Observation of ozone from GOMOS/ENVISAT in the tropical stratosphere : validation with SHADOZ, climatology and variability

• Main Author: Mzé, Nahoudha
• Other Authors: Laboratoire de l'Atmosphère et des Cyclones (LACy), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Météo-France, Université de la Réunion, Hassan Benchérif, Alain Hauchecorne
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2011
• Subjects: Ozone; Stratosphère; Tropics; Satellite; Trends; Isentropic transport; Filament; Observations; Model; Tropiques; Tendances; Transport isentropique; Modélisation; [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph]; Antarctic; The Antarctic; Antarc*
• Online Access: https://theses.hal.science/tel-04104765; https://theses.hal.science/tel-04104765/document; https://theses.hal.science/tel-04104765/file/11_37_N_MZE.pdf

The work presented in this manuscript is devoted to the analysis and the interpretation ofobservations in the tropics from the stellar occultation instrument GOMOS on board ENVISAT. We mainly focus on O3 datasets from GOMOS level 2 data processing, version GOPR 6.0cf (and IPF 5.0) between August 2002 and December 2008. A validation study was performed and a satisfactory agreement was observed between GOMOS and SHADOZ in the 21-30 km altitude range. We recommend using GOMOS measurements with caution below 21 km in the tropics. Furthermore, the altitude registration of the GOMOS profiles is accurate. The O3 differences between GOMOS and SHADOZ do not depend on the spatial and temporal coincidence criteria. We also evaluate the stability of GOMOS measurements. A singular isentropic transport event from the Antarctic polar vortex to the subtropics shows the ability of GOMOS to capture and to reproduce ozone structures. Our results illustrate that the ozone enhancement observed in the subtropical lower stratosphere is linked to a polar filament. It originates from the vortex edge region rather than the vortex core during ozone depletion. Finally, analyzing correlations between GOMOS observations and simulations from the high-resolution model MIMOSA, we established a first basis to extract ozone fields from the model. Le travail présenté dans ce manuscrit est consacré à l’analyse et à l’interprétation des observations au-dessus des tropiques de l’instrument à occultation stellaire GOMOS embarqué sur ENVISAT. On se focalise essentiellement sur les données d’O3 GOMOS de niveau 2 issues du processeur GOPR 6.0cf (et IPF 5.00) entre Août 2002 et Décembre 2008. Une validation des observations GOMOS a été menée et un accord satisfaisant est observé entre GOMOS et SHADOZ de 21 km à 30 km. Pour les régions tropicales, il est recommandé d’utiliser les mesures GOMOS avec précaution pour les altitudes inferieures à ~21 km. De plus, l’estimation de l’altitude des profils GOMOS est fiable. Les différences relatives calculées ...