Skip to Main content Skip to Navigation
Theses

Télédétection multispectrale des poussières désertiques dans l'infrarouge thermique au-dessus de l'Afrique à partir de MSG/SEVIRI

Abstract : The limited level of understanding of the interaction between desert dust and the climate arises to a large extent from the high spatio-temporal variations of this aerosol concentration and properties. Remote sensing from space is an essential tool to improve the knowledge of this aerosol, as it can provide a long-term and global observation. The thermal infrared (TIR) is a spectral domain where the desert dust remote sensing is particularly efficient. Thus a dust index called IDDI (Infrared Difference Dust Index), has been developed through the use of the TIR channel of Meteosat over land.
This study focusses on correcting the failings of the current IDDI and using the new MSG/SEVIRI TIR channels to develop a new multispectral IDDI.
Our approach is based on the analysis of the effects of dust, surface wind, Sun elevation and water vapour, on the top-of-atmosphere radiance, using the radiative transfer code MODTRAN. The influence of surface emissivity on TOA radiance is also analysed. A method of IDDI correction is then derived, with respect to the impacts of surface wind and Sun elevation. This study is extended to the MSG/SEVIRI TIR channels taking into account the spectral variations of aerosol properties and of surface emissivity. The results show an increased sensitivity for the 8.7 and 10.8 µm channels, and a multispectral IDDI is proposed in order to improve the correlation between IDDI and aerosol optical depth measured by the AERONET network at five Sahelian sites. This new IDDI is tentatively designed to improve the observation of the desert aerosol outbreaks over Africa.
Document type :
Theses
Complete list of metadatas

Cited literature [58 references]  Display  Hide  Download

https://tel.archives-ouvertes.fr/tel-00185300
Contributor : Gaëlle Vergé-Dépré <>
Submitted on : Monday, November 5, 2007 - 5:14:40 PM
Last modification on : Tuesday, November 24, 2020 - 11:00:10 AM
Long-term archiving on: : Monday, April 12, 2010 - 1:22:58 AM

Identifiers

  • HAL Id : tel-00185300, version 1

Collections

Citation

Gaëlle Vergé-Dépré. Télédétection multispectrale des poussières désertiques dans l'infrarouge thermique au-dessus de l'Afrique à partir de MSG/SEVIRI. Physique [physics]. Université des Antilles-Guyane, 2007. Français. ⟨tel-00185300⟩

Share

Metrics

Record views

422

Files downloads

1709