The main advantage in combining limb and nadir geometries is that it allows the stratospheric and tropospheric ozone concentrations to be separated which makes it possible to improve the tropospheric ozone retrieval. This paper presents the retrieval method which will be used to combine TES nadir measurements with MIPAS limb measurements and shows some preliminary results. The Tropospheric Emission Spectrometer (TES) is a high-spectral-resolution infrared imaging Fourier transform spectrometer operated by NASA's Jet Propulsion Laboratory(JPL). It has a spectral range from 3.2/μm to 15.4/μm and at present is mostly operating in the nadir mode. TES routinely measures temperature and concentrations of O3,H2O, CH4, CO, HNO3, and N2O. A local optimal estimation retrieval code (the MIPAS Orbital Retrieval using Sequential Estimation (MORSE)) was used to retrieve Volume Mixing Ratios (VMR's) from the low resolution ESA level IB MIPAS data and level IB TES data. A joint retrieval was achieved by using the MIPAS retrieved VMR profiles as the a priori for the TES retrieval. A similar method could be used in the future to combine MIPAS and IASI.
