What natural phenomena does this sentence reflect?

The arrival of the <> equinox marks the equinox of day and night, each of which is 12 hours; The second is that the spring equinox equalizes the meaning of spring. The vernal equinox is in the middle of the three months of spring, and in ancient times it was called "the middle of the day", "the equinox of day and night", and "the moon of mid-spring". "In the middle of February, the divider is also half a day, and this is ninety and a half days, so it is called a divide.

In the spring equinox, yin and yang are half of each other, so the day and night are even, and the cold and heat are flat. The vernal equinox has obvious climatic characteristics: cold spring, spring drought, dust, low temperature and rain.

Today's past few days have been marked by cold spring, cooler temperatures, cold winds, and cloudy weather.

In the process of warming up the weather in spring, due to the invasion of cold air, the temperature is significantly reduced, so that there is continuous rain. The weather forecast realizes early warning, reminds people to take precautions in advance, to cope with weather changes, observe weather changes, keep warm in time, and add clothes. In addition, spring drought and windy weather should be prevented (avoid falling objects, billboards, tree branches, reduce going out, slow driving, etc.).

During the vernal equinox, the sun hits the equator directly, and the day and night are almost equal, and the direct sunlight in the back slowly moves northward, gradually starting to get longer and shorter nights. During the vernal equinox, the frequency of rainfall increases significantly, and the average ground temperature tends to stabilize to 10 degrees, which is the spring temperature defined in climatology. After the spring equinox, the climate is gradually mild, the rain is relatively abundant, and there are more sunny days, and everything enters the spring stage.

When the South Garden is half green in spring, the wind and the horses neigh, the green plums are like beans and willows, and the butterflies fly in the long days. "Whether in the south or in the north, the spring equinox is a great time for spring.

Spring equinox tips: "For the spring equinox, the yin and yang are half of each other, so the day and night are even, and the cold and heat are even." Therefore, since ancient times, there has been a saying that "the spring equinox wind is not small, and it is necessary to prevent pain and deep disturbance", and the old people have been saying "spring cover, autumn freeze", so everyone should still pay attention to wind protection and keep warm, don't get sick to exercise outdoors and enhance immunity!

From the day of the spring breeze, the direct point of the sun will be from south to north, and the sun reaches zero ecliptic longitude on this day, so on this day the day and night are equally divided, each is 12 hours, and then there will be strong winds or blowing sand in the north.

It reflects natural phenomena such as a calm climate, almost equal day and night, the arrival of the spring equinox, the balance between cold and heat, and the transition from winter to early spring, which are common natural phenomena in spring.

This phrase reflects the fact that at the time of the vernal equinox, the day and night are more distinct, that is, the days will be shorter and the nights will be longer, so as to ensure that the day is warmer.

This sentence reflects natural phenomena such as the equal length of day and night, the gradual warming of the climate, the warming of the weather, the rejuvenation of the earth, and the beginning of the revival of all things.

Summer solstice: the days are longer and the nights are shorter in the Northern Hemisphere, and the days are longer the further north, with polar days occurring in the Arctic Circle and north of it; The days are short and the nights are long in the Southern Hemisphere, and the days become shorter the further south you go, and polar nights appear in the Antarctic Circle and south of it; The equator is equal in length for day and night.

Winter solstice: The days are short and the nights are long in the northern hemisphere, and the days are shorter the further north they go, with polar nights occurring in the Arctic Circle and north of it; The days are longer and the nights are shorter in the Southern Hemisphere, and the days get longer the further south you go, with polar days occurring in and south of the Antarctic Circle. The equator is equal in length for day and night.

Equinox and autumnal equinox days: the same length of day and night around the world.

The spring equinox, the spring equinox, the day and the night are equal, why? The vernal equinox is an astronomical solar term that has two meanings. One is that the sun shines directly on the equator on this day, and the time of day and night is equal everywhere.

The second is that since ancient times, the beginning of spring to the beginning of summer is spring, and the spring equinox is in the three months of spring, and the spring is equally divided. "The length of day and night is average, and the ninety days of spring are equally divided."

