Tropospheric ozone information from satellite-based polarization measurements

Many current and planned future satellite missions aim at the retrieval of tropospheric ozone from reflectance spectra. However, it is difficult to distinguish between stratospheric and tropospheric ozone on the basis of reflectance spectra only. In this paper we show that satellite-based polarization measurements of backscattered light contain valuable additional information on the tropospheric ozone profile. In contrast to the reflectance the polarization properties of backscattered light show higher sensitivity to ozone in the troposphere than to ozone in the stratosphere. This is because the polarization is most affected by ozone at that altitude where most scattering takes place, which is in the troposphere for wavelengths greater than similar to300 nm. Retrievals performed on synthetic Global Ozone Monitoring Experiment 2 data show that the vertical resolution of the tropospheric ozone profile is significantly improved if polarization measurements are used in addition to the reflectance spectrum. Problems that are currently encountered in tropospheric ozone retrieval from reflectance spectra may be solved by using additional polarization measurements.