================== Climate Simulation ================== Climate simulations, spanning months or years, require continuous data like reanalysis or future climate model data. Sea Surface Temperature (SST) is crucial for climate runs. Global atmospheric data often includes SST but may lack resolution. Supplement with higher-resolution SST, ensuring continuous updates. Since this is just a test exercise, this case only runs for 48 hours for a past-date event. |vspace| .. important:: Save WPS files from your single-domain/nested exercises. In *wps* create a new folder to store the *geo_em\**, *FILE\**, *met_em\**, and *namelist.wps* files. | | Geogrid ======= #. Edit *namelist.wps* to configure the following domain * A single domain over North America and the North Atlantic * Domain size: 110 x 65 grid points * Projection: mercator (because the domain is closer to the equator) * Grid resolution: 90 km In addition to the above modification, use the following *namelist.wps* settings to place the domain in the right location on the Earth: .. code-block:: &share max_dom = 1, &geogrid ref_lat = 15.00 ref_lon = -60.00 truelat1 = 0.0 truelat2 = 0.0 stand_lon = -60.00 |vspace| .. note:: Resolutions finer than 90 km are typically used for climate simulations, but this case uses a coarser setup to save time and computational cost. |vspace| #. Your domain should look like this: .. figure:: ./images/climate_run.png :align: center :width: 70% |vspace| #. Run geogrid.exe. | | Ungrib ====== Ungrib and reformat meteorological data from reanalysis or climate models for the following event: |vspace| **Event** * Duration : 48 hours * `Hurricane Matthew `_, which made landfall as a category 4 hurricane over Haiti, and then weakened before hitting the U.S. coast of South Carolina. * Dates: 2016-10-06_00:00:00 to 2016-10-08_00:00:00 Because you will be using GFS meteorological input and additional SST data, you will run ungrib twice to convert the data types separately. | Ungrib GFS Data --------------- The following describes the GFS Data: .. csv-table:: :escape: \ Type, Global `NCEP GFS `_ Interval, Every 3 hours Initial Time, 2016-10-06_00:00:00 End Time, 2016-10-08_00:00:00 Data Directory, */glade/campaign/mmm/wmr/wrf_tutorial/input_data/climate/* File Root, *gfs.0p25.2016100600.f0* Vtable, Vtable.GFS |vspace| #. Link in the GFS data. .. code-block:: :class: copyable ./link_grib.csh /glade/campaign/mmm/wmr/wrf_tutorial/input_data/climate/gfs.0p25.2016100600.f0 |vspace| #. Link in the correct Vtable (for GFS input, use *Vtable.GFS*). |vspace| #. Modify start/end dates/times in *namelist.wps*. |vspace| #. Because these data are available every 3 hours, set *interval_seconds = 10800*. |vspace| #. Run ungrib to create intermediate files (resulting files should have the prefix *FILE*). | | Ungrib SST Data --------------- The following describes the SST Data: .. csv-table:: :escape: \ Type, Archived global SST GRIB1 data Interval, Daily (every 24 hours) Initial Time, 2016-10-06_00:00:00 End Time, 2016-10-08_00:00:00 Data Directory, */glade/campaign/mmm/wmr/wrf_tutorial/input_data/sst/* File Root, *rtg_sst_grb_hr_0.083.2016100* Vtable, Vtable.SST |vspace| #. Link in the SST data. .. code-block:: :class: copyable ./link_grib.csh /glade/campaign/mmm/wmr/wrf_tutorial/input_data/sst/rtg_sst_grb_hr_0.083.2016100 |vspace| #. Link the correct Vtable (For SST input, use *Vtable.SST*). |vspace| #. Make the following changes to the *&ungrib* namelist record. .. code-block:: &ungrib prefix = 'SST', |vspace| .. note:: * These SST data are available every 24 hours. Keeping *interval_seconds=10800* allows ungrib to interpolate SST data to the temporal resolution of the GFS interval. * If, for e.g., the SST data were only available weekly, the namelist dates would be set to the two available files before and after the case dates, maintaining *interval_seconds=10800* for interpolation. * Changing the prefix prevents the GFS output from being overwritten. |vspace| #. Run ungrib to create SST intermediate files (the prefix should be *SST*). | | Metgrid ======= Modify the *&metgrid* namelist record to ensure metgrid uses both *FILE* and *SST* intermediate files: .. code-block:: &metgrid fg_name = 'FILE', 'SST' |vspace| Now run metgrid, as usual. | | Real & WRF ========== #. Edit *namelist.input* to match WPS settings, using the following considerations: * These GFS data have 32 levels. Set *num_metgrid_levels = 32*. * Set *frames_per_outfile=1* to create a *wrfout\** file for each history output time. This is recommended for longer runs because it limits files size, making them more manageable. * Long runs typically require frequent starts/stops. Set *restart_interval* to at least once daily so you will have restart files (*wrfrst\**) available to use as a starting place for each restart run. This particular run is **not** a restart run, so set *restart=.false.*. * Modify *time_step* based on the 90 km grid spacing. *time_step* should not be larger than 6xDX. To ensure stability, set this to 360. * This is a single domain simulation. * Using too few vertical levels for long simulations can cause systematic biases. 45 levels should be sufficient for this case. * Set *e_we*, *e_sn*, and the dates/times to match WPS settings. |vspace| #. Add the following to *namelist.input* in the *&time_control* and *&physics* records. .. code-block:: &time_control auxinput4_inname = "wrflowinp_d" auxinput4_interval = 180, io_form_auxinput4 = 2, &physics sst_update = 1, |vspace| .. note:: * These additions set SST to update every 3 hours. * SST uses the auxillary stream 4, which requires a file name specification for the real.exe output file containing SST data, an interval, and the output format (*2=netcdf*). * Do not change the syntax for the *auxinput4_inname* parameter (i.e., do not replace ** with the actual domain number). WRF understand this syntax and will translate it to the correct file name. |vspace| #. Now you are ready to run real and wrf. When running wrf.exe, **use the "runwrf_climate.sh" batch script**. | | Return to the Practice Exercise home to page to run another exercise. .. rst-class:: horizbuttons-primary-m * `Return to Practice Exercises <./practices.html>`_ .. toctree:: :maxdepth: 4 :hidden: | | | |