Remote sensing of CO, CH4, and O3 using a spaceborne nadir-viewing interferometer

Within the next 5 years, several instruments launched on polar orbiting satellites will provide high-resolution infrared remote-sensing measurements of CO, CH4, and O-3 on a global scale. The upwelling spectral radiances to be recorded by a nadir-looking remote sensor have been simulated using a high-resolution radiative code (line-by-line radiative transfer model (LBLRTM)) coupled to a three-dimensional chemical transport model (intermediate model of the annual and global evolution of species (IMAGES)). The instrumental specifications of the Fourier transform interferometric monitor for greenhouse gases/Advanced Earth Observing System (IMG/ADEOS) and infrared atmospheric sounding interferometer ( IASI/METOP) were used to generate realistic data. Calculations have been performed to assess the sensitivity of the nadir spectral radiances to changes in the gas concentration, temperature profile and to instrumental characteristics. We provide spectral intervals for an efficient retrieval of these species, together with a set of climatological tropospheric standard mixing ratio profiles.