Insolation ( input of solar energy) as a Function of Latitude and Season
To describe the relationship between Earth's surface temperature and the The intensity of insolation depends on the angle at which the sun's. At what time is the angle and intensity of insolation greatest? Why does the angle of insolation change between midday and evening?. Sun Angle, Duration, and Insolation. Understanding Earth's relationships with the sun leads us directly into a discussion of how the intensity of the sun's rays.
Lab 1 Solar Radiation & Seasons
The open water at the North Pole had been viewed by a couple of American scientists who were not meteorologists who journeyed on a commercial tour on a Russian ice-breaker in the summer time. The fact that it was summertime and that the Russians were taking customers on a regular basis to the North Pole should have alerted them that open water at the North Pole was not that unusual.
But if one has a mindset concerning catastrophic global warming any observation that can be construed as evidence for global warming is accepted as evidence for global warming.
Open water at the North Pole may have to do with ocean and wind currents as well as temperature. However it is not widely known that the North Pole in the summer time was never deficient in solar warming. The input of radiant energy from the Sun is called insolation.
Lab 1 Solar Radiation & Seasons |
Insolation is the amount of radiant energy from the Sun which impacts upon a unit surface area. This will depend upon the angle of the Sun with respect to the vertical over the surface. This date is an equinox.
How does the number of daylight hours change from the equator to the Arctic Circle i. Ignore the values at and near the North Pole. How does the number of daylight hours change from the equator to the Antarctic Circle i.
Ignore the values at and near the South Pole. Based on your responses to Questions 1 and 2, how would you define an equinox? Based on the definition you just wrote, it should make sense to you that there would be another equinox on or around September 21st.
Think about this and make sure you understand it before you proceed. This is the summer solstice in the Northern Hemisphere and the winter solstice in the Southern Hemisphere.
How does the number of daylight hours change from the equator to the Arctic Circle? How does the number of daylight hours change from the equator to the Antarctic Circle?
What is the range of latitudes that receive 24 hours of daylight? What is the range of latitudes that receive zero hours of daylight? This is the winter solstice in the Northern Hemisphere and the summer solstice in the Southern Hemisphere.
The Sun is huge and hot: The distance from the Sun to the Earth is approximately million kilometers; at this distance, Earth intercepts a tiny amount of the radiation emitted by the Sun. This value is known as the solar constant. Instruments on-board NASA satellites have been measuring the solar constant since ; click on the left-hand image below to see an example of such a satellite. Next to the satellite image is a graph showing changes in the solar constant.
You should notice at the value for the solar constant changes from year to year, but you should also recognize a long-term pattern in the values which repeats approximately every eleven years; this is notice the solar cycle this is an important cycle because peaks in the cycle can affect communication instruments. The third image below is a graph of the solar spectrum, which shows a breakdown of the radiation making up the solar constant.
Most of the solar radiation is in the visible, near-infrared, and ultraviolet portions of the electromagnetic spectrum; a representation of the electromagnetic spectrum is the fourth picture in the set below. For example, the next lab focuses on the absorption of solar radiation by a gas, ozone, in a layer of the atmosphere known as the stratosphere.
Note that the incoming solar radiation is The solar constant is averaged across the entire surface of Earth; therefore, the value is divided by four.
This is what causes changes in solar radiation received by locations on Earth over the course of a year. Examine the image below to visualize this tilt. It takes one day for Earth to complete a full rotation, and the Earth orbits around the Sun, which is typically million kilometers away, once every The axis remains tilted in the same direction towards the stars particularly the North star Polaris throughout a year. The tilt causes day-today changes in the duration and intensity of solar radiation at all latitudes.
Play the video below which shows the Earth revolving around the Sun and how the tilt of the Earth determines what latitudes receive the most solar radiation. The seasons pertain to the Northern Hemisphere.
This causes the rays to be spread out over a larger surface area reducing the intensity of the radiation. Effect of angle on the area that intercepts an incoming beam of radiation.
We can also model the effect the angle of incidence has on insolation intensity with the following simple equation: Let us compare this maximum value with values determined for other angles of incidence. Note the answers are expressed as a percentage of the potential maximum value. Longest days occur during the June solstice for locations north of the equator and on the December solstice for locations in the Southern Hemisphere.
The equator experiences equal day and night on every day of the year.
Day and night is also of equal length for all Earth locations on the September and March equinoxes. Figure 6i-2 describes the change in the length of day for locations at the equator, 10, 30, 50, 60, and 70 degrees North over a one-year period. The illustration suggests that days are longer than nights in the Northern Hemisphere from the March equinox to the September equinox.
Between the September to March equinox days are shorter than nights in the Northern Hemisphere.