Why is the air pressure higher in sunny days than in cloudy days and higher in winter than in summer?

The air density is small, so the air pressure is high on sunny days and low on cloudy days. In winter, the air is dry and cold with low humidity, low water vapor content and high air density, while in summer, the air humidity is high and the water vapor content is high.

Although air is a mixture containing many gases, it can be simply divided into two parts: water vapor and other dry air without water vapor. When the atmospheric change is regarded as a quasi-static process without heat exchange, that is, the formation of clouds, rain and snow is not considered, the pressure generated by these two parts adds up to form atmospheric pressure, which is the sum of the weight of water vapor in the above-mentioned gas column and the weight of dry air. ?

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Under normal circumstances, the ground continuously radiates long waves to the atmosphere effectively, and the atmosphere is also constantly radiating back to the ground. 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 role of clouds in protecting the surface and heating the liquid layer.

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. ?

In the same place, atmospheric pressure is not static, it changes with time. In a day, atmospheric pressure is usually the highest at 9 am and the lowest at 3 pm. The air pressure values are also different throughout the year. On the mainland, the air pressure is the highest in winter and lower in summer. On the contrary, the sea and mainland have higher air pressure in summer and lower air pressure in winter.

People's Network-Quanzhou dog days continue to be hot and sunny, and the public pays attention to heatstroke prevention and cooling.

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