Clouds

1
Clouds
2
Process of Cloud Formation

• Air parcel rises while cooling at DALR
• Air parcel reaches the dewpoint and condenses
  (bottom of the cloud)
• Air parcel keeps rising
• Air parcel is equal to the temperature around it,
  stops rising (Cloud top)

3
Case 1

• Steep lapse rate (________________ ATMOSPHERE)
  Parcel rises to the tropopause, you
  getThunderstorms

UNSTABLE
Parcel cools
...and if drops to dewpoint
Lapse Rate
(steep)
Saturation
z
Temperature
HOT
COLD
4
Case 2

• Steep lapse rate near the ground, but weak lapse
  rate aloft
• Parcel will rise to a point, then stop
• Result Cumulus

(weak)
Parcel cools
Lapse Rate
...and if drops to dewpoint
(steep)
Saturation
z
Temperature
HOT
COLD
5
Case 3

• Now there is a weak lapse rate (________
  ATMOSPHERE)
• Parcel only rises slightly
• Result Stratus

STABLE
Lapse Rate
(weak)
z
Temperature
HOT
COLD
6
Cirrus
30000 feet
Composed of Ice Crystals
7
Contrails
30000 feet
Composed of Ice Crystals
8
Summary of Clouds

• Cloud type reveals how quickly temperature is
  decreasing with height
• Cumulus Stratus
• Unstable Atmosphere -Stable Atmosphere
• High Lapse Rate -Low Lapse Rate
• Deep, vertical -Thin, spread out development

9
Summary Continued

• If the Parcel can rise
• Cloud Base where saturation occurs
• Cloud Top where the parcel is no longer warmer
  than the surrounding air
• What could you infer about the atmosphere if it
  is CLEAR?
• Sinking air
• Lack of moisture (low dewpoint)

10
CLOUD NOMENCLATURE