The Dominance of Weather Change-How is Air Mass Formed?

When you take a boat down the Yangtze River in the crisp autumn season, you will feel the sky is high and the clouds are light, the wind is beautiful and the air is pleasant. Why is this? It turns out that this area is in the same air, and the temperature, humidity and weather are similar. People call this large area of air with uniform physical properties an air mass. Air masses can be divided into cold air masses and warm air masses according to the different degrees of cold and warm in their moving areas.

Different air masses will form different weather. For example, when a cold air mass in the north moves south, the area it passes through is warm and humid, so the temperature of the air mass rises gradually and the water vapor in the air mass increases, which often leads to rainy weather.

Air pressure system How are the ever-changing winds on the earth formed? And why does the wind blow from high pressure to low pressure? This is about finding the answer from the air pressure system.

The pressure system, that is, the isobar, represents the high pressure area and the low pressure area. It can be divided into high pressure, low pressure, high pressure ridge and low pressure trough. On a curved isobar plan, we can know that the area where the isobar is closed is called high pressure if the air pressure is higher than the surrounding area; On the contrary, it is low pressure. In the high pressure area, the airflow is affected by the rotation of the earth, and the northern hemisphere is to the right, but the southern hemisphere is opposite. The weather in high-pressure areas is often sunny and rainy. The air in the low-pressure area rises, often accompanied by clouds, rain and strong winds. The wind is formed by this kind of airflow. On the plane with the same height, the central air pressure is higher than the air pressure around three sides, but lower than one side, which is called "high pressure ridge"; On the contrary, it is called "low pressure trough".