| 1 | subroutine pbl_profile(ps,td2m,zml1,t2m,tml1,u10m,uml1,stress,hf) |
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| 2 | |
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| 3 | !******************************************************************** |
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| 4 | ! * |
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| 5 | ! G. WOTAWA, 1995-07-07 * |
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| 6 | ! * |
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| 7 | !******************************************************************** |
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| 8 | ! * |
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| 9 | ! DESCRIPTION: CALCULATION OF FRICTION VELOCITY AND SURFACE SENS- * |
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| 10 | ! IBLE HEAT FLUX USING THE PROFILE METHOD (BERKOVICZ * |
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| 11 | ! AND PRAHM, 1982) * |
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| 12 | ! * |
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| 13 | ! Output now is surface stress instead of ustar * |
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| 14 | ! * |
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| 15 | ! * |
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| 16 | !******************************************************************** |
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| 17 | ! * |
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| 18 | ! INPUT: * |
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| 19 | ! * |
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| 20 | ! * |
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| 21 | ! ps surface pressure(Pa) * |
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| 22 | ! td2m two metre dew point(K) * |
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| 23 | ! zml1 heigth of first model level (m) * |
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| 24 | ! t2m two metre temperature (K) * |
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| 25 | ! tml1 temperature first model level (K) * |
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| 26 | ! u10m ten metre wind speed (ms-1) * |
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| 27 | ! uml1 wind speed first model level (ms-1) * |
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| 28 | ! * |
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| 29 | !******************************************************************** |
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| 30 | ! * |
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| 31 | ! OUTPUT: * |
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| 32 | ! * |
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| 33 | ! stress surface stress (i.e., friction velocity (ms-1) squared * |
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| 34 | ! multiplied with air density) * |
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| 35 | ! hf surface sensible heat flux (Wm-2) * |
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| 36 | ! * |
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| 37 | !******************************************************************** |
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| 38 | ! ustar friction velocity (ms-1) * |
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| 39 | ! maxiter maximum number of iterations * |
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| 40 | !******************************************************************** |
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| 41 | |
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| 42 | use par_mod |
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| 43 | |
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| 44 | implicit none |
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| 45 | |
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| 46 | integer :: iter |
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| 47 | real :: ps,td2m,rhoa,zml1,t2m,tml1,u10m,uml1,ustar,hf |
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| 48 | real :: al,alold,aldiff,tmean,crit |
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| 49 | real :: deltau,deltat,thetastar,psim,psih,e,ew,tv,stress |
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| 50 | integer,parameter :: maxiter=10 |
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| 51 | real,parameter :: r1=0.74 |
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| 52 | |
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| 53 | e=ew(td2m) ! vapor pressure |
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| 54 | tv=t2m*(1.+0.378*e/ps) ! virtual temperature |
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| 55 | rhoa=ps/(r_air*tv) ! air density |
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| 56 | |
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| 57 | deltau=uml1-u10m !! Wind Speed difference between |
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| 58 | !! Model level 1 and 10 m |
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| 59 | |
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| 60 | if(deltau.le.0.001) then !! Monin-Obukhov Theory not |
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| 61 | al=9999. !! applicable --> Set dummy values |
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| 62 | ustar=0.01 |
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| 63 | stress=ustar*ustar*rhoa |
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| 64 | hf=0.0 |
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| 65 | return |
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| 66 | endif |
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| 67 | deltat=tml1-t2m+0.0098*(zml1-2.) !! Potential temperature difference |
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| 68 | !! between model level 1 and 10 m |
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| 69 | |
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| 70 | if(abs(deltat).le.0.03) then !! Neutral conditions |
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| 71 | hf=0.0 |
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| 72 | al=9999. |
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| 73 | ustar=(vonkarman*deltau)/ & |
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| 74 | (log(zml1/10.)-psim(zml1,al)+psim(10.,al)) |
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| 75 | stress=ustar*ustar*rhoa |
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| 76 | return |
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| 77 | endif |
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| 78 | |
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| 79 | tmean=0.5*(t2m+tml1) |
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| 80 | crit=(0.0219*tmean*(zml1-2.0)*deltau**2)/ & |
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| 81 | (deltat*(zml1-10.0)**2) |
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| 82 | if((deltat.gt.0).and.(crit.le.1.)) then |
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| 83 | !! Successive approximation will |
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| 84 | al=50. !! not converge |
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| 85 | ustar=(vonkarman*deltau)/ & |
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| 86 | (log(zml1/10.)-psim(zml1,al)+psim(10.,al)) |
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| 87 | thetastar=(vonkarman*deltat/r1)/ & |
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| 88 | (log(zml1/2.)-psih(zml1,al)+psih(2.,al)) |
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| 89 | hf=rhoa*cpa*ustar*thetastar |
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| 90 | stress=ustar*ustar*rhoa |
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| 91 | return |
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| 92 | endif |
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| 93 | |
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| 94 | al=9999. ! Start iteration assuming neutral conditions |
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| 95 | do iter=1,maxiter |
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| 96 | alold=al |
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| 97 | ustar=(vonkarman*deltau)/ & |
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| 98 | (log(zml1/10.)-psim(zml1,al)+psim(10.,al)) |
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| 99 | thetastar=(vonkarman*deltat/r1)/ & |
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| 100 | (log(zml1/2.)-psih(zml1,al)+psih(2.,al)) |
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| 101 | al=(tmean*ustar**2)/(ga*vonkarman*thetastar) |
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| 102 | aldiff=abs((al-alold)/alold) |
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| 103 | if(aldiff.lt.0.01) goto 30 !! Successive approximation successful |
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| 104 | end do |
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| 105 | 30 hf=rhoa*cpa*ustar*thetastar |
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| 106 | if(al.gt.9999.) al=9999. |
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| 107 | if(al.lt.-9999.) al=-9999. |
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| 108 | |
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| 109 | stress=ustar*ustar*rhoa |
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| 110 | |
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| 111 | end subroutine pbl_profile |
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