1. Atmospheric Moisture and Cloud Formationby
Colleen Rae
Regional Training Centre

2. Atmospheric moisture Water vapour is an important atmospheric gas
Water Vapour is the source of moisture for:-
cloud development
resultant precipitation in solid and liquid forms
Composition of the Atmosphere
Nitrogen (N2) %
Oxygen (O2) %
Argon (A) %
Water vapor (H2O)
Carbon dioxide (CO2)
Neon (Ne)
Helium (He) %
Krypton (Kr)
Hydrogen (H)
Ozone (O3) 1
Document Reference: RTC-PRE Date of last revision: 15 September 2015

3. Atmospheric moisture <1% Water vapor (H2O)
MESOPAUSE
STRATOPAUSE
TROPOPAUSE
THERMOSPHERE
MESOSPHERE
STRATOSPHERE
Water vapor (H2O)
Carbon dioxide (CO2)
Neon (Ne)
Helium (He)
Krypton (Kr)
Hydrogen (H)
Ozone (O3)
<1%
Within the first 6 km of the troposphere
TROPOSPHERE 2
Document Reference: RTC-PRE Date of last revision: 15 September 2015

4. Cloud appearance Cloud shapes and forms are the expression of
the way in which the air has risen,
their height above the ground,
if they are composed of water or ice crystals
the location of the sun
Cloud size is influenced by
heat
seasons
bodies of water
mountain ranges
condensation nuclei 3
Document Reference: RTC-PRE Date of last revision: 15 September 2015

5. Atmospheric mechanisms leading to saturation of the air
Convective development
Orographic uplift
Frontal uplift
Mechanical turbulence
Slow wide-spread ascent 4
Document Reference: RTC-PRE Date of last revision: 15 September 2015

6. Convective cloud appearance Cumulus and Cumulonimbus
Heaps or piles of clouds formed as buoyant warm air rises by convection.
Cumulus and Cumulonimbus 5
Document Reference: RTC-PRE Date of last revision: 15 September 2015

7. Stratiform Cloud appearance
Widespread clouds either with rounded shapes or a smooth appearance.
Stratocumulus, Stratus, Altostratus, Altocumulus, 6
Document Reference: RTC-PRE Date of last revision: 15 September 2015

8. Cirriform cloud appearance
Fibrous or wispy clouds composed of ice crystals
Cirrus, Cirrostratus and Cirrocumulus 7
Document Reference: RTC-PRE Date of last revision: 15 September 2015

9. Thank you