Geography Compulsory 1 Solar Activity, High School Geography Compulsory 1 Combing of the Height of t

The ball of light is a sunspot.

Chromosphere flares. Coronal solar storm.

For a certain place on the earth, the solar altitude refers to the angle between the incident direction of sunlight and the ground plane, and professionally speaking, the solar altitude angle refers to the angle between the sun's rays and the earth's surface tangent perpendicular to the center of the earth. Sun.

Altitude is the most important factor that determines the amount of solar thermal energy received by the Earth's surface.

We use h to denote this angle, which is numerically equal to the horizon height of the Sun in the celestial horizon coordinate system.

The solar altitude angle changes with local time and the declination of the sun. The declination of the sun is expressed in δ, and the geography of the place of observation.

Latitude is denoted by , local time (hour angle) is denoted by t, and there is a formula for calculating the solar altitude angle:

sin h＝sin φ sin δ＋cos φ cos δ cos t

Sunrise and sunset, the angle of sun elevation in the same place is constantly changing throughout the day. The angle at sunrise and sunset is zero degrees, positive.

The solar altitude angle is greatest at noon.

The hour angle at noon is 0, and the above formula can be simplified to:

sin h＝sin φ sin δ＋cos φ cos δ

where h is the noon solar altitude angle.

From the trigonometric formula of the sum and difference of the two angles, it can be obtained.

sin h＝cos(φ－

Thus, for the Northern Hemisphere, h 90° (

For the southern hemisphere, h 90° (

Let's take an example to deduce, assuming that the day of the vernal equinox (the day of the autumnal equinox is also acceptable, and the direct point of the sun is at the equator).

At a certain point when the sun is directly shining (0°, 120°E), it is noon at all points on the 120°E meridian.

Of course, the latitude distance from the point where the sun shines directly is 0 degrees (because it's yourself).

At this time, the altitude angle of the sun (0°, 120°E) is 90° (because it hits it directly).

The other observation point, (1°N, 120°E), has a latitude difference of 1 degree from the point where the sun shines directly.

In this case, the solar altitude angle at this point is 89° (which I won't deduce in detail when it comes to solid geometric calculations).

If you're smart, you'll know that the difference in latitude between (1°S, 120°E) and the point where the sun shines directly is also 1 degree.

Therefore, the local solar altitude angle is also 89°! right！

1) The vernal or autumnal equinox at the equator.

2）18 90e

3) 14 50 degrees.

4）90w-180

2) Influence on the ionosphere: affect short-wave wireless communication;

3) Influence on the magnetic field: the phenomenon of "magnetic storm" and the phenomenon of auroras.