GMTB Common Community Physics Package (CCPP) Scientific Documentation  Version 1.0
module_radsw_cldprtb Module Reference

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

Variables

Hu and Stamnes (1993) coefficients for cloud liquid condensate (used if iswcliq=1)
real(kind=kind_phys), dimension(58, nblow:nbhgh), public extliq1
 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 asyliq1
 asymmetry 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
 
real(kind=kind_phys), dimension(nblow:nbhgh), public b0s
 single scattering albedo coefficients
 
real(kind=kind_phys), dimension(nblow:nbhgh), public b1s
 
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
 
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 Hu and Stamnes method (1993)[41]. For ice clouds, there are various choices for model applications, including data tables derived from Ebert and Curry (1992) [19], from the Streamer scheme (Key,2002 [46]), or from Fu (1996) [26] . 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 Chou and Suarez (1999) [14].
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.