Water in the Atmosphere

Chapter 16 Section 4Pages 545-550

Humidity

• Humidity- A measure of the amount of water vapor in the air.

• Relative Humidity- The percentage of water vapor in the air compared to the maximum amount that the air can hold at that temperature.

Relative Humidity Problems:

• If 10°C Holds a maximum of 8 grams of water vapor.

• What is the humidity if 8 grams of water vapor are in the air?

Relative Humidity Problems:

• If 10°C Holds a maximum of 8 grams of water vapor.

• What is the humidity if 8 grams of water vapor are in the air?

• If the air is holding 4 grams of water vapor, what is the relative humidity?.

R. Humidity Depends ON:

• The temperature.

• Warm air is less dense.– Has more room to hold water vapor.

• Cold air is more dense– Has less space to hold water vapor

Measuring Humidity• Psychrometer- An

instrument used to measure relative humidity, consisting of a wet-bulb thermometer, and a dry-bulb thermometer.

• Evaporation is a ____________ process.

Relative Humidity• If the relative

humidity is high, will there be much of a temperature difference between the thermometers and why?

Dew Point

• Dew Point- The temperature at which condensation begins.

• If the temperature= dew point– Relative humidity = 100%

Cloud Formation• 1. Air is warmed and rises

– Infrared Radiation Heats Surface.– Evaporates water.

Cloud Formation• 2. Warm, Moist air rises.• Air Expands as it rises.• Air Cools at the Dry Adiabatic Lapse Rate

(Dry ALR= 10°C for every 1km)

Cloud Formation• 3. Condensation Occurs.• Must occur on condensation nuclei

– Dust– Salt– Smoke

Cloud Formation• 4. Condensation Level

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

• Temp and Dew Point are =

Cloud Formation• 5. Cloud Forms:

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

some heat.

CloudIdentification

Chapter 16 Section 4Pages 548-550Main Menu

Click on an Icon to navigate:

Notes Quiz

Main Menu

Directions

1. Use the arrows to navigate through this PowerPoint

2. Click through the following slides on clouds and copy the notes onto your note sheet.

3. Be sure to sketch the shape of each cloud in your notes as well.

4. Take the Cloud Quiz.Main Menu

Directions

• Means heap or mass.

• Fair weather clouds.

• Can grow to be very tall.

Cumulus

Main Menu

• Alto- means that they form at a medium altitude.

• Look like cumulus clouds.

Altocumulus

Main Menu

• Thunderstorm Clouds sometimes called thunderheads.

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

• The suffix nimbus means rain.

Cumulonimbus

Main Menu

Mammatus Clouds• Round, downward-

extending protrusions.• Bag like sacs.• Usually occurs along

with some cumulonimbus clouds.

• May indicate very severe weather.

Main Menu

• Strato- means “spread out”

• Flat layered clouds.

• Usually cover most of the sky.

Stratus

Main Menu

• Prefix nimbus means rain.

• Flat layered clouds.

• Accompany warm fronts.

• Bring rain, snow, sleet or freezing rain.

Nimbostratus

Main Menu

• Look like stratus clouds high in the atmosphere.

Altostratus

Main Menu

• Feathery “hooked” ends

• Made up of ice crystals

• First to arrive with a warm front.

Cirrus Clouds

Main Menu

• Look like cumulus clouds.

• High in the atmosphere.

• Made of ice crystals.

Cirrocumulus

Main Menu

• 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

Main Menu

• Explain how clouds are classified?

• Use the Sky Watcher Chart to help you.

Question

Main MenuQuiz

• 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

Main Menu

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 167-173

Great Job!

Main Menu