cldprop()

subroutine rrtmg_sw::cldprop ( real (kind=kind_phys), dimension(nlay), intent(in) cfrac, real (kind=kind_phys), dimension(nlay), intent(in) cliqp, real (kind=kind_phys), dimension(nlay), intent(in) reliq, real (kind=kind_phys), dimension(nlay), intent(in) cicep, real (kind=kind_phys), dimension(nlay), intent(in) reice, real (kind=kind_phys), dimension(nlay), intent(in) cdat1, real (kind=kind_phys), dimension(nlay), intent(in) cdat2, real (kind=kind_phys), dimension(nlay), intent(in) cdat3, real (kind=kind_phys), dimension(nlay), intent(in) cdat4, real (kind=kind_phys), intent(in) cf1, integer, intent(in) nlay, integer, intent(in) ipseed, real (kind=kind_phys), dimension(nlay), intent(in) dz, real (kind=kind_phys), intent(in) delgth, real (kind=kind_phys), dimension(nlay), intent(in) alpha, integer, intent(in) iswcliq, integer, intent(in) iswcice, integer, intent(in) isubcsw, integer, intent(in) iovr, real (kind=kind_phys), dimension(nlay,nbdsw), intent(out) taucw, real (kind=kind_phys), dimension(nlay,nbdsw), intent(out) ssacw, real (kind=kind_phys), dimension(nlay,nbdsw), intent(out) asycw, real (kind=kind_phys), dimension(nlay), intent(out) cldfrc, real (kind=kind_phys), dimension(nlay,ngptsw), intent(out) cldfmc )

private

Parameters

cfrac	layer cloud fraction
cliqp	layer in-cloud liq water path ( $g/m^2$)
reliq	mean eff radius for liq cloud (micron)
cicep	layer in-cloud ice water path ( $g/m^2$)
reice	mean eff radius for ice cloud (micron)
cdat1	layer rain drop water path ( $g/m^2$)
cdat2	effective radius for rain drop (micron)
cdat3	layer snow flake water path( $g/m^2$)
cdat4	mean eff radius for snow flake(micron)
cf1	effective total cloud cover at surface
nlay	vertical layer number
ipseed	permutation seed for generating random numbers (isubcsw>0)
dz	layer thickness (km)
delgth	layer cloud decorrelation length (km)
alpha	EXP/ER cloud overlap decorrelation parameter
taucw	cloud optical depth, w/o delta scaled
ssacw	weighted cloud single scattering albedo (ssa = ssacw / taucw)
asycw	weighted cloud asymmetry factor (asy = asycw / ssacw)
cldfrc	cloud fraction of grid mean value
cldfmc	cloud fraction for each sub-column

cldprop General Algorithm

• Compute cloud radiative properties for a cloudy column.

• Compute optical properties for rain and snow.
  For rain: tauran/ssaran/asyran
  For snow: tausnw/ssasnw/asysnw
  • Calculation of absorption coefficients due to water clouds
    For water clouds: tauliq/ssaliq/asyliq
  • Calculation of absorption coefficients due to ice clouds
    For ice clouds: tauice/ssaice/asyice
  • For Prognostic cloud scheme: sum up the cloud optical property:
    $taucw=tauliq+tauice+tauran+tausnw$
    $ssacw=ssaliq+ssaice+ssaran+ssasnw$
    $asycw=asyliq+asyice+asyran+asysnw$

• If use fu's formula it needs to be normalized by snow/ice density. not use snow density = 0.1 g/cm**3 = 0.1 g/(mu * m**2)
  use ice density = 0.9167 g/cm**3 = 0.9167 g/(mu * m**2)
  1/0.9167 = 1.09087
  factor 1.5396=8/(3*sqrt(3)) converts reff to generalized ice particle size use newer factor value 1.0315

• Calculation of absorption coefficients due to water clouds.

• Calculation of absorption coefficients due to ice clouds.

• ebert and curry approach for all particle sizes though somewhat unjustified for large ice particles.

• streamer approach for ice effective radius between 5.0 and 131.0 microns.

• fu's approach for ice effective radius between 4.8 and 135 microns (generalized effective size from 5 to 140 microns).

• if isubcsw > 0, call mcica_subcol() to distribute cloud properties to each g-point.

References mcica_subcol().

Referenced by rrtmg_sw_run().

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