Analysis of MIPAS measurements with the Level 2 near real time code

MIPAS (Michelson Interferometer for Passive Atmospheric Sounding) is operating on board of the ENVISAT satellite and is acquiring for the first time high spectral resolution middle infrared emission limb sounding spectra of the Earth atmosphere from space. The measurement capabilities of this instrument make it possible to determine every 75 sec the vertical profile of several atmospheric trace constituents, during both day and night with an almost full coverage of the globe. This leads to a three dimensional measurement of the atmospheric composition. In order to handle the large data flow, an optimised code was developed for the Level 2 near real time analysis of MIPAS data. The code is designed to provide, in an automated and continuous way, atmospheric vertical profiles of temperature, pressure and concentrations of O3, H2O, CH4, HNO3, N2O and NO2, in the altitude range from 12 to 68 km. Indications on the quality of MIPAS data and on the performances of the code are herewith derived from the analysis of preliminary data obtained from the first orbits in which measurements were acquired. The assumptions made for the development of the optimised code are verified with the real data. The diagnostics of the instrument performances provide indications that there is good agreements with the results obtained by the Level 1 analysis. Good quality geophysical data are retrieved and no unexpected change to the algorithm baseline appears to be necessary from this preliminary analysis.