Remote sensing and hydrologic modeling of arid watersheds: A scale analysis. Final report, July 15, 1986-August 31, 1990.

摘要

The increasing availability of digital elevation data (DED) created from remotely sensed data has promoted the development of computer algorithms for the calculation of geomorphometric properties of the land surface. These include parameters that are tedious or impossible to do by hand, for example, stream properties by order and flow path mapping for every location within the drainage basin. Flow paths especially are critical for water routing in hydrologic models. These algorithms can be used to explore spatial trends in landscape properties as a function of rock type, climate or neotectonic environment. The DED can be readily linked with a geographic information system (GIS) which is used to parameterize a quasi-physically based surface runoff model. Various representations (Shreve orders) of the watershed are created by simplifying a stream network delineated from the DED. Different Shreve orders produce significantly different geomorphometrics that affect simulated runoff volumes. At one of the study sites, the DED are not of sufficient detail to allow stream network extraction. Therefore, classification of SPOT panchromatic data was used to delineate ephemeral, fluvial networks on this low-relief, arid basin. A one pixel proximity search classified correctly over 80 percent of the channelized flow. 3 figs., 2 tabs.