Moisture in the Atmosphere

Beaker demo

Humidity

• Humidity - how much moisture is in the air.

• Saturated air is air that is full of water.• Dew point is the point that air must be

cooled to for a cloud to form.

Humidity• How do we measure humidity?

i Sling Psychrometerii Dry Bulb- Air temperatureiii Wet Bulb – temperature of saturated air.

Write this down! (NEXT PAGE OF NOTES)

1) To find the RH you need the dry bulb (temperature) in oC

2) Then find the difference between Dry Bulb and Wet Bulb.

3) Look up DB4) Look up Difference5) Where they intersect

is the Rel Humidity.

• What is the Humidity if:– DB=10oC & WB=10oC

• 100%– DB=20oC & WB=7oC

• 5%– DB=0oC & WB=-1oC

• 81%– DB=-10oC & WB=-12oC

• 33%

Dew Point

• This is the point where water vapor condenses to form clouds.

• How do we measure it?– Same way we did with the humidity.

• How do we find it?– Same way as humidity but with different

chart.

ESRT Practice1) To find the DP you

need the dry bulb (temperature) in oC

2) Then find the difference between Dry Bulb and Wet Bulb.

3) Look up DB4) Look up Difference5) Where they

intersectis the Dew Point.

Dry Bulb ALWAYS greater then Wet Bulb

Practice

• What is the Dew Pt if DB=0oC & WB= -4oC?-15oC

• What is the Humidity if DB=0oC & WB=4oC?28%

• What is the WB if DB=4oC & DP= -11oC?-1oC

• What is the Dew P if the DB=8oC & Hum=39%?-5oC

Dry Bulb ALWAYS greater then Wet Bulb

The Water Cycle • The process of water flowing to an from the

oceans. Draw this

Important parts of Water Cycle• Evaporation

– Liquid water changing to gas• Condensation

– Gas vapor to liquid water• Precipitation

– Water falling to the ground• Infiltration

– Water being absorbed• Run off

– Water flowing off of surface