Solar energy to earth and the seasons
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Solar Energy to Earth and the Seasons. Monitoring the Climate System Electromagnetic Spectrum   Radiation Laws Greenhouse Effect Seasonality Solar Elevation at Noon For Wednesday: Read Christopherson Ch. 3 available on AsUlearn.

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Solar energy to earth and the seasons

Solar Energy to Earth and the Seasons

  • Monitoring the Climate System

  • Electromagnetic Spectrum  

  • Radiation Laws

  • Greenhouse Effect

  • Seasonality

  • Solar Elevation at Noon

  • For Wednesday: Read Christopherson Ch. 3 available on AsUlearn


2014 peru summer study abroad andean societies and environments

2014 Peru Summer Study Abroad: Andean Societies and Environments

July 15 to July 31, 2014

GHY 4530/5530: Andean Mountain Geography (3 hrs)

GHY 4531/5531: Climate and Tropical Glaciers (3 hrs)

This 17-day intensive program introduces students to AndeanMountain Geography and Climate and Tropical Glaciers through direct field experience and research activities, readings, discussions, and meetings with guest speakers. Field excursions to Machu Picchu and other locations in the Sacred Valley and an 8-day trek in the Cordillera Vilcanota (with strenuous ascents to over 17,000 ft) will provide an outstanding setting for the study of Andean human-environment interactions and the impacts of climate variability and change on tropical glaciers, ecosystems, and human populations.

Program Leaders: Dr. Baker Perry, Mrs. Patience Perry, and Dr. Anton Seimon

Interested? Contact Dr. Perry ([email protected]) to apply or for more information.


Observing the climate system

Observing the Climate System

  • Remote Sensing by Satellite

    • Sensors observing Earth from orbiting spacecraft measure selected wavelengths of the electromagnetic radiation reflected or emitted by the Earth’s climate system


Observing the climate system1

Observing the Climate System

  • Remote Sensing by Satellite

    • Satellites fly in either geostationary or polar orbits

Geostationary orbit

Polar orbit


Observing the climate system2

Observing the Climate System

Visible Satellite Image


Observing the climate system3

Observing the Climate System

Infrared Satellite Image


Observing the climate system4

Observing the Climate System

Water Vapor Satellite Image


International cooperation in understanding earth s climate system

International Cooperation inUnderstanding Earth’s Climate System

  • Intergovernmental Panel on Climate Change (IPCC)

    • Formed in 1988 by the World Meteorological Organization (WMO) and the United Nations Environmental Programme (UNEP)

    • Evaluates the state of climate science

    • Composed of three working groups and a task force


The electromagnetic spectrum

The Electromagnetic Spectrum

Figure 2.6


Wavelength and frequency

Wavelength and Frequency

Figure 2.5


Solar energy to earth and the seasons

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,  (nu), is inversely proportional to wavelength,  (lambda).

The longer the wavelength, the lower the frequency, and vice-versa.


Solar energy to earth and the seasons

Stefan Boltzmann Law

The total emitted radiation (Ml) from a blackbody is proportional to the fourth power of its absolute temperature. This is known as the Stefan-Boltzmann lawand is expressed as:

where s is the Stefan-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.


Solar energy to earth and the seasons

Wien’s Displacement Law

  • In addition to computing the total amount of energy exiting a theoretical blackbody such as the Sun, we can determine its dominant wavelength (lmax) based on Wien'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:


Solar vs 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

Solar and Terrestrial Energy

Figure 2.7


Group exercise

Group Exercise

  • What is the Greenhouse Effect and why is it important?


Solar energy to earth and the seasons

Figure 2.9


Outgoing infrared radiation

Outgoing Infrared Radiation

  • Greenhouse Effect

    • Heating of Earth’s surface and lower atmosphere caused by strong absorption and emission of infrared radiation (IR) by certain atmospheric gases

      • known as greenhouse gases

    • Similarity in radiational properties between atmospheric gases and the glass or plastic glazing of a greenhouse is the origin of the term greenhouse effect


Outgoing infrared radiation1

Greenhouse Effect

Responsible for considerable warming of Earth’s surface and lower atmosphere

Earth would be too cold without it to support most forms of plant and animal life

Outgoing Infrared Radiation


Outgoing infrared radiation2

Outgoing Infrared Radiation

  • Greenhouse Gases

    • Water Vapor is the principal greenhouse gas

      • Clear-sky contribution of 60%

    • Other contributing gases:

      • carbon dioxide (26%)

      • ozone (8%)

      • methane plus nitrous oxide (6%)


Outgoing infrared radiation3

Greenhouse Gases

Atmospheric window: range of wavelengths over which little or no radiation is absorbed

Visible atmospheric window extends

from about 0.3 to 0.7 micrometers

Infrared atmospheric window from

about 8 to 13 micrometers

Outgoing Infrared Radiation


Outgoing infrared radiation4

Outgoing Infrared Radiation

  • Greenhouse Gases

    • Water vapor strongly absorbs outgoing IR and emits IR back towards Earth’s surface

      • Does not instigate warming or cooling trends in climate

      • Role in climate change is to amplify rather than to trigger temperature trends

    • Clouds affect climate in two ways:

      • Warm Earth’s surface by absorbing and emitting IR

      • Cool Earth’s surface by reflecting solar radiation


Seasonality

Seasonality

  • Why is seasonality important?


Seasonality1

Seasonality

  • Two important seasonal changes

    • Sun’s altitude – angle above horizon or Solar Elevation at Noon (SEN)

    • Day length


Reasons for seasons

Reasons for Seasons 

  • Revolution

    • Earth revolves around the Sun

    • Voyage takes one year

    • Earth’s speed is 107,280 kmph (66,660 mph)

  • Rotation

    • Earth rotates on its axis once every 24 hours

    • Rotational velocity at equator is 1674 kmph (1041 mph)


Revolution and rotation

Revolution and Rotation

Figure2.13


Annual march of the seasons

Annual March of the Seasons

  • Winter solstice – December 21 or 22

    • Subsolar point Tropic of Capricorn

  • Spring equinox – March 20 or 21

    • Subsolar point Equator

  • Summer solstice – June 20 or 21

    • Subsolar point Tropic of Cancer

  • Fall equinox – September 22 or 23

    • Subsolar point Equator


Annual march of the seasons1

Annual March of the Seasons

Figure 2.15


11 30 p m in the antarctic

11:30 P.M. in the Antarctic

Figure 2.16


Midnight sun

Midnight Sun

Figure 2.17


Insolation at top of atmosphere

Insolation at Top of Atmosphere

Figure 2.10


Solar elevation at noon

Solar Elevation at Noon

Figure 2.18


Solar elevation at noon sen

Solar Elevation at Noon (SEN)

  • SEN is the angle of the noon sun above the horizon

  • SEN = 90˚ - ArcDistance

  • ArcDistance = number of degrees of latitude between location of interest and sun’s noontime vertical rays

  • If the latitude of location of interest and sun are in opposite hemispheres, add to get ArcDistance

  • If they are in the same hemisphere, subtract from the larger of the two values


Sen example

SEN Example

  • What is the SEN on June 21 for Boone (36 N)

  • SEN = 90 – ArcDistance

  • Where are the sun’s noontime vertical rays?

  • ArcDistance = 36 – 23.5

  • ArcDistance = 12.5

  • SEN = 90 – 12.5

  • SEN = 77.5˚


Analemma

Analemma


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