What is the cause of the heat wave?

(1) At present, the direct cause of heat wave formation is the anticyclone or high-pressure ridge phenomenon in the weather. The anticyclone causes the climate to be dry, which means that all heat waves will cause the temperature to rise without evaporating water. If there is a wet situation, such as the ground is wet, then to some extent, the ground plays the role of air conditioning.

There is a causal relationship between high temperature and heat wave. High temperature is the result of heat wave, and heat wave is the cause of high temperature formation, but it does not mean that all high temperatures are caused by heat wave attacks. For example, in the middle and lower reaches of the Yangtze River, hot and humid weather often occurs in midsummer under the control of the western Pacific subtropical high.

(2) Global warming and heat island effect are the main causes of heat waves. Global warming is the background of frequent high temperature and heat wave events in the northern hemisphere and China in summer. In the past century, the earth's climate is undergoing significant changes characterized by global warming. This global warming is caused by natural climate fluctuation and human activities.

The heat island effect caused by urbanization strengthens the severity of extreme high temperature events. With the rapid development of economy and the acceleration of urbanization, population, production and transportation are concentrated, industrial production, domestic stoves, internal combustion engines and motor vehicles consume energy, and at the same time, there is a certain amount of waste heat emission, which increases a lot of extra heat income in the city. At the same time, urban planning and construction have changed land use and reduced vegetation. The heat island effect brought by urbanization has also aggravated the extreme high temperature.