the summer solstice

the summer solstice

The summer solstice, also known as the summer festival and the summer solstice festival, is the 10th solar term of the 24 solar terms. Douzhi noon; taiyanghuang longitude 90 °; on June 21-22 of Gregorian calendar. The summer solstice is the best time for the sun to travel northward. On this day, the sun shines directly on the Tropic of cancer, and then the point of direct sunlight moves southward. On the day of the summer solstice, the height of the sun at noon is the highest in the northern part of the Tropic of cancer, and the time of the day is the longest in the whole year. After the summer solstice, the height of the sun decreases day by day. However, for the regions south of Tropic of cancer in the northern hemisphere, the sunlight is still increasing after the summer solstice.

The summer solstice is not only one of the 24 solar terms, but also one of the "four seasons and eight Festivals" in ancient times. There has been a custom of worshiping gods and ancestors in the summer solstice since ancient times. In the ancient farming society, when people lived and worked in peace and contentment, they chose to worship gods and ancestors on a certain day. Then there were various regular festivals, and gradually formed some conventional ways of celebration, namely the so-called festival folk custom. Heaven and earth are the origin of life, and ancestors are the origin of category; ancestor worship is a custom of inheriting filial piety. In addition, there are also some folk customs such as "eliminating summer and avoiding ambush" and "clearing and tonifying" during the summer solstice.

Characteristics of solar terms

The summer solstice is the 10th solar term of the "24 solar terms" and the fourth solar term in summer. "24 solar terms" was initially determined by the direction of the dipper handle of Beidou, which refers to the noon, which is the summer solstice. The current "24 solar terms" are based on the division of "degrees of the Yellow longitude of the great sun", that is, each solar term corresponds to a certain position of the earth for every 15 ° of the ecliptic. When the sun moves to 90 degrees of the Yellow longitude, it is the summer solstice. The summer solstice is the northernmost day of the year, the extreme northbound of the sun, and the longest day in the Tropic of cancer in the northern hemisphere. The higher the latitude, the longer the day. This is due to the "long day and short night effect" caused by the tilt of the earth's rotation axis, which is more obvious as it approaches two levels. On the day of the summer solstice, except for the Antarctic point and the polar night area in the Antarctic Circle, the sunrise direction of all places on the Earth starts from the northeast and sets in the northwest. On the day of the summer solstice, the area north of the Tropic of cancer in the northern hemisphere gets the most solar radiation. After the summer solstice, in the area north of the Tropic of cancer, the solar height angle at noon begins to decrease day by day. In the area to the south of Tropic of cancer, the sun moves southward after the summer solstice, the point of direct sunlight passes again, and the height of midday sun rises again. The significance of summer solstice to the north of Tropic of cancer is different from that to the south of Tropic of cancer. on the summer solstice, the position of the sun directly on the ground reaches the northernmost end of the year, almost directly on the Tropic of cancer. The Tropic of cancer passes through Yunnan, Guangxi, Guangdong, Fujian (sea area) and Taiwan from west to East. These areas are the areas where the sun is in the middle of the sky in China, and the shadow is the shortest, that is, as the ancient books say: "the sun is the longest, the shadow is the shortest, the shadow is the shortest It is also called the summer solstice. At the same time, for the Tropic of cancer and its northern regions, the summer solstice is also the highest day of the year at noon. The southern hemisphere is in the middle of winter. On the summer solstice, the higher the latitude, the longer the day. For example, Haikou City in Hainan Province is about 13 hours long, Hangzhou city is 14 hours long, Beijing is about 15 hours long, and Mohe city in Heilongjiang Province is more than 17 hours long. North of the Arctic Circle, the sun is above the horizon all day, making it the most extensive day of the year in the northern hemisphere. the summer solstice is the turning point of the sun's northbound. After the summer solstice, the sun will go back, and the point of direct sunlight begins to move southward from the Tropic of cancer. For the area north of the Tropic of cancer (23 ° 26 ') in China, after the summer solstice, the noon sun height begins to decrease day by day; for the area south of the Tropic of cancer, after the summer solstice, the noon sun height begins to decrease day by day after the direct sunlight from the south. The summer solstice is not the hottest time of the year in the northern hemisphere, because the heat close to the surface is still accumulating at this time, not reaching the maximum. As the saying goes, "hot in the dog days, cold in the four or nine days", the real hot weather, about in the summer - early autumn, the temperature in all parts of China is the highest.

