QUES . Which of the following is/are correct inference/inferences from isothermal maps in the month of january? UPSC 2024

1 . The isotherms deviate to the north over the Ocean and to the south over the continent.

2 . The presence of cold ocean currents, Gulf Stream and North Atlantic Drift make the North Atlantic Ocean colder and the isotherms bend towards the north.

Selected the answer using the code given below:

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

Ans (a)

Must read: Global distribution of temperature

EXPLANATION:

֍ In January the isotherms deviate to the north over the ocean and to the south over the continent. This can be seen on the North Atlantic Ocean.

֍ The presence of warm ocean currents, Gulf Stream and North Atlantic drift, make the Northern Atlantic Ocean warmer and the isotherms bend towards the north.

֍ Over the land the temperature decreases sharply and the isotherms bend towards south in Europe. It is much pronounced in the Siberian plain.

֍ The mean January temperature along 60° E longitude is minus 20° C both at 80° N and 50° N latitudes.

֍ The mean monthly temperature for January is over 27° C, in equatorial oceans over 24° C in the tropics and 2° C – 0° C in the middle latitudes and –18° C to –48° C in the Eurasian continental interior.

֍ The effect of the ocean is well pronounced in the southern hemisphere. Here the isotherms are more or less parallel to the latitudes and the variation in temperature is more gradual than in the northern hemisphere. The isotherm of 20° C, 10° C, and 0° C runs parallel to 35° S, 45° S and 60° S latitudes respectively.