¹ Space Research Organisation Netherlands (SRON), Utrecht
² ESA/ESTEC, Earth Observation Projects Dept., Noordwijk, The Netherlands
Amongst the many calibration modes of the GOME instrument there is one in which the Moon is being used for radiometric calibration. Because of the particular observational geometry of this mode, in which the scan mirror is tilted sideways by approx. 80 with respect to nadir, the number of Moon observations is limited and restricted to cases in which the Moon is at approx. 3/4 phase.
Also, the Moon does not completely fill the spectrometer slit in one direction, whereas in the other direction, its size exceeds the size of the slit, which therefore has to be scanned (by the satellite motion) over the entire Moon surface (Fig. 1).
Although mainly intended for the instrument calibration, the data from these measurements can also be used to study lunar properties. By dividing the lunar spectrum measured in this way by the solar spectrum measured on the same day, the lunar albedo can be derived (Fig. 2). This spectral albedo measurement compares favourably with ground-based measurements performed at specific wavelengths. To our knowledge, this is the first spectrally resolved geometrical Moon albedo over the complete 240-800 nm wavelength range and the first reported Moon albedo values in the ultraviolet as observed from a satellite-borne instrument. As can be seen, the lunar albedo is an almost linearly increasing function of wavelength from about 5% in the UV to 28% at 800 nm. The noise increases towards the ultraviolet as a result of dividing a low Moon radiance by the low solar irradiance in that part of the wavelength range. The features at 313, 403, and 605 nm are instrumental artefacts resulting from the channel boundaries.
A more comprehensive paper, mainly focussing on the calibration aspects of the Moon measurements, will be given by M. Dobber at the SPIE Conference in Denver in August 1996.
First Announcement of Opportunity
The German Aerospace Research Establishment (DLR) has been funded by the European Commission, through the TMR (Training and Mobility of Researchers) Programme, to offer to European research teams free of charge access to the Digital Airborne Imaging Spectrometer - Large-Scale Facility (DAIS-LSF). The DAIS-LSF is operated by the DLR Institute of Optoelectronics in Oberpfaffenhofen, Germany.
The DAIS-LSF consists of the hyper-possible spectral airbome sensor DAIS-7915, its laboratory calibration facility (LCF) and ist hyperspectral pre-processor.
More information available under: http:/ /www.op.dir.de/ne- oe/fo/dais/dais.html
The objectives of the DAIS-LSF are:
This announcement is intended for interested research groups both within the European Union and Associated States. Due to the evaluation criteria the proposal should highlight:
The evaluation of the proposals is subject of an European expert group in order to select projects eligible for participation. Priority will be given to those proposals which make best use of the VIS-TIR hyperspectral and wide-angle scanning features of the DAIS-7915 and which are performed in an interdisciplinary manner by a coordinated user group. The research will be performed on the basis of scientific collaboration and knowledge exchange for mutual benefit of the European investigators and of the DLR as the DAIS-LSF host Organisation.
The DLR Institute of Optoelectronics invites researcher groups
interested in hyperspectral remote sensing to make use of the
DAIS-LSF. For receiving the guidelines for the preparation of
proposals or any further question related to this Announcement,
the DAIS-LSF and its potential, please contact:
Frank Lehmann,
Project Manager DAIS-LSF
Tel.: +49-8153.28.1532. Fax: ...1458
e-
mail: sabine.tischlerdlr.de
Deadline for submission of proposals for research experiments in 1997: 15 November 1996
Next announcement of opportunity for experiments in 1997 will be issued at the end of 1996.
ESA EOQ 52