Climate conditions

air temperature

The summer solstice means that the hot weather officially begins, and then it gets hotter and hotter. Therefore, there is a folk saying that the summer solstice is not hot. After the summer solstice, although the direct point of the sun gradually moves southward, the day in most parts of the northern hemisphere is shorter and the night is longer, but the heat radiated by the sun to the ground is still more than that radiated from the ground to the air, so the temperature will continue to rise in the future.

precipitation

During the summer solstice, the temperature in most areas of China is higher, the sunshine is sufficient, the crops grow fast and need more water. At this time, the precipitation has a great impact on the agricultural yield. The summer solstice period is the rainy season in the south of China. The rainy season in the north is between the end of July and the beginning of August, and there is less precipitation during the summer solstice in the north.

historical origin

"Twenty four solar terms" is the product of ancient agricultural civilization. Agricultural production is closely related to the rhythm of nature. It is a knowledge system formed by ancient ancestors conforming to the farming time, observing the movement of celestial bodies, and recognizing the changing rules of the middle time of a year, climate, phenology, etc. The 24 solar terms are the specific seasons in the Ganzhi calendar, which indicate the changes of natural rhythm and establish the "December construction". In the historical development, the 24 solar terms have been listed in the lunar calendar and become an important part of the lunar calendar. The 24 solar terms are: the beginning of spring, rain, Jingzhe, vernal equinox, Qingming, Guyu, the beginning of summer, Xiaoman, mangzhong, summer solstice, Xiaoshu, Dashu, Liqiu, Chushu, Bailu, autumnal equinox, Hanlu, Shuangjiang, Lidong, Xiaoxue, Daxue, Dongzhi, Xiaohan and Dahai. Each solar term represents the different changes of climate, phenology and time. Yi · Xici: the combination of cold and heat. The ancients believed that December was the law of the operation of the universe, such as Wenzi · nature: "December runs, and it starts again and again." It means that heaven and earth turn round and round, again and again. In each year-old cycle, the bucket handle rotates to the "Twelfth hour" in turn, which is called "December construction" (or "December order"). In ancient times, the doubing of the Big Dipper refers to "Jian", and "JianZheng" is the concept of Ganzhi calendar. In Ganzhi calendar, doubing refers to Yin, which is the first month of JianZheng. December construction is based on the 24 solar terms, with numbers and 12 branches. "December construction" are: Jianyin in the first month, Jianmao in the second month, Jianchen in the third month Jianzi (sleepy town) in November and jianchou (chifenruo) in December. in ancient times, solar terms were established on the basis of "Dou Zhuan Xing shift" (doubing direction), while the current solar terms are established on the basis of "solar annual apparent motion" (degree of yellow longitude); although the two methods are different, in fact, the cause of Dou Zhuan Xing shift is that the earth revolves around the sun, so the intersection time of the two methods is basically the same.

Solar term reflection

Summer solstice and equinox, autumnal equinox and winter solstice are the solar terms reflecting the return movement of direct sunlight. When the sun is directly on the equator and moves to the Tropic of cancer, it is the vernal equinox; when the sun is directly on the equator and moves to the Tropic of cancer, it is the autumnal equinox; when the sun is directly on the Tropic of cancer, it is the summer solstice; when the sun reaches the Tropic of cancer, it is the winter solstice. There is a saying that "the winter solstice is a positive birth", which also leads to the saying that "the summer solstice is a Yin birth". In fact, strictly speaking, "Yang" has the concept of yin and Yang and the Yang of the sun. After the winter solstice, the height of the sun rises, not the Yang Qi in the concept of "Yin Yang". The solar term of winter solstice reflects the Yang of the sun, not the Yang of yin and Yang. The arrival of the summer solstice indicates that the sun is the highest and the day is the longest on the Tropic of cancer and other places to the north. It is not the day with the most Yang in the concept of yin and Yang. "Yin Yang and five elements" belong to the category of "Gan Zhi". The specific day when Yin Qi or Yang Qi is the most abundant is calculated according to "Gan Zhi". From the perspective of solar term law, the beginning of spring is the beginning of the rising of Yang Qi in the Qi of "Yin and Yang". Since the beginning of spring, yin and Yang have transformed, everything has been reborn, and a new cycle has opened. The winter solstice is the beginning of the return of the sun. Since the winter solstice, the sun returns to the north, and the day in the northern hemisphere increases day by day. The summer solstice is the beginning of the southward movement of the sun. After the summer solstice, the days in the area north of the Tropic of cancer in the northern hemisphere become shorter day by day, and the light is weakened; but for the area south of the Tropic of cancer, the sun is direct again after the summer solstice, and the light is still increasing.

Custom activities

The summer solstice is one of the four seasons and eight festivals. Since ancient times, there has been a custom of celebrating the harvest and offering sacrifices to ancestors at this time to pray for a good harvest. In ancient farming society, when people lived and worked in peace and contentment, there were all kinds of regular festivals for worshiping gods and ancestors. The rich offerings for worshiping gods and ancestors developed Festival banquets, and gradually formed some conventional celebration methods, namely the so-called festival folk customs. Heaven and earth are the origin of life; ancestors are the origin of category. Heaven and earth are the basis of life, and ancestors are the basis of human beings. Ancestor worship is a custom of inheriting filial piety. There is also the custom of eating noodles during the summer solstice. Since ancient times, there has been a saying among Chinese people that "winter solstice wonton and summer solstice noodles". People in many areas of Jiangnan regard eating noodles during the summer solstice as a very important custom. The summer solstice represents the coming of hot summer, people's diet should also be changed, with low calorie, easy to make food as the main food. Noodles are often the first choice for families, so summer solstice noodles are also called "Rufu noodles". Taoism regards the summer solstice as one of the holy treasures of the three Qing Dynasties.

Related culture

poetry

Summer solstice

Fan Cheng (Song Dynasty)

Chinese PinYin : Xia Zhi