Low latitude ocean surface!
Typhoons mostly form on the tropical ocean surface. In some sea areas, typhoons are more frequent and more abundant. For example, in the northwest Pacific Ocean where Taiwan is located, typhoons may form throughout the year; In some sea areas, such as the southeastern Pacific and South Atlantic, typhoons rarely form because the sea temperature is too low. The precursors of typhoons are tropical cumulus cloud clusters with strong convection. However, monitoring results show that only a few of the numerous cumulus cloud clusters can develop into typhoons. In other words, tropical cumulus cloud clusters must be under favorable environmental conditions before they can further intensify into typhoons. From a climate perspective, the generation of typhoons is related to at least the following five conditions:
Seawater surface temperature: Seawater surface temperature should be higher than 26°C. Generally speaking, if the sea surface temperature is lower than 26°C, typhoons are less likely to form; higher sea temperatures can provide more energy to cumulus cloud clusters, which is conducive to the formation of typhoons.
Water vapor content in the middle and lower atmosphere: The middle and lower atmosphere must be humid enough. If the air in the middle and lower layers is too dry, it will limit the development of convective cloud systems and be detrimental to the generation of typhoons.
Changes in the wind field with height: The environmental wind field cannot change much with height, because before a typhoon forms, strong convection must continue to develop upward. If the environmental wind field changes too much with height, It will limit the vertical extension of convection and be detrimental to the generation of typhoons.
Atmospheric instability: The higher the convective instability of the ambient atmosphere, the more it can lead to strong convection, which is conducive to the generation of typhoons.
Location of cumulus cloud clusters: Low latitude areas that are too close to the equator. Due to the effect of the earth's rotation, it is difficult for the airflow to rotate. Therefore, typhoons generally rarely form in the equatorial areas within 5 degrees of latitude.