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Detecting Change in Landscape Greenness over Large Areas: An Example for New Mexico, USA
Nash, M., D. Bradford, J. Wickham, AND T. Wade. Detecting Change in Landscape Greenness over Large Areas: An Example for New Mexico, USA. REMOTE SENSING OF ENVIRONMENT. Elsevier Science Ltd, New York, NY, 150(0):152-162, (2014).
Monitoring and quantifying changes in vegetation cover over large areas using remote sensing can potentially detect large-scale, slow changes (e.g., climate change), as well as more local and rapid changes (e.g., fire, land development). A useful indicator for detecting change in land cover is a measure of greenness, the Normalized Difference Vegetation Index (NDVI). Detecting change in NDVI, however, can be confounded by time-dependent patterns (e.g., seasonal effects) and variation associated with climate factors. In the present study we provide a method to address these confounding factors by evaluating NDVI change using autoregression techniques that compare results from univariate (i.e., NDVI vs. time) and multivariate analyses (NDVI vs. time and climate variables) for ~314,000 1-km2 pixels comprising the state of New Mexico over an 18-year period (1989−2006).
The ability to detect NDVI trend was greatly improved by including climate variables in the multivariate analyses of NDVI over time. The comparisons of univariate and multivariate analyses revealed that for most of the pixels with a significant NDVI trend in either analysis, the trend was consistent with changes in local factors rather than climate change; only 0.8% of the pixels had a significant NDVI trend associated with change in the climate variables.
URLs/Downloads:NASH ORD-007104 ARTICLE FINAL DETECTING CHANGE IN LANDSCAPE GREENNESS.PDF (PDF,NA pp, 972.564 KB, about PDF)
Record Details:Record Type: DOCUMENT (JOURNAL/PEER REVIEWED JOURNAL)
Organization:U.S. ENVIRONMENTAL PROTECTION AGENCY
OFFICE OF RESEARCH AND DEVELOPMENT
NATIONAL EXPOSURE RESEARCH LAB
ENVIRONMENTAL SCIENCES DIVISION
LANDSCAPE ECOLOGY BRANCH