P3: Microphysical rates

[haakon-e]

Rates:

Warm-rain (not needed)

• AUT (SB)
• ACC (SB)
• NUC (SB) (+Raindow/Amy for ice nucleation)
• CON (O)
• EVP (O)

Non-eq from Olivia (we have this already:

• DEP (O)
• SUB (O)

Remaining (need for ice):

• COL (collision/collection)
  • same category
  • between categories
• SLF (self-collection)
• SHD (shedding)
• HET/HOM (heterogeneous/homogeneous freezing)
  • get from rainbow or Amy
• MLT (melting)
  • might have something
• WET (riming?)

Start with COL

• Have draft code/PR
• See AppC, sec e. & f.
• collisions:
  • ice -- rain
  • ice -- cloud droplet
• Want to use cloud sedimentation velocity (not, as MM15, neglect velocities)
• Note: SB assumes Gamma distribution for droplets.
  • Take this size distribution.
  • Also take velocity parameterization (either SB or Chen -- see docs)
    • See "Terminal Velocity" in CM.jl docs
    • Anna leans towards using Chen
  • Assume you'll be coupling with 2M SB scheme
    • SB is written as function of mass. We write as function of (maximum) diameter.
      • Anastazia looked at this -- but double-check the math.

See "Accretion" in 1M in docs. (Eq 15)

• "continuous assumption": means multiply by q_c in integands.
• Otherwise, integrate over another distribution

Rate is derived nominally derived for mass (L_ice)

• See sec f. in App C.
• Wet growth section (sec. g in App C) describes L_rim and B_rim

TLDR;

• four missing rates: COL, SLF, SHD, WET
  • Some work needed to find what the rate is for each prognostic variable based on this.