1. PRESENTED BY
M. Fasihud Din Nauman
(Roll. No: 29)
Environmental Science
(4TH- Semester)

2. Clouds
visible mass of liquid droplets or
frozen crystals made of water and/or
aerosols is called cloud.

3. Cloud Location
 Majority of clouds form in the TROPOSPHERE
 Clouds can be observed in STRATOSPHERE
and MESOSPHERE
 Three layers of atmosphere collectively called
HOMOSPHERE where clouds are present
 Clouds are absent in the HETROSPHERE
(Thermosphere and Exosphere)

4. CLOUD FORMATION
 Warm air is forced upward, expands then
cools.
 As air cools the amount of water vapor needed
for saturation decreases (RH then increases).
 RH of 100%, air is saturated
 Water vapor begins to condense in tiny drops
around nuclei of dust, salt, and other particles.
 Drops of water are so small they are
suspended in air.
 Millions of these droplets collect forming
clouds.

5. CLOUDS CLASSIFICATION
There are following components which
summarize the classification system.
♣ Cirro : curl of hair, high
♣ Alto : mid
♣ Strato : layer
♣ Nimbo : rain, precipitation
♣ Cumulo: heap

6. CLOUD CLASSIFICATION
•Clouds are classified by texture and
height from the ground.
SHAPE
Cumulus : cotton ball shaped
Stratus : forms a blanket over
large areas.
Cirrus : feathery or wispy

7. 4 Major families of Clouds
A. High Clouds : above 5-13 km.
B. Middle Clouds : 2-7 km.
C. Low Clouds : 0-2 km.
D. Clouds with vertical development (0-13 km)

8. Cloud Types

9. TYPES OF CLOUDS
♦ High-level clouds:
♣ cirrus ♣ cirrostratus ♣ cirrocumulus
♦ Mid-level clouds:
♣ altostratus ♣ altocumulus
♦ Low-level clouds:
♣ stratus ♣ cumulus

10. HIGH-LEVEL
CLOUDS

11. High Clouds (Family A)
 Composed of ice crystals (Cirrostratus)
 Thin and wispy (Cirrus)

12. High Clouds Cont…
 High-level clouds form above 6 km
 The temperatures are so cold at such high
elevations, these clouds are primarily
composed of ice crystals.
 High-level clouds are typically thin and
white in appearance, but can appear in a
magnificent array of colors when the sun
is low on the horizon.

13. CIRRUS
Thin, featherlike clouds that are made of ice
crystals high in the atmosphere. Usually means a
change in the weather is coming.

14. High Clouds Cont…
 Cirrus (Thin and wispy)
 The most common form of high-level clouds are
thin and often wispy cirrus clouds.
 Typically found at heights greater than 20,000
feet (6,000 meters)
 cirrus clouds are composed of ice crystals that
originate from the freezing of supercooled
water droplets.
 Cirrus generally occur in fair weather and point
in the direction of air movement at their

15. CIRROSTRATUS

16. CIRROSTRATUS
Cirrostratus clouds form more of a
widespread, veil-like layer. When moon or
sun light passes through the ice crystals of
cirrostratus clouds, the light may dispersed.

17. High Clouds Cont…
 Cirrostratus (nearly transparent)
 Sheet-like, clouds composed of ice crystals.
 Though cirrostratus can cover the entire sky and be up
to several thousand feet thick
 They are relatively transparent, as the sun or the
moon can easily be seen through them.
 These high-level clouds typically form when a broad
layer of air is lifted by large-scale Convergence
 Its presence indicates a large amount of moisture in
the upper atmosphere
 These are not precipitation clouds, but signal the
approach of warm front

18. CIRROCUMULUS

19. High Clouds Cont…
 Cirrocumulus (Cloudlets) (Cc)
 Typically found at heights 5 to 12 km.
 These clouds signify convection
 It includes .
 Cirrocumulus usually only forms in patches

20. MID-LEVEL
CLOUDS

21. Mid-Level Clouds
 Composed of water droplets and ice
crystals

22. ALTOSTRATUS

23. ALTOSTRATUS CLOUDS
 Altostratus clouds “strato” type clouds
having flat and uniform type texture.
 Altostratus clouds themselves do not
produce precipitation at the surface.
 They frequently indicate warm wave front.

24. Altocumulus Clouds

25. LOW-LEVEL
CLOUDS

26. Low-Level Clouds
 Composed mostly of water droplets

28. STRATUS
Sheets of low, grey clouds that bring light
snow, rain, or drizzle.

29. NIMBOSTRATUS

30. NIMBOSTRATUS
Thicker layer than stratus clouds that
completely block out the sun. They cause
steady rain or snow.

32. CUMULUS
White and puffy clouds that usually
mean good weather.

33. CUMULONIMBUS

34. CUMULONIMBUS
Dark, towering clouds that are also called
“thunderheads”. These clouds produce
heavy rain, thunderstorm, and lighting.

35. Cumulonimbus

36. PRECIPITATION
Process by which water falls to Earth
from clouds in the atmosphere in the
form of rain, snow, sleet, or hail.

37. TYPES OF
PRECIPITATION

38. As raindrops
fall from the
clouds they join
with other
droplets of
water.
This causes
the raindrops
to grow in
size.