How to define the four seasons in meteorology: spring, summer, autumn and winter?

Spring turns from winter to spring, the weather gets warmer and the temperature rises rapidly. In February, the average 0℃ isotherm pushed across the Yellow River from the Huaihe River and reached southern Inner Mongolia in March. In April, except for the northern section of Daxinganling, Altai Mountain, West Tianshan Mountain and Qinghai-Tibet Plateau, all other areas were above 0℃.

0℃ to 6℃ in Northeast China and Junggar Basin, 12℃ to 16℃ in Yellow River, Huaihe River and Tarim Basin, and 16℃ to 26℃ in Jiangnan area. There is little precipitation in spring. Except for a fairly broad spring rain area in the south of the Yangtze River, other areas are still dry and rainy.

2. Summer:

Summer is characterized by high temperature and rainy weather. Except the Qinghai-Tibet Plateau, the temperature in China is generally high, and the temperature in most areas is between 20℃ and 28℃ in July. To the south of Huaihe River Basin, it is generally between 28℃ and 30℃. The extreme maximum temperature in Turpan Basin is 48.9℃. The Qinghai-Tibet Plateau is below 10℃. The summer monsoon comes from the tropical ocean, which is the season with the most precipitation in most parts of the country.

The areas from the south of the Yangtze River to the north of Nanling Mountain and the mountainous areas in northwest Xinjiang account for less than 40% of the annual precipitation, more than 60% in North China and Northeast China, and more than 70% in most parts of the Qinghai-Tibet Plateau. To the east of Yichang, the Meiyu area is between 26℃ and 34℃ north latitude. Generally, the rainy season lasts for nearly one month from mid-June to early July.

3. Autumn

Autumn Autumn is a "crisp autumn" weather, with clear skies and sunny days in Wan Li. The temperature changes in the opposite direction to that in spring, from warm to cold, and the isotherm distribution in 10 is basically similar to that in April. The average monthly temperature in Daxinganling, Tianshan and Qinghai-Tibet Plateau is below 0℃. The average monthly temperature in North China is between 6℃ and 65438 06℃.

The areas south of Huaihe River, south of Qinling Mountain and north of Nanling Mountain are between 16℃ and 22℃. South China is between 22 and 24 degrees Celsius. The precipitation is relatively small, accounting for more than 30% of the annual precipitation except the southeast coast, the east side of the Qinghai-Tibet Plateau, the south of the Qinling Mountains and the Sichuan-Guizhou region, and the rest of the country is between 15 ~ 20%.

4. Winter

Winter is the coldest season in the whole year, and June is 5438+ 10. The average temperature in more than two thirds of the country is below 0℃. The 0℃ isotherm in the L-month isotherm extends westward to the southeast edge of the Qinghai-Tibet Plateau through the Huaihe River and Qinling Mountains, and then to Linzhi and Delangzong in Tibet through the Hengduan Mountains. In the area north of this line, rivers are generally frozen.

The average temperature in the northeast, northwest and most parts of the Qinghai-Tibet Plateau 1 month is below-10℃, among which Daxing 'anling, Xiaoxing 'anling, Altai Mountain and northern Tibet Plateau are still below -20℃, and the northern part of Daxing 'anling is below -30℃. The extreme minimum temperature in Mohe Town, the "Arctic Village" in China, reaches 52.3℃. In the area south of 0℃ isotherm, the river has no freezing period, only snow drift.

The area south of Nanling is above 10℃. Taiwan Province Province, the southern tip of Hainan Island and the South China Sea Islands are all above 20℃. In a word, the distribution law of winter temperature in China is from south to north, and gradually decreases with the increase of latitude, and the temperature difference between north and south is very large, reaching more than 50℃. On average, the temperature drops by 65438 0.5℃ for every latitude added to the north.

Extended data

Four seasons refer to the four seasons that appear alternately in a year, namely, spring, summer, autumn and winter. Astronomically speaking, the division of the four seasons is determined by the orbital position of the earth around the sun. When the earth is in different positions in the orbit of revolution at different times of the year, different places on the earth receive different sunlight and different heat from the sun, which leads to seasonal changes and differences between cold and hot.

