subroutine gfdl_cloud_microphys::lagrangian_fall_ppm ( integer, intent(in)  ktop, integer, intent(in)  kbot, real, intent(in)  zs, real, dimension (ktop:kbot + 1), intent(in)  ze, real, dimension (ktop:kbot + 1), intent(in)  zt, real, dimension (ktop:kbot), intent(in)  dp, real, dimension (ktop:kbot), intent(inout)  q, real, intent(out)  precip, real, dimension (ktop:kbot), intent(inout)  m1, logical, intent(in)  mono  )

private

Lin et al., 1983 [60] and Rutledge and Hobbs, 1984 [87].

GFDL Cloud mpdrv Detailed Algorithm

• Prevent excessive build-up of cloud ice from external sources.
• Convert moist mixing ratios to dry mixing ratios.
• Calculate cloud condensation nuclei (ccn), following klein eq. 15
• Calculate horizontal subgrid variability, which is used in cloud fraction, relative humidity calculation, evaporation and condensation processes. Horizontal sub-grid variability is a function of cell area and land/sea mask:
  Over land:

  $$t_{land}=dw_{land}(\frac{A_{r}}{10^{10}})^{0.25}$$

  
  Over ocean:

  $$t_{ocean}=dw_{ocean}(\frac{A_{r}}{10^{10}})^{0.25}$$

  where $A_{r}$ is cell area. $dw_{land}=0.20$ and $dw_{ocean}=0.10$ are base value for sub-grid variability over land and ocean. The total horizontal sub-grid variability is:

  $$h_{var}=t_{land}\times fr_{land}+t_{ocean}\times (1-fr_{land})$$

  $$h_{var}=min[0.2,max(0.01,h_{var})]$$

• Calculate relative humidity increment.
• If requested, call neg_adj() and fix all negative water species.
• Do loop on cloud microphysics sub time step.
  • Define air density based on hydrostatical property.
  • Call warm_rain() - time-split warm rain processes: 1st pass.
  • Sedimentation of cloud ice, snow, and graupel.
    • Call fall_speed() to calculate the fall velocity of cloud ice, snow and graupel.
    • Call terminal_fall() to calculate the terminal fall speed.
  • Call sedi_heat() to calculate heat transportation during sedimentation.
  • Call warm_rain() to - time-split warm rain processes: 2nd pass
  • Call icloud(): ice-phase microphysics
• Calculate momentum transportation during sedimentation.
• Update moist air mass (actually hydrostatic pressure).
• Update cloud fraction tendency.

References cs_profile().

Referenced by terminal_fall(), and warm_rain().

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