Estimation of Synoptic Fields of Middle Atmosphere Parameters from Nimbus-7 LIMS Profile Data

Abstract

The most widely used version of the Nimbus-7 LIMS middle atmosphere dataset is the set of high quality, daily, and zonal Fourier coefficients that resolve information out to six wavenumbers at 12 UTC. A Kalman filter algorithm was applied to the original profile data in order to generate those fields for the data archive or LAMAT product. The characteristics and implementation of the algorithm are described in some detail, along with examples of the output for each of the LIMS parameters. Criteria for judging the quality of the derived results are discussed and include: (i) standard deviation of the fit between individual profiles and the mapped field at the same longitudes, (ii) comparisons between the separate analyses of the ascending and descending orbital mode coefficients, (iii) continuity of the fields with latitude and pressure and (iv) comparisons of sequences of daily maps of the different parameters. The degree to which the filter fits the original data is determined by the estimated precision of the satellite measurements.