Solar Radiation and Insolation Insolation INcoming SOLar radi

Solar Radiation and Insolation

Insolation • INcoming SOLar radi. ATION • Insolation is the portion of the Sun’s radiation that is received by Earth at the outermost part of the atmosphere. • All objects radiate energy depending on their temperature.

Effects of Earth’s Atmosphere on Insolation • Insolation may be absorbed, reflected, or scattered before reaching Earth’s surface.

Effects of Earth’s Atmosphere on Insolation • Absorption of UV and Infrared – O-zone: absorbs nearly all UV radiation – Water vapor, CO 2, methane absorb infrared

These images from the Total Ozone Mapping Spectrometer (TOMS) show the progressive depletion of ozone over Antarctica from 1979 to 1999. This "ozone hole" has extended to cover an area as large as 10. 5 million square miles in September 1998. The previous record of 10. 0 million square miles was set in 1996.

Effects of Earth’s Atmosphere on Insolation • Reflection & Scattering – Clouds – Aerosols • The amount of energy absorbed from insolation is generally equal to Earth’s surface radiation. (Temperature and heat are balanced)

Absorption & Reflection at Earth’s Surface 1. Angle of Incidence – the angle at which the insolation strikes Earth’s surface. 2. Surface Characteristics – texture and color 3. Change of State and Transpiration – insolation energy used for phase changes or plant transpiration is not available to raise the temp. of Earth’s surface.

The Greenhouse Effect • Most of the energy re-radiated by Earth’s surface does not escape to outer space. • Long-wave radiation can be absorbed by greenhouse gases • Without greenhouse gases, Earth’s surface would be about 59 o. F colder than it would otherwise be.

The Greenhouse Effect • The greenhouse effect may be causing global warming. – Burning of wood and fossil fuels