The four seasons on the earth are not only periodic changes in temperature, but also periodic changes in the length of day and night and the height of the sun. It affects or determines the movement rhythm of many things in the earth's environment, especially the adaptation of creatures.

divide

The four seasons are divided according to the length of day and night and the change of sun height. The division of the four seasons is based on the apparent position of the sun on the ecliptic and bounded by the bisector, the second solstice or the fourth day. However, the dividing points used by eastern and western countries to divide the four seasons are not exactly the same.

1, China's traditional method of dividing the four seasons is to take four solar terms as the starting point of the four seasons and the bisector and two to one as the midpoint. For example, in spring, the starting point is beginning of spring, the solar line is 3 15, the spring is divided into the midpoint, the long summer is the end point, the solar line becomes 45, and the sun runs 90 on the ecliptic. This is a traditional and commonly used method.

2. Astronomical classification (that is, western classification) The division of the four seasons emphasizes the climatic significance of the four seasons, with the vernal equinox of the sun as the starting point of the four seasons, such as spring as the starting point and summer solstice as the end point. These four seasons are one and a half months later than the traditional four seasons in China.

3. In order to accurately reflect the actual climate situation in various places, climatology is often used to divide the four seasons, that is, the classification of modern scholar Zhang Baokun and the average climate temperature are used to divide the four seasons. It is also stipulated that the period when the average temperature is greater than or equal to 22℃ is summer, the period when it is less than or equal to 10℃ is winter, and the period between 10℃ and 22℃ is spring or autumn.

According to this standard, the seasons in mid-latitude areas are consistent with the climate, while the temperature changes in low-latitude areas and near the polar regions are not obvious. At the same time, in mid-latitude areas, the length of each season is different. This is the four seasons. For example, Beijing has 55 days in spring, 0/03 days in summer, 50 days in autumn and 0/57 days in winter. This method can be combined with the specific climate and agriculture in various places, so it is widely used.

4. Climate statistics, because 65438+ 10 is generally the most in Leng Yue, it is March, April and May in spring, June, July and August in summer, 9 10 in autumn, 1 1 in winter.

Open:

At the equinox, the length of day and night and the height of the sun around the world are equal to the annual average, which has the typical characteristics of transition from maximum (or minimum) to minimum (or maximum).

Therefore, it is very reasonable to regard the vernal equinox as the midpoint of spring and the autumnal equinox as the midpoint of autumn. In summer, the day is the longest and the night is the shortest. On the day of summer solstice, the height of the sun is the highest and the surface gets the most solar energy. Therefore, it is very reasonable to take the summer solstice as the midpoint of summer; Similarly, the winter solstice as the midpoint of winter is also very scientific.

However, from the actual climate, the summer solstice is not the hottest time, and the winter solstice is not the coldest time, so the extreme temperature should be delayed by 1 ~ 2 months respectively. There is a saying in China that "heat is in dogs" and cold is in Sanjiu. Therefore, taking summer solstice and winter solstice as the start dates of summer and winter respectively can better correspond to the actual climate.

Therefore, the division of four seasons in the west can better reflect the actual climate significance. Whether it is the division of four seasons with astronomical significance in China or the division of four seasons with climatic significance in the west, it is an astronomical division method.

This is because dichotomy, dichotomy and quartering all have exact meanings in astronomy. They all divide the year into four roughly equal seasons, each lasting for three months, and the sun runs 90 degrees on the ecliptic. None of them can reflect the actual situation of the local climate. The seasons divided in this way are the four seasons in astronomy.

The astronomical season is hemispherically unified. In the hemisphere, every season has a unified starting and ending time. In the hemisphere, there are four seasons everywhere, and each season is of equal length. Astronomical seasons are of theoretical significance, while climatic seasons are of practical value. Astronomical seasons are the basis for dividing climatic seasons.

The astronomical season is hemispherically unified. It is summer in the northern hemisphere and winter in the southern hemisphere; The climate of the four seasons is unified in some areas (mid-latitude areas). The division of astronomical seasons depends on the change of astronomical phenomena, and the division of climatic seasons depends on the change of temperature.

No matter where in any hemisphere, there are astronomical seasons of equal length; In the same place, the time of four climatic seasons is not necessarily equal. This is the main difference between astronomical season and climate season.

Baidu Encyclopedia-Four Seasons Climate in China

Baidu encyclopedia-four seasons