The Sun....

provides the energy that drives convection within the atmosphere and oceans, producing winds and ocean currents.

Ocean Currents

• Stream-like movements of water in oceans • Heat is transferred around the world by ocean currents through convection.

– Over ½ the heat that reaches the Earth from the sun is absorbed by the oceans surface.

• This heat affects the Earth’s weather and climate.

Surface Currents

• • Currents at or near the surface of the ocean Affect weather and climate for coastal regions around the world.

– Warm currents originate at the Equator and warm coastal areas – Cold currents originate at the Poles and cool coastal areas

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Surface Currents

Controlled by 3 factors:

– Global winds - Winds are named by the direction from which they blow. The globe is encircled by six major wind belts, three in each hemisphere. From pole to equator, they are the polar easterlies, the westerlies, and the tradewinds.

– Coriolis effect - curving of moving objects from a straight path due to the rotation of the Earth.

• • Currents in the Northern Hemisphere turn clockwise.

Currents in the Southern Hemisphere turn counter clockwise.

– Continental deflections - When surface currents meet continents, they deflect, or change direction.

Specific Heat Capacity of Our Oceans

– Ocean water has a high specific heat

capacity

• amount of energy needed to change it’s temperature – It takes far more energy to change the temperature of water than land or air • Water cools down and warms up much slower – This keeps coastal areas cooler in the summer and warmer in the winter.

Coriolis Effect

Currents Trade Places • Water from deep currents get warmer as they reach the equator and starts to rise.

• Water from surface currents get colder as they reach the poles and starts to sink • Heat is transferred by convection currents, continually moving from deep currents to surface currents

Changes in Ocean Currents

– El Nino – the warming of water in the Pacific Ocean – La Nina – the cooling of water in the Pacific Ocean

The Wind

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Winds are the result of uneven heating of the Earth’s surface

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This uneven heating causes differences in air pressure to develop

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Molecules always move from areas of high pressure to areas of low pressure

Convection of Air

Our Earth’s Weather and Climate

Weather and Climate

• • •

Complex interactions between the sun (energy) and the oceans, the land, and the atmosphere (matter)

Weather – The condition of the atmosphere at a certain time and place.

– Continually changes dynamically (daily) Climate – The overall weather patterns of an area during periods of seasons or years.

– Changes occur over long periods of geologic time (last ice age ended about 10,000 years ago).

Causes of Weather and Climate Changes • Amount of Solar energy from the sun.

• Natural events from Volcanoes and Fires • Human impacts contributing to global warming • Temperature of Ocean Waters

Weather Vocabulary

• • • • • • • • Water cycle – circulation of water Air Pressure –Weight of the air in the atmosphere Air Masses – Large bodies of air that have the same temperature and moisture.

Fronts – Areas where two different air masses meet.

Global winds – Wind caused by global circulation patterns.

Heat – Transfer of Thermal energy by infrared radiation from the sun.

Temperature – Kinetic energy of molecules in the atmosphere.

Humidity – Amount of water vapor in the air.

Evaporation

• Occurs when the sun heats up water and turns it into water vapor (a gas) or steam which travels into the air.

Condensation

Water vapor in the air gets cold and changes back into liquid, forming clouds.

Precipitation

• Occurs when so much water has condensed, turned back into liquid, that the air cannot hold it anymore. The clouds get heavy and water falls back to the earth in the form of rain, hail, sleet or snow.

Transpiration

• The process by which moisture is carried through plants and released to the atmosphere. Its the evaporation of water from plants.

Clouds

• • • Millions of tiny water drops or ice crystals Form as warm air rises and cools Water vapor condenses (changes to a liquid or a solid depending on the air temp.) and forms clouds.

Air Masses

• • Large bodies of air that have the same temperature and moisture throughout Causes changes in weather.

– Types of air masses • Continental - formed over land; dry • Maritime - formed over water; wet • Tropical - originated in a tropical region; warm • Polar - originated in a polar region; cold

Fronts

• The area where two different air masses meet.

– 4 types of fronts • Cold • Warm • • Occluded Stationary

Fronts – Where air masses meet

Earth’s Energy Source The Sun – Solar Energy • Energy from the sun is electromagnetic radiation (Waves).

– Electromagnetic Spectrum • Radio waves • Microwaves • Infrared waves • Visible light • Ultraviolet light • X-rays • Gamma Rays • Cosmic Radiation

Earth’s Matter

• • • • Atmosphere – Mixture of Nitrogen (N 2 ), Oxygen (O 2 ) and small amounts of other gases including Carbon Dioxide (CO 2 ) and water vapor (H 2 O).

Hydrosphere – All liquid and solid form of water (H 2 O).

Lithosphere – The Earth (all rocks and minerals) Biosphere – Living matter made of cells (prokaryotic and eukaryotic cells)

The Atmosphere

A 500 mile thick sphere of gases that separate the Earth from the inhospitable climate of Space

Earth’s Atmosphere

• • • Primarily made of nitrogen and oxygen Also made of Carbon dioxide, ozone and small amounts of other gases.

These gases keep our planet warm and protect us from the direct effects of the Sun’s radiation (x rays and gamma rays).

Layers of the Atmosphere

Determined by: - Temperature - Chemical composition - Movement - Density Layers: 1.

Troposphere 2.

3.

4.

5.

Stratosphere Mesosphere Ionosphere Exosphere

Layers of our Atmosphere

Troposphere

• • • • • Lower atmosphere 8-14.5 Km High (5-9 miles) Where all weather occurs Most dense As you climb higher, temperatures drop from about 17 to -52 degrees Celsius

Stratosphere

• • • • • 2nd layer 50 Km (31 miles) high.

Dry and less dense Temperature increases due to ultraviolet radiation from the sun.

Contains the Ozone Layer, which absorbs most ultraviolet radiation

Mesosphere

• • • Extends 85 Km (53 miles) above the stratosphere.

Temperatures fall as low as -93 degrees Celsius.

Known as the Middle atmosphere

Ionosphere

• • • • Starts about 70-80 Km high (43-50 miles) and continues for hundreds of Km (about 640 Km = 400 miles) Contains ions and free electrons (plasma).

Ions are created when sunlight hits atoms and tears off electrons Auroras occur here.

Exosphere

• • • • • Outermost layer of the atmosphere From about 640 Km (400 miles) to 1,280 Km (800 miles) high.

Atmospheric pressure, density and temperature is very low.

Mostly hydrogen and helium Reaches out to space

Formation of our Atmosphere

• • Formed by planetary degassing, a process in which gases like carbon dioxide, water vapor, sulfur dioxide and nitrogen were released from the Earth’s interior by volcanoes and other processes.

Life forms on Earth have modified the composition of the atmosphere since their evolution.