1 | # *Station Air-Sea Fluxes* demonstration case |
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2 | |
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3 | Last successful test done with NEMOGCM trunk: `r13263` |
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4 | |
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5 | Author: Laurent Brodeau, 2020 |
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6 | |
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7 | NOTE: if working with the trunk of NEMO, you are strongly advised to use the same test-case but on the `NEMO-examples` GitHub depo: |
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8 | https://github.com/NEMO-ocean/NEMO-examples/tree/master/STATION_ASF |
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9 | |
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10 | ## Objectives |
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11 | |
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12 | ```STATION_ASF``` is a demonstration test-case that mimics a (static) in-situ station (buoy, platform) dedicated to the estimation of surface air-sea fluxes by means of *widely-measured* (bulk) meteorological surface parameters. |
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13 | |
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14 | ```STATION_ASF``` has been constructed by merging the *single column* and the *standalone surface module* configurations of NEMO. In short, it can be defined as "SAS meets C1D". As such, the spatial domain of ```STATION_ASF``` is punctual (1D, well actually 3 x 3 as in C1D). |
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15 | |
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16 | ```STATION_ASF``` is therefore a versatile tool, and extremely lightweight in terms of computing requirements, to test the different bulk algorithms and cool-skin/warm-layer parameterization options included in NEMO. |
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17 | |
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18 | As input ```STATION_ASF``` will require the traditional *bulk* sea surface parameters: |
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19 | |
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20 | - Bulk sea surface temperature (SST) at _z<sub>SST</sub>_ meters below the surface |
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21 | - Surface current vector |
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22 | - Sea surface salinity |
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23 | |
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24 | as well as the usual surface atmospheric state: |
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25 | |
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26 | - air temperature at _z<sub>t</sub>_ meters above the surface |
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27 | - air humidity at _z<sub>t</sub>_ meters above the surface (specific humidity or relative humidity or dew-point temperature) |
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28 | - wind speed vector at _z<sub>u</sub>_ meters above the surface |
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29 | - Sea level atmospheric pressure (SLP) |
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30 | - Downwelling solar radiation |
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31 | - Downwelling longwave radiation |
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32 | |
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33 | ### Example of diagnostics from `STATION_ASF` |
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34 | |
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35 | (Generated with script `./EXPREF/plot_station_asf_simple.py`) |
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36 | |
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37 | ![plot](https://github.com/NEMO-ocean/NEMO-examples/blob/master/STATION_ASF/figs/01_temperatures_ECMWF.svg) |
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38 | |
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39 | ![plot](https://github.com/NEMO-ocean/NEMO-examples/blob/master/STATION_ASF/figs/Cd.svg) |
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40 | |
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41 | ![plot](https://github.com/NEMO-ocean/NEMO-examples/blob/master/STATION_ASF/figs/dT_skin.svg) |
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42 | |
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43 | ![plot](https://github.com/NEMO-ocean/NEMO-examples/blob/master/STATION_ASF/figs/Qlat.svg) |
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44 | |
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45 | |
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46 | ## Physical description |
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47 | |
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48 | ### Important namelist parameters specific to STATION_ASF |
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49 | |
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50 | * ```rn_dept1@namusr_def:``` depth (m) at which the prescribed SST is taken (*i.e.* depth of first T-point); important due to impact on warm-layer estimate, the deeper, the more pronounced! |
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51 | |
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52 | * ```rn_lat1d,rn_lon1d@namc1d:``` fixed coordinates of the location of the station (buoy, platform, etc). |
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53 | |
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54 | * ```namsbc_blk:``` to be filled carefully, just as for "C1D", the prescribed surface ATMOSPHERIC state (files) are time series of shape 3x3 in space |
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55 | |
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56 | * ```namsbc_sas:``` to be filled carefully, just as for "C1D", the prescribed surface OCEAN state (files) are time series of shape 3x3 in space |
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57 | |
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58 | |
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59 | |
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60 | ## Input files to test STATION ASF |
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61 | |
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62 | One full year (2018) of processed hourly data from the PAPA station (buoy) is found into the `input_data` directory. |
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63 | These three files are everything you need to play with the set of *namelists* provided for this test-case. |
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64 | |
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65 | - ```Station_PAPA_50N-145W_atm_hourly_y2018.nc``` → contains hourly surface atmospheric state |
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66 | - ```Station_PAPA_50N-145W_precip_daily_y2018.nc``` → contains daily precipitation |
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67 | - ```Station_PAPA_50N-145W_oce_hourly_y2018.nc``` → contains hourly sea surface state |
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68 | |
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69 | For station PAPA (50.1 N, 144.9 W), air temperature and humidity are measured at 2.5 m, the wind speed at 4 m, and the SST at 1 m below the surface, hence the following namelist parameters are given: |
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70 | |
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71 | - `&namusr_def` |
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72 | - ```rn_dept1 = 1. ``` |
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73 | - `&namc1d` |
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74 | - ```rn_lat1d = 50.1 ``` |
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75 | - ```rn_lon1d = 215.1``` |
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76 | - `&namsbc_blk` |
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77 | - ```rn_zqt = 2.5``` |
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78 | - ```rn_zu = 4.``` |
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79 | |
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80 | |
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81 | |
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82 | ## Playing with STATION_ASF |
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83 | |
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84 | First compile the test-case as follows (compile with xios-2.5 support → check your ARCH file): |
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85 | |
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86 | ```./makenemo -a STATION_ASF -m <your_arch> -n STATION_ASF2 -j 4``` |
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87 | |
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88 | Then you can use the script ``launch_sasf.sh`` found in ```EXPREF/``` to launch 3 simulations (one for each bulk parameterization available). You need to adapt the following variable to your environment in the script: |
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89 | |
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90 | - ```NEMO_ROOT_DIR``` : NEMO root directory where to fetch compiled STATION_ASF ```nemo.exe``` + setup (such as ```${NEMO_ROOT_DIR}/tests/STATION_ASF```) |
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91 | |
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92 | - ```PROD_DIR``` : Directory where to run the simulation |
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93 | |
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94 | - ```DATA_IN_DIR``` : Directory containing sea-surface + atmospheric forcings (found here in ```input_data/```) |
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95 | |
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96 | If everything goes according to plan, ``launch_sasf.sh`` should have generated the 3 following sets of output files into `${PROD_DIR}/output`: |
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97 | |
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98 | STATION_ASF-COARE3p6_1h_20180101_20181231_gridT.nc |
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99 | STATION_ASF-COARE3p6_1h_20180101_20181231_gridU.nc |
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100 | STATION_ASF-COARE3p6_1h_20180101_20181231_gridV.nc |
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101 | STATION_ASF-ECMWF_1h_20180101_20181231_gridT.nc |
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102 | STATION_ASF-ECMWF_1h_20180101_20181231_gridU.nc |
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103 | STATION_ASF-ECMWF_1h_20180101_20181231_gridV.nc |
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104 | STATION_ASF-NCAR_1h_20180101_20181231_gridT.nc |
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105 | STATION_ASF-NCAR_1h_20180101_20181231_gridU.nc |
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106 | STATION_ASF-NCAR_1h_20180101_20181231_gridV.nc |
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107 | |
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108 | --- |
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109 | |
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110 | */Laurent, July 2020.* |
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111 | |
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