Gravity Wave Sources and Parameterization

Northwest Research Associates, Incorporated, Seattle WA

Investigators

Abstract

Gravity waves with periods ranging from minutes to hours are believed to affect the atmospheric circulation, temperature, and mixing processes at levels extending from the troposphere through the mesosphere and above. However, they are too small to be resolved in general circulation models (GCMs) and must be treated via parameterization. That is, their effects must be described approximately for inclusion in large-scale models. This research program aims to quantify the properties of gravity waves and determine their sources, their geographic and seasonal variations, and their effects on the atmosphere. Emphasis is on the waves generated by hurricanes and other convective storm systems. The goal is to improve the ways of parameterizing their effects in GCMs. The approach focuses on analysis of aircraft and balloon observations from previous field experiments to derive information on the momentum flux and the temperature perturbations associated with gravity waves, which information is then employed for developing parameterizations. Collaboration on including the parameterizations in GCMs is planned with researchers at the NOAA Geophysical Fluid Dynamics Laboratory and other organizations. These studies will provide a means of both studying the global-scale effects of gravity waves and refining the parameterizations. The goal of the work is to improve large-scale atmospheric simulations by approximating more accurately the effects of the waves.