Let me explain to you using physics knowledge. Strong convection is actually a weather phenomenon caused by strong vertical movement of air. The most typical one is the strong convective weather in summer afternoons: During the day, the ground continuously absorbs short-wave radiation emitted by the sun, causing the temperature to rise, and emits long-wave radiation to heat the atmosphere. When the air near the ground receives enough heat from the earth's surface, it expands and decreases in density. At this time, the atmosphere is in an unstable state.