The Atmosphere and Climate

Unit 2 Topic 5

The Atmosphere• Atmosphere pie• Layers of air above us, separated by

thermoclines• Troposphere

– 78% N2

– 21% O2

– 1% Gases, water vapor, dust, soot particulates

– Involved in biogeochemical cycling

• Stratosphere– Similar concentrations of gases with two

exceptions: H2O is much lower and O3 is much higher

– ozone layer= “global sunscreen”– produced when O2 interacts with UV

light

Figure 19.2

The Earth Greenhouse

• Naturally occurring CO2, H2O, N2O, and CH4 help to keep the earth warm. This supports life.

• Historically, CO2 has been 300 ppm, now it is 392 ppm

© NPS

• Local climates are affected by– uneven heating of the

earth’s surface by solar energy

– seasonal changes in temperature and precipitation

– rotation of earth on axis

– properties of air, land, and water

Properties of air

• Density

• Water vapor holding capacity

• Response to pressure changes

• Latent heat release

SO, in the atmosphere there is lots of heat transfer going on. What is the fancy name for this?

CONVECTION!

Convection Currents

BASIC PATTERNS OF AIR MOVEMENT

Reality: factor in the Coriolis Effect

• Earth is spinning faster at the equator than the poles.

Coriolis Effect

• This causes a deflection of things traveling straight north or straight south.

Coriolis Effect

• In the northern hemisphere, deflection is to the right of the wind direction.

• In the southern hemisphere, deflection is to the left of the wind direction.

Prevailing wind patterns= convection cells+Coriolis effect

Ocean surface currents

Deeper water currents (thermohaline circulation)

Local climate is determined by…• Distribution of heat by air and ocean

currents

• Distribution of precipitation by air currents

• Seasonal changes in solar radiation distribution (which in turn affects the two properties above)

Seasons

Earth’s Current Climate Zones

Figure 5-2Figure 5-2

Topography and Local Climate:Land Matters

• Interactions between land and oceans and disruptions of airflows by mountains and cities affect local climates.

Miller 15th edition Miller 15th edition Figure 5-8Figure 5-8

© McGraw-Hill

“Normal” Circulation in the Pacific Ocean

© McGraw-Hill

El Niño-Southern Oscillation (ENSO)