20 19 sunrise and sunset time from summer solstice, characteristics of summer solstice
Sunrise time and sunset time of summer solstice
In summer solstice, the sunrise time is 6: 34: 08 am and the sunset time is 6: 43 pm:12.
Given the latitude a of the point where sunlight directly hits the earth, we get a formula: T= 12*arcCos(tgA*tgB)/? (for the northern hemisphere)
Calculate, summer solstice: the direct point of the sun is also on the tropic of cancer, A=B=23? 26? T=5.28 is brought into the formula, and the sunrise time is 6: 34: 08 in the morning. Sunrise time and sunset time are symmetrical at noon 12, so the sunset time from summer to morning is 6: 43 pm12 seconds.
The time of sunrise and sunset will change with the season and the latitude of different places. The summer solstice is the longest day and the shortest night in the northern hemisphere. Most people intuitively think that the sunrise time from summer solstice is also the earliest in a year, and the sunset time is the latest. But in fact, the earliest sunrise usually occurs in the early June before the summer solstice, and the latest sunset is from the end of June to the beginning of July after the summer solstice.
Representative cities with long summer to day and long days.
Representative cities are: Harbin day length 15 hours and 43 minutes; Beijing days 15 hours 1 min; The length of Jinan day is 14 hours and 40 minutes; Shanghai days 14 hours 1 1 min; Hangzhou day length is 14 hours and 7 minutes; The length of Fuzhou day is 13 hours and 46 minutes; Guangzhou day length is 13 hours and 34 minutes; The length of daylight in Hong Kong is 13 hours and 30 minutes.
The time of sunrise will change with the season and the latitude of different places. Traditionally, in the northern hemisphere, the sunrise time from winter solstice is the latest, but in fact, the latest sunrise time should be 65438+1early October. By the same token, the earliest sunrise on the solstice is not in summer, but in mid-June.
The time of sunset will change with the seasons and latitudes in different places. Traditionally, in the northern hemisphere, the sunset time is the earliest from winter to Sunday, and the sunset time is the latest from summer to Sunday. But in fact, due to the influence of the ecliptic angle and the elliptical orbit of the earth, the earliest sunset will not fall on the winter solstice, but in early February. The latest time of sunset will not fall on the summer solstice, but at the end of June.
Even in the equatorial region, the time of sunrise and sunset will change a little during the year. These changes can be represented by daily trajectories. The time of sunrise and sunset can be calculated by tracking the sun's trajectory. In addition, sunlight will be refracted by the influence of the earth's atmosphere, so the sun can still be seen after it drops below the horizon, which is an illusion generated at sunset every day.
Characteristics of summer solstice
Although the summer solstice has the longest day and the highest sun angle, it is not the hottest time of the year. Because, close to the surface of the heat, at this time still continue to save, did not reach the maximum time. As the saying goes? Trivolt fever? Real hot weather is based on the solstice of summer and the beginning of autumn. From mid-July to mid-August, the temperature is the highest in all parts of China, and the highest temperature in some areas can reach about 40 degrees. On the summer solstice, the position where the sun directly hits the ground reaches the northernmost point of the year, almost directly on the tropic of cancer (latitude 23? 27? ), the day is the longest in the northern hemisphere, and the farther north it is, the longer it is. After the summer solstice, the position of direct sunlight on the ground gradually moved southward, and the days in the northern hemisphere became shorter and shorter.
? But isn't the summer solstice hot? ,? How many heads are there on the summer solstice? . Although the summer solstice indicates that the hot summer has arrived, it is not the hottest time. After the summer solstice, the temperature will continue to rise for some time, and about twenty or thirty days is the hottest weather. After the summer solstice, the ground is heated strongly and the air convection is strong, and thunderstorms are often easy to form in the afternoon to evening. This kind of hot thunderstorm comes and goes, and the rainfall range is small. People call it summer rain over the mountains. In the south, Liu Yuxi, a poet in the Tang Dynasty, skillfully used this weather and wrote a famous poem about the sunrise in the east and the rain in the west, saying that there is no sunny, only sunny.