The formation of hurricanes, also known as tropical cyclones or typhoons depending on the region, is a complex process that involves various factors. While hurricanes do not technically “start” in Africa, the continent can play a role in their formation through a phenomenon known as the African Easterly Jet (AEJ) and African easterly waves. Here, we will explore how these factors contribute to the formation of hurricanes and their potential connection to Africa.
African Easterly Jet (AEJ): The African Easterly Jet (AEJ) is a high-altitude wind flow that occurs in the tropics over Africa, particularly during the summer months. The AEJ is formed due to the temperature differences between the Sahara Desert and the Gulf of Guinea, resulting in a pressure gradient that drives strong winds from east to west at high altitudes (around 10-15 kilometers above the Earth’s surface).
The AEJ can influence the formation of hurricanes by creating favorable conditions for their development. The strong winds of the AEJ can help to create a disturbance in the atmosphere, known as an African easterly wave, which is a type of atmospheric wave that can travel westward from Africa towards the Atlantic Ocean. These easterly waves can serve as a triggering mechanism for the formation of tropical cyclones, as they can initiate the process of gathering energy and moisture from the warm ocean waters.
African Easterly Waves: African easterly waves are elongated areas of low pressure that form along the AEJ and can travel westward across the Atlantic Ocean. These waves can stretch for thousands of kilometers and can persist for several days to weeks. As they move over the warm waters of the Atlantic Ocean, they can serve as a focal point for the development of thunderstorms and convection.
When these thunderstorms and convection persist and organize around the area of low pressure, they can begin to develop a circular motion and gather energy from the warm ocean waters. This can lead to the formation of a tropical depression, which can further intensify into a tropical storm and eventually a hurricane, under favorable environmental conditions such as warm ocean temperatures, low wind shear, and high atmospheric moisture.
The Role of Africa in Hurricane Formation: While Africa, particularly the AEJ and African easterly waves, can play a role in the formation of hurricanes, it’s important to note that hurricanes do not technically “start” in Africa. The process of hurricane formation is complex and involves various factors, including the interaction between the atmosphere and ocean, the Coriolis effect (due to the rotation of the Earth), and other atmospheric conditions.
The AEJ and African easterly waves are just one piece of the puzzle in the formation of hurricanes. Other factors, such as ocean temperatures, wind shear (the change in wind speed and direction with altitude), atmospheric stability, and moisture availability, also play critical roles in the formation and intensification of hurricanes. Additionally, the exact mechanisms and pathways of how African easterly waves evolve into hurricanes are still a subject of ongoing research and study in the field of meteorology and atmospheric science.
It’s also important to note that not all African easterly waves develop into hurricanes. Many of them do not have the necessary environmental conditions to intensify into tropical cyclones, and they may dissipate or weaken before reaching the Atlantic Ocean. Additionally, hurricanes can also form from other sources, such as tropical waves that originate from other parts of the tropics or even from pre-existing tropical cyclones that move into the Atlantic from other ocean basins.
