The formula for calculating the sun zenith angle, what is the formula for calculating the solar alti

The formula for calculating the solar altitude angle at noon is: 90° -where is the noon solar elevation angle, which is the latitude of the observer, and where the sun shines directly.

Note: Represents the "latitude difference" between the observer and the point where the sun is shining directly. The closer the ground is to the direct point of the sun, the greater the solar altitude angle at noon.

The law of change. 1. In the entire southern or northern hemisphere, the solar elevation angle at noon can reach the minimum value of the whole year (the winter solstice day of the hemisphere) at the same time, but it cannot reach the maximum value of the whole year at the same time.

2. The area between the Tropic of Cancer reaches the annual maximum when the sun shines directly, not on the summer solstice in that hemisphere.

3. The annual maximum (summer solstice of the hemisphere) and the minimum (the winter solstice of the hemisphere) on the Tropic of Capricorn; The area between the Tropic of Cancer has a maximum twice a year (when the sun is in direct sunlight) and a minimum (the winter solstice in that hemisphere), but twice a year at the equator.

4. For areas outside the Tropic of Capricorn, the maximum value (summer solstice day of the hemisphere) and the minimum value (the winter solstice day of the hemisphere) are held once a year.

The solar altitude angle changes with local time and the declination of the sun. The solar declination (equal to the latitude of the direct point of the sun) is expressed in δ, the geographical latitude of the observation place is expressed by (the solar declination and the geographical latitude are both positive north latitude and negative south latitude), local time (time angle) is expressed by t, and there is a formula for calculating the solar altitude angle: sin h= sin sinδ cos cosδcos t.

Sunrise and sunset, the angle of sun elevation in the same place is constantly changing throughout the day. The hour angle is calculated from 12 noon to 0 degrees, and every hour is 15 degrees. That is, 14 o'clock and 10 o'clock are 30 degrees and 30 degrees respectively.

The angle at sunrise and sunset is 0, the solar altitude angle is the largest (90°) at noon, and the hour angle is 0, the above formula can be simplified as: sin h=sin sinδ cos cosδ.

From the trigonometric formula of the sum and difference of the two angles, we get sin h=cos ( Thus, for the region north of the zenith, h=90° ( for the region south of the zenith, h=90° (

Because both ( and (δ are to find the difference between the latitude of the earth and the latitude of the direct sun, which will not be negative, so it is equal to its absolute value, so the formula for calculating the solar altitude angle at noon is: h=90°-|

h=90º-|Local latitude Direct point latitude|.

The formula for calculating the solar altitude angle at noon is h=90 -|Local latitude Direct point latitude|. , h represents the local noon sun height, the local latitude refers to the latitude of a certain place required, and the latitude of the direct point refers to the latitude where the direct point is located at this time, if the local latitude and the latitude of the direct point are in the same hemisphere, use the minus sign, if in different hemispheres use the plus sign, and then take the absolute value.

There are three variables in the formula: h, the latitude of the local area, and the latitude of the direct point. Among the three variables, h is generally told indirectly or directly through the height of the object and the length of the shadow of the object; The latitude of the land is told by the latitude and longitude chart; The latitude of the point of direct exposure is indirectly told by the date, the polar day and night range, or the angle between the morning and dusk lines and the meridians.

The law of change.

1. The law of latitude change: the latitude and longitude where the direct sun point is located decreases to the north and south. The latitude of the direct point of the sun is one degree apart, and the angle of the sun's altitude at noon decreases by one degree.

For example, if the sun shines directly at 20°N, the elevation angle of the Sun at noon in the world will gradually decrease from 20°N to the north and south, and the solar elevation angle at noon at 19°N is equal to 89°.

That is, the height of the sun at noon at 19°n = 90° - (direct point of the sun - latitude of the place) = 90° - (20° - 19°) = 89°.

2. The law of seasonal changes: the direct sun point gradually increases when it moves, and gradually decreases when it moves (the direct sun point is relative to the latitude of a certain place). For example:

For regions at 31°N, the solar elevation angle increases at noon from December 22 (winter solstice) to June 22 (summer solstice), and decreases at noon from June 22 (summer solstice) to December 22 (winter solstice).

Sun altitude angle = 90- latitude + latitude of the direct sun (same hemisphere).

Sun altitude angle = 90 - latitude - latitude of the sun directly (hemisphere).

It should be the noon sun altitude angle!

Calculation of the solar altitude angle at noon = 90° - (latitude of the point sought - latitude of the point of direct sunlight).

It is calculated according to the latitude where the place is located, the longitude spanned by the arc where the hemisphere is located. 15° = 1 hour.

The calculation of the solar altitude angle on the winter solstice can be derived from a formula, just know your latitude and longitude.

The formula for calculating the solar altitude angle on the winter solstice is an 90° (b1 b0), an is the solar altitude angle, b1 is the city latitude, and b0 is the tropic of cancer latitude 23°26.

The latitude of Nanjing is 32°03, so the formula is substituted to obtain: the solar altitude angle of Nanjing on the winter solstice is 90° (32°03 23°26) 34°71.

In the history of Nanjing, there is a saying that the winter solstice is like a year. The winter solstice custom is very rich, mainly burning buns and eating tofu in nine years. In the saying of the old Nanjing people, burning buns is to burn packets of paper money!

This is mainly to pay tribute to the ancestors. The number nine is a ballad, due to the cold weather, people can only live on their fingers, through the observation of the weather cold and warm, phenology and people and things, interspersed with the song of ninety-nine, widely circulated, to count nine to eliminate the cold.

In the past, there was a saying in old Nanjing called fried tofu with green onion and roasted large intestine, which said that at that time, eating tofu should be accompanied by green onion and large intestine, so that the oil and water are abundant, which can meet the needs of people in the period of material scarcity. There is also a kind of implication of amusing wealth and long-term prosperity.