Insolation INcoming SOLar radiATION Strength is dependent on 1.Angle of insolation 2.Duration of insolation 3.Type of surface receiving the insolation

EM Energy Interactions in Environment Refracted – bent as pass through Reflected – bounced off Scattered – refracted or reflected in various directions Transmitted – passed through Absorbed – taken into

Electromagnetic Spectrum Organisms vary in their ability to sense different parts of the spectrum.

Angle of Insolation A measure of how high the Sun is in the sky The higher the Sun, the more direct the Sun’s rays. The more direct the rays, the greater the amount of insolation. What time of day is insolation the greatest?

Angle changes throughout the year In Northern Hemisphere – Rays are most direct in summer. Direct rays strike the Tropic of Cancer on the Summer Solstice. What time of the year is insolation the greatest in the S. Hemisphere?

As you travel poleward, the angle of insolation decreases. How does this affect global heating? How do temperatures compare between the tropics and the poles? This difference in heating drives the Earth’s weather systems.

Effect of Angle of Insolation Same amount of incoming energy. The more direct the angle the more ‘concentrated’ the energy

Equator 30 ° 45° Poles ___________ _______________________________________ Relative amount of incoming energy Greater the angle, the less ‘concentrated’ the energy

Intensity of insolation depends upon: Latitude –Farther you are from the equator the less energy reaches you

Same area covered Different amounts of energy Less energy: colder More energy: warmer Less energy: colder

Season –More energy reaches you in summer than in winter

Monthly Insolation Values

Annually, energy transfers from the Equator to the Poles on a global scale. Watch how this happens over a year!....

JANUARY ( o C )

FEBRUARY

MARCH

APRIL

MAY

JUNE

JULY

AUGUST

SEPTEMBER

OCTOBER

NOVEMBER

DECEMBER

JANUARY

Duration of Insolation This is the length of daylight in a day. The longer the amount of daylight, the greater the amount of insolation. What time of year has the longest hours of daylight?

Length of Daylight

Absorption of Insolation Absorption depends on texture and color. The rougher the texture, the more absorption takes place. Darker colors absorb insolation at a greater rate the lighter colors. Which absorbs more? A blacktop parking lot or a snowy field?

Since dark colors absorb heat radiation then light colors reflect radiation. Light energy reflected from a surface is called a aa albedo. Surfaces with high albedo reflect a lot of light For instance, snow has a high albedo. The surface of the moon has a high albedo. A mirror has a high albedo. Name a type of surface with a low albedo.

Albedo of selected surfaces SURFACE% reflected Dense, dry, clean snow86-95 Clean sand37 Ice sheet26 Grass25 Decidudous forest17 Pine forest14 Ploughed field---moist14 Swamp 10-14

Presence of cloud cover fClouds absorb and reflect some incoming energy. In the day, less heat will reach the ground fAt night, clouds act as blankets to prevent heat from returning to space

Effect of Angle of Insolation More energy reaches the equator than the poles There is a gain of energy at the equator There is a loss of energy at the poles Unequal heating of earth causes giant convection cells to form Result = global winds

Winds and Ocean Currents 2 The energy of the earth is not static 2 It can be transferred either by winds or ocean currents. 2 Most of the insolation reaches the earth and heats up the oceans and the seas 2 Temperatures of areas near the coast are modified. Example Vancouver and Ottawa

Formation of convection cells

Warm air rises Cool air sinks Convection cells form Earth is spinning: adds another factor in formation of global winds –Coriolis effect

Coriolis Effect objects moving in the northern hemisphere are deflected toward the right of their direction of motion Objects moving in the southern hemisphere are deflected toward the left of their direction of motion

Resulting wind pattern is called 3-celled model of global air circualtion

Review What is insolation? What are 3 things that affect insolation? What time of day is insolation the greatest? What time if year is insolation the greatest? How does latitude affect insolation?

Review How does color affect absorption of radiation? What is albedo? Name a surface that has high albedo.

Lag Time of Maximum Heat The maximum heat produced by the Sun does not occur at the same time as maximum insolation This is due to the time it takes for the object or surface to heat up.

June 21 Dec 21

So, even though maximum insolation is in June, the warmest month is July/August due to the time it takes for the atmosphere to warm to the max. The same is true for daily heating. Even though the maximum insolation is at noon, the hottest time of day is late afternoon

The Greenhouse Effect The greenhouse effect is the rise in temperature of Earth’s atmosphere. This rise is caused by certain gases.(Water vapor, carbon dioxide, nitrous oxide, and methane, for example)

These gases trap energy from the sun. Without these gases, heat would escape back into space and Earth’s average temperature would be about 60ºF colder. Because of how they warm our world, these gases are referred to as greenhouse gases. Greenhouse Effect cont.

Global Warming This is NOT the same as the Greenhouse Effect This is due, in part, to a build up of greenhouse gases. The increase in theses gases are due, in part, to human influences.

Review Why is the hottest part of the day not the same as the time of maximum insolation? What is the Greenhouse Effect? What are some greenhouse gases? Is the Greenhouse Effect the same as Global Warming? What is Global Warming?