module_radsw_cldprtb Module Reference

This module contains cloud radiative property coefficients. More...

Variables
updated Hu and Stamnes (1993) coef for cloud liquid condensate (used if iswcliq=2)
real(kind=kind_phys), dimension(58, nblow:nbhgh), public	extliq1
	extinction coefficients
real(kind=kind_phys), dimension(58, nblow:nbhgh), public	extliq2
	extinction coefficients
real(kind=kind_phys), dimension(58, nblow:nbhgh), public	ssaliq1
	single scattering albedo coefficients
real(kind=kind_phys), dimension(58, nblow:nbhgh), public	ssaliq2
	extinction coefficients
real(kind=kind_phys), dimension(58, nblow:nbhgh), public	asyliq1
	asymmetry coefficients
real(kind=kind_phys), dimension(58, nblow:nbhgh), public	asyliq2
	extinction coefficients
Streamer V3 (Key 2002) coefficients for cloud ice condensate (used if iswcice=2)
real(kind=kind_phys), dimension(43, nblow:nbhgh), public	extice2
	extinction coefficients
real(kind=kind_phys), dimension(43, nblow:nbhgh), public	ssaice2
	single scattering albedo coefficients
real(kind=kind_phys), dimension(43, nblow:nbhgh), public	asyice2
	asymmetry coefficients
Fu(1996) coefficients for cloud ice condensate (used if iswcice=3)
real(kind=kind_phys), dimension(46, nblow:nbhgh), public	extice3
	extinction coefficients
real(kind=kind_phys), dimension(46, nblow:nbhgh), public	ssaice3
	single scattering albedo coefficients
real(kind=kind_phys), dimension(46, nblow:nbhgh), public	asyice3
	asymmetry coefficients
real(kind=kind_phys), dimension(46, nblow:nbhgh), public	fdlice3
	fdelta from fu, unitless
Ebert and Curry (1992) coefficients for cloud ice condensate (used if iswcice=1)
real(kind=kind_phys), dimension(5), public	abari
	extinction coefficients
real(kind=kind_phys), dimension(5), public	bbari
	extinction coefficients
real(kind=kind_phys), dimension(5), public	cbari
	single scattering albedo coefficients
real(kind=kind_phys), dimension(5), public	dbari
	single scattering albedo coefficients
real(kind=kind_phys), dimension(5), public	ebari
	asymmetry coefficients
real(kind=kind_phys), dimension(5), public	fbari
	asymmetry coefficients
Fu (2001, personal communications) coefficients for cloud snow particles
real(kind=kind_phys), public	a0s
	optical depth coefficients
real(kind=kind_phys), public	a1s
	optical depth coefficients
real(kind=kind_phys), dimension(nblow:nbhgh), public	b0s
	single scattering albedo coefficients
real(kind=kind_phys), dimension(nblow:nbhgh), public	b1s
	optical depth coefficients
real(kind=kind_phys), dimension(nblow:nbhgh), public	c0s
	asymmetry coefficients
Chou(1999) coefficients for cloud rain particles
real(kind=kind_phys), public	a0r
	optical depth coefficients
real(kind=kind_phys), public	a1r
	optical depth coefficients
real(kind=kind_phys), dimension(nblow:nbhgh), public	b0r
	single scattering albedo coefficients
real(kind=kind_phys), dimension(nblow:nbhgh), public	c0r
	asymmetry coefficients

Detailed Description

For liquid water clouds, cloud radiative property coefficients are derived from [97]. For ice clouds, there are various choices for model applications, including data tables derived from [47], from the Streamer scheme [106], or from [65] . Components of snow particles and rain droplets are not parameterized in the operational NEMS/GSM cloud microphysics scheme, and their radiative properties are neither well established yet. Coefficients for those components listed in the module are more experimental oriented that include the entries for snow from Fu (2001, personal communications), and for rain from [39].

In common practices, the cloud radiative properties (optical depth, single scattering albedo, and asymmetry factor) are usually parametized in the form of a truncated Laurent series (generalized Taylor series)

\[ f(x)=\sum_{n=-N}^Na_{n}(x-c)^n \]

Where \(x\) represents the cloud particle's effective radius (in Fu's scheme, it is called as generalized size parameter) in unites of micro-meters, \(a_{n}\) represents the corresponding coefficients, and the constant \(c\) will be zero. The number of terms, \(n\), are usually kept small, such as \(n=0,-1\) for the extinction coefficients and \(n=0,1,2\) (or a bit larger) for the coefficients of single scattering albedo and asymmetry factor. When using the Ebert and Curry cloud optical property scheme, cloud optical properties are computed 'on the fly' by using the power series in five broad spectral bands (similar expressions are used for Fu's snow and Chou's rain schemes). While for other schemes, optical properties are precomputed for each of the 14 RRTMG-SW bands in corresponding to evenly distributed particle effective radius (e.g. 1 or 3 micro-meter intervals for water or ice clouds, respectively). Simple linear interpolations will be used during radiative transfer calculations.