The reason why the air pressure measured on cloudy days is smaller than that measured on sunny days

Atmospheric pressure is closely related to weather changes. If the atmospheric pressure in a certain place is high, the atmosphere in this area flows horizontally to the surrounding low-pressure area, and the air above it drops, the temperature rises, and the water droplets in the air evaporate and dissipate, so it is often sunny. On the contrary, rainy days often occur in low-pressure areas.

Generally speaking, the water vapor content in sunny days is less than that in cloudy days, and that in winter is less than that in summer. Under normal circumstances, the density of water vapor is much smaller than that of air. According to the law of liquid internal pressure p = p=ρgh:

Let P Yin and P Qing be the atmospheric pressure on cloudy and sunny days respectively, and P Yin and P Qing be the atmospheric density on cloudy and sunny days respectively.

Yin = ρ Yin gh 1

P fine = ρ fine gh2

In the same geographical location

∴g=g,h 1=h2

∵ ρ Yin

Yin < p clear.

Similarly, pSummer < pWinter.

According to the above analysis, in the same place, generally speaking, the air pressure in sunny days is higher than that in cloudy days, and that in winter is higher than that in summer.