What is the sign of the division of temperature zones in our country

Qinling. The dividing line of zero degrees in January, the dividing line of 800 millimeters of precipitation, the dividing line of humid and semi-humid humid and so on....The north of the Qinling Mountains is the north, and the south is the south!

The temperature zone is a zone based on the amount of accumulated temperature in various regions of the world and the heat index required for agricultural production.

It is usually divided into five temperature zones according to the amount of accumulated temperature of 10: boreal zone, north temperate zone, tropical zone, southern temperate zone, and southern cold zone. Most of China is located in the north temperate zone, and a small part is located in the tropics.

Classification criteria: The division of the world's temperature zones.

1. Based on the amount of accumulated temperature in each region, the zone is divided according to the heat index required for agricultural production

23°26 N (Tropic of Cancer) to 23°26 S (Tropic of Cancer) is tropical;

North (South) 23°26 to 66°34 North (Arctic Circle, Antarctic Circle) is the north-south temperate zone;

North and south latitude 66°34 to north (south latitude) 90 degrees is the north-south cold zone.

2. Due to the existence of the yellow and equatorial angles, the sun also shows a round-trip motion relative to the celestial equator while moving annually. Specifically, the sun on the celestial sphere is half the year north of the celestial equator and half the year south of the celestial equator. This is because half of the ecliptic is north of the celestial equator and the other half is south of the celestial equator.

This movement of the sun, which is another aspect of its annual movement, is called the solar return movement.

The north-south boundary that it can reach on the celestial sphere is called the Tropic of Cancer and Tropic of Capricorn. The cycle of the return movement is the return year. The regression movement, the regression line, and the regression year, are three different sides of the same thing.

The regression motion of the Sun relative to the celestial equator is also manifested as the round-trip motion of the direct point of the Sun to the Earth's equator: half a year in the northern hemisphere and half a year in the southern hemisphere; Half a year to the north, half a year to the south. The concept of the Tropic of Cancer on Earth is also relative to the return movement of the Sun.

The dividing line between day and night hemispheres on Earth is called the morning and dusk circle. This is a great circle of the earth. As the direct point of the sun moves from north to south, the circle of morning and dusk oscillates on both sides of the north and south, and the amplitude of the oscillation is also 23°26.

In this latitude range, there are astronomical phenomena unique to the polar region - polar day and polar night, so the two parallels of 66°34 north and south latitude are called the north and south arctic circles.

In the Arctic and Antarctic Circles, there are polar days and polar nights. Their range size, which varies with the declination of the sun (δ). The greater the δ value, the wider the range of polar day (night).

From the spring equinox to the summer solstice (δ increased from 0° to 23°5), the polar day in the Arctic and the polar night in the Antarctic expand from the pole to the polar circle; From the summer solstice to the autumnal equinox (δ by 23°5 is reduced to 0°), then the polar circle is reduced to the pole.

In the winter half of the year, the situation is reversed: 23°26 23°26.

Accumulated temperature

Accumulated temperature refers to the sum of the daily average temperature 10 during the continuous period of daily average temperature in a certain period of time, that is, the sum of active temperatures, referred to as accumulated temperature. It is an index to study the relationship between temperature and the development rate of biological organisms, and represents the effect of temperature on the growth and development of biological organisms from two aspects: intensity and action time.

The accumulated temperature is generally measured in degrees Celsius (d·day) for units.