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2.1 Atmosphere and land surface
| Model | CESM 1.2 - CAM 5.3 (Atmosphere) CESM 1.2 - CLM 4.5 (Land surface) | |||
|---|---|---|---|---|
| Horizontal resolution and grid | 1/2° lat-lon approx | |||
| Atmosphere vertical resolution | 46 levels in the vertical | |||
| Land vertical resolution | 15 layers (see table below) | |||
| Top of atmosphere | 0.2 hPa (60 km approx.) | |||
| Soil levels (layers) | 15 | layers: 10
| (for layer depths, see table below)Time step | Main (Physics) | Time-step: 30 minutes.
Layer |
1 (soil) |
: 0 |
-0. |
0175m |
: 0. |
0175-0. |
0451m |
: 0. |
0451-0. |
0906m |
: 0. |
0906-0. |
1655m |
: 0. |
1655-0. |
2891m |
: 0. |
2891-0. |
4929m |
: 0. |
4929-0,8289m |
: 0. |
8289-1. |
3828m |
: 1. |
3828-2. |
2961m |
: 2. |
2961- |
3. |
11 (bedrock)
4.7392-7.8298
12 (bedrock)
7.8298-12.9253
13 (bedrock)
12.9253-21.3265
14 (bedrock)
21.3265-35.1776
15 (bedrock)
8019m | |
| Time step | Main (Physics) Time-step: 30 minutes. “Tracer” Advection Time step: 225 seconds Fluid-Dynamics Time step: 56.25 seconds |
|---|
Detailed documentation:
CAM Model documentation http://www.cesm.ucar.edu/models/cesm1.2/cam/
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3. Initialization and initial condition (IC) perturbations
3.1 Atmosphere and land
| Hindcast | Forecast | |
|---|---|---|
| Atmosphere initialization | ERA5 | ECMWF IFS operational analysis |
| Atmosphere IC perturbations | 10 | 10 |
Land Initialization | Forced |
monthly run |
initialized from 10-year spin-up
Forced (obs. atmosphere) monthly run
initialized from 10-year spin-upfrom a continuous transient simulation with initial-date January 1993, started after a 10 year spinup (with climatological forcings) | Forced monthly run from a continuous transient simulation with initial-date January 1993, started after a 10 year spinup (with climatological forcings) | |
| Land IC perturbations | 3 | 3 |
|---|---|---|
| Soil moisture initialization | From land initialization | From land initialization |
| Snow initialization | From land initialization | From land initialization |
| Unperturbed control forecast? | NO | NO |
| Horizontal resolution of perturbation | N/A | N/A |
| Perturbations in +/- pairs | NO | NO |
| Data assimilation method for control analysis | ERA5 | ECMWF operational |
Detailed documentation:
For more details on atmospheric DA, see ECMWF operational analysis documentation at: https://www.ecmwf.int/en/elibrary/16666-part-ii-data-assimilation
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| Hindcast | Forecast | |
|---|---|---|
| Ocean initialization | C-GLORS Global Ocean 3D-VAR | C-GLORS Global Ocean 3D-VAR |
| Ocean IC perturbations | 4 | 8 |
| Unperturbed control forecast? | NONO | YES |
Detailed documentation:
More details on ocean data assimilation at http://c-glors.cmcc.it/index/index.html
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| Model dynamics perturbations | NO |
|---|---|
| Model physics perturbations | YES (Ocean Model only, only during perturbed data assimilation cycles) |
If there is a control forecast, is it perturbed? | There is no control forecast |
Detailed documentation: For more info on ocean DA perturbations, see Brankart (2013) DOI: https://doi.org/10.1016/j.ocemod.2013.02.004
CMCC technical documentation Gualdi et al (2020) CMCC Technical Note RP0288 DOI: https://doi.org/10.25424/CMCC/SPS3.5
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The 10 atmospheric perturbed initial conditions, the 3 land perturbed initial conditions and the 8 (4 9 ocean initial conditions (8 perturbed plus the unperturbed, only 4 perturbed in hindcast mode) ocean perturbed initial conditions are combined to yield 240 270 (120 in hindcast mode) possible perturbed forecast system initial conditions from which 50 initial conditions (40 in hindcast mode) are chosen at random, to produce the forecast ensembleForecast Ensemble.
Detailed documentation:
CMCC technical documentation Gualdi et al (2020) CMCC Technical Note RP0288 DOI: https://doi.org/10.25424/CMCC/SPS3.5
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