Atmospheric water vapour content retrieval from visible and thermal data in the framework of the DAISEX campaigns
Abstract:In this paper three methods are presented that retrieve the atmospheric water vapour from DAIS (digital airborne imaging spectrometer) data in the framework of the DAISEX (DAIS Experiment) campaigns carried out by ESA (European Space Agency). The three methodologies analysed in the paper are: (i) the ratio technique, in which the water vapour is obtained from visible and near‐infrared bands; (ii) the split‐window technique; and (iii) the split‐window covariance‐variance ratio technique, in which the water vapour content is retrieved from thermal infrared bands. A comparison between the atmospheric water vapour content extracted from the DAIS images using these techniques and that obtained from in situ radiosoundings shows a root mean square deviation of around 0.1gcm −2 for the first two methods and 0.4gcm −2 for the last one. Finally, as an application, the atmospheric water vapour retrieved was used to perform the atmospheric correction for DAIS thermal bands and retrieve land surface temperatures, obtaining in this way root mean square deviations less than 2K for the least absorbent bands.
Document Type: Research Article
Affiliations: Global Change Unit, Department of Thermodynamics, Faculty of Physics, University of Valencia, Dr. Moliner 50, 46100, Burjassot, Spain
Publication date: August 10, 2005