Presenter

Miss Ilse Decoster [Email]

Abstract

Since more than 30 years, the Meteosat satellites of EUMETSAT have been measuring the thermal emitted and visible reflected outgoing radiation of the Earth. Due to their long time period in space, the data from these instruments is very useful for climatology, especially because they provide half hourly measurements, allowing to address the full diurnal cycle.
However, since the beginning, contamination has built up on the mirrors, causing a decrease in time of the signal of the visible channel. For the first generation of instruments, a spectral character to this decrease has been detected, which has, so far, not been corrected yet by any available calibration methods.
In this work, a semi-empirical model is proposed to correct the Meteosat First Generation satellite images (1982 – 2006) for this in-flight spectral degradation. The spectral response curve, which shows the percentage of incoming radiation that is observed at each wavelength, is modelled, both in time and wavelength. The result of applying this model to the visible data of the satellite imagers is shown, together with validation work. For some of the satellites, especially the oldest ones, additional problems have been detected, which are explained and corrected when it was possible. Evidence is also given that the pre-launch characterisation of the Meteosat spectral response shows some discrepancies in representing the sensitivity to the visible radiation, which strengthens the need of further investigation into the accuracy of the spectral response curve of the visible channel of the older Meteosat instruments.

Short CV

Master in Physics, KU Leuven, 2009