Description of some of the input files
Forcing of the biogeochemical model
Deposition of Fe and Si from dust
Dust deposition fields are usually given in g of dust/m2/month. The DGOM PlankTOM5 uses
monthly iron deposition values (Tegen & Fung 1995) as input in kg Fe/m2/month (variable dust(i,j)).
To convert we assume there are 0.035 g of iron per g of dust. The solubility of
Fe in water is taken into account directly in the model.
In the model, we use the following values: 2% solubility for Fe,
7.5% solubility for Si, and 8.8 gSi/gFe. Variables irondep
and sidep are in mol/L/time_step for Fe and Si, respectively.
The molecular weights of Fe and Si are 55.85 and 28.01, respectively.
Download the dust deposition file on an orthogonal grid with unequal spacing in latitude
Input of nutrients and carbon from rivers
River input of NO3, PO4, SiO3,
DIC, Fe (including Fe in DOM), DOC, POC, and POFe (download on the ORCA2 grid).
This file is described in da Cunha et al. (2007).
Gas exchange with the atmosphere
Gas exchange of CO2 and O2 is calculated according to Wanninkhof et al (1992),
correcting for 100% water vapor according to Sarmiento et al. JGR (1992).
PlankTOM5 Initialisation
The model is initialised with GLODAP observations of DIC, Alkalinity,
World Ocean Atlas 2005 NO3, PO4, SiO3, O2.
For the "biological" state variables we use the output of the previous model version:
Download the restart file on an orthogonal grid from TOM5_ET_NCCL9 2005
Download the restart file on the ORCA2 grid
Download restart files on the ORCA2 grid for 1948 from our OpenDAP server.
Physical forcing files
We force the model with NCEP reanalysis. The forcing files have been produced from data downloaded from the NOAA Earth System Research Laboratory.
The data have been interpolated to the required grid using the INTERP tool available from Laboratoire d'Océanographie Dynamique et de Climatologie.
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for each YEAR: file /esdata/env/e031/Input/ncep_bulk_YEAR.nc contains daily values for
| model variable | NetCDF variable | description | units |
|---|
| tatm | air | mean Daily Air temperature at 2 m | degrees C |
| hatm | humidity | mean Daily Humidity (see below) | - |
| vatm | wspd | mean Daily Windspeed at 10 m | m/s |
| catm | cloud | daily mean Total cloud cover | - |
| watm | rain | mean Daily Precipitation Rate | kg/m2/s |
- for each YEAR: file /esdata/env/e031/Input/taux_1d_YEAR.nc
for each YEAR: file /esdata/env/e031/Input/tauy_1d_YEAR.nc
contain daily values for
| taux | uflx | Zonal wind stress | N/m2 |
| tauy | vflx | Meridional wind stress | N/m2 |
- averaged : file /esdata/env/e031/Input/runoff_1m_nomask.nc contains monthly values for
| sorunoff | sorunoff | freshwater input from rivers and ice | kg/m2/s |
In NEMO, humidity is calculated offline:
The humidity values are calculated from the specific humidity at 2m (shum) using the following relationship:
humidity = (shum*pres)/(.622 +.378*shum/sat_p)
where:
pres is the air pressure and sat_p = 611*10(7.5(T-273.15)/(T-35.86))
In OPA8, the forcing files contained the specific humidity at 2m, the air temperature at 2 m (T), and the air pressure, and humidity was calculated online.
Download forcing files from 1948 onwards on the ORCA2 grid from our OpenDAP server.
Initialisation of the physical model
The NEMO GCM is initialised with temperature and salinity from WOA 2005.
The LIM ice model is initialised with ice cover fraction, ice thickness and snow thickness from GIOMAS.
Download restart files on the ORCA2 grid for 1948 from our OpenDAP server.
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