A Simple Test of the Initialization of Gravity Modes

Abstract

The initialization schemes of Machenhauer (1977), Baer and Tribbia (1977), and one requiring the initial second time derivatives of gravity modes to be zero are tested by application to a simple differential equation, which partially simulates the behavior of gravity modes in a forecast model. These initialization schemes are tested to see under what conditions they converge, and they are tested on how well they eliminate future gravity wave oscillations. Preliminary results of initialization experiments with the National Meteorological Center's spectral forecast model are in support of the conclusions derived from analyzing this differential equation.