Chapter 5 Earth’s Weather
Lesson 3: Oceans and Air Temperature - Notes
Main Idea:
Ocean water helps determine the weather and climate of nearby land.
Vocabulary:
Climate (255) – average weather condition (temperature, rainfall, humidity, and wind
conditions) of a place or region
Current (256) – an ongoing movement of ocean water
Main Idea:
Earth’s oceans keep Earth’s temperature moderate.
Supporting Details
1. Weather along the coast will be cooler than the weather inland during the summer.
2. Weather along the coast will be warmer than weather inland during the winter.
3. The air above the ocean is warmed by the heat from the surface of the ocean. Air in
contact with water is tempered (warmed in the winter and cooled in the summer).
4. Oceans moderate temperatures throughout the year both locally and over the entire
planet.
5. Differences in temperature between the equator and the polar regions would be much
greater if we did not have oceans.
Main Idea:
Ocean currents move heat and water around the Earth.
Supporting Details
1. Currents carry ocean water from one region to the next.
2. Since the temperature of the water can either be warm or cold, the currents are also
responsible for transferring heat from one place to another.
a. Ocean currents move heat around the world in water.
b. The current also move heat around the world in the atmosphere through the
water vapor.
3. Water may evaporate in one area of the world and condense in a different area because
the winds carry the water vapor.
a. As the water evaporates, it transfer the heat from the surface of the ocean to
the water vapor.
b. As the water vapors reach a level in the atmosphere, they cool and condense.
c. When they condense, heat is released from the water and into the atmosphere.
4. The transfer of heat around the world through the atmosphere and through the water is
an important way that oceans keep temperatures on Earth in a narrow range.
Main Idea:
An El Niño can cause weather changes over a large area.
Supporting Details
1. Normal Times
a. Cold current along the coast of Peru keeps the temperature of the ocean water
cool and causes high pressure along the west coast of South America.
b. At the same time, the water near northeastern Australia is warm which causes
warm air with low pressure.
c. Winds generally blow across the southern Pacific from the high pressure in the
west to the low pressure in the East.
2. El Niño
a. Every 2 – 7 years, the cold current sinks and does not push cold water to the
surface.
b. The warmer temperature at the surface of the ocean causes the air pressure
over the water to fall.
c. With the area of low pressure in the west, the winds change directions an blow
from East to West.
i. The wind pushes ocean water in front of them causing higher tides in
western portions of North and South America.
ii. The wind also moves moist air to this region causing heavy rain and
storm.
3. Convection of heat across the Pacific Ocean changes and causes changes in weather
around the world.