Near-infrared radiative transfer modeling to retrieve atmospheric methane total amount

Abstract

Atmospheric methane total amount can be retrieved from measurements of solar radiation propagated through the atmosphere in the near infrared spectral region where the space-borne and ground-based spectrometers carry out regular measurements of the atmospheric spectra. At present, discrepancies between measured and modelled atmospheric spectra are observed and can lead to a significant error in the methane concentration retrieval. The possible causes of the discrepancies are the uncertainties of the spectroscopic line parameters in the HITRAN database, often used for atmospheric calculations, neglecting of the CH4 line-mixing effects and uncertainties in the extraterrestrial solar spectrum. These uncertainties and their influence on atmospheric radiation transfer calculations are investigated. A comparison of atmospheric ground-based measured and simulated spectra, modelled with HITRAN and new CH4 line lists, are presented. © 2012 Nova Science Publishers, Inc. All rights reserved.