var/da/da_ssmi/cal_sigma_v.inc

   1       subroutine cal_sigma_v(ifreq,p0,wv,hwv,ta,gamma,sigma_v)
   2       integer ifreq
   3       real sigma_v,p0,wv,hwv,ta,gamma
   4 !
   5       real wvc, wvcor(4)
   6       real sigv
   7 !
   8       real voh1,otbar1,pbar1
   9       real term21,term31,term41,term51,term61
  10       real a11,a21,a31,a41,a51,a61
  11 !
  12       real voh2,otbar2,pbar2
  13       real term22,term32,term42,term52,term62
  14       real a12,a22,a32,a42,a52,a62
  15 !
  16       real voh3,otbar3,pbar3
  17       real term23,term33,term43,term53,term63
  18       real a13,a23,a33,a43,a53,a63
  19 !
  20       real voh4,otbar4,pbar4
  21       real term24,term34,term44,term54,term64
  22       real a14,a24,a34,a44,a54,a64
  23 !
  24       real const1,const2,const3,const4
  25       real h1,h2,h3,h4
  26 !
  27       data const1,const2,const3,const4/0.6,2.8,0.2,0.2/
  28       data h1,h2,h3,h4/5.0,4.9,6.8,6.4/
  29 !
  30       data a11,a21,a31,a41,a51,a61/-.13747e-2,-.43061e-4, .14618e+1,  &
  31         .25101e-3, .14635e-1,-.18588e+3/
  32       data a12,a22,a32,a42,a52,a62/ .22176e-1,-.32367e-4,-.10840e-4,  &
  33         -.63578e-1, .16988e-7,-.29824e+2/
  34       data a13,a23,a33,a43,a53,a63/-.10566e-2,-.12906e-3, .56975e+0,  &
  35          .10828e-8,-.17551e-7, .48601e-1/
  36       data a14,a24,a34,a44,a54,a64/-.60808e-2,-.70936e-3, .28721e+1,  &
  37          .42636e-8,-.82910e-7, .26166e+0/
  38 !
  39 !      data wvcor/1.01,0.95,1.06,0.92/
  40       data wvcor/1.02,0.98,1.02,0.88/
  41 ! use modified water vapor value to correct for errors in theoretical absorption
  42 !
  43       wvc = wv*wvcor(ifreq)
  44 !
  45       if (ifreq.eq.1) then
  46         pbar1 = p0/(1.0 + hwv/h1)
  47         voh1   = wv/hwv
  48         term21 = a21*voh1
  49         otbar1 = 1.0/(ta - const1*gamma*hwv)
  50         term31 = a31*otbar1
  51         term61 = a61*otbar1*otbar1
  52         term41 = a41*pbar1*otbar1
  53         term51 = a51*voh1*otbar1
  54         sigv = a11 + term21 + term31 + term41 + term51 + term61
  55       else if (ifreq.eq.2) then
  56         pbar2 = p0/(1.0 + hwv/h2)
  57         term22 = a22*pbar2
  58         term52 = a52*pbar2*pbar2
  59         voh2   = wv/hwv
  60         term32 = a32*voh2
  61         otbar2 = 1.0/(ta - const2*gamma*hwv)
  62         term42 = a42*otbar2
  63         term62 = a62*otbar2*otbar2
  64         sigv = a12 + term22 + term32 + term42 + term52 + term62
  65       else if (ifreq.eq.3) then
  66         pbar3 = p0/(1.0 + hwv/h3)
  67         term43 = a43*pbar3*pbar3
  68         voh3   = wv/hwv
  69         term23 = a23*voh3
  70         otbar3 = 1.0/(ta - const3*gamma*hwv)
  71         term33 = a33*otbar3
  72         term53 = a53*pbar3*voh3
  73         term63 = a63*otbar3*voh3
  74         sigv = a13 + term23 + term33 + term43 + term53 + term63
  75       else if (ifreq.eq.4) then
  76         pbar4 = p0/(1.0 + hwv/h4)
  77         term44 = a44*pbar4*pbar4
  78         voh4   = wv/hwv
  79         term24 = a24*voh4
  80         otbar4 = 1.0/(ta - const4*gamma*hwv)
  81         term34 = a34*otbar4
  82         term54 = a54*pbar4*voh4
  83         term64 = a64*otbar4*voh4
  84         sigv = a14 + term24 + term34 + term44 + term54 + term64
  85       else
  86         sigv = 0.0
  87       endif
  88       sigma_v = sigv*wvc
  89
  90       end subroutine cal_sigma_v
  91