when the insolation rays comes from the sun can u explain what happens then
Answers
Answer:
Explanation:
Understanding Earth’s relationships with the sun leads us directly
into a discussion of how the intensity of the sun’s rays varies from
place to place throughout the year and into an examination of the
seasonal changes on Earth. Solar radiation received by the Earth
system, known as insolation (for incoming solar radiation), is the
main source of energy on our planet. The seasonal variations in
temperature that we experience are due primarily to fluctuations
in insolation.
What causes these variations in insolation and brings about
seasonal changes? It is true that Earth’s atmosphere affects the
amount of insolation received. Heavy cloud cover, for instance,
will keep more solar radiation from reaching Earth’s surface than
will a clear sky. However, cloud cover is irregular and unpredictable, and it affects total insolation to only a minor degree over
long periods of time.
The real answer to the question of what causes variations
in insolation lies with two major phenomena that vary regularly
for a given position on Earth as our planet rotates on its axis and
revolves around the sun: the duration of daylight and the angle
of the solar rays. The amount of daylight controls the duration
of solar radiation, and the angle of the sun’s rays directly affects
the intensity of the solar radiation received. Together, the intensity and the duration of radiation are the major factors that affect the amount of insolation available at any location on Earth’s
surface.
Therefore, a location on Earth will receive more insolation if (1) the sun shines more directly, (2) the sun shines longer, or (3) both. The intensity of solar radiation received at any
one time varies from place to place because Earth presents a
spherical surface to insolation. Therefore, only one line of latitude on the Earth’s rotating surface can receive radiation at right
angles, while the rest receive varying oblique (sharp) angles
( ● Fig. 3.15a). As we can see from Figure 3.15b and c, solar
energy that strikes Earth at a nearly vertical angle renders more
intense energy but covers less area than an equal amount striking
Earth at an oblique angle.
The intensity of insolation received at any given latitude
can be found using Lambert’s Law, named for Johann Lambert,
an 18th-century German scientist. Lambert developed a formula
by which the intensity of insolation can be calculated using the
sun’s zenith angle (that is, the sun angle deviating from 90° directly overhead). Using Lambert’s Law, one can identify, based
on latitude, where greater or lesser solar radiation is received on
Earth’s surface. ● Figure 3.16 shows the intensity of total solar
energy received at various latitudes, when the most direct radiation (from 90° angle rays) strikes directly on the equator.
In addition, the atmospheric gases act to diminish, to some extent, the amount of insolation that reaches Earth’s surface. Because
oblique rays must pass through a greater distance of atmosphere
than vertical rays, more insolation will be lost in the process. In
1854, German scientist and mathematician August Beer established a relationship to calculate the amount of solar energy lost as
it comes through our atmospheric gases. Beer’s Law, as it’s called, is
strongly affected by the thickness of the atmosphere through which
the energy must pass.
Since no insolation is received at night, the duration of solar
energy is related to the length of daylight received at a particular
point on Earth (Table 3.2). Obviously, the longer the period of
daylight, the greater the amount of solar radiation that will be received at that location. As we will see in our next section, periods
of daylight vary in length through the seasons of the year, as well
as from place to place, on Earth’s surface.