Why does it rain so much at night in the Sichuan Basin? What is the temperature inversion phenomenon in the basin?

It rains frequently at night in the Sichuan Basin, mainly because the air in the basin is humid and the sky is cloudy. Clouds cover part of the sun's radiation, so the temperature under the clouds is less likely to rise during the day and convection is less likely to develop. Clouds at night can absorb heat radiated from the ground and then transfer the heat to the ground in the form of back radiation, so the clouds have a warming effect on the ground, which keeps the temperature under the clouds from being too low at night. However, the cloud itself is good at radiation and heat dissipation. The temperature of its upper layer drops rapidly due to radiation heat dissipation, which creates a significant temperature difference between the upper and lower parts of the cloud layer. As a result, convection and churning will occur in the upper and lower air, causing clouds to develop and rainfall to occur.

The temperature inversion phenomenon in the basin belongs to the topographic inversion. Topographic inversion refers to the fact that due to radiation cooling in low-lying areas (valleys and basins), cold air sinks along the slopes and flows into the low-lying areas to form a temperature inversion, which is called topographic inversion. temperature. Topographic inversion: mainly caused by topography, mainly in basins and valleys. Because the hillside dissipates heat quickly, the cold air sinks along the hillside to the valley bottom. The original warm air at the valley bottom is pushed up by the cold air, resulting in an inversion of temperature.