At present, the earliest documentary record of solar terms is found in the "Shangshu Yaodian": "The star bird in the middle of the day, with Yin Zhongchun; The sun is always sparking, and it is midsummer: the stars are empty in the night, and the mid-autumn is in Yin; The days are short and the stars are high, so as to stop in the middle of winter.

"Mid-day", "Riyong", "Mid-Night", and "Short Day" are equivalent to the spring equinox, summer solstice, autumn equinox, and winter solstice, respectively. It is presumed to be a celestial phenomenon around the 11th century BC (on the occasion of the Yin Zhou Dynasty). It can be seen that the concept of the spring equinox was born at that time.

Seventy-two Candidate Explanations of the Lunar Order: "In the middle of February, half of the dividers are also, which should be half of the ninety days, so it is called the divide. Autumn synonymous. ”

Han Dong Zhongshu's "Spring and Autumn Dew, Yin and Yang in and Out": "As for the moon of mid-spring, the yang is in the east and the yin is in the west, which is called the spring equinox. In the spring equinox, yin and yang are half of each other, so the day and night are even, and the cold and heat are flat. ”

Since ancient times,"Xuanniao, swallow also. The spring equinox refers to the letter type, and the autumn equinox goes. "As one of the 24 solar terms, the vernal equinox guides agricultural affairs.

The diurnal variation of the vernal equinox, summer solstice, autumn equinox, and winter solstice is the northern and southern hemispheres at the spring and autumn equinoxes.

Both days and nights are of equal length, while the summer solstice is long and short in the northern hemisphere and the southern hemisphere.

The days are short and the nights are long; The winter solstice is a short day and a long night in the Northern Hemisphere, and a short day and a short night in the Southern Hemisphere.

Day and night are produced by rotation, but the length of day and night is not equal to the rotation period because the earth rotates.

A week later, there was a simultaneous revolution, which changed the Earth's relative angle to the Sun, and day and night were seen in terms of the extent of the Sun shining on the Earth, so that one day and night were 3 minutes and 56 seconds longer than the rotation period.

Northern Hemisphere spring to autumn equinox, days longer than night; From the autumnal equinox to the spring equinox of the following year, the night is longer than the day, and the opposite is true in the southern hemisphere.

During the Earth's revolution around the Sun, the Earth's axis is always tilted at an angle of 66 degrees and 34 minutes to the orbital plane. Due to the tilt of the Earth's axis, the height of the Sun at different points on the Earth's surface is different when the Earth is in different positions in orbit.

When the sun is high, the sun shines directly and the heat is concentrated, as if it were facing a furnace; Moreover, the path of the sun in the sky is long, the sunshine hours are long, the days are long and the nights are short, and the temperature is bound to be high, which is the spring equinox to the autumn equinox.

On the contrary, when the sun is at a low altitude, the sunlight hits the ground obliquely, and the heat is dispersed, which is equivalent to an oblique furnace; Moreover, the path of the sun in the sky is short, the sunshine hours are short, the days are short, the nights are long, and the temperature is low, which is the autumn equinox to the spring equinox of the following year.

In the Northern Hemisphere, for example, the location of the direct sun on the spring and autumn equinoxes is the equator, and the day and night are of equal length. On the summer solstice, the direct point of the sun is the Tropic of Capricorn, and the days are long and the nights are short. On the winter solstice, the location of the direct sun is the Tropic of Capricorn, and the days are short and the nights are long.

From the spring equinox to the summer solstice, and from the winter solstice to the spring equinox of the following year in the northern hemisphere, the direct sun point moves northward, and the days are getting longer and longer. From the summer solstice to the winter solstice, the direct point of the sun moves southward, and the days get shorter and shorter.

The diurnal variation of the spring equinox, summer solstice, autumn equinox and winter solstice is that the day and night are equal in the northern and southern hemispheres during the spring and autumn equinoxes, while the days and nights in the northern hemisphere are short in the northern hemisphere during the summer solstice, and the days are short and the nights are long in the southern hemisphere. The winter solstice is a short day and a long night in the Northern Hemisphere, and a short day and a short night in the Southern Hemisphere.

Day and night are produced by rotation, but the length of day and night is not equal to the rotation period, because after the earth's rotation is completed for one time, it rotates at the same time, and the revolution changes the relative angle of the earth towards the sun, and day and night are seen in terms of the range of the sun shining on the earth, so one day and night is 3 minutes and 56 seconds longer than the rotation period.

