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DSWEmod surface water map composites generated from daily MODIS images - California

January 11, 2021

USGS researchers with the Patterns in the Landscape ? Analyses of Cause and Effect (PLACE) project are releasing a collection of high-frequency surface water map composites derived from daily Moderate Resolution Imaging Spectroradiometer (MODIS) imagery. Using Google Earth Engine, the team developed customized image processing steps and adapted the Dynamic Surface Water Extent (DSWE) to generate surface water map composites in California for 2003-2019 at a 250-m pixel resolution. Daily maps were merged to create 6, 3, 2, and 1 composite(s) per month corresponding to approximately 5-day, 10-day, 15-day, and monthly products, respectively. The resulting maps are available as downloadable files for each year. Each file includes 72, 36, 24, or 12 bands that coincide with the number of maps generated in the 5-day, 10-day, 15-day, and monthly products, respectively. The bands are ordered chronologically, with the first band representing the beginning of the calendar year and the last band representing the end of the year. The maps for each scenario are labeled according to year and product type. There are 17 GeoTIF (.tif) raster data files for each composite product. The document included as part of the data release includes the Google Earth Engine Javascript code, which can be used online (https://code.earthengine.google.com/) to generate DSWEmod maps for any location in the conterminous United States. The code block includes comments to explain how each step works.