DOI: 10.5281/zenodo.7071659
title: Development of a global inundation map at high spatial resolution from topographic downscaling of coarse-scale remote sensing data

description: <strong>Overview:</strong> The Global Inundation Extent from Multi-Satellites (GIEMS; Prigent et al. 2007, Papa et al. 2010) downscaled at 15 arc-second (GIEMS-D15; Fluet-Chouinard et al. 2015) was produced through the downscaling of the GIEMS database (natively at 0.25°). The downscaling procedure predicts the location of surface water cover with an inundation ranking surface generated by bagged decision trees. The decision trees were trained on binary presence/absence of wetland in the GLC2000 global land cover map (Bartholomé & Belward 2005) and used 13 topographic and hydrographic predictors derived from the SRTM-derived HydroSHEDS database (Lehner, Verdin & Jarvis 2008). The downscaling technique to three temporal aggregation of the GIEMS dataset representing three states of land surface inundation extents: mean annual minimum (MA<sub>Min</sub>; total area, 6.5 × 106 km<sup>2</sup>), mean annual maximum (MA<sub>Max</sub>; 12.1 × 106 km<sup>2</sup>), and long-term maximum (LT<sub>Max</sub>; 17.3 × 106 km<sup>2</sup>). The area of MAMin and MAMax from GIEMS were supplemented with the minimum area value from lakes, river and reservoirs from GLWD (Lehner & Döll 2004; classes 1,2,3). LTMax was corrected as the mean area from 3-year rolling maximum from GIEMS and the total wetland area from GLWD (classes 1-12). The accuracy of GIEMS-D15 reflects distribution errors introduced by the downscaling process as well as errors from the original satellite estimates. Yet, a comparison against independent regional wetland maps showed adequate agreement over large floodplains and wetlands. GIEMS-D15 offers a higher resolution delineation of inundated areas than originally offered by GIEMS, allowing for the assessment of global freshwater resources and the study of large floodplain and wetland ecosystems. <strong>Projection:</strong> WGS84 (EPSG:4326) <strong>Geographic extent:</strong> Longitude: -180° to 180° Latitude: -56° to 84° <strong>Spatial resolution: </strong>15 arc-second (500m at equator) <strong>Legend</strong> (for discrete pixel values): 0 = Upland 1 = Mean Annual Minimum (MA<sub>Min</sub>) 2 = Mean Annual Maximum (MA<sub>Max</sub>) 3 = Long Term Maximum (LT<sub>Max</sub>)
description: For questions/comments contact: Etienne Fluet-Chouinard (etienne.fluet@env.ethz.ch) Filipe Aires (filipe.aires@obspm.fr)
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