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Full-Text Articles in Earth Sciences
Random Forests Applied As A Soil Spatial Predictive Model In Arid Utah, Alexander Knell Stum
Random Forests Applied As A Soil Spatial Predictive Model In Arid Utah, Alexander Knell Stum
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Initial soil surveys are incomplete for large tracts of public land in the western USA. Digital soil mapping offers a quantitative approach as an alternative to traditional soil mapping. I sought to predict soil classes across an arid to semiarid watershed of western Utah by applying random forests (RF) and using environmental covariates derived from Landsat 7 Enhanced Thematic Mapper Plus (ETM+) and digital elevation models (DEM). Random forests are similar to classification and regression trees (CART). However, RF is doubly random. Many (e.g., 500) weak trees are grown (trained) independently because each tree is trained with a new randomly …
A River Transformed: Historic Geomorphic Changes Of The Lower Rio Grande In The Big Bend Region Of Texas, Chihuahua, And Coahuila, David James Dean
A River Transformed: Historic Geomorphic Changes Of The Lower Rio Grande In The Big Bend Region Of Texas, Chihuahua, And Coahuila, David James Dean
All Graduate Theses and Dissertations, Spring 1920 to Summer 2023
Over the last century, the construction and management of large dams and stream-flow diversions, and periodic drought have resulted in significant declines in stream flow of the lower Rio Grande in the Big Bend region. Reductions in mean annual flow and peak discharge have resulted in channel narrowing by the formation of vertically accreting inset floodplains. Narrowing has been temporarily interrupted by infrequent large dam releases greater than 1000 m3/s that have temporarily widened the channel; however, after each of these events, narrowing has resumed. Prior to 1942, floods of this magnitude occurred approximately once every 4 years …