What are the weather characteristics controlled by cyclones and anticyclones? Why?
Weather characteristics under cyclone control: cyclone transit, low pressure control, rainy weather, typhoon disaster; violent storms, tropical cyclones.
Reason: The ground is unevenly hot and cold. When the ground is hot in a certain place, the air expands and becomes less dense when heated, so the airflow rises and low pressure is formed near the ground. The surrounding relative air pressure is high, so the airflow flows from high pressure to low pressure, that is The flow from the surroundings to the center (the center is rising) forms a cyclone.
2. Weather characteristics under anticyclone control: anticyclone transit, high pressure control, clear weather, crisp autumn air, cold wave in winter and drought in summer.
The reason is that when a certain ground is cold, the air expands and shrinks in density when it encounters cold, forming high and low pressures near the ground, and the surrounding relative air pressure is low, so the airflow flows from high pressure to low pressure, that is, from the center to the surroundings (the center sinks and rises) ) forms an anticyclone.
Low pressure or cyclone, high pressure or anticyclone are different descriptions of the same weather system. Cyclones and anticyclones describe the airflow conditions of weather systems; low pressure and high pressure describe the pressure conditions of weather systems. Because there are significant differences in air pressure and airflow conditions between cyclones and anticyclones, the weather conditions in the areas they control are also different.
A cyclone refers to a large vortex in the northern (southern) hemisphere where the horizontal airflow in the atmosphere rotates counterclockwise. At the same height, the air pressure at the center of a cyclone is lower than that around it, also known as low pressure. It appears as a low-pressure area surrounded by closed isobars on the contour map, and as a low-pressure area surrounded by closed contours on the isobaric map. Cyclones are approximately circular or oval in shape and vary in size. The horizontal scale of small cyclones is several hundred kilometers, and large ones can reach three to four thousand kilometers. They are synoptic-scale weather systems. In cyclones, the weather often changes dramatically, and it is the weather system that people are most concerned about and the earliest to study.
Anticyclone refers to a horizontal air vortex in which the central air pressure is higher than the surrounding air pressure. It is also the high pressure in the air pressure system. In the Northern Hemisphere anticyclone, the low-level horizontal airflow diverges outward in a clockwise direction, while in the Southern Hemisphere anticyclone, the low-level horizontal airflow diverges outward in a counterclockwise direction. The horizontal scale of anticyclones is larger than that of cyclones. For example, the Mongolia-Siberia High in winter occupies 1/4 of the Eurasian continent. The central pressure value of each anticyclone is generally around 1020-1060hPa, with the highest pressure record reaching 1101.6hPa. The wind speed of an anticyclone is small, the maximum wind speed on the ground is only 20-30m/s, and the wind in the central area is weak. The weather will be mostly fine under the control of the anticyclone.