Research On The Frequency Distribution Of Global Land Surface Slope At 30m Resolution

Slope frequency distribution is one of popular quantitative slope analyze method.Global land slope frequency distribution can provide information for further understanding earth surface ground slope,and can also provide a reference for related geological studies.This paper compared two prevalent DEM datasets,ASTER GDEM v3.0 and SRTMGL1 v3.0,from spatial distribution and land slope frequency distribution.Then chosen SRTMGL1 v3.0 due to its stability on land slope expression.Using SRTM to calculate global land surface slope,and then generate global land and land covers slope frequency distributions between 60°N and 56°S latitude.Land cover types are from Globe Land30.After analyzing land and land covers slope frequency distributions,the following conclusions are obtained.(1)Land slope frequency distribution is similar in different units(globe,continents,and tiles).Slope distributions in 3 units are right skewed and unimodal,and the frequency value increases as slope increases first,and then decreases as slope increases.(2)Global land slope frequency distributions are significantly concentrate in the section that ground surface slope gentler than 5°.(3)Land cover slope frequency distributions(except water body,permanent snow and ice)are consistent in the global range,and have a high degree of overlap with surface slope distribution.Similar to land slope frequency the frequency value increases as slope increases first,and then decreases as slope increases.(4)According to the artificial surface,cultivated land and forest slope frequency distributions,it is found that the artificial land surface and cultivated land have obvious flattening tendency,and the forest slope distribution range is wider.