Improvement of distributed snowmelt energy balance modeling with MODIS-based NDSI-derived fractional snow-covered area data

摘要

Describing the spatial variability of heterogeneous snowpacks at a watershed or mountain-front scale is important fornimprovements in large-scale snowmelt modelling. Snowmelt depletion curves, which relate fractional decreases in snow-ncovered area (SCA) against normalized decreases in snow water equivalent (SWE), are a common approach to scale-upnsnowmelt models. Unfortunately, the kinds of ground-based observations that are used to develop depletion curves are expensivento gather and impractical for large areas. We describe an approach incorporating remotely sensed fractional SCA (FSCA) datanwith coinciding daily snowmelt SWE outputs during ablation to quantify the shape of a depletion curve. We joined meltnestimates from the Utah Energy Balance Snow Accumulation and Melt Model (UEB) with FSCA data calculated from annormalized difference snow index snow algorithm using NASA’s moderate resolution imaging spectroradiometer (MODIS)nvisible (0Ð545–0Ð565 µm) and shortwave infrared (1Ð628–1Ð652 µm) reflectance data. We tested the approach at three 500 m2nstudy sites, one in central Idaho and the other two on the North Slope in the Alaskan arctic. The UEB-MODIS-derivedndepletion curves were evaluated against depletion curves derived from ground-based snow surveys. Comparisons showednstrong agreement between the independent estimates. Copyright  2010 John Wiley & Sons, Ltd.