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20050117: Ice bulb temperature
- Subject: 20050117: Ice bulb temperature
- Date: Mon, 17 Jan 2005 13:50:09 -0700 (MST)
Pat,
your PR_ routine would be used for SF and SN programs.
You need to add your function to $GEMTBL/parms/pcconv.tbl,
and
Add your PR_TMIB routine to the call list in $GEMPAK/sounrce/gemlib/pc/pcfunc.f.
To create a grid program function, you would need to create a
DF library function to call your PR routine for every grid point
and add this routine to the call list of $GEMPAK/source/gemlib/dg/dgdriv.f.
Steve Chiswell
On Mon, 17 Jan 2005, Patrick S. Market wrote:
> Steve:
>
> I am trying to include a subroutine into GEMPAK that I have modified.
>
> I have rewritten TMWB to calculate to include the latent heat of fusion
> as well (see below). The code compiles alright, but trying to use it
> turns up:
>
> [DG -19] Operator TMIB is not recognized.
>
> How do I get this new function into GEMPAK?
>
> Pat
>
>
>
> *******************************begin include****************************
> FUNCTION PR_TMIB ( tmpk, rmix, pres )
> C************************************************************************
> C* PR_TMIB *
> C* *
> C* This function computes ice bulb temperature from the temperature, *
> C* mixing ratio, and pressure. The result is obtained by solving *
> C* for the temperature at which saturation occurs when the latent *
> C* heat required to vaporize/melt ice is provided by a cooling of *
> C* the air. The equation representing the process is *
> C* *
> C* ( TMPK - TMWB ) * CP - ( Rsat (TMWB) - RMIX ) * LVAP = 0 *
> C* *
> C* This implicit equation is solved by Newton's method, since the *
> C* saturation mixing ratio Rsat is a transcendental function of *
> C* TMWB. *
> C* *
> C* The expressions for the heat of vaporization (LVAP) and saturation *
> C* vapor pressure are equations (2) and (10) from Bolton (MWR, 1980). *
> C* *
> C* REAL PR_TMIB ( TMPK, RMIX, PRES ) *
> C* *
> C* Input parameters: *
> C* TMPK REAL Temperature (K) *
> C* RMIX REAL Mixing ratio (g/kg) *
> C* PRES REAL Pressure (mb) *
> C* *
> C* Output parameters: *
> C* PR_TMIB REAL Wet bulb temperature (K) *
> C** *
> C* Log: *
> C* K. Brill/NMC 4/94 *
> C* S. Jacobs/NMC 4/94 Changed input RMIX from kg/kg to g/kg *
> C* G. Krueger/EAI 4/96 Replaced C->K constant with PR_TMKC *
> C* T. Lee/GSC 11/96 Changed constant *
> C* S. Jacobs/NCEP 8/97 Changed latent heat calc to use PR_LHVP *
> C* T. Lee/GSC 8/97 Set TMWB <= temp; Simplify computation *
> C************************************************************************
> INCLUDE 'GEMPRM.PRM'
> C*
> PARAMETER ( A = 6.112, B = 17.67, C = 243.5, EPSI = .622 )
> PARAMETER ( G = B * C )
> PARAMETER ( ERRMAX = .001 )
> C*
> LOGICAL convrg
> C*
> INCLUDE 'ERMISS.FNC'
> C------------------------------------------------------------------------
> C* Check for missing values.
> C
> IF ( ERMISS ( tmpk ) .or. ERMISS ( rmix ) .or. ERMISS ( pres )
> + .or. ( pres .le. 0. ) ) THEN
> PR_TMWB = RMISSD
> ELSE
> C
> C* Change temperature to degrees Celsius.
> C
> tmp = PR_TMKC (tmpk)
> C
> C* Compute the latent heat of sublimation.
> C
> lvap = PR_LHVP ( tmp ) + (0.333 * 1.0E6)
> C
> C* Compute the specific heat of moist air.
> C
> rmix = rmix / 1000.
> cp = 1005.7 * ( 1. + .887 * rmix )
> C
> C* Compute L / cp.
> C
> rlocp = lvap / cp
> C
> C* Do Newton iteration.
> C
> iter = 0
> tib = tmp
> convrg = .false.
> DO WHILE ( iter .le. 50 .and. .not. convrg )
> iter = iter + 1
> bt = B * tib
> tpc = tib + C
> d = ( pres / A ) * EXP ( -bt / tpc )
> dm1 = d - 1.
> f = ( tmp - tib ) - rlocp * ( EPSI / dm1 - rmix )
> df = - G / ( tpc * tpc )
> df = d * df * rlocp * EPSI / ( dm1 * dm1 ) - 1.
> cor = f / df
> tib = tib - cor
> IF ( ABS ( cor ) .le. ERRMAX ) convrg = .true.
> END DO
> C*
> IF ( .not. convrg ) THEN
> PR_TMWB = RMISSD
> ELSE
> twk = PR_TMCK (tib)
> IF ( twk .gt. tmpk ) twk = tmpk
> PR_TMIB = twk
> END IF
> END IF
> C*
> RETURN
> END
>
> *******************************begin include****************************
>
> --
> ========================================================================
> Dr. Patrick S. Market
> Dept. of Soil, Env. & Atmospheric Sci.
> University of Missouri-Columbia Phone: (573) 882 - 1496
> 331 ABNR Hall Lab: (573) 882 - 4401
> Columbia, MO 65211 USA E-mail: address@hidden
> ========================================================================
>
