The modified gamma distribution PSD¶
The form of the modified gamma distribution (MGD) used here is as follows:
The distribution is described by four parameters:
- The intercept parameter \(N\)
- The slope parameter \(\lambda\)
- The shape parameter \(\alpha\)
- The parameter \(\nu\)
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class
parts.scattering.psd.modified_gamma.
ModifiedGamma
(size_parameter, intercept_parameter=None, alpha=None, lmbd=None, nu=None)[source]¶ Bases:
parts.scattering.psd.arts.arts_psd.ArtsPSD
The
ModifiedGamma
class describes the size distribution of scattering particles in an atmosphere using the four parameters of the particle size distribution.-
evaluate
(x)[source]¶ Computes the values of this modified gamma distribution evaluated at the given size grid
x
.Parameters:
x(numpy.array): Array containing the values of the size parameter at which to evaluate the PSD.Returns:
PSDData
object containing the numeric PSD data obtained by evaluating this PSD at the given values of the size parameter.
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get_mass_density
()[source]¶ Computes the mass density :math: rho_m for the given bulk elements using
\[\rho_m = a \cdot M(b).\]where \(a\) and \(b\) are the coefficients of the mass-size relation of the size parameter.
Returns:
numpy.ndarray
containing the mass density corresponding to each volume element described by the PSD.
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get_moment
(p, reference_size_parameter=None)[source]¶ Computes the \(p\) th moment \(M(p)\) of the PSD using
\[M(p) = \frac{N}{\lambda} \frac{\Gamma (1 + \alpha + p / \nu )} {\Gamma({1 + \alpha})}.\]- Parameters:
- p(np.float): Which moment of the PSD to compute.
- Raises:
- Exception: If any of the parameters of the PSD is not set.
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moment_names
¶ The free parameters of the PSD.
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pnd_call_agenda
¶ ARTS agenda that contains the call to the WSM that computed this PSD.
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