Analysis of numerically simulated gravity waves generated by convection

Convectively generated gravity waves have recently been identified as a source of momentum flux that affects the mean flow in the stratosphere and higher levels. The waves are easily identified in the stratosphere, but difficult to discern in the troposphere due to the much larger amplitude of the convection. In this study, we examine a two-dimensional simulation of squall line convection that produces vertically propagating gravity waves. Trajectory and empirical orthogonal function (EOF) analyses are applied to the velocity and potential temperature fields simulated by the model, obtaining some separation of wave and convective motions. Momentum fluxes are calculated for both convective and non-convective motions in the troposphere, and are compared to one another. Measures of tropospheric convective activity are compared to the wave energy flux in the lower stratosphere, allowing for an estimate of the amount of energy drain that the vertically propagating waves have on the convection. One of the goals of this research is to develop improved parameterizations of convectively generated gravity waves for large-scale models.