Incorporating the spatial variability in topography, hydrometeorology and hydrological processes within a multi-resolution watershed model
by Enrique R. Vivoni, Ralph M. Parsons Laboratory, Massachusetts Institute of Technology

ABSTRACT
Hydrologists have long recognized that the interaction of climate, topography, soils and vegetation leads to observable spatial and temporal patterns in hydrological response in watersheds. Our understanding of these complex relationships is aided through numeric models that best represent our current knowledge of the physical processes occurring within basins. The aim of this talk is to introduce a new modeling framework for studying land-surface and subsurface hydrologic response to meteorological forcing. The computational model has several distinguishing features that will be highlighted:

    (1) coupled unsaturated and saturated zones through a dynamic water table
    (2) coupled energy and hydrologic balance at the land surface
    (3) topographically-driven soil moisture redistribution, radiation and evapotranspiration.

Accurate topographic representation with minimal computational expense is achieved through the use of a triangulated irregular network (TIN) terrain model. Methods for deriving the multiple-resolution TIN terrain within geographic information systems (GIS) will be discussed. By integrating topography, land-surface properties and rainfall measurements, obtained from remote sensing (RS), the distributed model has been used in a variety of studies, including multi-year flood simulations in operational watersheds, flood forecasting with radar-based rainfall forecasts and sensitivity studies on terrain resolution and catchment response. Most importantly, the tool provides a complete description of the spatio-temporal variability and organization of the underlying hydrologic processes (e.g., soil moisture, runoff, water table position, evapotranspiration). Future developments point to the incorporation of additional processes (e.g., vegetation dynamics, snow, sediment transport), coupling to atmospheric models, and application to diverse settings (e.g. semi-arid, mountain) in conjunction with field measurements.


Seminar held January 27, 2003 at New Mexico Tech, at 3:15 pm, MSEC 103
Sponsored by Hydrology Program