Validation of the ORA spatial inversion algorithm with respect to the Stratospheric Aerosol and Gas Experiment II data.

ABSTRACT

We present the results of a comparison of the total extinction altitude profiles measured at the same time and at same location by the ORA (Occultation Radiometer) and Stratospheric Aerosol and Gas Experiment II solar occultation experiments at three different wavelengths. A series of 25 events for which the grazing points of both experiments lie within a 2 degrees window has been analyzed. The mean relative differences observed over the altitude range 15-45 km are -8.4%, 1.6%, and 3% for the three channels (0.385, 0.6, and 1.02 microm). Some systematic degradation occurs below 20 km (as the result of signal saturation and possible cloud interference) and above 40 km (low absorption). The fair general agreement between the extinction profiles obtained by two different instruments enhances our confidence in the results of the ORA experiment and of the recently developed vertical inversion algorithm applied to real data.