1. The vernal equinox is around March 21, and day and night are equinox.

The "minute" of the spring equinox refers to the ninety days of spring divided into two halves, and since then it has entered the season of spring and sunshine, and thousands of red and thousands of greens compete for beauty. At this time, the yang is due east and the yin is due west, so that the day and night are evenly divided, and the cold and heat are balanced, which is the best climate of the year.

2. The summer solstice is around June 22, which is the shortest night and longest day of the year.

The summer solstice is in the middle of the fifth month of the lunar calendar. Summer is the greatest, the extreme, all things grow and flourish to the extreme, and the yang energy also reaches the extreme, so it is the shortest night and the longest day of the year.

3. The autumnal equinox is around September 23, and the day and night are of equal length.

The autumnal equinox is in the middle of autumn, and after the autumnal equinox, you can clearly feel the gradual decrease in temperature and the increase in the temperature difference between day and night. In terms of data, the average daily temperature has basically dropped below 22 degrees Celsius.

4. The winter solstice is the shortest day and longest night of the year around December 22.

The winter solstice is the eleventh month of the lunar calendar, and "solstice" is the ultimate meaning, with the shortest day and the longest night. The breath of winter storage is extremely extreme.

The spring and autumn equinoxes are equinoxical to day and night, the summer solstice has long days and short nights, and the winter solstice has short days and long nights.

When the height of the sun is small, the sunlight hits the ground obliquely, and the heat is dispersed, which is equivalent to facing the furnace obliquely; Moreover, the path of the sun in the sky is short, the sunshine hours are short, the days are short and the nights are long, and the temperature is low; From winter to summer, the height of the sun changes from low to high. In the same way, changes in the height of the sun affect the length of days and nights and the level of temperature, forming autumn and spring, respectively.

The spring equinox is the same as the autumn equinox, the day is the same length as the day and the night, the summer solstice is the day is long and the day is short, and the winter solstice is the day is short and the day and night are long.

The spring and autumn equinoxes are equinoxical to day and night, the summer solstice has long days and short nights, and the winter solstice has short days and long nights.

Day and night are divided into equal parts.

The days are long and the nights are short. Day and night are divided into equal parts.

The days are short and the nights are long;

Diurnal equinox Short night, long day equinox Dinox Night, long night, short day?

On the day of the vernal equinox (March 21) and the day of the autumnal equinox (September 23), the sun shines directly on the equator, and the global day and night are of equal length, and there are no infinite days and pole nights.

On the summer solstice (June 22), the sun shines directly on the Tropic of Capricorn, the days and nights are short in the Northern Hemisphere, the days are short and the nights are long in the Southern Hemisphere, the polar day in the Arctic Circle, and the polar night in the Antarctic Circle.

On the winter solstice (December 22), the sun shines directly on the Tropic of Capricorn, the days are short and the nights are long in the Northern Hemisphere, the days are long and the nights are short in the Southern Hemisphere, the polar night in the Arctic Circle, and the polar day in the Antarctic Circle.

Spring and autumn, the global day and night are of equal length, and do not exist.

Polar day and polar night. Summer solstice.

The days are long and the nights are short in the Northern Hemisphere, and the polar day appears in the Arctic Circle and north of it;

The Southern Hemisphere has short days and long nights, with polar nights occurring in and south of the Antarctic Circle.

On the winter solstice, the days are longer and the nights are shorter in the Southern Hemisphere, and the polar day appears in the Antarctic Circle and its north; The days are short and the nights are long in the Northern Hemisphere, and the polar nights occur in the Arctic Circle and south of it.

a, the spring equinox search day, day and night equinox, Taiyuan sunrise is the earliest, so it does not meet the theme;

b. On the summer solstice, the days are longer and the nights are shorter in the northern hemisphere, the higher the latitude, the longer the days and the shorter the nights, and the Baizi in Jiuquan has the longest day, so it is correct;

c. The north-south horizontal reed distance between the north and south of the Wenchang building is the smallest, so it does not conform to the theme;

d. The angular velocity of rotation in the four places is equal, so it does not conform to the topic

Therefore, b