A43B-01
Observing the Earth's radiation budget at the top of the atmosphere using photometers on the Moon's surface
The Earth's albedo is one the least studied of the fundamental climate parameters. The albedo is a bi-directional property, and there is a high degree of anisotropy in the reflected light from a given surface. However, simultaneously observing all points on Earth from all reflecting angles is a practical impossibility. Therefore, all measurements from which albedo can be inferred require assumptions and/or modeling to derive a good estimate. Nowadays, albedo measurements are taken regularly either from low Earth orbit satellite platforms or from ground-based measurements of the earthshine in the dark side of the Moon. But the results from these different measurements are not in satisfactory agreement. Clearly, the availability of different albedo databases and their inter-comparisons can help to constrain the assumptions necessary to reduce the uncertainty of the albedo estimates. In recent years, there has been a renewed interest in the development of robotic and manned exploration missions to the Moon. This return to the Moon will enable diverse exploration and scientific opportunities. Here we discuss the possibility of a lunar-based Earth radiation budget monitoring experiment, the Lunar Terrestrial Observatory (LTO), and evaluate its scientific and practical advantages compared to the other, more standard, observing platforms.
A43B-02
Land Surface Albedo Derived in Near Real Time from Meteosat Second Generation Observations
The European Meteorological Satellite Organization (EUMETSAT) maintains a number of decentralized processing centers dedicated to different scientific themes. The Satellite Application Facility on Land Surface Analysis (Land-SAF) is hosted by the Portuguese Meteorological Institute. Its objective is to provide value added products for the meteorological and environmental science communities with main applications in the fields of climate modeling, natural hazards management, and climate change detection. Since 2005 data from Meteosat Second Generation satellite are routinely processed in near real time by the Land-SAF operational system. Presently, the delivered operational products comprise land surface albedo and temperature, short-wave and long-wave downwelling radiation fluxes, and snow cover. Within the project consortium Meteo-France is responsible for the development of several products, of which one is the daily surface albedo product. After about seven years of research, development, and progressive operational activities, a summary of the albedo product characteristics and performances is presented on the basis of the end of the Initial Operational Phase (Feb. 2007). The outline of the next phase (the Continuous Development and Operational Phase, 2007- 2012) is presented for the surface albedo: to provide a new product generation by means of merging data between the polar satellite MetOp (Meteorological Operational, launched in Oct. 2006) and the MSG-2 geostationary satellite data. The LSA SAF program provides a mean to constrain the model representation of the climate trend as a consistent production of data sets guaranteed until at least 2019 with the forthcoming MSG-3 mission. Moreover, a reconstitution on daily basis of the Earth's albedo is made possible with the addition of cloud albedo fields based on the cloud classification. In addition to the presentation of the SAF-Land project, it is discussed that the retrieval of the surface albedo cannot be dissociated from the retrieval of the Aerosol Optical Thickness. An experimental method of simultaneous albedo and AOT daily retrieval is presented.
A43B-03
Earth's spectral reflectivity
Cyclic spectroscopic observations of the dark and bright sides of the moon (or earthshine and moonshine) have been carried out in the visible spectral region from several astronomical observatories as Earth rotates. The ratio of the earthshine to moonshine has been analyzed to determine the globally-integrated Earth's albedo during the observations. Information concerning to the search of terrestrial planets beyond the solar system can also be obtained from these results.