Energy Exchanges in the

Atmosphere

Atmosphere - blanket of gas that surrounds the earth (the air around us)

Atmospheric Variables that cause weather conditions

TemperaturePressure

Air MovementVisibilityHumidity

Weather - a description of the

atmospheric variables at a given place during a short period of time

Where does most weather occur?

In the TROPOSPHERE which is the LOWEST

PART OF THE ATMOSPHERE

Atmospheric Variables

Temperature Variationsaffected byInsolationAltitudeClouds

Pollution

Pressure Variations

What causes air Pressure?Gravity

Differences in Pressure are due to:

TemperatureAltitude

Humidity

TemperatureWhat is heavier warm

air or cold air?COLD AIR

COLD AIR is more dense and wants to sink causing an increase in

pressure

AltitudeAs altitude increases air pressure DECREASES

Because a smaller amount of air above you

weighs less

Effect ofMoisture Content

orHumidity

on Pressure

Opposite of what you normally expect

As the amount of Water Vapor in the air

INCREASES, the weight of the air DECREASES

Because: water vapor molecules weigh less than dry air molecules

Measuring Air PressureAir Pressure is

measured using a BAROMETER

Atmospheric Pressure is measured in

MILLIBARS and INCHES

Aneroid Barometer

ISOBAR-Line of equal air

pressure.

Isobars are used ON WEATHER MAPS

They help show us the location of HIGHS &

LOWS

Air Movement

Wind -the horizontal

movement of air

Atmospheric Transparency

- a measure of the ability of the

atmosphere to pass light

Dust, Smoke, Water Droplets, etc. in the air

are calledAEROSOLS /

Condensation Nuclei

They directly affect Transparency which

means, as the stuff in the air increases the amount

of light that can pass through decreases.

Ingredients of Weather8min video