Weather system of tropical climate

Tropical area is the convergence and rising area of airflow. Such thermal and dynamic conditions are conducive to the vigorous development of convective clouds and their aggregation into huge clouds. It is the background and condition for the occurrence and activity of disastrous weather system.

Intertropical convergence zone and intertropical convergence zone are narrow convergence zones formed by the confluence of trade winds in the northern and southern hemispheres, also known as equatorial convergence zones. Because the pressure value of convergence zone is lower than that of nearby areas, it was once called equatorial trough. Intertropical convergence zone is one of the important large-scale weather systems in tropical areas, and it is distributed in discontinuous bands around the earth. Its fluctuation, intensity, movement and change have great influence on the long, medium and short-term weather changes in tropical areas.

The second easterly wave is caused by the disturbance of the deep easterly airflow on the south side of the subtropical high (northern hemisphere). Generally, the wavelength is1000 ─1500 km+0500 km, the elder is 4 000 ─5 000km, and the extension height is generally 6-7 km, and some of them reach the tropopause. The maximum intensity occurs between 700 and 500 hectopascals. The cycle is 3-7 days. The moving speed is about 20-25 km/h, and the easterly wave is generally characterized by shear between the northeast wind and the southeast wind. Its structure varies from region to region. In the western Atlantic and Caribbean, the easterly wave is inverted V-shaped, and the wave axis inclines eastward with height. The northeast wind blows in front of the trough and the southeast wind blows behind the trough. There is a divergent downdraft area in front of the trough, and the wet layer is thin, only some small cumulus clouds or clear skies are generated. There is a convergent updraft area behind the trough, a large amount of water vapor is transported upwards, and the wet layer is thick, forming clouds and rain.

Three Tropical Clouds It is found from satellite cloud images that there are a large number of deep cloud areas in tropical areas, which are composed of convective clouds with a diameter within the range of 100 ─ 1000km, and are called cloud clusters. It is difficult to analyze the weather system corresponding to the cloud cluster on the weather map, but most weather systems such as easterly wave and tropical cyclone are developed on the basis of the cloud cluster. Strong winds and heavy rains often occur in areas where clouds pass. Cloud clusters can be divided into three types according to their scale and production area: □ monsoon cloud cluster, named after the southwest monsoon activity, is the largest cloud cluster on the earth.