The Importance of Early Morning Local Overpass Times of BRDF Retrieval, Modeling of Spectral Reflectance and Fapar Estimation
Blueprints for near-future moderate resolution satellite-borne sensor systems such as the VIIRS (Visible Infrared Imaging Radiometer Suite) sensor on the National Polar-orbiting Operational Environmental Satellite System (NPOESS) do not include plans to ensure that land surface observations are made from an early morning (AM) orbit (07:30-08:30 local time) as well as in the afternoon (PM), and current spaceborne sensors designed to sample the bidirectional reflectance distribution function (BRDF) achieve this by off-nadir viewing with a small range of solar zenith angles (SZA). This many limit the utility of current and future systems in important Earth observation applications such as estimating the fraction of absorbed photosynthetically-active radiation (fAPAR). The lack of observations at 50° < SZA < 70° may only be partly offset by the 09:30 orbit foreseen for EUMETSAT's METOP satellite, to carry a third generation Advanced Very High Resolution Radiometer (AVHRR). Here existing AVHRR data are used to examine the likely impact of inverting models with observations at a small range of sun angles.
MSU Digital Commons Citation
Chopping, Mark; Rango, Albert; and Gomez-Landesa, Enrique, "The Importance of Early Morning Local Overpass Times of BRDF Retrieval, Modeling of Spectral Reflectance and Fapar Estimation" (2002). Department of Earth and Environmental Studies Faculty Scholarship and Creative Works. 585.