Meteorological characteristics of tropical meteorology

The tropical earth-atmosphere system gets net heat, almost all of which is absorbed by the surface, but the atmosphere above it is still dissipating heat. Only a small part of the heat obtained from the surface is directly transmitted to the atmosphere through turbulence, and most of it is converted into latent heat through the evaporation of water on the surface (ocean surface), and then released into the atmosphere through the condensation process of water vapor in the atmosphere.

Due to the high temperature and humidity in the tropical lower atmosphere, the middle and lower atmosphere in tropical areas is often in an unstable state (see atmospheric static stability), forming a unique tropical cloud cluster (see tropical cloud cluster). The occurrence and development of strong tropical weather systems such as typhoons are closely related to the activities of such clouds.

The tropics are located at low latitudes, and the Coriolis parameters (f=2ωsin, ω is the angular velocity of the earth's rotation, ω is the latitude) are very small (see forces in the atmosphere). This dynamic feature makes the horizontal pressure gradient force of tropical atmosphere very small when there is no large-scale strong convection rising, that is, the horizontal gradient of pressure field is smaller than that of middle and high latitudes, but the horizontal difference of flow field is very obvious. When a weather system occurs, the vortex, convergence and divergence of the flow field, as well as the horizontal shear and vertical shear of the wind often appear first, and the characteristics of the pressure field gradually become obvious after strong convection. Compared with the middle and high latitudes, the change of tropical flow field is more important.