Forming of equivalent barotropy
相当正压性的形成

A numerical experiment is carried out by using two-layer quasi-geostrophic model to explore the mechanism of equivalent barotropy. It is concluded that baroclinic disturbance, whose isopaches and isohypses are out of phase initially, can reach a state, in which the isopaches and the isohypses are parallel, a few days later owing to the effect of absolute vorticity advection. Through this process barotropy formed. Further experiment shows that beta-effect has played an important role in such process.