Ecology Lecture 2 - Global ClimatesD

Define Atmosphere

600km thick layer of air surrounding Earth

Define Climate

Atmospheric conditions found within a specific region throughout the year and measured over many years

What is the greenhouse effect?

Solar radiation hitting Earth, converting to infrared radiation, and being absorbed and re-emitted by atmospheric gases

Which 2 gases make up 99% of Earth’s atmosphere?

Diatomic Oxygen and Nitrogen

What are the 2 main greenhouse gases?

Water vapor and carbon dioxide

What is the albedo effect?

The fraction of solar energy reflected by an object

How many degrees is Earth’s axis tilted?

23.5

Explain Earth’s seasonal heating pattern

• Earth is tilted 23.5 degrees

• Between March and September, the northern hemisphere received more solar energy than the southern. 

• Opposite is true between September and March

• The solar equator moves with the seasons which provides the Tropic of Cancer and Capricorn - the most perpendicular path of the sun

Define Atmospheric currents

The circulation of air between the surface of Earth and the atmosphere due to unequal heating, and the fact that warmer air is less dense, rises, and holds more moisture than cold air

The two circulation cells of air between the equator and 30 degrees north and south are called…

Hadley Cells

Where do Hadley cells converge?

Intertropical convergence zone

Briefly describe the Hadley cell cycle

• sun heats moist tropical air at ITCZ which causes it to rise

• raising air starts cooling - water vapor condenses to rain and falls to Earth

• Cool air returns to Earth at 30 degrees north and south

• The cool, dry air begins warming and flowing back to the equator at the surface picking up water again

Is there another location on Earth that has a similar pattern to Hadley cells?

Yes, Polar cells at 60-90 degrees north and south

This area sees 2 distinct rainy seasons

The equator

The phenomena of how the various rotation speeds of Earth deflect an objects path is know as…

The Coriolis effect

What does the Coriolis effect create?

All of the above

Circular currents in the ocean created by the dominant winds and the Coriolis effect are called

Gyres

What is the term that refers to prevailing winds on the west coasts of continents push the warm surface water away from shore, drawing deep cold water to the shore and upwards?

Upwelling

What does ENSO stand for?

El Niño-Southern Oscillation

The periodic changes in winds and ocean currents in the South Pacific which causes weather changes throughout the world is referred to as

El Niño Southern Oscillation

Describe Thermohaline Circulation

Variations in temperature and salinity causing density changes. Cold, salty at high latitudes sink.

• warm surface water flows from Gulf of Mexico to N. Atlantic

• cools and/or freezes ‘releasing’ salt

• saltier water sinks to the bottom

• cold water travels along ocean floor connecting Earth’s oceans

• deep, cold water eventually rises to the surface - and circulates back to the N. Atlantic