___ is greatest near equator where air usually rises
Heat
The atmospheric phenomenon you are referring to is known as the Intertropical Convergence Zone (ITCZ). The ITCZ is a low-pressure belt that encircles the Earth near the equator, typically between 5 degrees north and south of the equator. It is characterized by the convergence of trade winds from the Northern Hemisphere and Southern Hemisphere.
The ITCZ is associated with the rising of warm, moist air near the equator. Due to intense solar heating, the air at the equator becomes heated and starts to rise. As it rises, it cools and condenses, forming clouds and precipitation. This upward motion of air creates an area of low pressure and relatively calm winds, making it an ideal location for the formation of thunderstorms and rain.
To understand why the air rises near the equator, we need to consider the basic principle of atmospheric circulation. The equator receives more solar radiation compared to the poles because the sun's rays are more direct. This leads to greater heating of the surface, warming the air above it. Warm air is less dense than cool air, so it tends to rise. As it rises, cooler air from the surrounding areas moves in to replace it, creating a region of converging air near the equator.
In summary, the air is greatest near the equator because of the intense solar heating, which leads to the rising of warm, moist air and the formation of the Intertropical Convergence Zone.