#include <misc.h> #include <params.h> subroutine trcmix(pmid , clat , coslat ,n2o ,ch4 , 1 $ cfc11 , cfc12 ) C----------------------------------------------------------------------- C c Specify zonal mean mass mixing ratios of CH4, N2O, CFC11 and c CFC12 C C Distributions assume constant mixing ratio in the troposphere C and a decrease of mixing ratio in the stratosphere. Tropopause C defined by ptrop. The scale height of the particular trace gas C depends on latitude. This assumption produces a more realistic C stratospheric distribution of the various trace gases. C C-------------------------Code History---------------------------------- C C Original version: J.T.Kiehl Nov 21 1994 C Standardized: T. Acker, Feb 1996 C Reviewed: J. Kiehl, April 1996 C C----------------------------------------------------------------------- c c $Id: trcmix.F,v 1.1 1998/04/01 07:22:44 ccm Exp $ c C----------------------------------------------------------------------- #include <implicit.h> C-----------------------------Parameters-------------------------------- #include <prgrid.h> C------------------------------Commons---------------------------------- #include <comvmr.h> C-----------------------------Arguments--------------------------------- C C Input C real pmid(plond,plev) ! model pressures real clat ! current latitude in radians real coslat ! cosine of latitude C C Output C real n2o(plond,plev) ! nitrous oxide mass mixing ratio real ch4(plond,plev) ! methane mass mixing ratio real cfc11(plond,plev) ! cfc11 mass mixing ratio real cfc12(plond,plev) ! cfc12 mass mixing ratio C C--------------------------Local Variables------------------------------ C integer i ! longitude loop index integer k ! level index C real dlat ! latitude in degrees real ptrop ! pressure level of tropopause real pratio ! pressure divided by ptrop C real xn2o ! pressure scale height for n2o real xch4 ! pressure scale height for ch4 real xcfc11 ! pressure scale height for cfc11 real xcfc12 ! pressure scale height for cfc12 C real ch40 ! tropospheric mass mixing ratio for ch4 real n2o0 ! tropospheric mass mixing ratio for n2o real cfc110 ! tropospheric mass mixing ratio for cfc11 real cfc120 ! tropospheric mass mixing ratio for cfc12 C C C----------------------------------------------------------------------- C C set tropospheric mass mixing ratios C ch40 = rmwch4 * ch4vmr n2o0 = rmwn2o * n2ovmr cfc110 = rmwf11 * f11vmr cfc120 = rmwf12 * f12vmr C C set stratospheric scale height factor for gases C dlat = abs(57.2958 * clat) if(dlat.le.45.0) then xn2o = 0.3478 + 0.00116 * dlat xch4 = 0.2353 xcfc11 = 0.7273 + 0.00606 * dlat xcfc12 = 0.4000 + 0.00222 * dlat else xn2o = 0.4000 + 0.013333 * (dlat - 45) xch4 = 0.2353 + 0.0225489 * (dlat - 45) xcfc11 = 1.00 + 0.013333 * (dlat - 45) xcfc12 = 0.50 + 0.024444 * (dlat - 45) end if C C pressure of tropopause C ptrop = 250.0e2 - 150.0e2*coslat**2.0 C C determine output mass mixing ratios C do k = 1,plev do i = 1,plon if(pmid(i,k).ge.ptrop) then ch4(i,k) = ch40 n2o(i,k) = n2o0 cfc11(i,k) = cfc110 cfc12(i,k) = cfc120 else pratio = pmid(i,k)/ptrop ch4(i,k) = ch40 * (pratio)**xch4 n2o(i,k) = n2o0 * (pratio)**xn2o cfc11(i,k) = cfc110 * (pratio)**xcfc11 cfc12(i,k) = cfc120 * (pratio)**xcfc12 end if end do end do C return C end