The Colorado Basin River Forecast Center (CBRFC) is responsible for the entire Colorado Basin and the eastern Great Basin. From a water management perspective, the commitment of water to various users most often occurs in the spring, and is almost entirely based on estimates of the western USA snowpack. Improving seasonal drought predictions requires use of models that provide physically realistic simulations of fundamental hydrologic processes. Among these, for the western USA, representation of snow is perhaps most critical.
As drought frequency increases in the Colorado River Basin and the Great Basin, it is critical that the CBRFC and the dependent water managers have more comprehensive real-time knowledge of the snow cover and its properties for more precise runoff forecasting and stakeholder decision support. The primary objective of this project is to integrate real-time high precision MODIS Snow Covered Area and Grain size (MODSCAG) fractional snow covered area (SCA) into CBRFC modeling and analysis systems and into stakeholder oriented data products, drastically reducing SCA uncertainties that have hampered forecasting operations for decades. A secondary objective is to ingest and study MODIS Dust Radiative Forcing in Snow (MODDRFS) radiative forcing imagery, to better understand its value as an input to modeling and forecasting approaches.
This collaboration addresses drought prediction, assessment, adaptation, and mitigation in support of energy security/efficiency; natural resource conservation; and household, municipal, industrial, and in-stream demands for water. It will also improve access and availability of actionable water monitoring, hence drought information. The Snow Cover and Dust Forcing products are generated and distributed in near real-time by the JPL Snow Server for access by CBRFC. CBRFC provides a direct connection to stakeholders (End Users) and, together with other linked NWS operational centers, provides an institutional home to maintain the advances of this effort beyond the project's end.
Geographic Focus
Colorado River Basin, Western United States
Application Readiness Level
ARL = 8 (Application completed and functionality has been proven)
MODSCAG data products have been validated in the Colorado River Basin and the benefits of integration of these data for river forecasting and water management have been clearly identified. CBRFC is currently integrating MODSCAG data products into CBRFC forecasts, and testing improved forecasts with end-users and stakeholders. Integration and testing of the MODDRFS data products is ongoing.
Principal Investigator
Thomas H. Painter, NASA JPL/Caltech
Project Team
Chris Mattmann, NASA JPL/Caltech
Kevin Werner, NWS Colorado Basin River Forecast Center
Collaborators and Stakeholders
NASA JPL/Caltech, National Weather Service, Denver Water, Colorado River Water Conservation District, US Bureau of Reclamation
Project Overview
CBRFC snow analyses are currently derived from or validated by the in situ observation network (Snow Telemetry-SNOTEL), which provides critical information to characterize mountain snowpack, but is limited in capacity to measure snow-covered areas in heterogeneous terrain, and at higher and lower elevations. As a consequence, streamflow forecasts are limited in that they currently rely on spatially sparse measurements to force the hydrological modeling to track snow pack conditions. This limitation is particularly important during the melt season when the snow pack rapidly changes and the in situ network does not capture the broader geographic distribution.
The other primary approach for real-time snow analysis is the CBRFC’s hydrologic and snow modeling, which forecasts runoff at 458 locations with the Community Hydrologic Prediction System (CHPS) software. Its snow model is a simple temperature index model (SNOW-17; [Anderson, 1973]). In the model, winter snow accumulation and spring melt depend on observed precipitation and accumulated temperature anomalies. CBRFC makes periodic adjustments to the model snow water content to correct for biases in the daily realtime precipitation-observing network. In addition, CBRFC forecasters often make manual ad hoc modifications to the snow model states (water content, SCA, and melt rate) during the melt season to correct the model streamflow, using data sources such as anecdotal reports.
These approaches overlook a major source of spatially dense snowpack information: remotely sensed snow covered area (SCA). This projects major objective is to operationalize an objective snow model adjustment process that applies the MODSCAG snow covered area in real-time in the CBRFC modeling and forecasting framework (CHPS). Forecasters are evaluating and assimilating MODSCAG data into snow model simulations, thereby forming the initial watershed conditions for streamflow forecasts. Given our increasing knowledge of the marked acceleration of snowmelt by dust radiative forcing in the Upper Colorado and Wasatch Mountains, the project is also exploring the use of the MODIS Dust Radiative Forcing in Snow product in the CBRFC system.
Researchers at JPL and forecasters at CBRFC are jointly developing and testing approaches in the CBRFC operational setting. This collaborative approach is a necessary component for successful bridging from research to operations. A major strength of this project is the close involvement of the project team with an operational agency that serves the US water sector and plans to institutionalize the results of the research effort beyond the funding term of the project.
Project Publications
Deems, J. S., T. H. Painter, J. J. Barsugli, J. Belnap, and B. Udall (2014), Combined impacts of current and future dust deposition and regional warming on Colorado River Basin hydrology, Hydrol. Earth Syst. Sci. Discuss., 10, 6237-6275, doi:10.5194/hessd-10-6237-2013.
Related Research Areas