What atmospheric phenomenon contributes to the existence of many deserts between 20 degrees and 35 degrees latitude?

The existence of many deserts between 20 degrees and 35 degrees latitude is primarily attributed to sinking air associated with the Hadley cell. In the Hadley cell circulation, warm air rises near the equator, cooling as it moves poleward. As this air cools, it descends around 20 to 30 degrees latitude in both hemispheres. This sinking air creates high-pressure regions that inhibit cloud formation and precipitation, leading to arid conditions typical of deserts.

The mechanics of this process are essential in explaining desert formation. When the warm air rises, it holds moisture; upon cooling, the moisture condenses and falls as rain in the tropics. However, when this air descends, it warms again, increasing its capacity to hold moisture without condensing, resulting in dry air and minimal rainfall in the subtropical regions, which is characteristic of many deserts.

Understanding this process highlights why this particular atmospheric phenomenon is critical for desert existence, especially in the latitudinal bands mentioned. The other options, while related to atmospheric dynamics, do not specifically account for the desert formation in the same manner as the sinking air of the Hadley cell.