Analysis of factors variability of stratospheric temperatures.

• Main Author: Cagnazzo, Chiara
• Other Authors: Laboratoire de Météorologie Dynamique (UMR 8539) (LMD), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-École polytechnique (X)-École des Ponts ParisTech (ENPC)-Centre National de la Recherche Scientifique (CNRS)-Département des Géosciences - ENS Paris, École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL)-École normale supérieure - Paris (ENS-PSL), Université Paris Sciences et Lettres (PSL)-Université Paris Sciences et Lettres (PSL), Ecole Polytechnique X, Chantal Claud
• Format: Doctoral or Postdoctoral Thesis
• Language: French
• Published: HAL CCSD 2004
• Subjects: Interannual variability of the stratospheric temperature; Stratospheric temperature trends; Mean residual circulation; Stratospheric ozone depletion; Quasi-Biennial Oscillation; El Nino Southern Oscillation; Arctic Oscillation; Variabilité inter-annuelle de la température stratosphérique; Tendances de température; Circulation moyenne résiduelle; Diminution de l'ozone stratosphérique; Oscillation Quasi Biennale; Oscillation Arctique; [SPI]Engineering Sciences [physics]; Arctic; Arctique*
• Online Access: https://pastel.hal.science/pastel-00002293; https://pastel.hal.science/pastel-00002293/document; https://pastel.hal.science/pastel-00002293/file/Cagnazzo.pdf

The stratospheric processes play an important role in the climate system and addressing the issue of the impact of the stratosphere on climate is of fundamental importance to the scientific community. Observed long term changes in the stratosphere include increase of GHG (greenhouse gases), of lower stratospheric water vapour, decrease of stratospheric ozone and a systematic cooling of the stratosphere during the last two decades (1980-2000). This research was dedicated to the estimation of thermal and dynamical long term changes of the stratosphere and to the attribution of the causes, in particular the role of the ozone in the observed changes. The work was designed to cover the recent past (1980 to 2000), for which good data coverage exists; data analysis has then been coupled with GCM transient simulations to identify the role of the ozone decrease on the observed changes. Three datasets based on monthly-mean satellite and radio sounding product analysis have been considered: the TOVS/3I dataset gives a high resolution picture of the lower stratosphere on a short timescale, the FUB one has a lower resolution but is available for a longer period for the northern hemisphere; finally, the SSU/MSU dataset provides the entire vertical thermal structure of the stratosphere with a coarse vertical resolution (SSU/MSU). Stratospheric temperature trends for the period 1980-2000 have been determined using a multiple linear regression model (AMOUNTS) to separate the effect of the major sources of atmospheric temperature variability from a long-term linear trend. First, a detailed analysis of the impact of the factors of temperature variability is given: the stratospheric Quasi-Biennial Oscillation (QBO), the troposphere pattern of variability described by the El Nino Southern Oscillation (ENSO), the external solar variability and the low-frequency extra tropical mode of variability defined as the Arctic Oscillation. It has been found that the amplitude of the response of temperature to some of these forcing are of the ...