C, B, A, C, D, D, B, A

1
(C, B, A, C, D, D, B, A)
x
x
x
x
x
2
x
x
x
CISK air/sea interaction
Evaporation from the earths Surface
Condensation in clouds and precipitation
Photochemical reaction at 20-60km
Reaction with plants at the surface and
dissolution in water
Mixing due to fluid motion and molecular
diffusion
Mixing due to fluid motion
downward
decreases
increases
geostrophic
right
ITCZ
paRd T
paRd Tv
CCN
3
Collision and coallescence Riming and aggregation
Coriolis force vanishes on the equator, and
hurricane growth needs the Coriolis force
Physically, it means that the upward pressure
gradient force is Balanced by the downward
gravitational force.
The first law of thermodynamics is dqdudw
heat absorbed by a system is used to increase its
internal Energy (du) and do external work (dw).
For adiabatic processes, Dq0. So, du-dw.
When an air mass comes down a big mountain, it
experiences adiabatic compression because
pressure increases toward the earths surface.
Compression reduces its volume and thus
dwpdalt0, and du-dwgt0. Internation energy
increae indicates temperature increase. This is
why we often observe warm air at foothills.
The entropy is higher in the case with
precipitation. This is because when there isnt
precipitation, The process is adiabatic and
reversible, wherease with precipitation the
process is Pseudoadiabatic and irreversible. For
irreversible process, its entropy increases. The
second law of thermodynamics says The sign
hlods for reversible and gt sign for irrervisble
process.
Convection will not occur because the atmosphre
is under an absolutely stable stratification.
4
Yes. Convection will occur if the air parcel is
lifted above the level of free convection. This
is because the atmosphere is conditionally
unstable. Below the level of free convection
bouyancy of the air parcel is smaller than its
weight (it is heavier than Surrounding iar).
Above the level of free convection the air parcel
is more buoynant than its surrounding air and
thus can go up without external lifting.
See figure 1 for level of free convection. We
expect convective clouds because of the free
Convection. Layered clouds requires stable
stratification.
It is evident that the two curves coincide well
high (low) nuclei concentration corresponds to
high (low) electric field. This is because
aerosols are much bigger than electrons, and thus
aerosols move much slower than electrons under
the same electric fields. The slow motion reduces
electrical currents and and thus reduces the
neutralization between the positive and negative
Charges that generates the electric fields,
resulting an increase in the electric field.
The major difference between air mass
thunderstormand the squall line is that the
former has no shear but the latter has a strong
shear between their updraft and downdraft winds.
In the airmass thunderstorm, precipitation
causes downdraft, which cuts off the moisture
source provided by the updraft. It has a
self-destroying mechanism and thus this type of
thunderstorm seldom causes severe damagement. In
the squall line, updraft and downdraft winds
strengthen each other the cold downdraft lifts
up the warm air and thus increases the updraft
moisture brings up by the updraft condenses and
precipitates. Precipitation increases the
downdraft by drag effect, and by evaporative
cooling which increases density and thus
increases the sinking of air. This type of
thunderstorm can be very destructive because
winds /precipitation are strong due to the
self-enhancing mechanism.
5

• Weak disturbances containing vorticity in
  tropical ocean surface (5-20N(S) latitudes) when
  SST
• is gt26.5 for example, a low pressure
  prturbation
• Geostrophic adjustment (Coriolis force tends to
  balance pressure gradient force) will generate
• a cyclonic circulation Ekman layer frictional
  convergence forces the warm air to go up, which
• will cause convection, condensation, and thus
  latent heat release
• Latent heat will increase air temperature and
  thus further reduce the low pressure
  perturbation
• Reduced low pressure results in faster rotation
  and increased frictional convergence, results
• in increased convection and latent heat release
  and even warmer air temperature
• Increased reduction of low pressure.

6
B
D
Level of free convection
x
Height
LCL
C
A
Temperature
Figure 1
7
Nuclei
Height (km)
Electric field
Figure 2.
8
Figure 3 Hurricane Andrew, 1992