Urban Land Cover and Spatial Variation Observation Using Aster and Modis Satellite Image Data

Land cover and land use changes associated with urbanization are important drivers of local geological, hydrological, ecological, and climatic change. Quantification and monitoring of these changes in 100 global urban centres are part of the mission of the ASTER instrument on board the NASA Terra satellite, and comprise the fundamental research objective of the Urban Environmental Monitoring (UEM) Program at Arizona State University. Data have been acquired for the majority of the target urban centres and are used to compare landscape fragmentation patterns on the basis of land cover classifications at both local and global scales. The primary application of remote sensing data in this study is to provide a means for extrapolating detailed measurements at local sites to a regional context. Specifically, multi-spectral image classification, vegetation indices, and multi-kernel texture analysis are used to identify both natural and built land cover types. This information is combined with ancillary data such as land use using an expert system framework, to obtain final pixel classifications. Because modifications of the urban environment are coupled frequently with modifications of the spatial structure, the investigation of texture and shape parameters, or neighbourhood relations, out of remote sensing data apart from the spectral investigation applied so far represents an additional analysis potential. Thus, a methodological approach using and analyzing landscape metrics is presented and compared with biogeophysical variables obtained from the MODIS sensor for the Phoenix, AZ metropolitan area. * Corresponding author. ** Current address: Lockheed Martin Space Operations, Earth Sciences and Image Analysis Laboratory SX3, NASA Johnson Space Center, Houston, Texas, 77058, USA. 1. CURRENT RESEARCH While characterization and monitoring of ongoing urbanization processes is important, equally important is the ability to predict the local and regional environmental effects and feedbacks associated with expanding urban centres (Grimm et al., 2000). We define six major research objectives to achieve this goal: Objective 1: Tracking urban area growth and change: speed, density, direction, structures, impervious surfaces, land use consumed. Objective 2: Spatial arrangement of green/open space within cities and at periphery: amount distribution, links. Objective 3: Track changes in peri-urban regions: farmland conversions, wetland infringement, biodiversity