Using the Utah Energy Balance Snow-Melt Model to Quantify Snow and Glacier Melt in the Himalayan Region

Quantification of the melting of glaciers in the Hindu-Kush Himalayan (HKH) region is important for decision making in water sensitive sectors, and for water resources management and provide flood protection. Access to and monitoring of the glaciers and their melt outflow is challenging, thus modeling based on remote sensing offers the potential for providing information to improve water resources decision making and management. In this paper we report on a distributed version of the Utah Energy Balance (UEB) snowmelt model, referred to as UEBGrid, which was adapted to quantify the melting of glaciers taking advantage of NASA remote sensing and earth science data products such as, satellite data, reanalysis data and climate model outputs. The representations of surface energy balance fluxes in the UEB snowmelt model have been extended to include the capability to quantify glacier melt. To account for clean and debris covered glaciers, substrate albedo, determined from remote sensing and glacier mapping is taken as an input. Representation of glacier within the model involves inclusion of glacier ice as a substrate and generation of melt from the ice substrate when seasonal snow has melted. In UEBGrid, a watershed is divided into a mesh of grid cells and the model runs individually for each grid cell. Users have control to provide separate inputs for each grid cell, or spatially constant inputs for the entire domain. Therefore, regional variability in snow and glacier melting is computed. Outflow can be aggregated over subwatersheds defined, for example, from a digital elevation model, and input into other hydrologic models. UEBGrid was tested using weather, climate and hydrologic data at Langtang Khola watershed, Nepal. UEBGrid is being included into the EPA BASINS software to facilitate this linking to other models and to take advantage of BASINS\u27 capability to manage input data and visualize results. This capability for using gridded NASA Earth Science data, and the associated data model and workflow for storage and processing of data into and out of models linked in BASINS advances hydrologic information science. The capability for estimating the melt from glaciers and snow in a data sparse region will help water managers in decision making and management of water resources in areas impacted by glacier and snow melt