How do dark clouds form? Are there dark clouds in the picture below?

Dark clouds are mainly formed by the condensation of water vapor in humid air.

1. The formation process of clouds is a process in which water vapor in the air reaches a saturated or supersaturated state through various reasons and condenses. Saturating the water vapor in the air is a necessary condition for the formation of clouds. The main methods are: (1) The water vapor content remains unchanged and the air cools down; (2) The temperature remains unchanged and the water vapor content is increased; (3) The water vapor content is increased, Lower the temperature again.

2. But for the formation of dark clouds, the cooling process is the most important process. In the cooling process, the cooling effect caused by rising motion is the most common.

3. The specific formation process of dark clouds is that surface water evaporates rapidly under the scorching sun in summer, causing the air humidity to increase. However, the temperature at high altitude is lower than the surface temperature, so the water vapor first reaches saturation at high altitude. state and supersaturation state. There is always some dust in the high altitude. When these dust and water vapor meet, they form water mist. When the temperature is low enough, it condenses saturated steam and supersaturated steam into fine droplets. When the droplets are dense enough, they become visible to the naked eye. The white clouds and fog droplets become larger and larger, and the white clouds turn into dark clouds.