MIPAS TEMPERATURE VALIDATION BY RADIOSONDE AND LIDAR

摘要

The operational data products for the Michelson interferometerrnMipas on the ESA satellite Envisat include amongrnothers vertical prou0002les of temperature, two geometric altitudernscales, and pressure. Checks show that pressurernacts as a better vertical scale than either of the geometricrnaltitude scales. The geometric altitude scales suffer fromrnoccasional latitude-dependent differences. About 15%ofrnthe 60 000 available prou0002les have no temperature values.rnIn addition there are unphysical values for pressure, temperature,rnand errors in the data products. Comparing thernremaining Mipas temperature prou0002les with temperaturesrnfrom radiosondes and Rayleigh lidars shows the MipasrnT accuracy to be -0.35 and -0.3 K, respectively, which isrnbetter than predicted before launch. Below 18 km altitudernthere is an increasing positive bias of Mipas temperaturesrnw.r.t. radiosonde temperatures with decreasing altitude.rnThe precisions of ≈ 3 K and ≈ 5 K, respectively, arernfactors of 3 and 5 times times larger than predicted. Contributionsrnto the precision come from the Mipas measurement,rnits conversion to temperature, the altitude assignedrnto the Mipas measurement, the precision of the comparingrninstrument, the differing observation geometries, andrnthe geophysical variability of the atmosphere.