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subroutine da_predictor_crtm(pred,npred,nlevels,temp,hum,t_skin,pf) 3,2
implicit none
! temp - model level temperatures (k)
! hum - model level moistures (g/kg)
! t-skin - model skin temperature (k)
! nlevels - number of model levels (0:model top)
! pm - model level pressure (hpa)
! pf - full level pressure (hpa)
! pred(1) - 1000-300 thickness
! pred(2) - 200-50 thickness
! pred(3) - t_skin
! pred(4) - total column precipitable water
integer, intent(in) :: npred,nlevels
real, intent(in) :: temp(nlevels), hum(nlevels), t_skin
real, intent(in) :: pf(0:nlevels)
real, intent(out) :: pred(npred)
real, parameter :: kth = gas_constant/gravity
real, parameter :: kpc = 100.0/gravity
real :: tv(nlevels), qm(nlevels)
real :: dlp(nlevels), dp(nlevels)
real :: add_thk
integer :: itmp(1)
integer :: index1000, index300, index200, index50
if (trace_use) call da_trace_entry
("da_predictor_crtm")
qm=hum*0.001 ! g/kg to kg/kg
dlp(1:nlevels) = log(pf(1:nlevels)) - log(pf(0:nlevels-1))
dp(1:nlevels) = pf(1:nlevels) - pf(0:nlevels-1)
! 0.0 find the pressure level index that is closest to
! 1000hPa, 300hPa, 200hPa, and 50hPa respectively
! note: pf levels are 0:nlevels,
! return values of minloc are 1:nlevels+1
itmp(1:1) = minloc(abs(pf(:)-1000.0))
index1000 = itmp(1)-1
itmp(1:1) = minloc(abs(pf(:)-300.0))
index300 = itmp(1)-1
itmp(1:1) = minloc(abs(pf(:)-200.0))
index200 = itmp(1)-1
itmp(1:1) = minloc(abs(pf(:)-50.0))
index50 = itmp(1)-1
! 1.0 convert all temperatures to virtual temperatures
! ----------------------------------------------------
tv = temp*(1.0+0.608*qm)
if ( (1000.0 > pf(nlevels)) ) then
add_thk = kth*( tv(nlevels)*(log(1000.0)-log(pf(nlevels))) ) ! approximation
else
add_thk = 0.0
end if
! 2.0 construct averages for nesdis thick layers
! ----------------------------------------------
pred(1) = kth*sum( tv(index300+1:index1000)*dlp(index300+1:index1000) ) + add_thk
pred(2) = kth*sum( tv(index50+1:index200)*dlp(index50+1:index200) )
pred(3) = t_skin
pred(4) = kpc*sum( qm(1:nlevels)*dp(1:nlevels) )
if (trace_use) call da_trace_exit("da_predictor_crtm")
end subroutine da_predictor_crtm