Comparing AVHRR and hydrologically modelled discontinuous alpine snow-covered area estimates

Snowcover and snowpack information are used extensively by water resources managers to estimate peak streamflows and seasonal runoff volumes. In the southwestern US, the NASA EOS Southwestern Regional Earth Science Applications Center is providing these data to users, such as the Salt River Project, to improve hydrologic predictions. Snowpack water volumes are derived from the combination of snow covered area estimates and snow water equivalent estimates. NOAA Advanced Very High Resolution Radiometer imagery are used to generate a daily fractional SCA product on a I km grid. These data are compared to modelled SCA generated from the USGS Precipitation Runoff Modelling System. The meteorological data driving the PRMS model are sparse across the study area (White River Basin in Arizona). Overall, the PRMS-modelled SCA is greater than AVHRR-derived SCA at higher elevations and lesser at lower elevations, predicting too much snowmelt streamflow too early in the winter season.