Solar Energy to Earth Current News and Weather Finish Maps and GIS Electromagnetic Spectrum   Insolation (Short-Wave Energy) Terrestrial Radiation (Long-Wave Energy) Greenhouse Effect For Next Class: Read Ch. 2: pp. 45-55

Classes of Map Projections Figure 1.21

Passive and Active Remote Sensing Figure 1.25

Remote Sensing RADARSAT-1 GOES-12 Figure 1.26 Figure 1.27

GIS Model Figure 1.29

Dimensions and Distances Earth’s orbit Average distance from Earth to the Sun is 150,000,000 km (93,000,000 mi) Perihelion – closest at January 3 147,255,000 km (91,500,000 mi) Aphelion – farthest at July 4 152,083,000 km (94,500,000 mi) Earth is 8 minutes 20 seconds from the Sun Plane of Earth’s orbit is the plane of the ecliptic

Our Solar System Figure 2.1

Discussion Questions 1. What is the electromagnetic spectrum and why is it important?

The Electromagnetic Spectrum Figure 2.6

Wavelength and Frequency Figure 2.5

Wave Model of Electromagnetic Energy The relationship between the wavelength, , and frequency, , of electromagnetic radiation is based on the following formula, where c is the speed of light: Note that frequency,  is inversely proportional to wavelength,  The longer the wavelength, the lower the frequency, and vice-versa.

Stephan Boltzmann Law The total emitted radiation (Ml) from an objet is proportional to the fourth power of its absolute temperature. This is known as the Stephan-Boltzmann law and is expressed as: where s is the Stephan-Boltzmann constant, 5.6697 x 10 -8 W m-2 K -4. Thus, the amount of energy emitted by an object such as the Sun or the Earth is a function of its temperature.

Wein’s Displacement Law In addition to computing the total amount of energy exiting an object such as the Sun, we can determine its dominant wavelength (lmax) based on Wein's displacement law: where k is a constant equaling 2898 mm K, and T is the absolute temperature in kelvin. Therefore, as the Sun approximates a 6000 K blackbody, its dominant wavelength (lmax ) is 0.48 mm:

Sources of Electromagnetic Energy Jensen 2005 The 5770 – 6000 Kelvin (K) temperature of thermonuclear fusion on the sun produces a large amount of relatively short wavelength energy that travels through the vacuum of space at the speed of light. Some of this energy is intercepted by the Earth, where it interacts with the atmosphere and surface materials. The Earth reflects some of the energy directly back out to space or it may absorb the short wavelength energy and then emit it at a longer wavelength.

Discussion Questions 1. What is the electromagnetic spectrum and why is it important? 2. What is the difference between solar and terrestrial radiation?

Solar vs. Terrestrial Radiation Solar Radiation (Insolation): Short-wave, high intensity, mostly in the visible portion of the EM spectrum. Source is the Sun. Terrestrial Radiation: Long-wave, lower intensity. Source is the Earth and Atmosphere (or Earth-Atmosphere System)

Solar and Terrestrial Energy Figure 2.7

Discussion Questions 1. What is the electromagnetic spectrum and why is it important? 2. What is the difference between solar and terrestrial radiation? 3. How does latitude influence incoming solar radiation and temperature?

Figure 2.9

Feedback on Today Name one thing you learned today. What questions do you have?