In the tropics, the stratosphere is:

• A. Hotter than in the middle latitudes
• B. Colder than in the middle latitudes
• C. Similar to the middle latitudes
• D. More variable than in the middle latitudes

Answer: (B)

In the tropics, the stratosphere is colder than in the middle latitudes primarily due to the distinct temperature profile that characterizes the stratospheric layer. As one moves higher in altitude within the stratosphere, temperatures generally increase because of the absorption of ultraviolet (UV) radiation by ozone. However, this warming effect varies significantly between tropical regions and middle latitudes.

In the tropics, the height of the tropopause is higher—often reaching altitudes around 16 to 18 kilometers (approximately 52,000 to 60,000 feet)—which allows for greater stratification and cooling processes at higher altitudes. The air is often drier and has a more stable temperature profile in the stratosphere, which leads to less mixing and cooler temperatures compared to the middle latitudes. In contrast, the middle latitudes experience more variable weather patterns, with significant mixing that can influence temperature distributions. This dynamic results in the stratosphere being relatively cooler in the tropics compared to regions at middle latitudes.