Which of the following statements concerning temperature is/are correc

Which of the following statements concerning temperature is/are correct ?

1. In winter season isotherms in Northern Hemisphere are more or less circular on continents
2. Isotherms are parallel to latitude in Southern Hemisphere in oceans
3. Minimum temperature during winter is recorded in Northern Canada

Select the correct answer using the code given below :

1 and 2 only

1 and 3 only

1, 2 and 3

2 only

This question was previously asked in

UPSC NDA-2 – 2016

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Statement 1: In winter season, continents in the Northern Hemisphere become significantly colder than the surrounding oceans due to differential heating and cooling rates. This thermal contrast leads to isobars bending equatorward over land and poleward over oceans. While not perfectly circular, the isotherms tend to form closed patterns reflecting cold centers over the large landmasses, deviating from the zonal pattern. Compared to the Southern Hemisphere, the influence of land is pronounced, making the continental isotherms less parallel to latitudes and somewhat ‘circular’ around cold pools. This statement is generally considered correct in depicting the characteristic pattern.
Statement 2: The Southern Hemisphere is dominated by oceans. Oceans have a more uniform temperature distribution and heat/cool more slowly than land. As a result, isotherms in the Southern Hemisphere, particularly over vast oceanic areas and away from significant landmasses like Antarctica or the southern tips of continents, tend to be more regular and run broadly parallel to the lines of latitude. This statement is correct.
Statement 3: While Northern Canada experiences extremely low temperatures in winter, the absolute minimum temperatures on Earth during winter are typically recorded in places like Siberia (Russia) or Antarctica (Vostok Station holds the world record). Northern Canada is among the coldest regions, but it doesn’t necessarily record *the* minimum temperature globally. This statement is incorrect.

Isotherms are lines connecting points of equal temperature. Their patterns are influenced by latitude, altitude, distribution of land and water, ocean currents, and winds. Landmasses cause greater temperature extremes (hot summers, cold winters) compared to oceans, leading to bending of isotherms. The Southern Hemisphere’s oceanic dominance results in more zonal (latitude-parallel) temperature distribution.

The bending of isotherms over landmasses in winter (equatorward bend) and summer (poleward bend) is a direct consequence of the continentality effect. The Southern Hemisphere’s temperature patterns are simpler due to the lack of large east-west oriented landmasses at middle and high latitudes.

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