Model:VIC

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VIC

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Summary Contact Technical specs In/Output Process Testing Other Component info Also known as Model type Single Model part of larger framework Note on status model Date note status model Spatial dimensions 3D Spatial extent Global, Continental, Regional-Scale Model domain One-line model description VIC (Variable Infiltration Capacity) is a macroscale hydrologic model that solves full water and energy balances, originally developed by Xu Liang at the University of Washington. Extended model description The VIC model is a large-scale, semi-distributed hydrologic model. As such, it shares several basic features with the other land surface models (LSMs) that are commonly coupled to global circulation models (GCMs): The land surface is modelled as a grid of large (>1km), flat, uniform cells Sub-grid heterogeneity (e.g. elevation, land cover) is handled via statistical distributions. Inputs are time series of daily or sub-daily meteorological drivers (e.g. precipitation, air temperature, wind speed). Land-atmosphere fluxes, and the water and energy balances at the land surface, are simulated at a daily or sub-daily time step Water can only enter a grid cell via the atmosphere Non-channel flow between grid cells is ignored The portions of surface and subsurface runoff that reach the local channel network within a grid cell are assumed to be >> the portions that cross grid cell boundaries into neighboring cells Once water reaches the channel network, it is assumed to stay in the channel (it cannot flow back into the soil) This last point has several consequences for VIC model implementation: Grid cells are simulated independently of each other Entire simulation is run for each grid cell separately, 1 grid cell at a time, rather than, for each time step, looping over all grid cells Meteorological input data for each grid cell (for the entire simulation period) are read from a file specific to that grid cell Time series of output variables for each grid cell (for the entire simulation period) are stored in files specific to that grid cell Routing of stream flow is performed separately from the land surface simulation, using a separate model (typically the routing model of Lohmann et al., 1996 and 1998) Keywords: global, Name Dennis Lettenmaier Type of contact Technical contact Institute / Organization Postal address 1 Dept. of Civil and Env. Engineering Postal address 2 University of Washington, Box 352700 Town / City Seattle Postal code 98195-2700 State Washington Country United States Email address vicadmin@hydro.washington.edu Phone 206.685.1796 Fax Supported platforms Unix, Linux Other platform Programming language Other program language Code optimized Single Processor Multiple processors implemented Nr of distributed processors Nr of shared processors Start year development Does model development still take place? Yes If above answer is no, provide end year model development Code development status When did you indicate the 'code development status'? Model availability As code Source code availability (Or provide future intension) Through web repository Source web address http://www.hydro.washington.edu/Lettenmaier/Models/VIC/Development/BetaTesting.shtml Source csdms web address Program license type Other Program license type other Memory requirements Typical run time Describe input parameters Global Parameter File user_def.h File Meteorological Forcing Files Soil Parameter File Vegetation Library File Vegetation Parameter File (Optional) Initial State File (Optional) Elevation Band File (Optional) Lake/Wetland Parameter File Input format Other input format http://www.hydro.washington.edu/Lettenmaier/Models/VIC/Documentation/Inputs.shtml Describe output parameters http://www.hydro.washington.edu/Lettenmaier/Models/VIC/Documentation/Inputs.shtml Output format ASCII, Binary Other output format http://www.hydro.washington.edu/Lettenmaier/Models/VIC/Documentation/OutputVarList.shtml Pre-processing software needed? Yes Describe pre-processing software Post-processing software needed? Yes Describe post-processing software http://www.hydro.washington.edu/Lettenmaier/Models/VIC/Documentation/PostProcessing.shtml Visualization software needed? No If above answer is yes Other visualization software Describe processes represented by the model Land Cover and Soil Snow Model Meteorology (Inputs, Distributed Precip, and Snow/Elevation Bands) Frozen Soil (including Permafrost) Dynamic Lake/Wetland Model (new to 4.1.1) Flow Routing Describe key