Isolation of the Gravity-Inertial Motion Component in a Nonlinear Atmospheric Model

Abstract

Diagnostic methods me considered for isolating gravity-inertial motions in the output of a nonlinear atmospheric numerical model. The gravity-inertial component is defined by the nongeostrophic motions not directly incorporated with the synoptic-scale evolution according to quasi-scostrophic or balance model relationships. The analysis methods am applied to the solutions for a propagating jet stream maximum generated by a simple two-layer hydrostatic numerical model. Results identify a coherent pattern in the gravity-inertial motion component but details of the horizontal structure and propagation characteristics are only partially resolved. Results also elucidate relative merits of a number of physical variables and difference fields for defining the gravity-inertial component.