| 1 | SUBROUTINE FLUX(TAIR,PAIR,dt,sig,r,M3g,dM0,dM3) |
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| 2 | |
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| 3 | !* Masses flux = Condensation/Evaporation + Thermodynamical equilibrium |
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| 4 | !* |
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| 5 | !* Condensation/Evaporation: |
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| 6 | !* Sulfuric acid drive this process (James 1997): most present in droplets |
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| 7 | !* more or less 95% |
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| 8 | !* |
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| 9 | !* Thermodynamical equilibrium: |
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| 10 | !* Only water flux here (James 1997) => compare to acid vapor, water |
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| 11 | !* vapor is most present in the atmosphere |
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| 12 | !* |
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| 13 | !* ONLY FOR ONE MODE HERE |
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| 14 | |
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| 15 | use free_param |
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| 16 | use donnees |
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| 17 | |
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| 18 | IMPLICIT NONE |
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| 19 | |
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| 20 | real, intent(in), dimension(3) :: M3g ! Third moment of the mode |
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| 21 | real, intent(in) :: TAIR, PAIR, dt ! Temp, timestep, pressure |
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| 22 | real, intent(in) :: r, sig ! Mean radius and variance of the mode |
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| 23 | real, intent(out) :: dM3, dM0 ! Tendancy |
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| 24 | |
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| 25 | real :: RDSA, RCSA ! Resistance |
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| 26 | real :: A , B, cste, a1, a2, a3 ! Calculus cstes |
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| 27 | real :: alpha_k ! Function |
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| 28 | real :: MSAD ! Mass of sulfuric acid in the droplet, in kg |
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| 29 | real :: mk3 ! Tendancy |
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| 30 | real :: gamma |
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| 31 | |
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| 32 | |
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| 33 | ! ----- EQUILIBRIUM ----- |
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| 34 | CALL WSA_ROSA_NEW(TAIR,PAIR,r,WSAEQ,MSAD) ! Calculation of WSA |
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| 35 | |
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| 36 | ! ----- CONDENSATION / EVAPORATION ----- |
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| 37 | IF (WSAEQ .gt. 0) THEN |
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| 38 | ! Resistance due to the VAPOR diffusion (s/m2) |
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| 39 | ! Here, we supposed a Dirac function for the calculation of D (Kn(r) |
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| 40 | RDSA = (RHOSA*RGAS*TAIR) / (D*MSA*RHOsasat) |
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| 41 | ! Resistance due to the HEAT diffusion (s/m2) |
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| 42 | RCSA = (LSA*RHOSA)/(KAIR*TAIR) * ((LSA*MSA)/(RGAS*TAIR)-1.0D0) |
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| 43 | |
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| 44 | A = 2.0D0*ST*MSA / (RHOSA*RGAS*TAIR) !m |
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| 45 | B = exp(A/r) |
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| 46 | cste = 3.0D0/(RCSA+RDSA) |
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| 47 | |
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| 48 | a1 = SH2SO4-B-A*B/r-(r**2)*B*A/2.0D0*(2.0D0*r+A)/(r**4) |
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| 49 | a2 = A*B/(r**3) * (A+3.0D0*r) !m-1 |
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| 50 | a3 = (-1.0D0)*A*B * (2.0D0*r+A)/(2.0D0*r**4) !m-2 |
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| 51 | |
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| 52 | gamma = (a1 * r**(-2) * alpha_k(1,sig)/alpha_k(3,sig) + & |
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| 53 | & a2 * r**(-1) * alpha_k(2,sig)/alpha_k(3,sig) + & |
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| 54 | & a3) * cste |
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| 55 | |
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| 56 | mk3 = (1.D0/dt)*((WSA/WSAEQ) - 1.D0)*dt |
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| 57 | mk3 = mk3 + (gamma/WSAEQ) |
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| 58 | mk3 = 1.D0 - mk3 |
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| 59 | mk3 = (1.D0/mk3) * (M3g(1)+M3g(2)+M3g(3)) |
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| 60 | |
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| 61 | ! ----- TOTAL FLUX ----- |
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| 62 | ! dm < 0: evaporation and dm > 0: condensation |
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| 63 | dM3 = mk3 - (M3g(1) + M3g(2) + M3g(3)) !m3 s |
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| 64 | dM0 = dM3 / (r**3*alpha_k(3,sig)) |
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| 65 | ELSE |
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| 66 | dM3 = 0.D0 |
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| 67 | dM0 = 0.D0 |
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| 68 | END IF |
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| 69 | |
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| 70 | WSA = WSAEQ |
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| 71 | |
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| 72 | RETURN |
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| 73 | END SUBROUTINE FLUX |
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