A simulation of atmospheric blocking with a forced barotropic model

Nearly stationary states (NSSs) of the barotropic vorticity equation (BVE) on the sphere that are closely related to observed atmospheric blocking patterns have recently been derived. Examining the way such NSSs affect integrations of the BVE is of interest. Unfortunately, the BVE rapidly evolves away from the neighborhood of blocking NSSs due to instability and never again generates sufficient amplitude to return to the vicinity of the blocking NSSs. However, forced versions of the BVE with both a high amplitude blocking NSS and more zonal low amplitude NSSs can be constructed. For certain parameter ranges, extended integrations of these forced BVEs exhibit two "regimes', one strongly blocked and the other relatively zonal. Somewhat realistic simulations of low and high frequency variability and individual blocking event life cycles are also produced by these forced barotropic models. -from Author