Ozone profiles retrieved from SCIMACHY Chappuis-Wulf limb scatter measurements using MART

The SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) instrument, launched on the Envisat satellite in March 2002, will measure the earthshine radiance, simultaneously from the ultraviolet (UV) to the near infrared (NIR), in the three viewing geometries nadir, limb, and occultation. These measurements will be used to retrieve both the total amount and vertical profiles of a large number of atmospheric constituents. In this paper, stratospheric ozone profiles between 15 and 40 km altitude are retrieved on 3 km grids from SCIMACHY limb scattered radiance in the Chappuis-Wulf band. It employs a new multiplicative algebraic reconstruction technique (MART) coupled with the radiative transfer model SCIATRAN. Radiance normalization and wavelength pairing is applied to radiance as an intermediate step, using the wavelengths 525 nm, 600 nm and 675 nm. The sensitivity of ozone retrieval by this method to tangent altitude pointing, surface albedo, aerosol and cloud parameters is studied, the results show that the retrieval impact due to tangent altitude pointing bias is the biggest can be up to 75% with 1 km shift, and the impact of albedo is limited within 5%. The effect of boundary visibility and cloud parameters can be ignored since these impact is too small. The effectiveness of the retrieval is demonstrated using a set of coincident SCIMACHY product at Hefei that shows a mean bias of less than 12% between 15 and 40 km, and with a better accuracy of 5% from 16 to 36 km.