Microphysical and dynamical constraints on GCM simulation of the Mars water cycle

1
Microphysical and dynamical constraints on GCM
simulationof the Mars water cycle

• A.V.Rodin,
• Moscow Institute of Physics and Technology,
• Space Research Institute, Moscow, Russia
• R.J.Wilson,
• Geophysical Fluid Dynamics Laboratory, Princeton,
  USA

2
GFDL Mars GCM

• FMS FV dynamical core
• Built-in advection
• Radiatively active dust and clouds
• 5??6? or 2??2? resolution

3
Elements of aerosol model

• Resolved dust size distribution (2-6 bins)
• Very small dust particles included
• Moment scheme for cloud microphysics
• Each dust bin associated with ice moment set
• Convective-driven dust lifting

Microphysics-dependent processes

• Nucleation
• Condensation/sublimation
• coagulation
• Sedimentation
• Radiative transfer

?
4
No CCN
5
0.02 mm CCN
6
0.2 mm CCN
7
Ls 20? Ls 120? Ls 160?
Supersaturation at the condensation level along
with finite condensation rate allows water vapor
to penetrate through the hygropause and to be
trapper on the poles in the equinoctial seasons
8
Water vapor vertical profiles Ls 130?,
60?N?21?E SPICAM data simulationIf the model
lacks CCNs, significant amounts of water
penetrates hygropause
Excessive CCN
Lack of CCN
Z, km
Water vapor, ppm
9
Dust
Cloud
Fine component Normal component
Fine component Normal component
Pressure, mbar
Pressure, mbar
ppb
ppm
x10 ppb
x10 ppm
RCCN 0.2 ?m
10
Dust
Cloud
Fine component Normal component
Fine component Normal component
Pressure, mbar
Pressure, mbar
ppb
ppm
x10 ppb
x10 ppm
RCCN 0.01 ?m
11
Annual average unnormalized water columna
signature of wave processes
12
N
S
0
360
13
Conclusions

• CCN of 0.2 mm size ned to be represented
• Supersaturation is very important
• Dust microphysics is equally important as cloud
  microphysics
• Models need to be accurate representing planetary
  wave activity