Land Cover Characterization and Land Surface Parameterization Research

• Published in: Ecological applications 1997-02, Vol.7 (1), p.1-2
• Main Authors: Steyaert, Louis T., Loveland, Thomas R., Parton, William J.
• Format: Article
• Language: English
• Subjects: Advanced Very High Resolution Radiometer (AVHRR); land cover characterization; land cover data; land process modeling; land surface parameterization; Landsat TM; remote sensing
• ISSN: 1051-0761; 1939-5582
• DOI: 10.1890/1051-0761(1997)007[0001:LCCALS]2.0.CO;2

The understanding of land surface processes and their parameterization in atmospheric, hydrologic, and ecosystem models has been a dominant research theme over the past decade. For example, many studies have demonstrated the key role of land cover characteristics as controlling factors in determining land surface processes, such as the exchange of water, energy, carbon, and trace gases between the land surface and the lower atmosphere. The requirements for multiresolution land cover characteristics data to support coupled-systems modeling have also been well documented, including the need for data on land cover type, land use, and many seasonally variable land cover characteristics, such as albedo, leaf area index, canopy conductance, surface roughness, and net primary productivity. Recently, the developers of land data have worked more closely with the land surface process modelers in these efforts. The six papers published here illustrate some of the contemporary research issues associated with the implementation of land cover characteristics data into various types of land surface process models. The scientific findings reported in these papers are based on the testing, evaluation, and application of a prototype 1-km land cover characteristics database developed for the conterminous United States by the U.S. Geological Surveys (USGS) EROS (Earth Resources Observation System) Data Center and the University of Nebraska--Lincoln (UNL) (T.R. Loveland, J. W. Merchant, B. C. Reed, J. B. Brown, D. O. Ohlen, P. Olson, and J. Hutchinson, 1995. Seasonal land cover regions of the United States. Annals of the Association of American Geographers 85(2):339-355). This experimental land cover characteristics data set was developed as part of the USGS's global-change research program. Biweekly composites of the 1-km advanced very high resolution radiometer (AVHRR) normalized difference vegetation index (NDVI) images for 1990 were analyzed in combination with elevation, climatic, ecoregion, and other ancillary data sources to derive 159 seasonal land cover classes of vegetation mosaics for the conterminous United States. Thus, temporal profiles of vegetation greenness, as depicted in the seasonal variations of the NDVI for 1990 for each 1-km pixel, were the essential input to this classification. The principal focus of the experiments reported in these papers was on the use of various land cover classification schemes derived from the 159 seasonal land cover classes. In