Hi Freddy, Hi all,
A great idea to brake down the calculations into more steps than we
discussed in Hamburg. A general OK to your plans, but I think we need to
establish what terminology to use in ARTS before discussing the details.
I got dizzy when reading your plan ...
In ARTS we call spectral radiance for intensity, i for short.
"Intensity" is a vague name, but it would be a big thing to change this
nomenclature now. But I think we should use more clear names when adding
new WSVs. On the same time, we have discussed to rename doit_i_field, as
well as having i_field for both total atmosphere and cloudbox.
I have quickly tried to make a naming suggestion of main WSVs, found
below. (It seems we both have looked at Wikipedia). I picked flux
density (fluxd) in favor for irradiance to have a more distinct
difference to radiance. Can be discussed.
I am not clear about where we need to keep upward and downward streams
separated in these new WSVs. So I am not sure about the exact tensor
dimensions needed yet. For example, it seems that you have a directional
dimension for heating rates. That I don't get? By the way, what unit
shall we use for heating rates? SI should be K/s!?
Regarding "IfieldFromIycalc1DPP". I have long planned to make a
ppath1DPP. Would fit well here. The new iyEmissionStandard will make
this very easy. You will just need to do calculations at TOA and
surface. (In principle only TOA could suffice with a limitation to
specular surfaces, but I think it is better to be general despite a bit
slower)
All written very quickly. Let's discuss during the video con later today.
Bye,
Patrick
Name: Spectral radiance
Unit: W/(m2 Hz sr)
ARTS: i_field [Tensor 7]
ARTS: cloudbox_i_field [Tensor 7]
Name: Radiance
Unit: W/(m2 sr)
ARTS: radiance_field [Tensor 6]
Name: Spectral irradiance
Name: Spectral flux density
Unit: W/(m2 Hz)
ARTS: spectral_fluxd_field [Tensor 5]
Name: Irradiance
Name: Flux density
Unit: W/m2
ARTS: fluxd_field [Tensor 4]
Name: Heating rate
Unit: ?
ARTS: heating rate [Tensor 3]
Angular grids:
field_za_grid
field_aa_grid
cloudbox_field_za_grid
cloudbox_field_aa_grid
On 2017-11-30 14:35, Manfred Brath wrote:
Hello all,*
*I plan to implement functions in ARTS to calculate monochromatic
(spectral) radiatiative fluxes also called as monochromatic (spectral)
irradiance, radiatiative fluxes also called irradiance, radiance and
heating rates from the radiation field. Any comments, suggestions are
welcome.
For that purpose I would like to implement five new workspace methods,
which will be explained below.
RFAngularGridsSet
This method will be similar to DOAngularGridsSet and set up the angular
grids for the flux calculation but it also calculate the integration
weights for the zenith angle integration. (Maybe this function can be
included in a revised version of DOAngularGridsSet)
Input:
n_za
Number of grid points in zenith direction per hemisphere (Index)
n_aa
Number of grid points in azimuth direction per hemisphere (Index,
default=1)
gridtype_az
Defines the type of azimuth grid (string):
* double_gauss, double gauss in μ =cos θ
* linear_mu, linear in μ =cos θ
* linear, linear in θ
Output:
doit_za_grid_size
Number of equidistant grid points of the zenith angle grid, defined
from 0° to 180°, for the scattering integral calculation.
scat_aa_grid
Azimuth angle grid (Vector)
scat_za_grid
Zenith angle grid (Vector)
za_grid_weights
integration weights for zenith angle integration (Vector, new
workspace variable///
1
Italics indicate new workspace variables
/)
IrradianceFromIfield
This method will calculate the monochromatic (spectral) irradiance and
irradiance (radiatiative fluxes). Important, this function will only use
the first Stokes component of the doit_i_field and iy_unit must be “1”.
Input:
doit_i_field
Radiation field (Tensor7)
scat_aa_grid
Azimuth angle grid (Vector)
scat_za_grid
Zenith angle grid (Vector)
f_grid
Frequency grid (Vector)
Output:
sir_field
spectral irradiance (radiative flux) (Tensor5, new workspace
variable)) [Wm -2 Hz -1 ]. Size: [Nf, size(doit_i_field, dim=1) ,
size(doit_i_field, dim=2), size(doit_i_field, dim=3), 2 ], last
dimension is upward and downward direction.
ir_field
//irradiance (radiative flux) (Tensor4, new workspace variable)) [Wm
-2 ]. Size: [size(doit_i_field, dim=1) , size(doit_i_field, dim=2),
size(doit_i_field, dim=3), 2 ]
RadianceFromIfield
This method will calculate the radiance and irradiance (radiatiative
fluxes). Important, this function will only use the first Stokes
component of the doit_i_field and the iy_unitmust be “1”.
Input:
doit_i_field
Radiation field (Tensor7)
scat_aa_grid
Azimuth angle grid (Vector)
scat_za_grid
Zenith angle grid (Vector)
f_grid
Frequency grid (Vector)
Output:
r_field
radiance (Tensor6, new workspace variable)) [Wm -2 sr -1 ]. Size:
[Nf, size(doit_i_field, dim=1) , size(doit_i_field, dim=2),
size(doit_i_field, dim=3), N_za, N_aa ]
ir_field
//irradiance (radiative flux) (Tensor4, new workspace variable)) [Wm
-2 ]. Size: [size(doit_i_field, dim=1) , size(doit_i_field, dim=2),
size(doit_i_field, dim=3), 2 ]
HeatingRatesFromIRField
This method will calculate heating rates from irradiance (radiative flux).
Input:
ir_field
irradiance (radiative flux) (Tensor4, new workspace variable)
p_grid
pressure grid (Vector)
Output:
heating_rates
heating rates (Tensor4, new workspace variable) [Ks -1 ]. Size:
[size(doit_i_field, dim=1) , size(doit_i_field, dim=2),
size(doit_i_field, dim=3), 2 ]
IfieldFromIycalc1DPP
This method will calculate the radiation field using iyCalcfor several
directions. This method will work only for clearsky cases and 1D
atmospheres. It internally assumes a plane parallel atmosphere and
therefore sets internally the earth radius to 1 0 15 m to mimic a plane
parallel atmosphere.
Input:
scat_za_grid
Zenith angle grid (Vector)
The other inputs are similar to iyCalc, except that rte_pos, rte_pos2
are set internally and rte_los is set internally by scat_za_grid.
Output:
doit_i_field
Radiation field (Tensor7)
Cheers,
Freddy
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