High-resolution AIRS/AMSU swath-scanned radiances acquired from Aqua resolve two-dimensional horizontal gravity wave structures at a series of vertical levels throughout the stratosphere. Our objective is to use this unique observational capability to characterize the full three-dimensional properties of these resolved gravity waves. Such measurements will provide the first unambiguous global observations of key gravity wave properties such as momentum flux, horizontal wavelength, and propagation direction, all of which are needed to constrain the critical subgridscale gravity wave drag parameterizations in global weather forecasting and climate models. We will use AIRS/AMSU wave imagery to study gravity waves in the upper troposphere and stratosphere that were generated by underlying mountain ranges, deep tropical convection, and jet stream instabilities. Measured wave properties from each source will be compared with those explicitly simulated using high-resolution NWP model runs and simpler regional wave generation and propagation models. The improved AIRS/AMSU observations of gravity waves radiating away from these sources will lead to improved descriptions of source dynamics in gravity wave generation models, which will in turn improve and observationally constrain the subgrid-scale parameterizations of gravity waves from each source currently used in global weather and climate models. Gravity wave modeling results and observed wave fields will be interrelated using detailed three-dimensional in-orbit forward models that simulate acquisition of AIRS/AMSU-A radiances in the presence of prescribed three-dimensional gravity wave oscillations of different wavelengths and amplitudes. The forward-model results will accurately define each instrument's spectral visibility to gravity waves, permitting proper geophysical interpretation of the gravity wave data and aiding design of retrieval algorithms that correct for the attenuation of resolved wave amplitudes by the three-dimensional AIRS/AMSU-A weighting functions. Our work will also investigate how well AIRS/AMSU temperature retrieval algorithms capture the intrinsic amplitudes and wavelengths of gravity waves, providing objective tests of the ability of these retrieval algorithms to capture fine-scale atmospheric temperature structures. Our research makes full use of the high spatial resolution of the AIRS/AMSU data acquired from Aqua, and provides NASA with new global gravity wave data that, through improved gravity wave parameterization, enhances NASA's strategic goals of improving understanding of and predictive capabilities for both weather and climate.
