Latitude

Phenomenon

Temperatures at the poles are cold all year. Temperatures in the mid-latitudes vary by season. Temperatures at the equator tend to be warm all year. Why?

Latitude lines run east to west around the Earth. The lines are parallels that represent angles from 0º at the equator to 90º at the poles. Latitudes north or the equator are designated by the angle degree and N for north. Latitudes south of the equator are designated with the angle degree and S for south.

The Tropic of Cancer is 23.5º N. The Tropic of Capricorn is 23.5º S. The Arctic circle is 66.5ºN. The Antarctic circle is 66.5ºS. For climate studies, 0º, 30º, 60º. and 90º are important reference latitudes for describing events that influence regional climates.

How does solar radiation affect air and water? Use the simulation to find the answer. Heating of Air and Water Simulation

Use a Model

Examine the digital composite image of Earth's surface. Complete the statements:

  • Most deserts (sand colored areas) are located....
  • Most areas of ice cover (white areas) are located...
  • Rainforests of South America and Africa are located...
  • Most of the Earth's surface is covered by (water, land, ice)...
  • Most of the land Earth's land mass is (north, south) of the equator.

Analyze a Graph

The global average of incoming solar energy is 300 Watts per square meter. However, there is wide variation in solar energy depending on location of on Earth. The graph shows monthly average solar energy for the equator, 23.5ºS and 23.5ºN, 45ºS and 45ºN, and 60ºS and 60ºN latitudes.

  • Explain the pattern of solar energy shown on the graph.
  • Explain why variations in solar energy are linked to differences in climate.

Graph credit: NASA Image credit: Ecology, 3rd Edition

Compare the climographs of Reykjavik and Recife.

Explain how latitude affects the climate at each location.

Annual Climatology: Recife, Brazil

Elev: 97 ft Lat: 08 o 04' S Long: 34 o 53'W

Annual Climatology: Reykjavik, Iceland

Elev: 92 ft Lat: 64 o 09' N Long: 21 o 56' W

Big Idea

Earth's surface materials absorb, transmit, or reflect incoming solar radiation.

Analyze the Data Model

The gif shows average air temperatures by month.

What patterns do you observe? Explain why air temperatures change by month.

Earth receives energy from the sun. The diagram shows the processes by which energy is gained and lost to maintain Earth's energy balance.

Optional Challenge Link: Explore Earth's Energy budget at NASA.

Read the background information, then do the next activity linked at the end of the reading.