12 Topics.
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What to Study: What is insolation, and in which wavelengths does the Earth mostly receive it? Understand why the Earth intercepts only a small part of the Sun's energy, and why the Earth's shape makes the Sun's rays fall obliquely at the top of the atmosphere. Remember the solar constant, in calories per sq. cm per minute.
What to Study: Remember the names and distances of the Earth's farthest and nearest positions from the Sun, and which one falls in early January and which in early July. On which of the two dates is insolation slightly higher? Be able to explain why this difference has little effect on daily weather. Does the Earth's nearest position to the Sun fall in the northern hemisphere's summer?
What to Study: Insolation changes during a day, a season and a year. Remember the five factors behind this. Which two have less influence than the others? Also understand how the length of the day changes insolation at different latitudes.
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What to Study: What angle does the Earth's axis make with the plane of its orbit? Understand how this tilt changes the insolation received at different latitudes through the year. At which latitude is the Sun overhead at noon on 21 June?
What to Study: How does latitude decide the angle of the Sun's rays? Be able to explain the two reasons why slant rays give less energy per unit area than vertical rays: the area they cover, and the depth of atmosphere they pass through.
What to Study: Is the atmosphere largely transparent or opaque to short-wave solar radiation? Which gas is the main absorber of near infrared radiation in the troposphere? Where is most ozone found, and which kind of radiation does it absorb?
What to Study: Which wavelengths of visible light does the atmosphere scatter most, and do gas molecules or larger particles scatter them? In which directions is the light scattered? Be able to explain why the sky looks blue and why the rising and setting Sun looks red.
What to Study: Remember the surface insolation at the tropics and at the poles, in watts per sq. metre. Over which regions is it highest, and why? Does the equator get more or less insolation than the tropics, and why?
What to Study: At the same latitude, does insolation reach a higher level over land or over the oceans? How does winter insolation differ from summer insolation in the middle and higher latitudes?