The tomography algorithm for ozone retrieval from the NPOESS OMPS limb measurements

Abstract

ABSTRACT The Ozone Mapping and Profiler Suite (OMPS), which is a component of the National Polar-Orbiting EnvironmentalSatellite System (NPOESS), will provide high-resolution vertical ozone profiles in the atmosphere from limbmeasurements of scattered solar radiation retrieved from limb-geometry measurements of scattered solar radiation in theultraviolet, visible and near-infrared spectral ranges. Due to the long path of scattered limb radiation through theatmosphere, ozone variations along the line of sight can have a significant impact on the measured radiance and, if notaccounted for, result in significant deterioration of retrieval accuracy. In this paper we describe a tomographic retrievalalgorithm, which accounts for the effects of horizontal ozone variations on the target ozone profile retrieval by restoringa fragment of the 2D ozone distribution in the neighborhood of the target profile. Our simulated retrievals of realistic 2Dozone distributions demonstrates that the tomographic algorithm provides remarkably better retrieval accuracy than thebaseline 1D algorithm, which neglects horizontal ozone inhomogeneities. Special measures are taken to reduce thetomographic inversion execution time. We demonstrate that acceptable execution times can be achieved if fragments ofthe ozone field are retrieved sequentially along a satellite orbit.Keywords : NPOESS, OMPS, ozone, profile, 2D distribution, limb, tomography, retrieval, algorithm.