Model:WRF-Hydro

WRF-Hydro

Metadata

Also known as	WRF-Hydro Modeling System
Model type	Modular
Model part of larger framework
Note on status model
Date note status model

Incorporated models or components:	NOAH-MP,

Spatial dimensions	1D, 2D
Spatial extent	Continental, Regional-Scale, Landscape-Scale, Watershed-Scale, Reach-Scale, Point-Based
Model domain	Terrestrial, Hydrology, Coastal, Climate, Ecosystems, Cryosphere
One-line model description	The WRF-Hydro® Modeling System, an open-source community model, is used for a range of projects, including flash flood prediction, regional hydroclimate impacts assessment, seasonal forecasting of water resources, and land-atmosphere coupling studies. It produces forecasts and analyses for all major terrestrial water-cycle components: Precipitation, Streamflow, Soil moisture, Snowpack, Flooding, Groundwater.
Extended model description	The Weather Research and Forecasting Model Hydrological modeling system (WRF-Hydro) was developed as a community-based, open source, model coupling framework designed to link multi-scale process models of the atmosphere and terrestrial hydrology to provide: An extensible multi-scale & multi-physics land-atmosphere modeling capability for conservative, coupled and uncoupled assimilation & prediction of major water cycle components such as: precipitation, soil moisture, snow pack, ground water, streamflow, and inundation Accurate and reliable streamflow prediction across scales (from 0-order headwater catchments to continental river basins and from minutes to seasons) A research modeling testbed for evaluating and improving physical process and coupling representations.

Keywords:	model, software, hydrometeorology, land-atmosphere interactions, terrestrial hydrology, hydrology, Earth science, Fortran, hydrologic model,

Name	Molly McAllister
Type of contact	Technical contact
Institute / Organization	National Center for Atmospheric Research (NCAR
Postal address 1	3450 Mitchell Ln
Postal address 2
Town / City	Boulder
Postal code	80301
State	Colorado
Country	United States
Email address	mollymca@ucar.edu
Phone
Fax

Name	David Gochis
Type of contact	Model developer
Institute / Organization	NCAR
Postal address 1	3450 Mitchell Ln
Postal address 2
Town / City	Boulder
Postal code	80301
State	Colorado
Country	United States
Email address	gochis@ucar.edu
Phone
Fax

Name	WRF-Hydro Team
Type of contact	Model developer
Institute / Organization	NCAR
Postal address 1	3450 Mitchell Ln
Postal address 2	3450 Mitchell Ln
Town / City	Boulder
Postal code	80301
State	Colorado
Country	United States
Email address	wrfhydro@ucar.edu
Phone
Fax

Name
Type of contact
Institute / Organization
Postal address 1
Postal address 2
Town / City
Postal code
State
Country	United States
Email address
Phone
Fax

Supported platforms	Unix, Linux
Other platform
Programming language	Fortran90
Other program language
Code optimized	Multiple Processors
Multiple processors implemented	Shared memory
Nr of distributed processors
Nr of shared processors
Start year development	2008
Does model development still take place?	Yes
If above answer is no, provide end year model development
Code development status	Active
When did you indicate the 'code development status'?	2020
Model availability	As code, As teaching tool
Source code availability (Or provide future intension)	Through web repository
Source web address	https://ral.ucar.edu/projects/wrf_hydro/model-code
Source csdms web address
Program license type	Other
Program license type other	https://ral.ucar.edu/projects/wrf_hydro/terms-of-use
Memory requirements	8GB min
Typical run time	Depends

