1. Parameters module¶
This module defines the parameters for the model.
Note
The python code is available here : params_maooam.py .
Example: |
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>>> from params_maooam import ndim,natm,noc
>>> from params_maooam import oms,nboc,ams,nbatm
>>> from params_maooam import *
There are three types of parameters :
- integration parameters : simulation time (transient and effective), time step, writeout and write step time
- dimensional parameters : dimensions of the truncation of fourier for the atmosphere and the ocean
- physical parameters : they are used in the tensor for the integration
1.1. Integration parameters¶
Warning
Time is adimensional. If t_real is in seconds, then t_model = t_real * f_0 where f_0 is the Coriolis parameter at 45 degrees latitude ( 1.032e-4 )
- t_trans : the transient simulation time of the model to be on the attractor. The states vectors are not written on evol_field.dat.
- t_run : the running simulation time of the model. The states vectors are written on evol_field.dat every tw.
- dt : the step time.
- writeout : boolean value to decide if the module produces evol_field.dat.
- tw : the step time to write on evol_field.
- f2py : boolean to activate the f2py optimization.
1.2. Dimensional parameters¶
- oms and ams : the matrices that gives the possible values of the modes Nx and Ny.
- nboc and natm : the numbers of oceanic and atmospheric blocs.
- natm and noc : the numbers of functions available.
- ndim : the total dimension.
Example: |
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>>> oms =get_modes(2,4)# ocean mode selection
>>> ams =get_modes(2,2)# atmosphere mode selection
>>> nboc,nbatm = 2*4,2*2 # number of blocks
>>> (natm,noc,ndim)=init_params(nboc,nbatm)
>>>
>>> # Oceanic blocs
>>> #( x block number accounts for half-integer wavenumber e.g 1 => 1/2 , 2 => 1, etc...)
>>> OMS[0,:] = 1,1
>>> OMS[1,:] = 1,2
>>> OMS[2,:] = 1,3
>>> OMS[3,:] = 1,4
>>> OMS[4,:] = 2,1
>>> OMS[5,:] = 2,2
>>> OMS[6,:] = 2,3
>>> OMS[7,:] = 2,4
>>> #Atmospheric blocs
>>> AMS[0,:] = 1,1
>>> AMS[1,:] = 1,2
>>> AMS[2,:] = 2,1
>>> AMS[3,:] = 2,2
Typical dimensional parameters: | |
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- atmosphere 2x,2y ; ocean 2x,4y ; ndim = 36
- atmosphere 2x,2y ; ocean 4x,4y ; ndim = 52
- atmosphere 2x,4y ; ocean 2x,4y ; ndim = 56
1.3. Physical parameters¶
Some defaut parameters are presented below. Some parameters files related to already published article are available in the params folder.
1.3.1. Scale parameters¶
- scale = 5.e6 : characteristic space scale, L*pi
- f0 = 1.032e-4 : Coriolis parameter at 45 degrees latitude
- n = 1.5e0 : aspect ratio (n = 2Ly/Lx ; Lx = 2*pi*L/n; Ly = pi*L)
- rra = 6370.e3 : earth radius
- phi0_npi = 0.25e0 : latitude exprimed in fraction of pi
1.3.2. Parameters for the ocean¶
- gp = 3.1e-2 : reduced gravity
- r = 1.e-8 : frictional coefficient at the bottom of the ocean
- h = 5.e2 : depth of the water layer of the ocean
- d = 1.e-8 : the coupling parameter (should be divided by f0 to be adim)
1.3.3. Parameters for the atmosphere¶
- k = 0.02 : atmosphere bottom friction coefficient
- kp = 0.04 : atmosphere internal friction coefficient
- sig0 = 0.1e0 : static stability of the atmosphere
1.3.7. Key values¶
- k is the friction coefficient at the bottom of the atmosphere. Typical values are 0.01 or 0.0145 for chaotic regimes.
- kp is the internal friction between the atmosphere layers. kp=2*k
- d is the friction coefficient between the ocean and the atmosphere. Typical values are 6*10^{-8} s^{-1} or 9*10^{-8} s^{-1}.
- lambda is the heat exchange between the ocean and the atmosphere. Typical values are 10 W m^{-2} K^{-1} or 15.06 W m ^{-2} K^{-1}.
1.4. Dependencies¶
>>> import numpy as np