Validating MODIS Terrestrial Ecology Products: Linking In Situ and Satellite Measurements
✍ Scribed by Warren B Cohen; Christopher O Justice
- Publisher
- Elsevier Science
- Year
- 1999
- Tongue
- English
- Weight
- 92 KB
- Volume
- 70
- Category
- Article
- ISSN
- 0034-4257
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✦ Synopsis
MODIS (the Moderate Resolution Imaging Spectrome-
rithms, the generation of the associated geophysical ter) is the principal high temporal frequency global mapproducts, and their validation. These MODLAND data ping sensor on-board NASA's Earth Observation System products include surface reflectance, spectral albedo, (EOS) (http://modarch.gsfc.nasa.gov/MODIS/). The MOland surface temperature, spectral vegetation indices, DIS instrument views the entire Earth's surface every leaf area index and the absorbed fraction of photosyn-1-2 days, acquiring data in 36 spectral bands at spatial thetically active radiation (LAI/fAPAR), fire, snow, ice, resolutions from 250 m to 1 km (Running et al., 1994).
and land cover, and net primary productivity (NPP). The specifications for the MODIS instrument push the These and other, higher-order products derived from limits of engineering (Barnes et al., 1998), and MODIS MODIS data will play an important role in measuring data volumes will be several times that of the NOAAand monitoring surface variables and in the development AVHRR (Masuoka et al., 1998). MODIS data are proof global, interactive Earth-system models that are able cessed to provide well-quantified and calibrated data sets to predict global change accurately enough to assist polof the Earth's surface, corrected for instrument radiomeicy makers in making sound decisions concerning the try, geometric distortions, atmospheric attenuation, and management of our environment. MODIS data will be cloud effects (Justice et al., 1998a). As these data are used to parametrize and/or validate models of landused, they will improve our understanding of global dyatmosphere interactions, ecosystem processes, biogeonamics and processes occurring on the land surface and chemical cycles, surface hydrology, land cover, and in the oceans and atmosphere.
land use. This unprecedented data volume has led the MO-Validation of these global data products is crucial, DIS instrument team to develop a number of derived both to establish the accuracy of the products for the scidata products, with the intent of reducing the burden of ence-user community and to provide feedback so that data processing on the user. A series of land product althe data processing algorithms and product-oriented gorithms were selected by open competition and have models can be improved. The MODLAND validation been peer-reviewed twice during their development. The approach developed around the hierarchical test-site MODIS Land Discipline Group (MODLAND) has been concept of the Terrestrial Observation Panel for Climate charged with development of the MODIS-based algo-(GCOS, 1997). The intensive study sites which form a major component of the MODLAND validation plan have evolved into a number of Core Land Validation Sites for