Earth sun relationships
Download
1 / 23

Earth-Sun Relationships - PowerPoint PPT Presentation


  • 77 Views
  • Uploaded on

Earth-Sun Relationships. The Reasons for the Seasons. Solar Radiation. The earth intercepts less than one two-billionth of the energy given off by the sun. However, the radiation is sufficient to provide 99.9% of the energy that heats the earth and drives our climate. Radiation.

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about ' Earth-Sun Relationships' - kioshi


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
Earth sun relationships

Earth-Sun Relationships

The Reasons for the Seasons


Solar radiation
Solar Radiation

  • The earth intercepts less than one two-billionth of the energy given off by the sun.

  • However, the radiation is sufficient to provide 99.9% of the energy that heats the earth and drives our climate.


Radiation
Radiation

  • Solar radiation is received as parallel rays of energy (“line of sight, speed of light”)

    • Earth’s diameter is 12,765 km

    • Sun’s diameter is 1,390,000 km

      (over 100 times that of the Earth)

      So is the Sun’s radiation felt the same everywhere on Earth?


The earth is curved causing its surface to receive the sun s radiation at different angles
The Earth is curved, causing its surface to receive the Sun’s radiation at different angles.


Intensity of incoming solar radiation (insolation) is related to angle of incidence. Higher angles = higher intensity.


Why is it hot in the tropics and cold at the poles
Why is it hot in the tropics and cold at the poles? related to angle of incidence. Higher angles = higher intensity.

  • The Earth’s surface is curved relative to the incoming solar radiation.

  • Direct rays (most intense) are always in the tropical latitudes (23.5 º S to 23.5º N)

  • As a result, solar radiation is diffused in the polar regions.


What causes the seasons
What causes the seasons? related to angle of incidence. Higher angles = higher intensity.

  • rotation of the earth on its axis?

  • revolution of the earth around the sun

  • 23.5 O tilt of the earth axis from perpendicular to the plane of the ecliptic

  • polarity (axial parallelism)


Rotation of the earth
Rotation of the Earth related to angle of incidence. Higher angles = higher intensity.

  • Rotate west to east or ‘counter-clockwise’ (when viewed from the North Pole)

    • sunset and sunrise

  • Rotation period is 24 hours per solar day (23 hours 56 minutes with respect to other stars)


Revolution of the earth
Revolution of the earth related to angle of incidence. Higher angles = higher intensity.

  • Period of revolution is 365.25 solar days

  • Elliptical orbit (plane of the ecliptic)

Aphelion - 94.5 million miles

(July 5)

Perihelion - 91.5 million miles

(Jan. 4)

93 million miles average distance


Tilt of the earth on its axis
Tilt of the earth on its axis related to angle of incidence. Higher angles = higher intensity.

  • The earth is tilted 23.5º from perpendicular to the plane of the ecliptic.

  • Tilt is currently constantly toward Polaris


SOLSTICES related to angle of incidence. Higher angles = higher intensity.

SUMMER, JUNE 21

WINTER, DECEMBER 21

Where are the overhead rays of the sun on these days?

Which parts of the earth are in darkness and light? For how long?


Notice these four important parallels. related to angle of incidence. Higher angles = higher intensity.

Where do they occur? Why?

Tropic of Cancer at 23.5º N

Tropic of Capricorn at 23.5º S

Arctic Circle (66.5 º N)

Antarctic Circle (66.5º S)


EQUINOXES related to angle of incidence. Higher angles = higher intensity.

VERNAL, MARCH 21

AUTUMNAL, SEPTEMBER 21


Effects of the Seasons related to angle of incidence. Higher angles = higher intensity.

  • Changes in solar intensity

  • Changes in solar altitude

  • Changes in day length

  • Changes in temperature

    All of these changes are most extreme at high latitudes and minimized at the equator.


Annual Changes in Daylength related to angle of incidence. Higher angles = higher intensity.


1 of 2 related to angle of incidence. Higher angles = higher intensity.

Annual Change in Noontime Solar Altitude

What is the change in height from the solstice to the equinox?

The total annual change?

Summer Solstice

Equinox

Winter Solstice

N

E

S

S

W

N


2 of 2 related to angle of incidence. Higher angles = higher intensity.

Annual Change in Noontime Solar Altitude

Total annual change: 47O

Summer Solstice

23.5O

Equinox

23.5O

Winter Solstice

N

E

S

S

W

N


Key points
Key Points related to angle of incidence. Higher angles = higher intensity.

  • Size and Shape of Earth.

  • Latitude and Longitude

  • Explain the basic earth-sun relationships.

  • Equinoxes, solstices and the relationship among

    • seasons

    • the latitude of the sun’s direct rays, and

    • the intensity of solar radiation received

    • changes in Daylight and Darkness

23.5º N


Time related to angle of incidence. Higher angles = higher intensity.

  • Standard Time

  • The International Date Line

  • Daylight Savings Time

    Year = 365 1/4 days or 365 days 5 hrs. 48 min. 45.685 seconds

    Solar Day = 24 hours on average. Changes slightly with the elliptical orbit around the sun.


Standard time
Standard Time related to angle of incidence. Higher angles = higher intensity.

360o / 24 hr. = 15o standard zones (7.5o E and W from standard meridian)


International date line
International Date Line related to angle of incidence. Higher angles = higher intensity.

Cross W to E - gain day; E to W - lose day


International date line1
International Date Line related to angle of incidence. Higher angles = higher intensity.

A day is 24 hours, but a date lasts for 48 hours!

At any given time on earth, except Greenwich noon, there are two dates on the planet.

The new date starts at the IDL when midnight crosses the IDL and moves westward around the planet for 24 hrs. displacing the old date. Then it fades out as the “old” date for 24 hrs.


Daylight savings time
Daylight Savings Time related to angle of incidence. Higher angles = higher intensity.

Day starts earlier April 1 - October 31

Started during war time to save energy (maximize morning sun and increase work day).

Arizona and Hawaii don’t use it.

Navajo and Hopi do - causes great confusion.


ad