Journal of Quantitative Spectroscopy & Radiative Transfer 107 (2007) 105–119 Gome ozone profiles retrieved by neural network techniques: A global validation with lidar measurements M. Iapaolo a , S. Godin-Beekmann b, , F. Del Frate a , S. Casadio c , M. Petitdidier d , I.S. McDermid e , T. Leblanc e , D. Swart f , Y. Meijer f , G. Hansen g , K. Stebel g a Dipartimento Informatica Sistemi e Produzione, Universita` Tor Vergata, Viale Politecnico 1, I 00133 Rome, Italy b Service d’Ae´ronomie, Institut Pierre Simon Laplace, CNRS, UPMC—Boite 102, 4 Place Jussieu, 75252 Paris Cedex 05, France c Institut for Geophysics, Karl Franzens University of Graz, c/o ESA/ESRIN, Via G. Galilei, I 00044 Rome, Italy d Centre d’e´tude des Environnements Terrestre et Plane´taires, Institut Pierre Simon Laplace, CNRS, 10-12 Avenue de l’Europe, 78140 Ve´lizy, France e Jet Propulsion Laboratory, Table Mountain Facility, California Institute of Technology, P.O. Box 367, Wrightwood, CA 92397, USA f National Institute for Public Health and the Environment, Laboratory for Environmen-tal Monitoring, Environment and Safety Division, P.O. Box 1, 3720 BA Bilthoven, The Netherlands g Norwegian Institute for Air Research, Polar Environment Centre, NO 9296 Tromsoe, Norway Received 23 March 2006; received in revised form 26 February 2007; accepted 26 February 2007 Abstract Ozone profiles retrieved from Global Ozone Monitoring Experiment (GOME, flying on ERS-2 satellite) spectra from July 1995 to June 2003 by means of 2 independent neural network (NN) schemes have been validated with ozone lidar measurements performed at different stations belonging to the network for the detection of atmospheric composition changes (NDACC). The retrieval and the whole validation have been carried out by using the performances and resources of the European project Enabling Grid for E-sciencE (EGEE) and of a local Grid at the European Space Research Institute of the European Space Agency (ESRIN/ESA). Roughly 1800 collocated profiles have been found, in tropical, mid-latitude and high-latitude regions; for each lidar station the differences between GOME and lidar profiles have been evaluated and the global performance of the proposed NN approaches has been critically discussed. The results indicate the potentialities for obtaining reliable ozone field analysis on global scale, including detailed altitude resolved trend analysis. r 2007 Elsevier Ltd. All rights reserved. 1. Introduction The stratospheric ozone layer is of crucial importance in determining the thermal structure of the atmosphere and has a significant impact on dynamical processes at global scale. The well-known depletion of the ozone layer was the first environmental issue to be raised at international level, leading to the signature of the Montreal protocol in 1987. This protocol emphasizes the need for a careful monitoring of the ozone layer ARTICLE IN PRESS www.elsevier.com/locate/jqsrt 0022-4073/$ - see front matter r 2007 Elsevier Ltd. All rights reserved. doi:10.1016/j.jqsrt.2007.02.015 Corresponding author. Tel.: +33 1 44274767; fax: +33 1 44273776. E-mail address: sophie.godin@aero.jussieu.fr (S. Godin-Beekmann).