Describe input parameters	For a complete explanation of input parameters please see the WRF-Hydro Technical Description https://ral.ucar.edu/projects/wrf_hydro/technical-description-user-guide WRF-Hydro requires a number of input files describing the model domain, parameters, initial conditions, hydrologic routing, and when run in a standalone configuration, meteorological forcing files.
Input format
Other input format	NetCDF
Describe output parameters	The following output files are available to the user, depending on their run configuration: 1. Land surface model output 2. Land surface diagnostic output 3. Streamflow output at all channel reaches/cells 4. Streamflow output at forecast points or gage reaches/cells 5. Streamflow on the 2D high resolution routing grid (gridded channel routing only) 6. Terrain routing variables on the 2D high resolution routing grid 7. Lake output variables 8. Ground water output variables 9. A text file of streamflow output at either forecast points or gage locations For a detailed table of each variable contained within each output file, see the WRF-Hydro Output Variable Matrix V5 located on our website https://ral.ucar.edu/projects/wrf_hydro/technical-description-user-guide
Output format
Other output format	NetCDF
Pre-processing software needed?	Yes
Describe pre-processing software	While some parameter files and templates are included with the model source code, most must be generated by the user. We provide a number of scripts and preprocessing utilities on the WRF-Hydro website (https://ral.ucar.edu/projects/wrf_hydro) in order to aid in this process. These include NCAR Command Language (NCL) scripts to regrid forcing data from commonly used data sources, R scripts to generate parameter and model initialization files, and a set of Python based ArcGIS pre-processing tools.
Post-processing software needed?	Yes
Describe post-processing software	It is helpful to utilize post-processing software considering the volume of output files, however, we do not recommend anything specific.
Visualization software needed?	Yes
If above answer is yes
Other visualization software	NCview, Panoply, NetCDF viewer is helpful

