Cover: Southern Africa, 2 February 2002 to 16 May 2002, Moderate Resolution Imaging Spectroradiometer (MODIS) 500 m land surface reflectance

摘要

Southern Africa's landscape exhibits a great natural variability owing to the region's range of climate, land covers and disturbance processes like biomass burning. With the vast underdeveloped areas, the variability helps make southern Africa a superior location in which to study land-atmosphere relationships and test satellite algorithms. The Southern Africa Regional Science Initiative (SAFARI 2000) was aimed at developing a better understanding of these relationships with the support of new, state-of-the-art satellite observatories that recently became available. For example, the cover image shows the SAFARI 2000 study area (sub-equatorial Africa) as observed by the Moderate Resolution Imaging Spectroradiometer (MODIS), a key instrument onboard NASA's Earth Observing System (EOS) Terra and Aqua satellites (launched in 1999 and 2002, respectively). MODIS is capable of viewing the entire globe on an almost daily basis at moderate spatial resolution, with nadir pixel dimensions of approximately 250 m, 500 m and 1 km, in 36 spectral bands. The MODIS Land surface reflectance product is defined as the reflectance that would be measured at the land surface if there were no atmosphere and is produced by applying corrections for the effect of gaseous absorption, molecules and aerosol scattering to the MODIS L1B data (Vermote et al. 1997). The land surface reflectance product is used to generate many of the standard MODIS land products (Roy et al. 2002), including Vegetation Indices, BRDF/Albedo, Thermal Anomaly, Fraction of Photosynthetically Active Radiation and Leaf Area Index. The product includes the surface reflectance in seven MODIS 500 m bands, centred at 470 nm, 555 nm, 648 nm, 858 nm, 1240nm, 1640nm, and 2130nm, a number of descriptive metadata and per-pixel quality assessment information (Vermote et al. 2002).