physical parameters and equations Land Cover can subdivide each grid cell's land cover into arbitrary number of "tiles", each corresponding to the fraction of the cell covered by that particular land cover (e.g. coniferous evergreen forest, grassland, etc.) geographic locations or configurations of land cover types are not considered; VIC lumps all patches of same cover type into 1 tile Snow Model VIC considers snow in several forms: ground snow pack, snow in the vegetation canopy, and snow on top of lake ice. Main features: Ground snow pack is quasi 2-layer; the topmost portion of the pack is considered separately for solving energy balance at pack surface Meteorological Input Data Can use sub-daily met data (prcp, tair, wind) at intervals matching simulation time step Can use daily met data (prcp, tmax, tmin, wind) for daily or sub-daily simulations Disaggregates daily met data to sub-daily via Thornton & Running algorithm and others (computes incoming sw and lw rad, pressure, density, vp) VIC can consider spatial heterogeneity in precipitation, arising from either storm fronts/local convection or topographic heterogeneity. Here we consider the influence of storm fronts and local convective activity. This functionality is controlled by the DIST_PRCP option in the global parameter file. Main features: Can subdivide the grid cell into a time-varying wet fraction (where precipitation falls) and dry fraction (where no precipitation falls). The wet fraction depends on the intensity of the precipitation; the user can control this function. Fluxes and storages from the wet and dry fractions are averaged together (weighted by area fraction) to give grid-cell average for writing to output files. Elevation Bands VIC can consider spatial heterogeneity in precipitation, arising from either storm fronts/local convection or topographic heterogeneity. Here we consider the influence of topography, via elevation bands. This is primarily used to produce more accurate estimates of mountain snow pack. This functionality is controlled by the SNOW_BAND option in the global parameter file. Main features: Can subdivide the grid cell into arbitrary number of elevation bands, to account for variation of topography within cell Within each band, meteorologic forcings are lapsed from grid cell average elevation to band's elevation Geographic locations or configurations of elevation bands are not considered; VIC lumps all areas of same elevation range into 1 band Fluxes and storages from the bands are averaged together (weighted by area fraction) to give grid-cell average for writing to output files However, the band-specific values of some variables can be written separately in the output files Liang et al. (1999): set QUICK_FLUX to TRUE in global parameter file; this is the default for FULL_ENERGY = TRUE and FROZEN_SOIL = FALSE. Cherkauer et al. (1999): set QUICK_FLUX to FALSE in global parameter file; this is the default for FROZEN_SOIL = TRUE. By default, the finite difference formulation is an explicit method. By default, the nodes of the finite difference formulation are spaced linearly. These apply to the case QUICK_FLUX = FALSE and FROZEN_SOIL = TRUE, i.e. the formulation of Cherkauer et al. (1999). Describe length scale and resolution constraints Describe time scale and resolution constraints Describe any numerical limitations and issues Describe available calibration data sets Upload calibration data sets if available: Describe available test data sets Upload test data sets if available: Describe ideal data for testing http://www.hydro.washington.edu/Lettenmaier/Models/VIC/Development/BetaTesting.shtml Do you have current or future plans for collaborating with other researchers? https://mailman2.u.washington.edu/mailman/listinfo/vic_users Is there a manual available? No Upload manual if available: Model website if any Model forum / discussion board Comments unsure what type of license This part will be filled out by CSDMS staff OpenMI compliant No but possible BMI compliant No but possible WMT component Not yet"Not yet" is not in the list (Yes, In progress, No but possible, No not possible) of allowed values for the "Code CMT compliant or not" property. PyMT component Is this a data component Can be coupled with:

Model info Authors Dennis Lettenmaier Source code Go to external source code site Model citations Nr. of publications: 810 Total citations: 46297 h-index: 101 m-quotient: 2.46 QR-code Link to this page Other models by author VIC

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Nr. of publications:	810
Total citations:	46297
h-index:	101
m-quotient:	2.46