Water in the Atmosphere

Chapter 2.4Pages 61-66

Cloud Formation1. Air is warmed and rises

– Infrared Radiation Heats Surface.– Evaporates water.

Cloud Formation2. Air Expands as it rises• Air Cools at the Dry Adiabatic Lapse Rate

(Dry ALR= 10°C for every 1km)

Cloud Formation3. Condensation Occurs• Must occur on condensation nuclei

– Dust– Salt– Smoke

Cloud Formation4. Condensation Level

– The level at which condensation occurs.– Relative humidity = 100%

• Temp and Dew Point are =

Cloud Formation5. Cloud forms

– Air now cools at the Wet ALR= 5-9°C– Cools slower because condensation releases

some heat.

Exit PassDescribe two of the Global

Winds (Where is it located, H or L pressure, direction, etc.)

CloudIdentification

Chapter 2.4Pages 63-66

• Mean’s heap or mass, have a rounded, cotton-like appearance

• Fair weather clouds• Form at altitude less

than 2km • Can grow to be very

tall, as high as 18km.

Cumulus

• Look the same as Cumulus clouds– In Italian, Alto means

‘high’

• Alto means that they form at a higher altitude, between 2 and 6km.

Altocumulus

• What does this cloud make you think of?

• The suffix Nimbus means rain

• Thunderstorm clouds, sometimes called thunderheads

• Tallest clouds, they grow from cumulus clouds. Produce heavy rainfall.

Cumulonimbus

• Strato means “spread out”

• Stratus are flat, layered clouds

• Usually cover most of the sky, creating “Overcast” days– They go ‘straight

across the sky’

Stratus

• The prefix Nimbus means rain

• When flat, layered stratus clouds thicken

• Bring drizzle, rain, or snow

• Accompany warm fronts.

Nimbostratus

• Prefix Alto

• Stratus clouds high in the atmosphere, between 2 and 6km.

Altostratus

• Feathery “hooked” ends; wispy

• Made up of ice crystals

• First to arrive with a warm front.

Cirrus Clouds

• Look like cumulus clouds

• High in the atmosphere, above 6km

• Made of ice crystals.

Cirrocumulus

Mammatus Clouds• Round, downward-

extending protrusions.• Bag-like• Usually occurs along

with some cumulonimbus clouds

• May indicate very severe weather.

• A cloud that occurs at or near the ground

• Forms when the ground cools after a warm humid day

• The air above the ground cools to the dew point

• The sun “burns” off the fog (evaporates).

Fog

Exit PassDescribe two of the three major cloud types and the type of weather they are

associated with.

• Explain how clouds are classified?

• Use the Sky Watcher Chart to help you.

Question

• Directions:– Read each question.– Click on the letter of your choice.– If you get a question wrong, the button will

turn red. Try again.– If you get the question right, move on to the

next question by clicking the arrow.– Click the arrow to the right to begin.

Quiz

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Quiz1. These clouds cover the sky

and bring rain, snow or sleet.

CD

BA

Cirrus

CumulusNimbostratus

Stratus

Quiz2. What type of cloud is

feathery or wispy?

CD

BA Cirrus

StratusCumulus

Nimbus

Quiz3. What type of cloud means

“heap” or “pile”?

CD

BA Stratus

CirrusCumulus

Mammatus

Quiz4. Identify this cloud that

occurs on the ground.

CD

BA Cirrus

CumulusStratusFog

Quiz

5. Identify this Cloud:

CD

BA Cirrus

MammatusCumulusCumulonimbus

• Congratulations on being able to correctly identify the types of clouds! You are on your way to becoming a meteorologist. Keep up the great work!

• Read pages 63-66

Great Job!

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