Formation and types of CLOUDS and their Genus.ppt

Formation and types of clouds

1. GHANA
METEOROLOGICAL
AGENCY
MET TRAINING FOR NABCO
RECRUITS
09/01/19
DAVID PERRY OSIKA

2. CLOUD
A cloud is the visible aggregate of minute
water particles or ice or mixture of both in
the atmosphere.
CLOUD FORMATION: Most clouds are
formed when moist air is subjected to
upward motion. In so doing, it cools as a
result of adiabatic expansion which takes
place at the lower pressure in the upper
atmosphere. Further cooling results in
condensation to form clouds.

3. CONT
Cloud formation and precipitation are largely
the result of vertical motions in the atmosphere.
Sometimes these motions are visible to the eye
as we watch the development of clouds in the
sky.
Varied weather phenomena arise from vertical
motion.

4. CONT
The various types of vertical motion that lead to
cloud formation are:
 Mechanical turbulence (or Frictional turbulence)
 Convectional (Thermal turbulence)
 Orographic ascent (effect of Topography)
 Slow widespread ascent (Frontal convergence)

5. ADIABATIC CHANGES
An Adiabatic process is one which takes place
without exchange of heat with the environment.
Thus a change in the volume or pressure of a
small parcel of a gas may occur without the flow
of heat into or out of the parcel.
A parcel of unsaturated air may expand
adiabatically when it rises and enters regions of
lower pressure aloft. In doing so, it cools at the
dry adiabatic lapse rate. Adiabatic cooling leads
to the condensation of some of the water
vapour and cloud begins to form.

6. CLOUD CLASSIFICATION
Clouds are usually classified in accordance
with their genera:
LOW CLOUD
MEDIUM CLOUD
HIGH CLOUD

7. CLOUD DISPERSAL
Cloud development will naturally begin to
weaken once any of the processes leading to
its formation cease to operate.
Other factors like warming of the air,
precipitation and mixing with drier
surrounding air also dissipate clouds.

8. QUESTION TIME
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