The blade froze a natural scene.

Frost on the blade (a meteorological word) answer: cold front

Extended application

Cold front refers to the front formed by the active movement of cold air mass to warm air mass. Cold front is the most common front in China, which can be moved to all parts of the country. Because of 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 obviously different, and some of them mainly appear behind the front; Others mainly appear in the front.

Brief introduction of weather:

Cold front is the abbreviation of cold air front, which is the Depth Charge where the cold air mass moves south, and it is the most common weather system that affects our country, especially in winter. Every few days in winter, there will be a cold air invading the inland from northwest and north China.

When the cold front crosses the border, it will be accompanied by the increase of northerly wind, the increase of air pressure and the decrease of temperature, sometimes causing rain and snow, and even causing heavy rain in summer. Under normal circumstances, after the cold front crosses the border, the local area will be controlled by cold high pressure and the weather will become clear.

During the front movement, the cold air mass plays a leading role, pushing the front to move to one 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.

Because cold air is heavy and warm air is light, when the cold air mass moves, it will form a cold air mass that actively wedges under the warm air mass, forming a front at the junction of cold and warm air. When a cold front crosses the border, cumulonimbus clouds, thunderstorms and heavy precipitation often occur. If the cold front moves fast, cumulonimbus clouds are distributed in the narrow area in front of the front, and then it will turn from local cloudy to sunny quickly after the front; If the cold front moves slowly, it will form a large range of high-level clouds and nimbostratus.

Weather characteristics

A cold front with fast moving speed and steep slope (1/40- 1/80). The cold air behind the front moves much faster than the warm air mass, affecting the warm air mass and forcing it to rise strongly. On the other hand, at the top floor, because the warm air mass moves faster than the cold air, the warm air slides down the front. Because this front is located behind the trough or near the trough line, the rising movement near the front and the sinking movement in the upper front area are further strengthened.

In summer, strong cumulonimbus clouds usually appear near the ground front of this cold front, and convective unstable weather such as thunderstorm, hail and squall line appears. At the top, there are often no clouds. Therefore, the fast-moving cold front cloud system presents a long and narrow accumulation cloud belt arranged along the front line. The fast-moving cold front lasts for a short time, and this cold front weather mostly occurs in winter and spring in northern China.