Expected accuracy of the CO2 retrieval from IASI

Abstract

The expected accuracy of CO2 retrieval from IASI data is assessed. A particular signal processing is developed to efficiently exploit the CO2 information of the IASI spectrum, through a Discrete Fourier Transform (DFT) filtering. the DFT filtering allows to process the entire IASI CO2 information in about 50 data elements. An information content analysis indicates that, providing a climatological prior knowledge on the CO2 concentration variability and the meteorological forecast of temperature and water vapour profiles, the mean tropospheric CO2 concentration can be derived from a single IASI spectrum with an accuracy of about 2 parts per million by volume (ppmv), i.e., better than 1 %. the DFT filtering allows to process the entire IASI CO2 information in about 50 data elements. IASI; Remote-sensing; Atmosphere; Tropospheric CO2;