Urgently ask for the height of the noon sun, how to calculate the height of the noon sun

Beijing is huge, with latitude around 40 north latitude. On the day of the autumnal equinox (around September 23), the sun shines directly on the equator. Therefore, the altitude angle of the sun at noon on the autumnal equinox is about 90°-40°=50°.

From September to October, the altitude angle of the sun at noon is between 40° and 60°. As for September 1 and October 1, the calculation is quite complicated, and the timing of the autumnal equinox is uncertain and varies from year to year.

From September to October, the direct sunlight point moves southward, and the solar elevation angle decreases at noon.

1.The formula for calculating the height of the sun at noon is: h=90° - the difference between the latitude of the earth and the point where the sun shines directly), where the value is based on the principle of subtraction of the same hemisphere and addition of the hemisphere.

2.Calculate using the solar shadow of a perpendicular object: coth=shadow length of the object.

3.The angle between the lighting surface of the solar water heater and the roof surface of the building = (the difference between the latitude of the local latitude and the direct sun point), where the value is according to the principle of subtraction of the same hemisphere and addition of different hemispheres.

4.Calculation of building room septum l in the middle latitudes of the northern and southern hemispheres: l = building height coth° (h° is the minimum noon solar altitude angle in the local year, the noon sun height on the winter solstice in the northern hemisphere, and the noon sun height on the summer solstice in the southern hemisphere).

It is recommended to use the northeast-southwest or northwest-southeast orientation for the layout of the building.

5.The elevation angle of the North Star, i.e., the height of the horizon, is equal to the local geographic latitude.

The midday sun altitude is described as follows:

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

The formula for calculating the solar altitude angle at noon is h=90 -|The latitude of the local direct point of direct illumination, h represents the height of the local noon sun, 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, and the range of the song, or the angle between the morning and dusk lines and the meridians.

Law. Since the direct point of the sun moves between the Tropic of Cancer, so:

1. In the area between the Tropic of Capricorn, there are two opportunities for direct sunlight a year, and the height of the sun at noon is the maximum, at 90°. A minimum occurs when the Sun shines directly on the Tropic of Capricorn. Except for the two minima, which are the lowest at the equator, the other regions are the smallest when the sun directly hits the Tropic of Cancer in the other hemisphere.

2. In areas above the Tropic of Capricorn, there is a chance for direct sunlight once a year, which are the summer solstice and the winter solstice.

3. In areas outside the Tropic of Cancer, the Tropic of Cancer can be included, which is the largest when the sun directly hits the Tropic of Cancer in the local hemisphere, and the smallest when it directly hits the Tropic of Cancer in the other hemisphere.

For example, Jue Zheng Beijing is about 40 degrees north latitude, in the northern hemisphere summer solstice, the sun directly hits the Tropic of Capricorn, at this time the noon sun height is the largest, about; On the winter solstice, the sun shines directly on the Tropic of Capricorn, and the height of the midday sun here is the smallest, about.

1) Vernal equinox: The height of the sun decreases from the equator to the north and south at noon.

2) Summer solstice: The height of the sun at noon decreases from the Tropic of Cancer to the north and south.

3) Autumnal equinox: The height of the sun decreases from the equator to the north and south at noon.

4) Winter solstice: The height of the sun at noon decreases from the Tropic of Cancer to the north and south.

The latitudinal distribution of the magnitude of the noon solar height change (the maximum difference in the solar altitude at noon in the year) is as follows:

1) The maximum difference between the annual noon solar altitude in the equatorial region and the North and South Pole regions is 23°26.

2) In the region between 0° and 23°26 north and south latitude (or tropical region), the maximum difference of solar altitude at noon increases from 23°26 to 46°52.

3) In the area between 23°26 north and south latitude and 66°34 north and south latitude (or north and south temperate zone), the maximum difference between the annual noon solar altitude is 46°52.

4) In the region between 66°34 and the pole (or the cold zone), the maximum difference in solar altitude at noon decreases from 46°52 to 23°26.

The geographical coordinates of Beijing are: 39"26' to 41"03' north latitude, which is about 40 north latitude

On the winter solstice, the sun shines directly at 23°26 s, and the solar altitude at noon in Beijing on that day = 90°-|40°-（23°26′）|26°34′

On the summer solstice, the sun shines directly at 23°26 n, and the solar altitude at noon in Beijing on that day = 90°-|40°--23°26′|=73°26′

On the spring and autumn equinoxes, the sun shines directly at the equator at 0°, and the solar height at noon in Beijing on that day = 90°-|40°-0°|=50°

The altitude angle of the sun at noon is the angle between the sun's rays and the ground at 12 o'clock.

1. The height of the sun at noon refers to the decrease from the latitude of the direct point of the sun to the north and south, and the degree of reduction is equal to the difference between the local geographical latitude and the latitude of the direct point (the difference between one southern latitude and one northern latitude is the sum of its values).

2. Because of the rotation of the earth, the direct point of the sun on the earth is reciprocated between the Tropic of Cancer and the Tropic of Cancer once a year. Take the area through the Tropic of Cancer in the northern hemisphere as an example: when the sunlight directly hits the Tropic of Cancer in a year, it is the summer solstice solar term in northern China, and the sun is directly above the head at noon, that is, the solar altitude angle is 90°, which is the maximum value of the year.

3. When the sunlight hits the Tropic of Capricorn directly, it is the winter solstice solar term in the north of China, and the solar altitude angle at this time is 43°, which is the minimum value of the year. Due to the rotation of the Earth, the apparent motion of the Sun (rising in the east and setting in the west) is produced, that is, the diurnal variation of the height of the Sun.

4. Due to the rotation of the earth, the direct point of the sun moves north and south, resulting in the latitudinal change and seasonal change of the height of the sun at noon.

What is the height of the sun at noon

1.The height of the sun at noon is the decrease from the latitude of the direct point of the sun to the north and south, and the degree of decline is equal to the difference between the local geographical latitude and the latitude of the direct point of the sun (the difference between one south latitude and one north latitude is the sum of its values).

2.Because of the Earth's revolution, the Sun travels back and forth between the Tropic of Cancer and the Tropic of Cancer within a year. Take, for example, the area through which the Tropic of Cancer passes in the Northern Hemisphere:

When the sun shines directly on the Tropic of Cancer during the year, it is the summer solstice solar term in northern China. At noon, the sun shines directly overhead, i.e. the solar altitude angle is 90°, which is the largest value of the year.

3.When the sun shines directly on the Tropic of Capricorn, it is the winter solstice solar term in northern China. At this time, the solar altitude angle is 43°, which is the minimum of the year. As a result of the rotation of the Earth, the apparent motion of the Sun occurs (rising in the east and setting in the west), that is, the diurnal variation of the height of the Sun.

4.Due to the rotation of the Earth, the direct point of the Sun shifts from north to south, resulting in latitudinal changes and seasonal variations in the height of the Sun at noon.

The noon sun is high and the socks degree angle h=90°-latitude difference.

The latitude difference is the number of degrees of latitude between the geographical latitude of the location and the geographical latitude of the direct solar point, subtracting from the same hemisphere and adding it to the hemisphere.

The day of the winter solstice is when the sun shines directly on the Tropic of Capricorn, 23 degrees 26 minutes south latitude.

So get the geographic latitude of the city you want on it.

Taking the Northern Imperial Tour of Beijing as an example, Beijing is almost 40 degrees north latitude, at this time, the noon solar height intersection of Beijing's grinding cavity is: 90 degrees - (40 degrees + 23 degrees 26 minutes) = 26 degrees 34 minutes.