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Carbon dioxide (CO2) transfer from inland waters to the atmosphere, known as CO2 evasion, is a component of the global carbon cycle. Global estimates of CO2 evasion have been hampered, however, by the lack of a framework for estimating the inland water surface area and gas transfer velocity and by the absence of a global CO2 database. Here we report(More)
Digital elevation models (DEMs) cover a wide range of scales, and allow statisticalanalysis of geomorphometric parameters. At global or continental scale, DEMs covering rectangular quadrangles can be considered random samples. Average quadrangle values can be compared at different DEM scales, and for different physiographic provinces. Three independent(More)
Intervisibility computed from a lidar point cloud offers several advantages compared to using a gridded digital surface model: (1) even with high resolution grids, the point cloud offers a better graphical depiction of the line-of-sight, and (2) the point cloud avoids interpolation problems that frequently result in the grid not accurately capturing the(More)
A suite of 42 morphometric parameters for each of 26 272 drainage basins larger than 100 km 2 from the Hy-drosheds Shuttle Radar Topography digital elevation model shows the global distribution of Strahler order for streams and drainage basins. At the scale of 15 arc s spacing (232 to 464 m) the largest basins are order 9. Many common parameters depend both(More)
This paper describes a Java application, Target 3D, that creates an interactive VRML model to visualize real terrain configurations. The application requires an input elevation grid and a texture to drape on the elevation framework, which can be provided by the freeware MICRODEM program from a wide variety of grid, raster, and vector map data. The most(More)
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