Atmospheric Gravity Wave Processes from Aqua Measurements

Although not originally designed for this purpose, the high spatial resolution of AIRS and AMSU measurements have revealed new details of small-scale atmospheric gravity waves and their many effects on climate processes during the last decade. Gravity waves themselves drive localized temperature fluctuations with important impacts on clouds, precipitation, and atmospheric chemistry. Drag forces associated with gravity wave breaking drive circulation changes in climate models with additional wide-ranging effects. Models used for global weather forecasting now resolve some gravity wave features with scales of several hundred km, but many other gravity waves remain unresolved, while climate models resolve only some of the largest scale gravity waves. Understanding these waves, how they are generated, and how their climate effects can be best parameterized have become important issues both for testing current models and improving next generation climate predictions. Our research focuses both on waves from convection and mountain waves. AIRS radiance measurements provide the highest resolution, and we use these data to quantify wave generation by small mountainous islands and the effects of these waves on the general circulation. We also estimate the relative importance of the smallest-resolvable versus larger-scale mountain waves to the circulation directly from AIRS measurements. Details of wave generation within convective clouds are also examined, where AIRS measurements provide the constraints for simulations of their generation and propagation. These studies allow us to test assumptions employed in current parameterization methods. We will also show how the local-time sampling of Aqua is an important limitation for studies of gravity waves generated by convection.