Describe processes represented by the model	See the WRF-Hydro Technical Description https://ral.ucar.edu/projects/wrf_hydro/technical-description-user-guide "First the 1-dimensional (1D) column land surface model calculates the vertical fluxes of energy (sensible and latent heat, net radiation) and moisture (canopy interception, infiltration, infiltration-excess, deep percolation) and soil thermal and moisture states. Infiltration excess, ponded water depth and soil moisture are subsequently disaggregated from the 1D LSM grid, typically of 1–4 km spatial resolution, to a highresolution, typically 30–100 m, routing grid using a time-step weighted method (Gochis and Chen, 2003) and are passed to the subsurface and overland flow terrain-routing modules. In typical U.S. applications, land cover classifications for the 1D LSMs are provided by the USGS 24-type Land Use Land Cover product or MODIS Modified IGBP 20-category land cover product (see WRF/WPS documentation); soil classifications are provided by the 1-km STATSGO database (Miller and White, 1998); and soil hydraulic parameters that are mapped to the STATSGO soil classes are specified by the soil analysis of Cosby et al. 20 (1984). Other land cover and soil type classification datasets can be used with WRF-Hydro but users are responsible for mapping those categories back to the same categories as used in the USGS or MODIS land cover and STATSGO soil type datasets. The WRF model pre-processing system (WPS) also provides a fairly comprehensive database of land surface data that can be used to set up the Noah and Noah-MP land surface models. It is possible to use other land cover and soils datasets. Then subsurface lateral flow in WRF-Hydro is calculated prior to the routing of overland flow to allow exfiltration from fully saturated grid cells to be added to the infiltration excess calculated by the LSM. The method used to calculate the lateral flux of the saturated portion of the soil column is that of Wigmosta et al. (1994) and Wigmosta and Lettenmaier (1999), implemented in the Distributed Hydrology Soil Vegetation Model (DHSVM). It calculates a quasi-3D flow, which includes the effects of topography, saturated soil depth, and depth-varying saturated hydraulic conductivity values. Hydraulic gradients are approximated as the slope of the water table between adjacent grid cells in either the steepest descent or in both x- and y-directions. The flux of water from one cell to its down-gradient neighbor on each timestep is approximated as a steady-state solution. The subsurface flux occurs on the coarse grid of the LSM while overland flow occurs on the fine grid. Next, WRF-Hydro calcuates the water table depth according to the depth of the top of the saturated soil layer that is nearest to the surface. Typically, a minimum of four soil layers are used in a 2-meter soil column used in WRF-Hydro but this is not a strict requirement. Additional discretization permits improved resolution of a time-varying water table height and users may vary the number and thickness of soil layers in the model namelist described in the Appendices A3, A4, and A5. Then overland flow is defined. The fully unsteady, spatially explicit, diffusive wave formulation of Julien et al. (1995-CASC2D) with later modification by Ogden (1997) is the current option for representing overland flow, which is calculated when the depth of water on a model grid cell exceeds a specified retention depth. The diffusive wave equation accounts for backwater effects and allows for flow on adverse slopes (Ogden, 1997). As in Julien et al. (1995), the continuity equation for an overland flood wave is combined with the diffusive wave formulation of the momentum equation. Manning’s equation is used as the resistance formulation for momentum and requires specification of an overland flow roughness parameter. Values of the overland flow roughness coefficient used in WRF-Hydro were obtained from Vieux (2001) and were mapped to the existing land cover classifications provided by the USGS 24-type land-cover product of Loveland et al. (1995) and the MODIS 20-type land cover product, which are the same land cover classification datasets used in the 1D Noah/Noah-MP LSMs. Additional modules have also been implemented to represent stream channel flow processes, lakes and reservoirs, and stream baseflow. In WRF-Hydro v5.0 inflow into the stream network and lake and reservoir objects is a one-way process. Overland flow reaching grid cells identified as ‘channel’ grid cells pass a portion of the surface water in excess of the local ponded water retention depth to the channel model. This current formulation implies that stream and lake inflow from the land surface is always positive to the stream or lake element. There currently are no channel or lake loss functions where water can move from channels or lakes back to the landscape. Channel flow in WRF-Hydro is represented by one of a few different user-selected methodologies described below. Water passing into and through lakes and reservoirs is routed using a simple level pool routing scheme. Baseflow to the stream network is represented using a conceptual catchment storage-discharge bucket model formulation (discussed below) which obtains “drainage” flow from the spatially-distributed landscape. Discharge from buckets is input directly into the stream using an empirically-derived storage-discharge relationship. If overland flow is active, the only water flowing into the buckets comes from soil drainage. This is because the 21 overland flow scheme will pass water directly to the channel model. If overland flow is switched off and channel routing is still active, then surface infiltration excess water from the land model is collected over the pre-defined catchment and passed into the bucket as well. Each of these process options are enabled through the specification of options in the model namelist file."
Describe key physical parameters and equations	See WRF-Hydro Technical Description https://ral.ucar.edu/projects/wrf_hydro/technical-description-user-guide
Describe length scale and resolution constraints	See WRF-Hydro Technical Description https://ral.ucar.edu/projects/wrf_hydro/technical-description-user-guide
Describe time scale and resolution constraints	See WRF-Hydro Technical Description https://ral.ucar.edu/projects/wrf_hydro/technical-description-user-guide
Describe any numerical limitations and issues	See WRF-Hydro Technical Description https://ral.ucar.edu/projects/wrf_hydro/technical-description-user-guide

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

Do you have current or future plans for collaborating with other researchers?	The development repository is public and has contribution guidelines https://github.com/NCAR/wrf_hydro_nwm_public We are open to avenues for collaboration WRF-Hydro Helpdesk: https://ral.ucar.edu/projects/wrf_hydro/contact WRF-Hydro User's Forum: https://groups.google.com/a/ucar.edu/g/wrf-hydro_users

Is there a manual available?	Yes
Upload manual if available:	Media:https://ral.ucar.edu/projects/wrf_hydro/technical-description-user-guide
Model website if any	https://ral.ucar.edu/projects/wrf_hydro
Model forum / discussion board	https://groups.google.com/a/ucar.edu/g/wrf-hydro_users

Comments

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OpenMI compliant	Not yet"Not yet" is not in the list (Yes, No but planned, No but possible, No not possible) of allowed values for the "Code openmi compliant or not" property.
BMI compliant	Not yet"Not yet" is not in the list (Yes, No but planned, No but possible, No not possible) of allowed values for the "Code IRF or not" property.
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.
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