CSE 2024 GS 1 Q4 – Isothermal Maps in January

PYQs (Previous Year Questions) – UPSC Civil Services Prelims Exam 2024, General Studies Paper 1, Set A Question #4

Question 4: Which of the following is/are correct inference/inferences from isothermal maps in the month of January?

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.

Select the answer using the code given below:

(a) 1 only

(b) 2 only

(c) Both 1 and 2

(d) Neither 1 nor 2

प्रश्न 4: जनवरी माह में समतापी रेखा-मानचित्रों (आइसोथर्मल मैप) से प्राप्त कौन-सा/कौन-से निष्कर्ष सही है/हैं?

1. समताप रेखाएँ महासागर के ऊपर उत्तर की ओर और महाद्वीप के ऊपर दक्षिण की ओर विचलित हो जाती हैं।

2. शीत महासागरीय धाराओं, गल्फ स्ट्रीम और उत्तरी अटलांटिक अपवाह (ड्रिफ्ट) की उपस्थिति उत्तरी अटलांटिक महासागर को शीतल बनाती हैं और समताप रेखाएँ उत्तर की ओर मुड़ जाती हैं।

नीचे दिए गए कूट का प्रयोग कर उत्तर चुनिए:

(a) केवल 1

(b) केवल 2

(c) 1 और 2 दोनों

(d) न तो 1, न ही 2

Answer

(a) 1 only

Subject & Topic

Geography – Atmosphere

Explanation

Isothermal Maps in January
In the Northern Hemisphere, the land surface area significantly exceeds that of the Southern Hemisphere. This disparity has a profound impact on climatic patterns, making the effects of landmasses and ocean currents more prominent in the north. One striking example of this influence can be observed in the behavior of isotherms—lines on a map that connect points of equal temperature.

During January, isotherms exhibit noticeable deviations due to the contrasting thermal properties of land and water. Over the oceans, these lines shift northward as the water retains heat and moderates the surrounding temperature. Conversely, over continental regions, isotherms bend southward because land surfaces cool more rapidly during winter.

This phenomenon is particularly evident in the North Atlantic Ocean, where the interplay between the warm Gulf Stream, the surrounding cooler waters, and the adjacent landmasses distinctly shapes the isothermal patterns. These deviations reflect the complex interactions between terrestrial and marine climates, underscoring the significant role of geography in influencing global temperature distribution.

Hence, statement 1 is correct.

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

Hence, statement 2 is incorrect, as it is warm ocean currents and not cold ocean currents.

Source(s)

NCERT Class 11 Geography Book: Fundamentals of Physical Geography – Chapter 8 Composition and Structure of Atmosphere

Difficulty level

Easy as straight forward from NCERT Textbook

Avatar for Brijesh SinghWritten By: Brijesh Singh

Brijesh Singh has been providing guidance to various aspirants for the last two decades across diverse forums and institutes. He has also authored four books for UPSC and State Civil Services aspirants. Among his authored works is the widely acclaimed "Comprehensive Modern Indian History" published by S. Chand. The book is highly recommended for aspirants and is readily available in online stores like Amazon, Flipkart, and various local bookstores. Brijesh holds diverse academic interests and is a postgraduate in History, Computers, and Management Certificate from IIM Indore. Apart from being UGC NET qualified, he has keen interest in writing articles and blogs.

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