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Fix to saturation vapor pressure at low temperatures #1328

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Merged
weiwangncar merged 1 commit into from
Dec 29, 2020
Merged

Fix to saturation vapor pressure at low temperatures #1328

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36 changes: 28 additions & 8 deletions phys/module_mp_morr_two_moment.F
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Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,8 @@
! 1) changes and cleanup of code comments
! 2) correction to universal gas constant (very small change)

! CHANGES FOR WRFV4.3
! 1) fix to saturation vapor pressure polysvp to work at T < -80 C
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

! THIS SCHEME IS A BULK DOUBLE-MOMENT SCHEME THAT PREDICTS MIXING
Expand Down Expand Up @@ -1287,6 +1289,7 @@ SUBROUTINE MORR_TWO_MOMENT_MICRO(QC3DTEN,QI3DTEN,QNI3DTEN,QR3DTEN, &
! SATURATION VAPOR PRESSURE AND MIXING RATIO

! hm, add fix for low pressure, 5/12/10

EVS(K) = min(0.99*pres(k),POLYSVP(T3D(K),0)) ! PA
EIS(K) = min(0.99*pres(k),POLYSVP(T3D(K),1)) ! PA

Expand Down Expand Up @@ -4080,29 +4083,46 @@ REAL FUNCTION POLYSVP (T,TYPE)
! POLYSVP = 10.**(-9.09718*(273.16/T-1.)-3.56654* &
! LOG10(273.16/T)+0.876793*(1.-T/273.16)+ &
! LOG10(6.1071))*100.
! hm 11/16/20, use Goff-Gratch for T < 195.8 K and Flatau et al. equal or above 195.8 K
if (t.ge.195.8) then
dt=t-273.15
polysvp = a0i + dt*(a1i+dt*(a2i+dt*(a3i+dt*(a4i+dt*(a5i+dt*(a6i+dt*(a7i+a8i*dt)))))))
polysvp = polysvp*100.
else

polysvp = 10.**(-9.09718*(273.16/t-1.)-3.56654* &
alog10(273.16/t)+0.876793*(1.-t/273.16)+ &
alog10(6.1071))*100.

dt = max(-80.,t-273.16)
polysvp = a0i + dt*(a1i+dt*(a2i+dt*(a3i+dt*(a4i+dt*(a5i+dt*(a6i+dt*(a7i+a8i*dt)))))))
polysvp = polysvp*100.
end if

END IF

! LIQUID

IF (TYPE.EQ.0) THEN

dt = max(-80.,t-273.16)
polysvp = a0 + dt*(a1+dt*(a2+dt*(a3+dt*(a4+dt*(a5+dt*(a6+dt*(a7+a8*dt)))))))
polysvp = polysvp*100.

! POLYSVP = 10.**(-7.90298*(373.16/T-1.)+ &
! 5.02808*LOG10(373.16/T)- &
! 1.3816E-7*(10**(11.344*(1.-T/373.16))-1.)+ &
! 8.1328E-3*(10**(-3.49149*(373.16/T-1.))-1.)+ &
! LOG10(1013.246))*100.
! hm 11/16/20, use Goff-Gratch for T < 202.0 K and Flatau et al. equal or above 202.0 K
if (t.ge.202.0) then
dt = t-273.15
polysvp = a0 + dt*(a1+dt*(a2+dt*(a3+dt*(a4+dt*(a5+dt*(a6+dt*(a7+a8*dt)))))))
polysvp = polysvp*100.
else

! note: uncertain below -70 C, but produces physical values (non-negative) unlike flatau
polysvp = 10.**(-7.90298*(373.16/t-1.)+ &
5.02808*alog10(373.16/t)- &
1.3816e-7*(10**(11.344*(1.-t/373.16))-1.)+ &
8.1328e-3*(10**(-3.49149*(373.16/t-1.))-1.)+ &
alog10(1013.246))*100.
end if

END IF
END IF


END FUNCTION POLYSVP
Expand Down
37 changes: 29 additions & 8 deletions phys/module_mp_morr_two_moment_aero.F
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,10 @@
! 1) changes and cleanup of code comments
! 2) correction to universal gas constant (very small change)

! CHANGES FOR WRFV4.3
! 1) fix to saturation vapor pressure polysvp to work at T < -80 C
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

! TWG 2017
! TWG = Timothy Glotfelty, EPA
! Adapted from WRFV3.8.1 Morrison Double Moment Scheme
Expand Down Expand Up @@ -5031,29 +5035,46 @@ REAL FUNCTION POLYSVP (T,TYPE)
! POLYSVP = 10.**(-9.09718*(273.16/T-1.)-3.56654* &
! LOG10(273.16/T)+0.876793*(1.-T/273.16)+ &
! LOG10(6.1071))*100.
! hm 11/16/20, use Goff-Gratch for T < 195.8 K and Flatau et al. equal or above 195.8 K
if (t.ge.195.8) then
dt=t-273.15
polysvp = a0i + dt*(a1i+dt*(a2i+dt*(a3i+dt*(a4i+dt*(a5i+dt*(a6i+dt*(a7i+a8i*dt)))))))
polysvp = polysvp*100.
else

polysvp = 10.**(-9.09718*(273.16/t-1.)-3.56654* &
alog10(273.16/t)+0.876793*(1.-t/273.16)+ &
alog10(6.1071))*100.

dt = max(-80.,t-273.16)
polysvp = a0i + dt*(a1i+dt*(a2i+dt*(a3i+dt*(a4i+dt*(a5i+dt*(a6i+dt*(a7i+a8i*dt)))))))
polysvp = polysvp*100.
end if

END IF

! LIQUID

IF (TYPE.EQ.0) THEN

dt = max(-80.,t-273.16)
polysvp = a0 + dt*(a1+dt*(a2+dt*(a3+dt*(a4+dt*(a5+dt*(a6+dt*(a7+a8*dt)))))))
polysvp = polysvp*100.

! POLYSVP = 10.**(-7.90298*(373.16/T-1.)+ &
! 5.02808*LOG10(373.16/T)- &
! 1.3816E-7*(10**(11.344*(1.-T/373.16))-1.)+ &
! 8.1328E-3*(10**(-3.49149*(373.16/T-1.))-1.)+ &
! LOG10(1013.246))*100.
! hm 11/16/20, use Goff-Gratch for T < 202.0 K and Flatau et al. equal or above 202.0 K
if (t.ge.202.0) then
dt = t-273.15
polysvp = a0 + dt*(a1+dt*(a2+dt*(a3+dt*(a4+dt*(a5+dt*(a6+dt*(a7+a8*dt)))))))
polysvp = polysvp*100.
else

! note: uncertain below -70 C, but produces physical values (non-negative) unlike flatau
polysvp = 10.**(-7.90298*(373.16/t-1.)+ &
5.02808*alog10(373.16/t)- &
1.3816e-7*(10**(11.344*(1.-t/373.16))-1.)+ &
8.1328e-3*(10**(-3.49149*(373.16/t-1.))-1.)+ &
alog10(1013.246))*100.
end if

END IF
END IF


END FUNCTION POLYSVP
Expand Down