What is a weather phenomenon?

Weather is the general name of atmospheric conditions (such as cold and warm, wind and rain, dry and wet, sunny and so on). ) and its changes in a short time in a certain area. Weather phenomenon usually refers to the atmospheric movement phenomenon with typical characteristics such as high pressure, low pressure, high pressure ridge and low pressure trough, which causes weather change and distribution. All kinds of weather phenomena have certain time and space scales, and various scale systems are intertwined and interact with each other. The combination of many weather systems constitutes a large-scale weather situation and hemispheric and even global atmospheric circulation.

Weather phenomena are always in the process of birth, development and extinction, and there are corresponding weather phenomena in different stages of development. Therefore, the weather and weather changes in a region are related to the weather system and its development stage, and are the comprehensive results of atmospheric dynamic and thermal processes.

All kinds of weather phenomena are formed, developed and evolved in a certain atmospheric circulation and geographical environment, and all reflect the environmental characteristics of a certain region. For example, the polar regions and their surroundings are covered with ice and snow all year round, and the air is cold and dry. This unique geographical environment has become the background condition for the formation and development of polar low-altitude cold high pressure and high-altitude polar vortex and low trough. It is a necessary condition for the emergence and development of convective weather system that the equatorial and low latitudes are hot and humid all the year round and the atmosphere is unstable. Mid-high latitudes are areas where cold and warm air currents often cross. Cold and warm air masses not only come and go frequently, but also have unstable baroclinic, which is an important basis for the formation and development of frontal and cyclone systems. The formation and activities of weather phenomena will in turn have a profound impact on the structure and evolution of geographical environment. Therefore, understanding the formation, structure, movement and change of weather phenomena and their relationship with geographical environment is of great significance for understanding the formation, characteristics and change of weather and climate and predicting the evolution of geographical environment.