This repository contains modified fortran code for running the Weather Research and Forecasting Model v 4.0. The model has been modified to include methods for irrigation in two land surface models based on land use categories.
It must be configured and compiled similarly to the original WRF model v 4.0. We briefly describe critical differences between the NCAR version and the version in this repository below.
The file namelist.input section &physics has an added irrigation parameter opt_irrig. This parameter has a default of 0, which is apply no irrigation, and only works for the Noah land surface model with mosaic option and the Noah-MP model. The land use categories must be based on USGS 24-category data, in particular, irrigated cropland must be designated as category 3. Running WRF using another land surface model such as CLM will not use this parameter.
The code is only written to simulate single growing seasons initalized after Jan 1 (northern hemisphere). However, it could easily be modified for multiple growing seasons or alternative purposes. We highly encourage this and hope you may find the modified code useful.
The major code modifications can be found in module_sf_noahmpdry.F and module_sf_noahdry.F under the physics (/phys/) directory.
References:
Link to online dissertation (Nov 2020): https://krex.k-state.edu/dspace/handle/2097/40906
Link to original WRF model repository and description: https://github.com/wrf-model/WRF
opt_irrig = 0,
DEFAULT. Apply no irrigation to any grid cell.
opt_irrig = 1,
Only check for dates after May 15. Set top two soil layers to field capacity at each time step if less than field capacity. If using Noah:Mosaic, it only performs these steps for the fraction of the gridc cell. In Noah-MP, applies to entire grid cell if dominant land use category is irrigated cropland.
opt_irrig = 2,
Noah-Mosaic: Apply irrigation after May 15 for only the irrigated fraction of the cell if the soil moisture drops to wilting point plus 20% of the plant available water. Apply at a constant rate of 20 mm hr-1 for two hours as non-convective precipitation.
Noah-MP: Apply irrigation after May 15 for grid cells with a dominant land type of irrigation if the soil moisture drops to wilting point plus 20% of the plant available water. Apply at a constant rate of 20 mm hr-1 for two hours as non-convective precipitation. Entire grid point receives application.