What is the weather?

The cold front at the front of common climate phenomena is represented by lines and (black) triangles.

The cold front is represented by a line plus a (black) triangle, which is added to the side of the warm air mass, and the rain area of the cold front is behind the front.

frontier

A narrow transition zone separating cold and warm air masses. This transition zone inclines from the ground to the side of high-altitude cold air mass. The width of the transition zone is only a few tens of kilometers near the ground, and it can reach 200-400 kilometers to the top. The length of the front can generally be several hundred kilometers to several thousand kilometers, and it can extend more than ten kilometers vertically. In this transition zone, the temperature changes greatly.

According to the thermodynamic classification method, if a cold air mass actively pushes a warm air mass, it is called a cold front. On the contrary, it is called warm front. If the cold and warm air masses are equal, it is called quasi-static front stop. If the cold front catches up with the warm front, it will form a closed front.

Cold front: During the movement of the front, the cold air mass plays a leading role, pushing the front to move to the side of the warm air mass. This front is called a cold front. After the cold front crossed the border, the cold air mass occupied the original position of the warm air mass. China has Lingfeng all year round, especially in winter. During the movement of cold air, behind the main front, that is, in the same air mass, a secondary front can be formed due to different degrees of denaturation or a small cold air supplement to the south. Generally speaking, the temperature difference between the two sides of the main front is large, and the temperature difference between the two sides of the secondary front is small. After the cold front crossed the border, the temperature dropped, the air pressure rose and the weather turned fine.

Warm front: when the front is moving, if warm air plays a leading role, it will push the front to move to one side of the cold air mass. This front machine is called warm front. After the warm front crossed the border, the warm air mass occupied the position of the original cold air mass. Warm fronts are mostly active in northeast China and the middle and lower reaches of the Yangtze River, and are mostly accompanied by cold fronts. After the warm front crossed the border, the temperature rose, the air pressure dropped, and the weather turned cloudy and rainy.

Quasi-static front: when the cold and warm air mass is quite strong and the front moves slowly, it is called quasi-static front. In fact, there is no absolute stillness. During this period, the cold and warm air masses are also fighting each other. Sometimes the cold air mass dominates, and sometimes the warm air mass dominates, making the front swing back and forth.

Blocking front: two fronts formed when a warm air mass, a cooler air mass and a cooler air mass (three air masses with different properties) meet, and then one front catches up with the other, that is, blocking is formed.

What is a cold front?

Cold front is the most common front in China, which can be moved to all parts of the country. However, due to the different configurations and moving speeds of the cold front and the upper trough, the distribution of clouds and precipitation near the cold front is also obviously different, and some mainly appear behind the front; Others mainly appear in the front.