Previous Year Question
Which of the following is/are correct inference/inferences from isothermal maps in the month of January?
The isotherms deviate to the North over the ocean and to the South over the continent.
The presence of cold ocean currents, Gulf Stream and North Atlantic Drift makes the North Atlantic Ocean colder and the isotherms bend towards the North.
Select the answer using the codes given below.
Correct Answer: A
Detailed Solution
Statement 1 is correct: January is a winter month in the Northern Hemisphere. Land cools more rapidly than water, while oceans remain comparatively warm because of their higher specific heat.
Therefore, at the same latitude:
Temperatures over oceans are higher than over continents, causing isotherms to bend poleward or northward over the oceans.
Continents are colder, causing isotherms to bend equatorward or southward over them.
Statement 2 is incorrect: The Gulf Stream and North Atlantic Drift are not cold currents; they are warm ocean currents. They transfer heat from tropical regions towards the North Atlantic and western Europe.
These currents keep the North Atlantic and western Europe warmer than other regions situated at comparable latitudes. This warming causes the January isotherms to bend northward over the North Atlantic. Thus, the statement is incorrect in describing these currents as cold and claiming that they make the North Atlantic Ocean colder.