A Physically Based Runoff Routing Model for Land Surface and Earth System Models

Abstract

A new physically based runoff routing model, called the Model for Scale Adaptive River Transport (MOSART), has been developed to be applicable across local, regional, and global scales. Within each spatial unit, surface runoff is first routed across hillslopes and then discharged along with subsurface runoff into a “tributary subnetwork” before entering the main channel. The spatial units are thus linked via routing through the main channel network, which is constructed in a scale-consistent way across different spatial resolutions. All model parameters are physically based, and only a small subset requires calibration. MOSART has been applied to the Columbia River basin at ⅙°, ⅛°, ¼°, and ½° spatial resolutions and was evaluated using naturalized or observed streamflow at a number of gauge stations. MOSART is compared to two other routing models widely used with land surface models, the River Transport Model (RTM) in the Community Land Model (CLM) and the Lohmann routing model, included as a postprocessor in the Variable Infiltration Capacity (VIC) model package, yielding consistent performance at multiple resolutions. MOSART is further evaluated using the channel velocities derived from field measurements or a hydraulic model at various locations and is shown to be capable of producing the seasonal variation and magnitude of channel velocities reasonably well at different resolutions. Moreover, the impacts of spatial resolution on model simulations are systematically examined at local and regional scales. Finally, the limitations of MOSART and future directions for improvements are discussed.

Modeling surface water dynamics in the Amazon Basin using MOSART-Inundation v1.0: impacts of geomorphological parameters and river flow representation

“…In the MOSART model, each computation unit (subbasin or grid cell) has a major channel (or main channel) and a tributary subnetwork that represents the combined equivalent transport capacity of all the tributaries within the computation unit (Li et al, 2013). Two simplified forms of the onedimensional Saint-Venant equations (i.e., kinematic wave or diffusion wave methods) are used to represent water flow over hillslopes, in the tributary subnetwork or in main channels.…”

“…The Model for Scale Adaptive River Transport (MOSART) was developed to simulate terrestrial surface water flow from hillslopes to the basin outlet (Li et al, 2013). It was designed to be applicable at the local, regional or continental scale.…”

Sensitivity of future U.S. Water shortages to socioeconomic and climate drivers: a case study in Georgia using an integrated human-earth system modeling framework

“…The 0.5°monthly GCAM demand was uniformly downscaled to 1/8th degree daily resolution to match with the resolution in the supply analysis. Water supply is simulated by a dynamically downscaled regional earth system model (RESM) (Leung et al 2006;Ke et al 2012;Gao et al 2014) coupled to a land surface model (Community Land Surface Model 4 or CLM) (Lawrence et al 2011), and a river routing model (Model for Scale Adaptive River Transport or MOSART) (Li, et al 2013). In contrast to statistical downscaling methods, use of a regional earth system model makes direct use of regional atmospheric physics and local geographic features such as elevation and water bodies, land surface processes to compute and allocate local runoff.…”

“…Projected regulated stream flows and water deficits are determined by a water resource management model (WM) (Voisin et al 2013a) that regulates natural flows using standardized reservoir rules and the downscaled water demands from GCAM-USA. WM is fully coupled to the routing model MOSART (Li et al 2013) which hydrodynamically transports the managed water through the river channels. The MOSART-WM model is forced by runoff and base flow simulated by CLM and water demand from GCAM.…”

Planning for climate change impacts on hydropower in the Far North

“…Because getting to detailed, precise information at the watershed scale requires intensive effort and significant computing power, these methods have mostly been applied to case studies of particular basins (Bennett et al, 2012;Shrestha et al, 2012 in the Far North). Land surface models within GCMs and regional climate models (RCMs) are another class of model that have been tested and compared for hydrologic applications, and are designed for global domains, but challenges of river routing (Li et al, 2013) and other local processes cause these tools to have large uncertainties at the watershed scale (Clark et al, 2015). The hydrologic modeling should also be used to drive models of sediment load for projecting reservoir in-filling and wear and tear on turbines (Toniolo and Schultz, 2005).…”