Summer afternoon or early evening often gives us an unusually hot feeling. Moments later, suddenly, thunder rumbled, then flashed, the torrential rain, immense, the sky was like anger. But a moment after the thunder passed, the dark clouds disappeared, the sky was blue, the clouds were free, unusually quiet and beautiful, the air was extremely fresh. These are showers, a common weather phenomenon in the summer.
Thunderstorms are due to the hot air in summer; strong local convection currents appear in the air, making the hot and humid air rise very strongly, forming rain clouds.
Summer in the air has a lot of water vapor. When the ground is intensely heated by the sun, the temperature rises, and the air rises rapidly. The water vapor pushed up by 1-2 km high will form large clouds. At that time, we often see each layer of clouds rolling like a layer of cotton flying in the air, which are clouds of clouds, the precursors of clouds that accumulate rain. The air kept rising, causing these clouds to thicken and grow, turning into dense clouds constantly. At that time, if meeting the appropriate conditions, the clouds’ density is continuously developing, flying up to a height of 7-10 km, forming clouds that accumulate rain. At this height, because the air layer is stable or when there is not enough growth in flying higher, the cloud will grow on four sides. Before a thunderstorm occurs, it is common to see dark clouds in the sky thickening and to grow very rapidly, just a few moments later spreading across the sky.
For in this layer of thousands of cumulative rain meters, large amounts of water vapor, small raindrops, and ice crystals are stored, in which small water droplets and ice crystals grow larger and larger with the clouds. When the rising air does not support them anymore, the rain will fall. Falling through relatively high-temperature clouds, large drops of water in it will form raindrops, and large ice crystals will turn into snow, then melt into thunderstorms.
Because the rainy clouds’ convective heat is very strong, it is easy for thunderstorms in the summer to happen. Also, because the convection heat violently disturbs the rain cloud accumulations, lightning often occurs. Moreover, because the convection airflow is strong and weak, so when one cloud accumulates rain to pass, another cloud comes, causing big and small rain, hence the name thunderstorm.
On the mainland, afternoon, the air temperature is the highest. The air movement goes up very strongly at that time, so thunderstorms usually arise afternoon or early evening.
In the sea, because of the large heat capacity of seawater and the solar heat absorbed by the seawater, it can be transferred to deeper water layers. So during the day, the air layer’s temperature close to the water surface is not high; the whole floor is not. The gas is extremely stable, not easy to produce thunderstorms caused by convection gas. At night, the air layer in the upper layer becomes cooler. In contrast, the air layer is close to the water surface due to its effect; the temperature is higher than the air in the upper layer. Hence, the air becomes unstable, creating convection forming thunderstorms. Therefore, it can be seen that it rains mostly during the day in the continent, and on the sea it rains mostly at night.