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In-Class Activity #5 Part A: Describe what this figure is showing.

Chapter 8:

Circulation of the Atmosphere

2Photo from The Cloud Appreciation Society

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Learning Goals:

Circulation of the Atmosphere

• More solar energy is absorbed near the Equator than near

the poles.

Atmospheric circulation is driven by this heating difference.

• The Coriolis effect causes moving objects to move to the

right of their initial course, in the northern hemisphere.

(to the left in the southern)

• The atmosphere circulates in six large circuits.

• But first – some weather and climate basics ….

Which describes weather? Which describes climate?

Examples of Weather and Climate

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The forecast this weekend calls for rain.

The low temperature yesterday in Miami was 64°F.

The record low temperature here is 33°F.

(Miami, 1941)

Winds up to 10 mph are possible tomorrow.

Our average annual temperature is 76°F.

Which describes weather? Which describes climate?

Examples of Weather and Climate

Weather

Weather

Climate

Weather

Climate

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The forecast this weekend calls for rain.

The low temperature yesterday in Miami was 64°F.

The record low temperature here is 33°F.

(Miami, 1941)

Winds up to 10 mph are possible tomorrow.

Our average annual temperature is 76°F.

How do we describe weather?

“Clouds that Look Like Things” Gallery

https://cloudappreciationsociety.org6

How do we describe weather?

“Clouds that Look Like Things” Gallery

https://cloudappreciationsociety.org

• temperature

• humidity

• wind

• amount of cloud cover

• type of cloud cover

• precipitation

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• The atmosphere is a mixture of gas molecules, small

suspended particles of solid and liquid, and falling

precipitation.

• Meteorology is the study of the atmosphere and the

processes that cause what we refer to as “weather.”

• Weather refers to the short-term phenomena.

• Climate refers to the long-term patterns.

• Climatology is the long-term study of the atmosphere

and the processes that cause what we refer to as

“climate.”

Atmospheric Definitions

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• Although the density of the atmosphere decreases rapidly

with height, the top of the atmosphere is undefined.

• Overall, the majority of atmospheric mass is contained in a

thin layer near the surface.

• The atmosphere still contains an impressive sum of mass.

Thickness of the Atmosphere

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“probably

hydrogen and

helium”

Why?

In-Class Activity #5 Part B: Describe what this figure is showing.

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Permanent Gases

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Variable Gases

What is meant by “variable”??

Variable in space and time.

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The Hydrologic Cycle

What is the main source of water vapor in the atmosphere?

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• Variable Gases: Water Vapor

– Water vapor is the most abundant variable

gas, as it is added or removed from

atmosphere through the hydrologic cycle.

– 0% (desert, poles – why??)

to

- 4% (tropics)

Composition of the Atmosphere

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Sensible heat –

causes temperature change

Latent heat –

causes phase change with no temperature change

Review: the three phases of water

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What are your observations about the composition of air in

the atmosphere?

(Think about temperature, oxygen, etc…)

Composition of the Atmosphere & Density

If oxygen is scarce at high

elevations, what does this imply

about the density of this air?

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Atmospheric Density and Pressure

Due to compressibility, atmospheric mass gradually “thins out” with height.

less overlying weight

more overlying weight

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Layers of the Atmosphere

Most humans stay in the

lowest layer only.

This layer, the troposphere,

contains most of the

atmosphere’s mass. (why?)

Density is so low in the

thermosphere that there can

be several kilometers in

between individual gas

molecules!

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In-class Activity #5 Part C:

Describe what this figure is showing.

Temperature lower at higher latitudes:

1) Bigger area

2) More atmosphere

3) Reflection is higher (albedo)

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What drives Earth’s temperatures?

The Earth’s tilt drives seasons.

closer

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Although average

temperature constant,

distribution not equal.

Oceans and atmosphere

move excess heat from

equator to poles.

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Convection, heat transfer

by moving fluids.

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Sea breeze – smaller monsoon, winds come from sea.

Air flow during stable weather conditions

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Land breeze – Winds go to sea.

Air flow during stable weather conditions

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Both cities

are located at

37.8 deg N

latitude.

Influences on Air Temperature: RecapRecall: water has a high heat capacity, and

moderates temperatures on land.

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Expect air to rise at Equator,

move to poles,

and sink.

Thickness of atmosphere is

not to scale!!

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Coriolis Force

But that’s not what happens

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Coriolis force cause objects to move:

right in northern hemisphere

left in southern hemisphere

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In-Class Activity #5 Part D: Describe what this figure is showing.

Another example of isobars…

http://www.youtube.com/watch?v=g3gw8DyVsco

What do you think this image is showing?

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