How long will the cold air in China last? When will it pick up? What is the temperature after recovery?

Subtropical high, referred to as subtropical high, is a warm and high pressure system located in subtropical areas. It plays an important role in the transport and balance of water vapor, heat and energy between middle and high latitudes, and is an important system of atmospheric circulation. The eastern part of the subtropical high is a strong subsidence movement area, and the descending airflow becomes warmer due to adiabatic compression, and there will be continuous sunny and hot weather in the control area. The western part of subtropical high is the convergence and rising area of low-level warm and humid air, which is prone to thunderstorm weather. With the change of seasons, the intensity and location of subtropical high will also change obviously between seasons. From June 65438 to July, the main body of subtropical high moved to the north-west and its intensity increased. In July-65438+10, the main body of the subtropical high moved from south to east, and its intensity weakened. This seasonal change also has obvious stages of slow change and sudden change.

Warm high pressure in the subtropical zone. It is located near 30 degrees north and south latitude. This high-pressure belt is the dividing line between the prevailing westerly belt and the easterly belt, and the westerly belt is on the high latitude side. Controlled by subtropical high, the weather is fine, and its northwest side is the southwest airflow jump control area (over-rain area). The high pressure between tropical and temperate zones is called subtropical high, which is usually called the Pacific subtropical high that controls the Pacific region. It generally moves between10 ~ 40 N with seasonal changes.

The subtropical high in the western Pacific, especially the high ridge in the west, has an important influence on the weather and climate in China. Its range is on the 500 hectopascal diagram, which is indicated by line 588. Its position and intensity change with the seasons. The change of its position: north-south direction, represented by the average latitude of subtropical ridge line. From June to August, the average ridge line is located at 24 north latitude. The east-west direction is expressed by the longitude of the west extension of line 588, which is located at east longitude 122 on average. The intensity and location of the western Pacific subtropical high have obvious seasonal variations. Before June every year, the ridge line of subtropical high is located in the south of 20 north latitude, and the northern edge of high pressure is the area where warm and humid airflow along the ridge line of subtropical high meets cold air south of mid-latitude. Frequent frontal and cyclone activities lead to a wide range of rainy weather, which affects the rainy season in South China. By the middle and late June, the subtropical high ridge jumped northward, stabilized at 20 ~ 25 north latitude, and the rain belt moved northward, and the middle and lower reaches of the Yangtze River entered the rainy season, that is, Meiyu; In early and middle July, the ridge line of subtropical high jumped northward again, swinging at 25 ~ 30 north latitude, and the lower reaches of the Yellow River entered the rainy season. Meiyu in the middle and lower reaches of the Yangtze River ended and entered midsummer. Due to the control of high pressure ridge, there is a summer drought; From the end of July to the beginning of August, the subtropical high ridge crossed 30 north latitude to reach the northernmost position in a year, and the rain belt moved northward, and the northern and northeastern parts of North China entered the rainy season. At the end of August or early September, the ridge of high pressure began to withdraw southward, and the rain belt moved southward. After 10, the ridge of high pressure retreated to the south of 20 north latitude, and the rainy season ended in most areas. As can be seen from the above, the seasonal activities of the western Pacific subtropical high are characterized by long duration and slow moving speed when it advances northward in summer, and short time and fast moving speed when it withdraws southward in autumn. The activities of subtropical high in the western Pacific vary greatly from year to year. When its activity is abnormal, it will often cause large-scale drought and flood disasters in China.

The subtropical high will affect the temperature in the area it controls. First, equatorial low is thermal low, subtropical high is dynamic high, subtropical low is dynamic low, and polar high is thermal high.

The equatorial depression caused by "thermal depression" makes the air flow rise from the equator to the high altitude and flow to the polar high pressure. Regardless of the friction with the ground, under the action of geostrophic deflection force (the vertical airflow direction in the northern hemisphere is right, while the southern hemisphere is opposite), the final airflow direction is parallel to the latitude around 30 degrees, which hinders the airflow movement and leads to air accumulation, thus forming a dynamic high pressure-subtropical high. Because of the high latitude,