Difference between revisions of "Rayleigh scattering"
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In exo_k we have : | In exo_k we have : | ||
| − | TRAY <math> \displaystyle = \sigma_{exok} dN </math> with | + | TRAY <math> \displaystyle = \sigma_{exok} dN </math> with <math> \displaystyle \sigma_{exok} </math> the cross section and dN in molecules/m2 |
| − | TRAY <math> \displaystyle = \sigma_{exok} \frac{dm}{m_{molecule}} </math> with dm in kg/m2 | + | which gives : TRAY <math> \displaystyle = \sigma_{exok} \frac{dm}{m_{molecule}} </math> with dm in kg/m2 |
| − | TRAY <math> \displaystyle = \frac{\sigma_{exok}}{g * m_{molecule}} dP</math> | + | and then : TRAY <math> \displaystyle = \frac{\sigma_{exok}}{g * m_{molecule}} dP</math> |
so | so | ||
Revision as of 15:04, 28 September 2022
About Rayleigh scattering in LMDZ Generic
Formalism
References
Hansen (1974) : https://ui.adsabs.harvard.edu/link_gateway/1974SSRv...16..527H/ADS_PDF
Rayleigh routine in exo_k : http://perso.astrophy.u-bordeaux.fr/~jleconte/exo_k-doc/_modules/exo_k/rayleigh.html#Rayleigh.sigma_mol
Exo_k uses formalism from : Caldas (2019) : https://hal.archives-ouvertes.fr/hal-02005332/document
Equation
in optcv.F90 :
TRAY(K,NW) = TAURAY(NW) * DPR(K)
In exo_k we have :
TRAY \( \displaystyle = \sigma_{exok} dN \) with \( \displaystyle \sigma_{exok} \) the cross section and dN in molecules/m2
which gives : TRAY \( \displaystyle = \sigma_{exok} \frac{dm}{m_{molecule}} \) with dm in kg/m2
and then : TRAY \( \displaystyle = \frac{\sigma_{exok}}{g * m_{molecule}} dP\)
so
\( \displaystyle \text{TAURAY} = \frac{\sigma_{exok}}{g * m_{molecule}} \)
To be noticed :
We write \( \displaystyle TRAY = \tau_{RAY} dP\)
TAURAY(NW) is calculated in calc_rayleigh.F90
For each channel, it is in fact TAUVAR which calculated, and then averaged by the black body function to give TAURAY \[ \text{TAURAY(NW)} = \frac{\int_{\lambda'} \text{TAUVAR} (\lambda') B_{\lambda} \, \mathrm{d}\lambda'}{\int B_{\lambda} \, \mathrm{d}\lambda'} \]
\( \displaystyle \tau(\lambda) \) is called TAUVAR
