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Workspace Method pnd_fieldSetup

Description

Calculation of pnd_field using ScatteringMetaData and massdensity_field.

The WSM first checks if cloudbox is empty. If so, the pnd calculations
will be skipped.
The cloudbox_limits are used to determine the p, lat and lon size for
the pnd_field tensor.
Currently there are three particle size distribution parameterisations implemented:
	1. MH97 for ice particles. Using a first-order gamma distribution for particles
	 smaller than 100 microns (melted diameter) and a lognormal distribution for
	 particles bigger 100 microns. Values from both modes are cumulative.
	 See internal function 'IWCtopnd_MH97' for implementation/units/output.
	 (src.: McFarquhar G.M., Heymsfield A.J., 1997)
	2. H11 for ice particles and precepitating ice (snow). H11 in NOT dependent
	 on massdensity of ice/snow, but on atmospheric temperature.
	 The PSD is scaled to the current IWC/Snow density in an additional step.
	 See internal function 'pnd_H11' and 'scale_H11' for implementation/units/output.
	 (src.: Heymsfield A.J., 2011, not published yet)
	3. Gamma distribution for liquid cloud particles.
	 See internal function 'LWCtopnd' for implementation/units/output.
	 (src.: Deirmendjian D., 1963 and Hess M., et al 1998)

According to the selection criteria in part_species, the first specified
psd parametrisation is selected together with all particles of specified phase
and size. Then pnd calculations are performed on all levels inside the cloudbox.
The massdensity_field input weights the pnds by the amount of scattering
particles in each gridbox inside the cloudbox. Where massdensity_field is zero,
the pnd_field will be zero as well.
Subsequently the pnd values get written to pnd_field.

Now the next selection criteria string in part_species is used to repeat
the process.The new pnd values will be appended to the existing pnd_field.
And so on...

NOTE: the order of scattering particle profiles in massdensity_field is HARD WIRED!

Authors: Daniel Kreyling

Synopsis

pnd_fieldSetup(

pnd_field, atmosphere_dim, cloudbox_on, cloudbox_limits, massdensity_field, t_field, scat_data_meta_array, part_species, scat_data_nelem )

Variables

OUT	pnd_field	(Tensor4)	Particle number density field.
IN	atmosphere_dim	(Index)	The atmospheric dimensionality (1-3).
IN	cloudbox_on	(Index)	Flag to activate the cloud box.
IN	cloudbox_limits	(ArrayOfIndex)	The limits of the cloud box.
IN	massdensity_field	(Tensor4)	The field of atmospheric scattering particle types in unit of massdensity (like IWC/LWC/Rain/Aerosol etc.).
IN	t_field	(Tensor3)	The field of atmospheric temperatures.
IN	scat_data_meta_array	(ArrayOfScatteringMetaData)	An Array of ScatteringMetaData.
IN	part_species	(ArrayOfString)	part_species is an Array of Strings containing user defined input, for particle number density calculations performed by pnd_fieldSetup.
IN	scat_data_nelem	(ArrayOfIndex)	This Array has the same size as part_species.