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10-Years Operational GOME/ERS-2 Total Column Products: The GDP 4.0 Algorithm

Diego Loyola(1), Michel Van Roozendael(2), Robert Spurr(3), Dimitris Balis(4), Jean-Christopher Lambert(5), Yakov Livschitz(1), Pieter Valks(1), Thomas Ruppert(1), Pepijn Kenter(6), Caroline Fayt(5) and Claus Zehner(7)

(1) DLR, Oberpfaffenhofen, D-82234 Wessling, Germany
(2) BIRA, 3 Avenue Circulaire, B-1180 Brussels, Belgium
(3) RT Solutions, Inc., 9 Channing Street, Cambridge MA 02138, United States
(4) Aristotle University of Thessaloniki, Box 149, 54124 Thessaloniki, Greece
(5) BIRA, Avenue Circulaire 3, 1180 Bruxelles, Belgium
(6) Science & Technology BV, PoBox 608, 2600 AP Delft, Netherlands
(7) ESA, Via Galileo Galilei CP. 64, 00044 Frascati, Italy

Abstract

GOME has become an important instrument for trace gases trend analysis, with a data record now exceeding ten years duration. The GOME Data Processor (GDP) operational retrieval algorithm has generated total ozone and NO2 columns since July 1995. This paper presents the GDP version 4.0 algorithm, a major upgrade to the operational system. The GDP 4.0 retrieval algorithm uses an optimized DOAS (Differential Optical Absorption Spectroscopy) algorithm; least-squares slant column fitting is followed by Air Mass Factor (AMF) conversions to generate vertical columns. GDP 4.0 has improved wavelength calibration and reference spectra, and includes a new molecular Ring correction scheme to deal with the distortion of ozone absorption features due to inelastic Raman scattering effects. The AMFs are calculated on-line using the pseudo-spherical multiple-scattering radiative transfer code LIDORT and adjusted iteratively to reflect the fitted slant column result. GDP 4.0 includes accurate cloud parameter estimation using the cutting-edge cloud correction algorithms OCRA and ROCINN. The geophysical validation demonstrated the long-term stability of the GDP 4.0 total column ozone, reaching an accuracy comparable to that obtainable from ground-based sensors.

 

Workshop presentation

Full paper

Keywords: ESA European Space Agency - Agence spatiale europeenne, observation de la terre, earth observation, satellite remote sensing, teledetection, geophysique, altimetrie, radar, chimique atmospherique, geophysics, altimetry, radar, atmospheric chemistry