In this study, the problem of geopotential variations minimization in the solution of balance equations is considered. Two approaches are discussed: the first is a modification of initialization equations in order to avoid the problem of non-ellipticity, and the second is the use of information on the distribution of non-elliptic regions for solution of the original balance equations. An analysis of a version of the modified balance equations is made for the case of barotropic and baroclinc models of the atmosphere. On the other hand, a solution algorithm of the balance equations, which allows small variations of the geopotential field, is proposed and its efficiency is compared to that of the conventional initialization algorithm.
atmospheric models; initialization of atmospheric fields; balance equations; ellipticity conditions; non-elliptic regions
