Development of a Sequential Estimator for Assimilation of Ground-And Space-Based Mesospheric and Lower Thermospheric Winds

A sequential estimator for assimilation of ground- and satellite-based MLT wind measurements has been developed in support of the TIMED mission science goals. Preliminary experiments focused on the retrieval of monochromatic waves sampled by the TIMED satellite and the MF observing network. Ground-based measurements are found to be a critical compliment to the satellite database for defining the migrating semidiurnal tide. The assimilation algorithm is currently being tested on output from the NCAR Whole Atmosphere Community Climate Model (WACCM). The sequential estimator is able to resolve nonmigrating diurnal variability on times scales of 7 days and longer.