬向型。更多还原

【Abstract】 Using the daily precipitation data of 119 observation stations in Henan and NCEP/NCAR reanalysis data in September 2011, the characteristics of the continuous precipitation and atmospheric circulation were analyzed. The key region affecting the continuous rain of Henan was found using correlation analysis method. The mechanism of atmospheric circulation anomaly in key region during the continuous precipitation was studied of by barotropic and baroclinic atmospheric decomposition and E-P flux diagnosis method from the angle of the interaction between the basic airflow and disturbed airflow. The evolution characteristics of barotropic vorticity and baroclinic vorticity shows that the formation and maintaining of the key region high-pressure systems are caused by the transporting of the minus barotropic vorticity from high latitude, while baroclinic vorticity tends to suppress the development of the key region high-pressure systems, but the minus barotropic vorticity of the basic flow plays the leading role, so the quasi-barotropy of the general atmospheric circulation and the barotropic vorticity of the basic flow play an important role on the formation and maintaining of the eddy flow. Diagnosis of E-P flux shows that during the continuous rain, the E-P flux is convergence at 40—120°E, the basic flow at central Siberia decelerates, and the circulation tends to be radial. During the weakening or intermission of the continuous rain, the E-P flux is divergence, the basic flow accelerates, and the circulation tends to be zonal.更多还原