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tools:ocean_nudging2 [2018/06/21 06:41] vsicardi |
tools:ocean_nudging2 [2019/08/12 12:53] (current) vlapin [How to run a nudging experiment with EC-Earth 3.2.3] |
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- | ==== How to run a nudging experiment with EC-Earth 3.2==== | + | ======PAGE UNDER CONSTRUCTION. PLEASE BE PATIENT================= |
+ | ==== How to run a nudging experiment with EC-Earth 3.2.3 ==== | ||
- | First of all, please check that the reference files for your nudged experiments are available on the platform you would like to run at the location : HSM_DIR/ | ||
- | If you would like to prepare new reference | + | You can run experiments activating surface restoring or Newtonian Damping (3D nudging). |
+ | Both features are already part of NEMO code, nevertheless with auto-ecearth there are some parameters | ||
+ | First of all, check that the nudging files you want to use are available on the platform you would like to run. | ||
+ | |||
+ | In MN4, data for surface restoring are located here: / | ||
+ | |||
+ | Any new surface restoring files should be located in the above path following this structure: ocean/ | ||
+ | |||
+ | For 3d nudging, the location in MN4 is / | ||
+ | |||
+ | |||
+ | If you would like to prepare new reference files, their naming should follow the convention : REFERENCE_fcMEMB_YYYYMM_grid_T.nc.gz = one file containing 3-dimensional monthly mean temperature and salinity. For a given year the previous year and the following year are linked. So be sure you have all the files before you start. | ||
+ | |||
+ | In theory the user should only specify the name of the file to be used, then auto-ecearth via templates (ecearth3.ini and nemo3.ini) will take care of creating the right link and put them in the right places. If not, then there is a bug to be fixed. No panic. We do it. | ||
+ | |||
+ | |||
+ | |||
+ | ========Surface Restoring======== | ||
+ | SST / SSS restoring | ||
+ | |||
+ | |||
+ | The following model variables can be restored: | ||
+ | |||
+ | temperature | ||
+ | salinity | ||
+ | |||
+ | |||
+ | |||
+ | STEPS to activate surface restoring: | ||
+ | |||
+ | **1. Proj.conf settings: | ||
+ | |||
+ | - Ordered List Item Activate the surface restoring | ||
+ | - Define the data restoring to be used: RESTO_DATA = s4/ | ||
+ | |||
+ | |||
+ | So far you can use oras4, | ||
+ | |||
+ | Please note that is responsibility of the user to be sure that the surface restoring data to be used are in the right format and in the right place. In case of doubts speak with Valentina or Yohan. | ||
+ | |||
+ | **2.Namelist settings** | ||
+ | |||
+ | Note that, depending on the branch the user wants to use this part is already set-up. See section about available branches for available branches. The following namelist refers to the branch: r5671-bsc_ocean_DA. some difference can be found when using a different branch. | ||
+ | |||
+ | You can use nemo-only or coupled version for your nudged experiments. Depending on this option, | ||
+ | |||
+ | |||
+ | Here is an example to activate SST restoring in **namelist_nemo-ORCA1L75-standalone.cfg.sh**. | ||
+ | |||
+ | in section nambsrc you will find: | ||
+ | |||
+ | | ||
+ | |||
+ | This is switched on from configuration file. So do not worry about it. If SURF_RESTO = TRUE in proj.conf, | ||
+ | |||
+ | |||
+ | Here there are some parameters that the user should check: | ||
+ | |||
+ | | ||
+ | & | ||
+ | | ||
+ | ! filename | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | ! | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | / | ||
+ | | ||
+ | |||
+ | |||
+ | |||
+ | Reference data | ||
+ | |||
+ | Note that the name of the file contains " | ||
+ | |||
+ | |||
+ | SST parameters to be set : | ||
+ | |||
+ | nn_sstr | ||
+ | |||
+ | sn_sst file name = name of the file, in the format: sst_restore_data. if you use s4 or one of your exp, do not modify it. auto-ecearth will do the job. The name of the nudging file, is defined in fldread.F90, | ||
+ | |||
+ | frequency : the frequency of the data, usually 1 month, i.e. -1 | ||
+ | |||
+ | variable name : the variable name in the nudging file | ||
+ | |||
+ | time interpol. : the nudging is usually done once a day, so unless you have hourly data, you'll want the model to interpolate your monthly data | ||
+ | |||
+ | clim : put this to .true., if you use climatological instead of interannual data | ||
+ | |||
+ | ' | ||
+ | |||
+ | weights filename : this is used only when your data is not already on the ORCA2 grid, to spatially interpolate it during the run | ||
+ | |||
+ | rotation pairing : in case you have to spatially interpolate vectors | ||
+ | |||
+ | rn_dqdt (-40 W/m2/K is the standard value based on physical considerations) | ||
+ | |||
+ | SSS parameters : | ||
+ | |||
+ | nn_sssr | ||
+ | sn_sss : same as above | ||
+ | rn_deds (-864 mm/day/psu is the standard value consistent with rn_dqdt = -40) | ||
+ | |||
+ | The user must create the nudging files, according to experiment needs. | ||
+ | |||
+ | The user can activate SST restoring and SSS restoring independently with nn_sstr and nn_sssr | ||
+ | |||
+ | =========== 3D Nudging ========== | ||
+ | |||
+ | 3D nudging in the ocean is done by using the tracer damping functionality of NEMO (tradmp.F90). The nudging can be don only under the mixed layer or in the entire water column. The user has to nudge both the temperature and salinity, while activating at the same time the restoring of SST and SSS is optional. | ||
+ | |||
+ | In order to activate the 3D nudging in the proj.conf OCE_NUDG must be set to true. This corresponds to the activation in the namelist of: | ||
+ | | ||
+ | |||
+ | | ||
+ | & | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | |||
+ | / | ||
+ | Th | ||
+ | The namelist parameter nn_zdmp sets whether the damping should be applied in the whole water column or only below the mixed layer (defined either on a density | ||
+ | or So criterion). The user should modify it the namelist according to the experiment necessity. | ||
+ | |||
+ | **resto.nc** files contains the restoration coefficient. A default one is located in: / | ||
+ | |||
+ | In proj.conf the use should specify the nudging files to be used: s4, | ||
+ | |||
+ | Example of proj.conf session: | ||
+ | OCE_NUDG = TRUE | ||
+ | |||
+ | # Toward which target ocean is nuged to; essential if " | ||
+ | # A directory ${DATA_OCE_NUDG} must exist in / | ||
+ | DATA_OCE_NUDG = s4 | ||
+ | # A different DATA_OCE_NUDG member per EXPID member [" | ||
+ | DATA_OCE_NUDG_member = fc0 | ||
+ | |||
+ | |||
+ | At this point the user must manually edit the corresponding namelist coupled or standalone, in the following session: | ||
+ | |||
+ | |||
+ | | ||
+ | & | ||
+ | | ||
+ | | ||
+ | ! (if <0 months) | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | | ||
+ | / | ||
+ | |||
+ | |||
+ | The 3D nudging files are genrically renamed to salinity_yXXXX and temperature_yXXXX. The user must be sure that the correct links are created in the inidata folder via eceart3.ini and nemo3.ini templates. | ||
+ | |||
+ | |||
+ | For any information contact valentina.sicardi@bsc.es and yohan.ruprich@bsc.es |