What Happens to Insolation?

Intro to Physical Geography

Energy Basics Energy Pathways and Principles 

Shortwave energy in from the Sun (ultraviolet, visible light, and near-infrared)

Longwave energy out from Earth (thermal infrared)

Transmission The passage of energy through atmosphere

or water

Insolation input All radiation received at Earth’s surface –

direct and indirect

What happens to insolation?

Scattering (diffuse radiation) Changing direction of light’s

movement, without altering its wavelengths

Rayleigh scattering makes our skies lookblue

Wavelengths

Wavelength image from Universe by Freedman and Kaufmann.

Because blue light has a shorter wavelength it scatters more easily.

Image from http://missionscience.nasa.gov/ems/09_visiblelight.html

What Happens to Insolation?

Refraction Change in speed and direction of light as

insolation travels from space through the atmosphere

Examples: Rainbows and mirages

What happens to insolation?

Some energy is reflected without being absorbed So we need to think about albedo (how

reflective a surface is) Clouds and aerosols have unpredictable

albedos

What types of surfaces are most reflective? What types of surfaces absorb more energy?

Albedo Values

Clouds and Albedo

Bottom images from http://earthobservatory.nasa.gov/Features/Clouds/clouds4.php

Changes in albedo

What happens to energy that reaches the surface?

Absorption – the assimilation of radiation by molecules of matter and conversion to different kinds of energy.

• Heat is energy produced by the motion of atoms and molecules.

• Heat flows from a region of higher temperature to a region of colder temperature, but not the other way around.

• Four types of heat transfer: • conduction, convection, advection, and

radiation.

Methods of Heat Transfer