Factors that Influence Climate

3 main factors:1. Latitude

• Distance from the equator

• Angle of suns rays– Why do we have

seasons?

Latitude

• • Latitude is at work here; what other factors?

• Patterns?• Temperature A

nimation

Factors that Influence Climate

3 main factors:1. Latitude2. Altitude

Temperatures fall by 6 °C with every 1000 m gained in elevation

Altitude

• Often said that:``altitude mimics latitude’’

What does that mean?

Swiss Alpshttp://traumwerk.stanford.edu/archaeolog/2005/12/some_effects_of_altitude_and_c.html

Factors that Influence Climate

3 main factors1. Latitude2. Altitude3. Oceanic Circulation

• currents

Ocean circulation• Global conveyor– Including surface currents such as Gulf stream that

influence climate

El niño

View animations

Factors that Influence Climate

3 main factors1. Latitude2. Altitude3. Oceanic CirculationOther important factors• Atmospheric

Circulation

• Winds• Cold air sinks– Compresses and warms

• Warm air rises– Expands and cools

Atmospheric circulation• Arrows show

direction of winds near ground

• Winds are angled because of Earth’s rotation (coriolis effect)

• Air at 60 deg N and S rises, most going toward the poles, where it gets cold and sinks. So, poles are cold and dry.

Factors that Influence Climate

3 main factors1. Latitude2. Altitude3. Oceanic CirculationOther important factors• Atmospheric Circulation• Solar activity

Radiation Animation

• Solar maximum– 11 year cycle

Factors that Influence Climate

3 main factors1. Latitude2. Altitude3. Oceanic CirculationOther important factors• Atmospheric Circulation• Solar activity• Volcanic activity

• Lots of ash and CO2• O2 and water create

atmospheric haze

volcanoes

• sulfur dioxide can remain in atmosphere for 3 years, forming haze that reflects sunlight, cooling the planet

• Mt. Pinatubo in 1991 had that affect

• 1815: Mt. Tambora erupts• 1816: Year without a summer

Factors that Influence Climate

3 main factors1. Latitude2. Altitude3. Oceanic CirculationOther important factors• Atmospheric Circulation• Solar activity• Volcanic activity• Topography

• Shape of the land• Rain shadow

How does the Earth gain heat?

• The Sun

What accounts for the Earth’s temperature?

• Energy balance– Electromagnetic energy (light, UV, IR) from the

Sun enters the Earth’s atmosphere– Electromagnetic energy is radiated back to space

3 waysfor transfer of heat energy

• Radiation: electromagnetic waves (such as light from the sun) travel through space

• Convection: warm gases or liquids rise, cool, and fall

• Conduction: warm body transfers heat directly to a colder body

Earth’s Greenhouse Effect

The greenhouse effect

• One of the main reasons Earth has a livable climate• Not in doubt• Greenhouse gases: ``Trap’’ heat that is radiated from

the earth’s surface and re-radiate it.– Water vapor – main greenhouse gas– Carbon dioxide– Methane -- 26 times CO2’s heat-trapping ability

– Nitrous oxide – 216 times CO2’s heat-trapping ability

Why the interest in CO2?

• Increasing rapidly in the atmosphere• Plays a big role high in the atmosphere, where

it is quite dry—i.e., little water vapor.

Greenhouse gases

• Carbon dioxide: released when biomass (wood) or fossil fuels are burned

• Methane: released when organic waste decomposes in landfills; by livestock; during processing of fossil fuels

• Water vapor: evaporation from ocean.

The Carbon Cycle

Some of the Sun’s energy is reflected back to space

• Albedo = how much light an object or surface reflects

1. Light ice reflects2. Dark land absorbs