Correct Option
The correct option isThe moderating influence of the sea is absent in the Thar Desert.
Explanation
The difference between day and night temperatures is known as the diurnal range of temperature. This phenomenon is primarily governed by the differential heating and cooling of land and water (specific heat capacity) and the distance from the sea. This concept distinguishes between Continental (extreme) and Maritime (moderate) climates.
Detailed Analysis:
- The Thar Desert is located at a higher altitude than the islands. is Incorrect: While altitude does influence temperature (lapse rate), the Thar Desert is not situated at an altitude significantly higher than the islands to cause such a drastic difference in diurnal range. The primary factor is the nature of the surface, not the elevation.
- The moderating influence of the sea is absent in the Thar Desert. is Correct: Land surfaces (sand in the Thar Desert) have a lower specific heat capacity than water. This means the desert heats up rapidly during the day and cools down very quickly at night (terrestrial radiation escapes easily in clear skies). In contrast, the Andaman and Nicobar Islands are surrounded by the ocean. Water heats up and cools down slowly. The moisture in the air and the presence of the sea exert a moderating influence (Maritime effect), keeping the difference between day and night temperatures minimal.
- The Thar Desert receives more rainfall than the islands. is Incorrect: This statement is factually wrong regarding the comparison. The Thar Desert receives scanty rainfall, whereas the Andaman and Nicobar Islands receive heavy rainfall. Furthermore, low humidity in the desert actually contributes to the wide temperature range (clear skies allow heat to escape at night), but the option claims the desert receives more rainfall, which is false.
- The Thar Desert experiences strong trade winds throughout the year. is Incorrect: While trade winds influence the general climate pattern, they are not the primary reason for the specific contrast in the diurnal range of temperature between a desert and an island. The fundamental reason remains the specific heat difference between land and water.
Key Takeaway:
Continentality refers to the condition of being far from the moderating influence of the sea, resulting in extreme temperature variations (high diurnal range), whereas the Maritime effect ensures moderate temperatures with a low diurnal range.