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Title: An integrated modelling framework of catchment-scale ecohydrological processes: 1. Model description and tests over an energy-limited watershed

item NIU, G.Y. - University Of Arizona
item PANICONI, C. - University Of Quebec
item TROCH, P.A. - University Of Arizona
item Scott, Russell - Russ
item DURCIK, M. - University Of Arizona
item ZENG, X. - University Of Arizona
item HUXMAN, T. - University Of Arizona
item Goodrich, David - Dave

Submitted to: Ecohydrology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2012
Publication Date: 4/1/2014
Citation: Niu, G., Paniconi, C., Troch, P., Scott, R.L., Durcik, M., Zeng, X., Huxman, T., Goodrich, D.C. 2014. An integrated modelling framework of catchment-scale ecohydrological processes: 1. Model description and tests over an energy-limited watershed. Ecohydrology. 7:427-439.

Interpretive Summary: An accurate prediction of the response of atmospheric, hydrological, and ecological processes in the face of climate change and other challenges requires accurate computer simulation models. In general it has been difficult to create models that are capable of simulating all these processes at the same time. A complex model was created to couple these processes together and then tested against observations collected in a cold and moist watershed from Vermont and a dry and hot watershed in Arizona. The coupled model, with minor changes, performed well in simulating the observed stream flow, snow amounts, soil moisture, surface energy, water, and carbon dioxide exchange. The resulting model provides a basis for pulling together other types of Earth system models (e.g., soil chemistry and erosion models) and for assessing the impacts of climate change on watershed hydrological and ecological processes.

Technical Abstract: The interactions between atmospheric, hydrological, and ecological processes at various spatial and temporal scales are not fully represented inmost ecohydrologicalmodels. This first of a two-part paper documents a fully integrated catchment-scale ecohydrological model consisting of a three-dimensional physically based hydrological model and a land surface model. This first part also presents a first application to test the model over an energy-limited catchment (8.4km2) of the Sleepers River watershed in Vermont. The physically based hydrological model (CATchment HYdrology, CATHY) describes three-dimensional subsurface flow in variably saturated porous media and surface routing on hillslopes and in stream channels, whereas the land surface model (LSM), an augmented version of Noah LSM with multiple parameterization schemes (NoahMP), accounts for energy, water, and carbon flux exchanges between various land surface elements and the atmosphere. CATHY and NoahMP are coupled through exchanges of water fluxes and states. In the energy-limited catchment of the Sleepers River watershed, where snowmelt runoff generation is the dominant hydrologic flux, the coupled CATHY/NoahMPmodel at both 90 and 30-msurface grid resolutions, with minimal calibration, performs well in simulating the observed snow accumulation, and melt and subsequent snowmelt discharge. The Nash–Sutcliffe model efficiency of daily discharge is above 0.82 for both resolutions. The simulation at 90-mresolution shows amarginal improvement over that at 30-m resolution because of more elaborate calibration of model parameters. The coupled CATHY/NoahMP also shows a capability of simulating surface-inundated area and distributed surface water height, although the accuracy of these simulations needs further evaluation. The CATHY/NoahMP model is thus also a potentially useful research tool for predicting flash flood and lake dynamics under climatic change.