Solar Radiation and Insolation Incoming solar radiation:

Intensity of radiation = X = wavelength Y = temperature Inverse relationship: The higher the temperature the shorter the wavelength of radiation. X Y Insolation is… ADD HERE The intensity of insolation from the Sun on a specific area of Earth is dependent on a number of factors.

Effects of Earth’s Atmosphere on Insolation Ozone Nearly all ultraviolet (short wave) radiation is ABSORBED by ozone (O 3 gas) in Earth’s upper atmosphere. H 2 0 vapor, methane and CO 2 can ABSORB infrared (long wave)radiation. Much of the incoming solar radiation is REFLECTED or SCATTERED back into space, into the atmosphere or to Earth. Aerosols --solids and liquids in the atmosphere – ie: pollutants, dust, ice, ash, water droplets, etc.. cause this scattering of radiation.

Balance of Energy from Insolation and Earth’s Surface Radiation Nearly 50% of insolation reaches Earth’s surface. Nearly 50% of insolation is absorbed or reflected by the atmosphere. Insolation received by the Earth’s surface is changed to heat energy. The Earth’s radiates this heat energy back into the atmosphere. The amount of energy absorbed from insolation = Earth’s surface radiation.

Factors Affecting Absorption and Reflection of Insolation Angle of Incidence The angle of incidence is.. ADD HERE The higher the angle of incidence = ADD HERE The lower the angle of incidence = ADD HERE Sun is high in the skySun is low in the sky

Factors Affecting Absorption and Reflection of Insolation Surface Characteristics ADD HERE… Rough, uneven surfaces and/or dark surfaces absorb more insolation. Light and smooth surfaces tend to reflect rather absorb insolation.

Factors Affecting Absorption and Reflection of Insolation Change of State and Transpiration Insolation may cause a change in phase for water. Insolation may fuel plant growth and increase the rate of transpiration -- the process whereby a plant releases water vapor into the atmosphere. In both cases… ADD HERE

Land vs. Water Heating Equal areas of land and water do not heat up and/or cool off at the same rate. Water is transparent and allows a greater area for insolation to penetrate compared to a land surface. Water has a higher specific heat than the land. Convection currents in water allow for the distribution of energy absorbed through insolation over a large volume. Some of the insolation striking the water may lead to a phase change (evaporation). The energy from insolation is transformed to potential energy.

The Greenhouse Effect 1. Short wave insolation… ADD HERE 2. The Earth’s surface reradiates the energy absorbed… ADD HERE 3. “Greenhouse gases” in the atmosphere… ADD HERE 4. The absorption of this radiation… ADD HERE

The Greenhouse Effect Modern history has shown an increase in the amount of “greenhouse gases” in the atmosphere. This increase is due primarily to human activity, such as the burning of fossil fuels and emission of pollutants in to atmosphere. The increase in “greenhouse gases” has led to an increase in the amount of radiation absorbed from the Earth. This, in turn, has led to an increase in average global temperatures. Result? Melting ice caps!!