Why is Hengyang so hot?

The latitude and longitude of Hengyang City is 26 90 ′ north latitude and112 57 ′ east longitude, and the latitude of the Tropic of Cancer is 23 26 ′ n .. The sun returns to the Tropic of Cancer every year. After the vernal equinox (March 2 1), the sun began to shine directly in the northern hemisphere, and it did not shine directly in the southern hemisphere until September 23. The variation law of solar altitude angle is decreasing from straight latitude to north and south sides.

Every year in late June, the direct point of the sun is near the Tropic of Cancer. At this time, the solar altitude angle of Hengyang is greater than 80 (note: the maximum solar altitude angle is 90). The greater the solar altitude angle, the greater the solar radiation and the higher the temperature.

It stands to reason that at this time, the direct point of the sun moves south, the solar altitude angle decreases, and the temperature should be lowered. So in recent months, the temperature is often around 35? This is because the Pacific High is formed in the ocean in the east of China, and it extends to Chinese mainland from July to September, which is the midsummer season. During this period, most days were sunny and sunny, which contributed to the high temperature weather.

2. Topography and vegetation.

From a small topography, Hengyang is located in Hengyang basin, and it is well known that the basin topography is not easy to dissipate heat, which will aggravate the high temperature. Vegetation, there are a lot of farmland around Hengyang City, which belongs to artificial vegetation, and the low coverage of natural vegetation will also aggravate the high temperature.

3. Urban heat island effect.

Go to Baidu to find out the city positioning of Hengyang, and you can find that the label posted on Hengyang is "old industrial base and core industrial city of Hunan Province". Moreover, Hengyang is a city with a built-up area of more than 100 square kilometers and an urban population of about 100 million.

Due to the urban population concentration, developed industry, traffic congestion and serious air pollution, the buildings in the city are mostly stone and concrete, with high thermal conductivity and heat capacity, and the buildings themselves can block or weaken the wind, so that the average temperature in the city in summer is more than 6℃ higher than that in the suburbs.