What is the reason why Chongqing is particularly hot in summer?

Chongqing, Wuhan and Nanjing have always been famous summer high temperature centers in China, and are known as the "three furnaces" in the Yangtze River Basin. Their popularity is second only to Turpan in Xinjiang. Every year to the midsummer of July, the sun is shining, there is no wind in the fields, and the temperature is always above 30℃. At the hottest time, Chongqing reached 44℃, Wuhan 42.2℃ and Nanjing 43℃. In the evening, although the sun sets in the west, the summer heat is still gone. Unlike Shanghai, although it is very hot during the day, there is a cool breeze at night to cool off the heat. Even if there is a little wind in these places, it is uncomfortable to be hot.

So, why are these places so hot? The main reason why Chongqing and Wuhan are particularly hot in summer is the influence of topography. These two places are located in the valley basin of the Yangtze River basin, surrounded by mountains, with a small plain in the middle, and the terrain is quite closed. The southeast wind blowing from the ocean was blocked by many mountains and hills on the way to these basins, and a considerable part of the water vapor turned into rain. When it reached the basin, there was not much water vapor. In addition, it blows from the mountains to the basin and from high to low. Instead of condensing into rain, the airflow is getting drier and hotter. There are fewer clouds and more sunny days in the basin, and the solar radiation is particularly strong.

Another reason is that the wind speed in the basin is very small (the average wind speed in Chongqing in July is 1. 1 m/s, and that in Wuhan is 2.2 m/s). ) is not conducive to ventilation, the hot air in the basin is difficult to disperse, which aggravates the summer heat.

Besides Chongqing and Wuhan, Jiujiang is particularly hot in summer for similar reasons.

As for the reason why Nanjing is particularly hot in summer, it is mainly because the rainy season in July in midsummer has passed, and the weather is fine and the sunshine is strong. At the same time, it has been under the control of subtropical high (that is, the tip of Pacific high) for a long time, and there is downdraft at high altitude. In addition, it is located in the Yangtze River basin, surrounded by hills, and the geothermal energy is not easy to be lost, and the climate is hot.