Satellite-derived digital elevation model accuracy: hydrological modelling requirements

✍ Scribed by T. A. Endreny; E. F. Wood; D. P. Lettenmaier

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 541 KB
• Volume: 14
• Category: Article
• ISSN: 0885-6087
• DOI: 10.1002/(sici)1099-1085(20000215)14:2<177::aid-hyp919>3.0.co;2-u

✦ Synopsis

Hydrological models can bene®t from satellite-derived digital elevation models (DEMs) only after determining the hydrological model sensitivity to DEM inaccuracies. This study examined how vertical errors within a SPOT satellite-derived DEM of the 532 km 2 Little Washita River, OK, watershed aected hydrological predictions in the TOPLATS (topographically based land±atmosphere transfer scheme) water and energy balance model. Model predictions based on SPOT-derived DEM inputs were compared with US Geological Survey (USGS) 7 . 5-minute level 1 and level 2 DEM-based predictions to determine model sensitivity. Ten-year simulation runs using a statistical formulation of TOPLATS indicated that while DEM inaccuracies had little eect on basin average output, they had a signi®cant eect on the upper and lower quartiles of predicted water table depth. In 12-day simulation runs using a spatially explicit formulation of TOPLATS, which used 30-m grid cells across a 600 000 pixel model domain, elevation errors propagated into model predictions of soil moisture, runo, evapotranspiration, incoming solar radiation and surface skin temperature. Aggregation of the 30-m pixel model output to scales of 0 . 25 km 2 , however, reduced dierences between model-predicted vadose zone hydrology. Agreement between model-predicted water table hydrology was achieved at much larger scales of 5 km 2 , indicating that topography and its associated error structure may have a greater in¯uence on saturated rather than unsaturated hydrological modelling.