阻塞环流生命史不仅是纬向平均流和经向扰动流之间的转换过程，还是正压环流与斜压环流之间的转换过程，这一重要过程尚未得到系统研究。首先揭示阻塞过程中正斜压模的演变规律，然后利用我们导出的正斜压涡度方程研究正、斜压模演变和转换的物理机制及其动力学原理，最后对偶极子阻塞形势中的高、低压中心的演变规律及其相互作用原理进行研究。

Firstly, the lifespan of the blocking case which is linked with barotropic and baroclinic flow field is analyzed by observation. Then we find that the transformation between barotropic and baroclinic flow field exists in the whole process of an Ural blocking system. Furthermore, the transformation mechanism between barotropic and baroclinic enstrophy in the development of an Okhotsk blocking circulation is studied. In this project, equations of barotropic and baroclinic enstrophy are established over a limited area and on a local basis and more diagnostic analyses are performed for two blocking processes by means of these equations. Results show that the net production of baroclinic (barotropic) enstrophy is the energy source (sink) for the formation and development (decaying and disappearance) of blocking processes. The transformation is always from baroclinic to barotropic enstrophy, which is an important physical mechanism in the evolvement of blocking circulation. The equations of barotropic and baroclinic enstrophy we developed do have the ability to depict the full history of the blocking circulation accompanied by conversions between barotropic and baroclinic flow field and other atmospheric circulation. The scientific values of the above studies are obvious.