What could be the main reason(s) for the formation of African and Eurasian desert belt?
- It is located in the sub-tropical high pressure cells.
- It is under the influence of warm ocean currents.
Which of the statement(s) give above is/are correct in this context?
[UPSC Civil Services Exam – 2011 Prelims]
(a) 1 only
(b) 2 only
(c) Both 1 and 2
(d) Neither 1 nor 2
Answer: (a)
Explanation:
- The natural zones located in the tropical belts of both the northern and southern hemispheres are primarily deserts. These zones can be found in the interior and along the western coasts of most continents.
- Subtropical deserts are caused by the circulation patterns of air masses. They are located between 15 and 30 degrees north or south of the Equator, along the Tropic of Cancer or the Tropic of Capricorn. Hot air rises from the Equator, cools, and drops its moisture as heavy tropical rains. The resulting cooler, drier air mass moves away from the Equator and descends, warming up as it approaches the tropics.
- The descending air hinders cloud formation, resulting in little rainfall. Around 30 degrees north or south, the air begins to descend toward the surface in subtropical high-pressure belts. Since the African and Eurasian desert belt lies in the sub-tropics, statement 1 is correct.
- Desert zones in tropical regions have a diverse relief, shaped by physical weathering and eolian accumulation. The aridest deserts, such as the Sahara and Arabian deserts, consist of vast expanses of gravel, sand, stone, and salt, almost completely devoid of vegetation, except along intermittent streams and in the foothills of mountain ranges. Cold ocean currents do not directly contribute to desert formation in west coast regions of the tropical and subtropical continents. Hence, statement 2 is not correct.
Therefore, option (a) is the correct answer.
