Summary: | This geospatial layer (shapefile) provides the spatial extent of 211 river deltas in the Arctic and was established by digitizing Arctic deltas based on (very) high resolution images, which are freely available on GoogleEarth. We digitized the deltas at mapping scale of 1:5,000 to 1:15,000 depending on the available GoogleEarth images. The area of the resulting polygon shapefile was calculated using ArcMap 10.6.1. The centroids of the polygons were calculated and used for the coordinates of the deltas. This simple mapping provided a first-order estimation of the total area covered by Arctic deltas. In our approach, we used a definition of 'Arctic delta' that includes typical prograding deltas but also estuaries and alluvial fans ending in the Arctic Ocean as well as inland deltas. This includes deltas of size >10 km2 and a representative subset of micro deltas (< 10 km2). Even though there are several (~100) micro deltas not covered by this data set (especially in Greenland, the Canadian Archipelago, or Novaya Zemlya), this only negligibly affects the total area of Arctic river deltas, as the 41 mapped micro deltas only contribute 0.2% of the total delta area in the Arctic. For mapping purposes, we set the beginning of a delta as the point where the river channels start to spread and lead independently to the sea and develop a distinct fan. Digitized Arctic deltas therefore include not only deltaic, fluvial deposits in a strict sedimentological definition, but are based on a geographic definition of deltas. This broad definition of deltas is a necessary simplification for the upscaling based on limited data available from Arctic deltas. The final data set includes a shapefile with the area (km2), coordinates (decimal degrees, WGS84), water area (% of area) based on Pekel et al. (2016) for each Arctic delta as well as a kmz file ready to use as a visualization in GoogleEarth. This geospatial data set was used as an input in combination with (link to data file 2) and (link to data file 3) to estimate the ...
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