README for wind turbine drag parameterization schemes, added 20101220. JM The code was modified to introduce the power curve and the thrust coefficient using tables. The parameterization is activated in the physics part of the namelist. NOTE: For V3.6 (April 2014) the namelist options and idealized set-up have been changed. Further description below and in README.namelist. The scheme is now activated with windfarm_opt = 1 in the physics namelist. *Specific note for the Fitch scheme.* !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !! NOTICE !! The following paper should be cited whenever presenting results using this scheme !! (using either the original version or any modified versions of the scheme): !! Fitch, A. C. et al. 2012: Local and Mesoscale Impacts of Wind Farms as Parameterized in a !! Mesoscale NWP Model. Monthly Weather Review, doi:http://dx.doi.org/10.1175/MWR-D-11-00352.1 !! !! Anna C. Fitch, National Center for Atmospheric Research (formerly University of Bergen) !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! The Fitch scheme is based on Blahak et al. (2010) of Wetter Jetzt GbR. It differs in that the kinetic energy (KE) extracted is based on the thrust coefficient of the turbine (representing the total fraction of KE extracted from the atmosphere due to the turbine), rather than the power coefficient plus an estimated loss factor. In addition the TKE generated is a function of wind speed. The thrust coefficients and the power curve should be obtained from the turbine manufacturer for the turbines of interest and incorporated into a table as described below. If you do not have access to these data an idealized wind turbine is provided in this release (./run/wind-turbine-1.tbl). It is strongly recomended to use the data from the manufacturer. The parameterization works with the MYNN PBL and modifies the QKE field representing 2xTKE to include the TKE produced by wind turbines. QKE can be advected as a part of the scalar 4D tracer array in WRF using the bl_mynn_tkeadvect switch for each domain (default =.false.) It is not recommended to run the parameterization at resolutions higher than 5 rotor diameters - at this resolution rotation of the rotor blades should be included (not represented in the current model). See 1st reference below and Wu and Porte-Agel (2011) and Porte-Agel et al. (2011). The specific implementation comes from Anna Fitch, Alok Gupta, and Idar Barstad at Uni Bergen, Norway. It was added to this release of WRF by Jimy Dudhia, Joe Olson (NOAA), Julie Lundquist (U. Colorado/NREL), and John Michalakes (NREL). Further development comes from Pedro A. Jimenez (CIEMAT/NCAR) who introduced the capability of introducing the manufacturer information via user specified tables as well as other functionalities. References: Fitch, A. C. et al. 2012: Local and Mesoscale Impacts of Wind Farms as Parameterized in a Mesoscale NWP Model. Monthly Weather Review, doi:http://dx.doi.org/10.1175/MWR-D-11-00352.1 Fitch, A. C. et al. 2013: Mesoscale Influences of Wind Farms Throughout a Diurnal Cycle. Monthly Weather Review, doi:http://dx.doi.org/10.1175/MWR-D-12-00185.1 Fitch, A. C. et al. 2013: Parameterization of Wind Farms in Climate Models. Journal of Climate, doi:http://dx.doi.org/10.1175/JCLI-D-12-00376.1 Jimenez, P.A., J. Navarro, A.M. Palomares and J. Dudhia: Mesoscale modeling of offshore wind turbines wakes at the wind farm resolving scale: a composite-based analysis with the WRF model over Horns Rev. Wind Energy, (In Press.). DOI: 10.1002/we.1708 *Compiling the code.* no different from normal *Running the code* To activate the parameterization the user needs to set the domain dependent variable windfarm_opt to 1 in the physics part of the namelist. WRF is expected to find a file called "windturbines.txt". Each line of the file specifies one turbine. The entries of a line are separated by spaces. The entries are listed in order on the line and specify the following, by position on the line: 1. True latitude of the wind turbine in degrees [real] 2. True longitude of the wind turbine in degrees [real] 3. Turbine type [integer] For example: 55.574051 6.883480 1 55.569066 6.884697 1 30.000000 -77.000000 1 The location of each turbine is specified using the lat and lon elements for the turbine's entry in the windturbines.txt file. That is, the i, j index in the grid is computed from the true latitude (entry 1) and the true longitude (entry 2). The type of turbine (entry 3) points to the file that contains the turbine specifications. If the turbine type is set to 1, WRF is expecting to find the file wind-turbine-1.tbl. The first line of the table is an integer, N, indicating the number of pairs entries for the power curve and the thrust coefficient; the second line contains 4 real values specifying the characteristics of the turbine: 1.- Height in meters of the turbine hub [real] 2.- Diameter in meters of the rotor [real] 3.- Standing thrust coefficient [real] 4.- Nominal power of turbine (MW) [real] and the following N lines contain 3 real values with the wind speed, thrust coefficient and power production (kW). For example: 23 80. 85. 0.1 2.0 3. 0.7 80. | 4. 0.75 150. | ..... | | 23 lines ..... | 25. 0.05 2000.0 | *Pseudo-real configuration.* This mode is only for testing the real-world specification mechanism. This option allows to define the position of the turbines using the i and j coordinates on the grid instead of the latitude and longitude. To activate this option the user needs to set the variable windfarm_ij to 1 in the physics part of the namelist. WRF is expecting to find a file "windturbines-ij.txt". Each line of the file is associated with a turbine and each line has three columns corresponding to the I (entry 1), J (entry 2) and kind of turbine (entry 3). For example: 10 10 1 10 10 1 10 11 1