Accuracy Analysis of New Freely Available Digital Terrain Models in the European Territory of Russia

Since 2019, several new global-coverage DEMs (Copernicus GLO-30, NASADEM, FABDEM) have become publicly available on the Internet. They could be used to obtain morphometric indicators and assess model soil erosion losses, including within the European Territory of Russia (ETR), where the main arable lands of the Russian Federation are located. To date, a number of studies have been carried out to assess the altitude accuracy of these models. However, in addition to absolute altitude errors, it is necessary to assess the accuracy of the of morphometric indicators calculated on the basis of these models. The article presents the results of the analysis of errors of such morphometric indicators as slope steepness, slope length, and relief erosion potential of three new global digital elevation models using the example of three sites located in the Voronezh, Saratov and Orenburg regions. The analysis of errors was performed by comparing with data calculated on the basis of DEMs constructed from large-scale topographic maps. It was found that the smallest errors in the estimated slope are demonstrated by the FABDEM model. In calculating slope lengths, none of the new models show a result that is superior in quality to what can be obtained using older DTMs (SRTM, etc.). However, for the LS-factor, the smallest errors are obtained when using the FABDEM model. The results obtained are valid both for the entire territory of each site in general and for arable lands in particular. The minimum values of errors in the LS-factor when using the FABDEM model lead to minimization of errors in calculating erosion losses of soil.