Why is the air pressure lower in rainy days than in sunny days?

On sunny days, the heat on the ground can be transported to the outside through the effective radiation and upward divergence of the convective gas layer.

On cloudy days, clouds reduce the outward divergence of troposphere atmosphere. The effect of clouds on preserving the surface and heating the liquid layer is called "greenhouse effect".

The atmospheric expansion in cloudy areas is more intense, which leads to the lateral outward diffusion of the atmosphere in cloudy areas and reduces the density of the air. At the same time, the atmospheric humidity in cloudy areas is high, which also reduces the density of the atmosphere. Due to these two factors, the air pressure on cloudy days is lower than that on sunny days.

Atmospheric pressure is the result of the earth's gravity. Due to the gravity of the earth, the atmosphere is "sucked" to the earth, producing pressure, and the atmospheric pressure near the ground is the highest. Atmospheric pressure in meteorological science refers to the weight of atmospheric column per unit area (atmospheric pressure), that is, the pressure exerted by atmospheric column per unit area. So why is the air pressure lower in rainy days than in sunny days?

Atmospheric pressure under normal conditions:

Scientifically, the pressure generated by a mercury column (mercury column) with a height of 760mm or a quintic Pascal 1.0 13× 10 is called 1 standard atmospheric pressure, which is abbreviated as atmospheric pressure. ?

Standard atmospheric pressure: 760mmhg or1.013x105pa.