eMODIS NDVI

Moderate resolution remote sensing provides a means for operational monitoring communities to develop historical trend information and use near real-time deviations from temporal averages to identify areas of change. High quality, consistent and well-calibrated satellite measurements are needed to detect and monitor changes and trends, especially in vegetation patterns useful for drought, crop yield, phenology and fire potential studies. The eMODIS collection is based on the Moderate Resolution Imaging Spectroradiometer (MODIS) data acquired by the National Aeronautics and Space Administration's (NASA) Earth Observing System (EOS). Even though MODIS data are beneficial in vegetation studies, there have been usability issues encountered with the reprojection, file format and subsetting. Therefore, eMODIS was developed to specifically address these issues. The eMODIS suite of products includes either 7- or 10-day data composited data sets. Expedited (near real-time) production runs daily for the 7-day continental U.S. products and every five days for the 10-day products in other areas using the last interval of input. There is no expedited production over Alaska. Each data set delivers acquisition, quality and Normalized Difference Vegetation Index (NDVI) information at 250-meter (m) spatial resolution. Because each of the composites are created from a varying number of images, the eMODIS composites include acquisition files to identify which of the possible inputs were used to populate the final composite. The metadata accompanying the data files summarize geographic bounds, projection parameters and product contact information. eMODIS currently produces NDVI and reflectance over the continental U.S., Alaska and Central America/Caribbean and Mexico while Africa and Central Asia production contain NDVI only.