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*** S/P CONDLOAD
SUBROUTINE CONDLOAD(QLIQ,QICE,WTW,DZ,BOTERM,ENTERM,RATE,QNEWLQ, 1
* QNEWIC,QLQOUT,QICOUT,GRAV)
*
*
#include "impnone.cdk"
*
*
REAL BOTERM,CONV,DQ,DZ
REAL ENTERM,GRAV,G1,OLDQ,PPTDRG
REAL QEST,QICE,QICOUT,QLIQ,QLQOUT,QNEW
REAL QNEWIC,QNEWLQ,QTOT,RATE
REAL RATIO3,RATIO4,WAVG,WTW
*
*AUTHOR
* Kain and Fritsch (1988)
*
*REVISION
* 001 Stephane Belair (1994)
* 002 A-M Leduc (2001) Adaptation to physics 3.7
*
*OBJECT
* to perform the precipitation fallout
*
*ARGUMENTS
*
* - INPUT/OUTPUT -
* QLIQ liquid water in the cloud layer as input
* liquid water after the precipitation fallout as output
* QICE cloud ice in the cloud layer as input
* cloud ice after the precipitation fallout as output
* WTW W*W of the updraft as input
* new vertical velocity with the condensation load
* effect as output
*
* - INPUT -
* DZ row number
* BOTERM buoyancy term for the updraft
* ENTERM entrainment term for the updraft
* RATE rate of precipitation fallout production in the
* updraft (= 0.01)
* QNEWLQ fresh liquid water condensate in the updraft
* QNEWIC fresh cloud ice in the updraft
*
* - Output -
* QLQOUT precipitation fallout (liquid water)
* QICOUT precipitation fallout (cloud ice)
*
*
*Notes
* 9/18/88...This precipitation fallout scheme is based on the scheme
* used by Ogura and Cho (1973). Liquid water fallout from a parcel
* is calculated using the equation dq=-rate*q*dt, but to simulate a
* quasi-continuous process, and to eliminate a dependency on vertical
* resolution, this is expressed as q=q*exp(-rate*dz).
**
*
QTOT=QLIQ+QICE
QNEW=QNEWLQ+QNEWIC
*
*
*
* Estimate the vertical velocity so that
* an average vertical velocity can be
* calculated to estimate the time required
* ascent between model levels.
*
QEST=0.5*(QTOT+QNEW)
*
* Solve for the vertical motion.
*
G1=WTW+BOTERM-ENTERM-2.*GRAV*DZ*QEST/1.5
IF(G1.LT.0.0)G1=0.
WAVG=(SQRT(WTW)+SQRT(G1))/2.
*
* Conversion
*
CONV=RATE*DZ/WAVG
*
*
* RATIO3 is the fraction of liquid water
* in fresh condensate.
* RATIO4 is the fraction of liquid water in
* the total amount of condensate involved
* in the precipitation process.
* Note that only 60% of the fresh condensate
* is allowed to participate in the conversion
* process.
*
RATIO3=QNEWLQ/(QNEW+1.E-10)
QTOT=QTOT+0.6*QNEW
OLDQ=QTOT
RATIO4=(0.6*QNEWLQ+QLIQ)/(QTOT+1.E-10)
*
* Apply the rate equation.
*
QTOT=QTOT*EXP(-CONV)
*
*
* Determine the amount of precipitation that
* falls out of the updraft parcel at this
* level.
*
DQ=OLDQ-QTOT
QLQOUT=RATIO4*DQ
QICOUT=(1.-RATIO4)*DQ
*
*
* Estimate the mean load of condensate on
* the updraft in the layer.
* Calculate the vertical velocity.
*
* PPTDRG = precipitation drag
*
PPTDRG=0.5*(OLDQ+QTOT-0.2*QNEW)
*
* Apply again equation for vertical motion.
*
WTW=WTW+BOTERM-ENTERM-2.*GRAV*DZ*PPTDRG/1.5
*
*
* Determine the new liquid water and ice
* concentrations including lost due to
* precipitation and gains from condensation.
* Don't forget to include the fraction 0.4qnew
* which was not involved in the conversion
* process.
*
QLIQ=RATIO4*QTOT+RATIO3*0.4*QNEW
QICE=(1.-RATIO4)*QTOT+(1.-RATIO3)*0.4*QNEW
QNEWLQ=0.
QNEWIC=0.
*
*
RETURN
END