Titan aerosol models

Install

With pip:

$ pip install titan-aerosols

Or directly from the source files:

$ git clone https://github.com/seignovert/python-titan-aerosols.git
$ cd python-titan-aerosols ; python setup.py install

Python usage

>>> from aerosols import index_tholins

>>> nr, ni = index_tholins(338e-9)
(1.6489699384541059, 0.2392676321412895)


>>> from aerosols import mie_tholins

>>> wvln = 338e-9 # Wavelength (m)
>>> rm = 50e-9 # Monomer radius (m)

>>> qsct, qext, qabs, gg, theta, P = mie_tholins(wvln, rm)
(2.150748326506086e-15,
6.519732093912762e-15,
4.368983767406676e-15,
0.19301947916187234,
array([0., 0.01745329, ..., 3.14159265]),
array([2.23653193, ..., 0.88785229]))


>>> from aerosols import fractals_tholins

>>> Df = 2.0
>>> N = 266

>>> qsct, qext, qabs, gg, theta, P = fractals_tholins(wvln, rm, Df, N)
(1.5986535423863113e-12,
2.5652821769307767e-12,
9.666286345444654e-13,
None,
array([0, ..., 3.14159265]),
array([135.83547352468324, ..., 0.16033083012643]))

>>> N = 3000

>>> qsct, qext, qabs, gg, theta, P = fractals_tholins(wvln, rm, Df, N)
ValueError: Model tested only for N = 2 - 1024 (received N=3000)

>>> qsct, qext, qabs, gg, theta, P = fractals_tholins(wvln, rm, Df, N, force=True)
(1.877008401099561e-11,
2.829777018602765e-11,
9.527686175032043e-12,
None,
array([0, ..., 3.14159265]),
array([1.20358413e+03, ..., 1.27914327e-01]))


>>> from aerosols import mie

>>> qsct, qext, qabs, gg, theta, P = mie_tholins(wvln, nr, ni, rm)
(...)

>>> from aerosols import fractals

>>> qsct, qext, qabs, gg, theta, P = fractals(wvln, nr, ni, rm, Df, N)
(...)

CLI usage

$ fractal_tholins --help
usage: fractal_tholins [-h] [--phase-function] [--nang NANG]
                    [--fractal-dimension FRACTAL_DIMENSION] [--force]
                    wvln rm N
Fractals cross-sections and phase function for tholin aggregate. Use default
tholins indexes (CVD) and Tomasko et al. 2008.

positional arguments:
wvln                  Wavelength (m)
rm                    Monomer radius (m)
N                     Number of monomers

optional arguments:
-h, --help            show this help message and exit
--phase-function, -p  Display the phase function
--nang NANG           Number of angles for the phase function (0 -> pi/2)
--fractal-dimension FRACTAL_DIMENSION, -df FRACTAL_DIMENSION
                        Fractal dimension
--force, -f           Bypass validity checks


$ fractal_tholins 338e-9 60e-9 266
# Cross sections:
Scattering: 2.715e-12 m^-2
Absorption: 1.558e-12 m^-2
Extinction: 4.273e-12 m^-2


$ fractal_tholins -p 338e-9 60e-9 266
# Phase function
0.0     1.86e+02
1.0     1.78e+02
...
179.0   1.15e-01
180.0   1.15e-01


$ fractal_tholins -p --nang 10 338e-9 60e-9 266
# Phase function
0.0     2.52e+02
10.0    2.37e+01
...
170.0   1.55e-01
180.0   1.56e-01


$ fractal_tholins -df 2.3 338e-9 60e-9 266
Model tested only for Df = 2 (received Df=2.30)


$ fractal_tholins 338e-9 60e-9 266 -df 2.3 --force
# Cross sections:
Scattering: 2.657e-12 m^-2
Absorption: 1.351e-12 m^-2
Extinction: 4.008e-12 m^-2

This package is an early attempt to model Titan's aerosols scattering based on Tomasko et al. 2008 paper (doi:10.1016/j.pss.2007.11.019)