UPSC MainsGEOGRAPHY-PAPER-II201620 Marks250 Words
Q4.

Discuss the role of spatial pattern of rainfall and temperature in the delimitation of climatic regions of India especially with reference to Stamp's climatic regionalization.

How to Approach

This question requires a detailed understanding of India’s climate and how its spatial variations in rainfall and temperature are used to define climatic regions. The answer should focus on Stamp’s classification, explaining its methodology and highlighting how rainfall and temperature patterns are crucial to its delineation. Discussing the limitations of the classification would add value. Structure the answer by first introducing Stamp’s classification, then detailing how rainfall and temperature are used, and finally, briefly mentioning its criticisms.

Model Answer

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Introduction

India, due to its vast geographical expanse and diverse topographical features, exhibits a remarkable variety of climatic conditions. Climatic regionalization is the process of dividing a country into areas with similar climatic characteristics. Several attempts have been made to classify the climate of India, with one of the most influential being that of Dudley Stamp. Stamp’s classification, published in 1959, is a widely recognized scheme that utilizes the interplay of temperature and rainfall, along with other factors like natural vegetation, to delineate distinct climatic regions. Understanding the role of spatial patterns of these two elements is fundamental to comprehending Stamp’s approach.

Stamp’s Climatic Regionalization: A Framework

Dudley Stamp’s classification divides India into eight major climatic regions based on a combination of factors, with rainfall and temperature being the most significant. He considered the average annual rainfall, temperature variations, and their seasonal distribution to identify these regions. The classification is largely based on the concept of ‘effective rainfall’ – the portion of rainfall that is actually available for plant growth after accounting for evaporation and transpiration.

The Role of Spatial Rainfall Patterns

Rainfall distribution across India is highly uneven, largely influenced by the monsoon winds. Stamp utilized this spatial variation to differentiate climatic zones.

  • Regions with over 200 cm of rainfall: These areas, primarily along the Western Ghats and parts of Northeast India, are categorized under the ‘Tropical Rainforest’ and ‘Tropical Monsoon’ climates. The high rainfall supports dense vegetation and influences the soil characteristics.
  • Regions with 100-200 cm of rainfall: This range characterizes the ‘Tropical Monsoon’ climate prevalent in eastern and central India. The seasonal distribution of rainfall is crucial, with a distinct wet and dry season.
  • Regions with 50-100 cm of rainfall: The ‘Tropical Savannah’ climate, found in parts of the Deccan Plateau, is defined by this rainfall range. It experiences a prolonged dry season and supports grasslands with scattered trees.
  • Regions with less than 50 cm of rainfall: The ‘Semi-Arid’ and ‘Arid’ climates, covering Rajasthan and parts of Gujarat, are characterized by scarce rainfall and high evaporation rates.

The Role of Spatial Temperature Patterns

Temperature variations, both spatial and seasonal, also play a vital role in Stamp’s classification.

  • High Temperature Regions: The Peninsular India generally experiences higher temperatures throughout the year. This, combined with rainfall patterns, defines the ‘Tropical’ climates.
  • Moderate Temperature Regions: The Northern Plains and Himalayan foothills experience moderate temperatures with distinct seasonal variations. This leads to the classification of ‘Tropical Monsoon with Dry Winter’ and ‘Humid Subtropical’ climates.
  • Cold Temperature Regions: The Himalayan region, with its altitudinal variations, experiences cold temperatures and is classified under ‘Alpine’ and ‘Cold Steppe’ climates.

Illustrative Table of Stamp’s Climatic Regions and Key Parameters

Climatic Region Average Rainfall (cm) Average Temperature (°C) Dominant Vegetation
Tropical Rainforest >200 27-30 Dense evergreen forests
Tropical Monsoon 100-200 24-27 Moist deciduous forests
Tropical Savannah 50-100 24-30 Grasslands with scattered trees
Semi-Arid 30-50 25-30 Thorny shrubs and grasslands
Arid <30 28-32 Desert vegetation

Stamp’s classification also considers the influence of altitude, aspect, and soil types, but the fundamental basis remains the spatial distribution of rainfall and temperature. For instance, the Thar Desert’s arid climate is a direct consequence of its location in the rain shadow area of the Aravalli hills and its high temperatures.

Conclusion

Stamp’s climatic regionalization remains a valuable framework for understanding the climatic diversity of India. By meticulously analyzing the spatial patterns of rainfall and temperature, he successfully delineated regions with distinct climatic characteristics. While the classification has been criticized for being overly generalized and not fully accounting for microclimates and recent climate change impacts, it provides a foundational understanding of India’s climate and its influence on various aspects of the environment and human life. Further refinements incorporating modern data and techniques are necessary to enhance its accuracy and relevance in the context of a changing climate.

Answer Length

This is a comprehensive model answer for learning purposes and may exceed the word limit. In the exam, always adhere to the prescribed word count.

Additional Resources

Key Definitions

Isohyet
A line on a map connecting points having equal rainfall amounts.
Orographic Rainfall
Rainfall that occurs when moist air is forced to rise over mountains, cools, and condenses.

Key Statistics

Approximately 65% of India’s total geographical area is prone to drought.

Source: National Disaster Management Authority (NDMA), 2023 (Knowledge Cutoff)

The Indian monsoon contributes to approximately 80% of the annual rainfall in India.

Source: India Meteorological Department (IMD), 2022 (Knowledge Cutoff)

Examples

Western Ghats Rainfall

The Western Ghats receive extremely high rainfall (over 200 cm annually) due to orographic lift, leading to the formation of rainforests and influencing the region’s biodiversity.

Frequently Asked Questions

Is Stamp’s classification still relevant today?

While Stamp’s classification is a foundational work, it’s important to acknowledge its limitations in the face of climate change. Modern classifications incorporate more detailed data and consider factors like humidity and wind patterns, but Stamp’s work remains a useful starting point for understanding India’s climate.

Topics Covered

GeographyClimatologyClimateRainfallTemperatureRegionalization