TOPIC 6 INSOLATION BELL WORK Insolation Be able

TOPIC 6 INSOLATION

BELL WORK: Insolation Be able to explain… • Why it is warmer in summer than in winter. • Why it is warmer in Miami than in Holland Patent.

INSOLATION: Incoming Solar Radiation • The portion of the Sun’s energy that is received by the Earth. Intensity of insolation- the rate at which insolation is received v. How strong the insolation is. Angle of insolation- angle at which the Sun’s energy strikes Earth

• As the angle of insolation increases the intensity of insolation increases. (direct relationship) High angle= High Intensity Low Angle= Low Intensity

Factors Affecting Angle of Insolation 1. TIME OF DAY • angle increases until solar noon then decreases. mid 6 am noon 6 pm mid

2. SEASONS Minimum Intensity - Dec 21 Maximum Intensity - June 21 Northern Hemisphere Intensity of Insolation • • • Jan June Dec

3. Latitude • As latitude increases the intensity of insolation generally decreases

Duration of Insolation: • Length of daylight Factors Affecting Duration 1. Seasons. Maximum Duration – June 21 (≈15 hrs. ) Minimum Duration – Dec 21 (≈9 hrs. ) Equinox – March 21 & Sept 23 (≈12 hrs. )

2. Latitudeas the latitude increases, the range of duration increases.

Effects of the Atmosphere on Insolation 1. Most Ultraviolet radiation (UV) is absorbed in the atmosphere by Ozone. 2. Most Visible wavelengths make it to the surface. 3. Infrared energy is absorbed by CO 2, Water Vapor and Methane ( “Greenhouse Gasses”). 4. Clouds reflect insolation 5. Aerosols scatter insolation.

Aerosols- very fine solids and liquids dispersed and suspended in the air. Examples: dust, pollen, volcanic ash, smoke. v. As the amount of aerosols increases, the amount of insolation making it to Earth’s surface decreases

Greenhouse Effect GREENHOUSE GASSES -Carbon Dioxide -Methane -Water Vapor Absorbed and re. Earth -radiated as heat (infrared)

Terrestrial Radiation • Energy radiated from Earth’s surface. • Infrared (heat) Radiative Balance • Occurs when the amount of energy absorbed by Earth = the amount of energy radiated by Earth. How will this effect Earth temperatures over a long period of time?

Heating of Land Water • Water surfaces will heat up & cool off more slowly than land surfaces. Why? • Water has a higher specific heat • Water is transparent • Convection currents distribute energy • Water evaporates (becomes potential energy). • Reflection by water surface

Factors Affecting Absorption & Reflection of Insolation 1. Color / Texture of the Surface 2. Angle of Insolation More Reflection More Absorption 3. Changes in Phase and Transpiration

Wavelengths of Insolation • The maximum intensity of insolation occurs in the range of visible light. • ALL of the energy radiated by the Earth is in the form of infrared

Relationship Between Insolation and Earth Temperatures

Global Warming • An increase in the average global temperatures due to an increase in the amount of greenhouse gasses. Causes: • The burning of fossil fuels and wood. • Deforestation Effects • Rising sea levels due to melting of glaciers and sea ice. • Shifting of climate zones.