Title :
Cloud Properties Derived From GOME/ERS-2 Backscatter Data for Trace Gas Retrieval
Author :
Rodriguez, Diego Guillermo Loyoda ; Thomas, Werner ; Livschitz, Yakov ; Ruppert, Thomas ; Albert, Peter ; Hollmann, Rainer
Author_Institution :
Deutsches Zentrum fur Luft- und Raumfahrt, Oberpfaffenhofen
Abstract :
We focus on the retrieval of cloud properties appropriate for trace gas retrieval from sun-normalized ultraviolet/visible backscatter spectra obtained from the Global Ozone Monitoring Experiment (GOME) onboard the European Space Agency´s European Remote Sensing 2 Satellite (ERS-2). Retrieved quantities are the fractional cloud coverage of the GOME footprint, the cloud-top albedo, and the cloud-top height. A data fusion technique is applied to calculate the fractional cloud cover of GOME footprints from GOME´s polarization measurement devices. Furthermore, cloud-top albedo and cloud-top height are retrieved simultaneously from GOME measurements around the oxygen A-band by a neural network approach. We compare our results with corresponding results from the Spinning Enhanced Visible and Infrared Imager (SEVIRI) radiometer onboard the first European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT) METEOSAT Second Generation 1 geostationary spacecraft. Our analysis revealed that GOME-derived basic cloud properties are of remarkably high quality. GOME slightly underestimates the cloud coverage of footprints, which was expected since GOME is mainly sensitive to optically thick water clouds. GOME measurements are limited to the ultraviolet and visible part of the solar spectrum, which hampers the detection of optically thin clouds. For both the cloud-top height and the cloud-top albedo, we found a small bias relative to SEVIRI results. The overall uncertainty of retrieved total ozone columns with respect to cloud parameters is about 1%-2%. Our approach is applied to the operational processing of GOME/ERS-2 and will be applied to GOME-2/METOP (launched in 2006) in the framework of EUMETSAT´s Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring (O3M-SAF).
Keywords :
atmospheric composition; atmospheric spectra; clouds; neural nets; ozone; sensor fusion; ERS-2; EUMETSAT; European Organisation for the Exploitation of Meteorological Satellites; European Remote Sensing 2 Satellite; European Space Agency; GOME footprints; GOME-2-METOP; Global Ozone Monitoring Experiment; METEOSAT Second Generation 1 geostationary spacecraft; O3M-SAF; SEVIRI radiometer; Satellite Application Facility on Ozone and Atmospheric Chemistry Monitoring; Spinning Enhanced Visible and Infrared Imager; cloud-top albedo; cloud-top height; data fusion technique; fractional cloud coverage; neural network approach; oxygen A-band; polarization measurement devices; solar spectrum; total ozone columns; trace gas retrieval; ultraviolet backscatter spectra; visible backscatter spectra; Backscatter; Clouds; Information retrieval; Infrared imaging; Neural networks; Optical sensors; Polarization; Remote monitoring; Satellite broadcasting; Spinning; Cloud properties retrieval; Global Ozone Monitoring Experiment (GOME); data fusion; neural networks;
Journal_Title :
Geoscience and Remote Sensing, IEEE Transactions on
DOI :
10.1109/TGRS.2007.901043