| 1 | module sens_heat_rain_m |
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| 2 | |
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| 3 | implicit none |
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| 4 | |
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| 5 | contains |
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| 6 | |
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| 7 | elemental real function sens_heat_rain(rain, t, q, rhoa, xlv, t_int, p) |
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| 8 | |
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| 9 | ! Computes heat flux due to rainfall, in W m-2, positive upward. |
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| 10 | |
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| 11 | use const, only: cpa, cpw, rgas |
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| 12 | #ifndef IN_LMDZ |
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| 13 | use const, only: eps_w |
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| 14 | #endif |
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| 15 | use esat_m, only: esat |
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| 16 | |
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| 17 | #ifdef IN_LMDZ |
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| 18 | include "YOMCST.h" |
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| 19 | ! for eps_w |
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| 20 | #endif |
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| 21 | |
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| 22 | real, intent(in):: rain ! rain mass flux, in kg m-2 s-1 |
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| 23 | real, intent(in):: t ! air temperature at 10 m, in K |
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| 24 | real, intent(in):: q ! specific humidity at 10 m |
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| 25 | real, intent(in):: rhoa ! density of moist air (kg / m3) |
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| 26 | real, intent(in):: xlv ! latent heat of evaporation (J / kg) |
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| 27 | real, intent(in):: t_int ! interface temperature, in K |
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| 28 | real, intent(in):: p ! surface pressure, in Pa |
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| 29 | |
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| 30 | ! Local: |
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| 31 | |
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| 32 | real es ! saturation pressure of wator vapor, in Pa |
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| 33 | real alfac ! wet bulb factor |
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| 34 | real dwat ! water vapour diffusivity |
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| 35 | real dtmp ! heat diffusivity |
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| 36 | real q_int ! specific (saturation) humidity at ocean interface |
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| 37 | real t_celsius ! air temperature at 10 m, in Celsius degrees |
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| 38 | |
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| 39 | real wetc |
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| 40 | ! derivative of saturated mass fraction of water vapor with |
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| 41 | ! respect to temperature, at constant total pressure |
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| 42 | |
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| 43 | !--------------------------------------------------------------------- |
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| 44 | |
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| 45 | es = esat(t_int, p) * 0.98 ! reduced for salinity, Kraus 1972 page 46 |
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| 46 | q_int = eps_w * (es / (p - (1. - eps_w) * es)) |
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| 47 | wetc = eps_w * xlv * q_int / (rgas * t_int**2) |
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| 48 | dwat = 2.11e-5 * (t / 273.15)**1.94 |
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| 49 | t_celsius = t - 273.15 |
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| 50 | dtmp = (1. + 3.309e-3 * t_celsius - 1.44e-6 * t_celsius**2) * 0.02411 & |
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| 51 | / (rhoa * cpa) |
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| 52 | |
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| 53 | ! Gosnell 1995 k0991, equation (11): |
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| 54 | alfac = 1. / (1. + (wetc * xlv * dwat) / (cpa * dtmp)) |
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| 55 | |
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| 56 | ! Gosnell 1995 k0991, equation (12): |
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| 57 | sens_heat_rain = rain * alfac * cpw * (t_int - t + (q_int - q) * xlv / cpa) |
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| 58 | |
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| 59 | end function sens_heat_rain |
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| 60 | |
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| 61 | end module sens_heat_rain_m |
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