Chapter 8: Solar Radiation, Heat Balance and Temperature
Geography - Fundamental of Physical Geography • Class 11
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Chapter Analysis
Intermediate8 pages • EnglishQuick Summary
This chapter discusses the Earth's energy balance, focusing on solar radiation, the process of heat transfer, and temperature variations globally. It explains how the Earth receives energy from the Sun and sheds this energy through various methods such as radiation, conduction, and convection. The chapter also elaborates on concepts such as the heat budget, terrestrial radiation, and factors affecting temperature distribution.
Key Topics
- •Solar radiation
- •Heat budget
- •Temperature distribution
- •Conduction and convection
- •Terrestrial radiation
- •Inversion of temperature
- •Factors controlling temperature
- •Spatial distribution of insolation
Learning Objectives
- ✓Understand the concept of solar radiation and insolation.
- ✓Explain the Earth's heat budget and its components.
- ✓Identify the various methods of heat transfer in the atmosphere.
- ✓Discuss the factors affecting global temperature distribution.
- ✓Describe the phenomena of temperature inversion.
- ✓Analyze the Earth's energy balance and its climatic impacts.
Questions in Chapter
The sun is directly overhead at noon on 21st June at:
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In which one of the following cities, are the days the longest?
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The atmosphere is mainly heated by the:
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Make correct pairs from the following two columns.
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The main reason that the earth experiences highest temperatures in the subtropics in the northern hemisphere rather than at the equator is:
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How does the unequal distribution of heat over the planet earth in space and time cause variations in weather and climate?
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What are the factors that control temperature distribution on the surface of the earth?
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In India, why is the day temperature maximum in May and why not after the summer solstice?
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Why is the annual range of temperature high in the Siberian plains?
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How do the latitude and the tilt in the axis of rotation of the earth affect the amount of radiation received at the earth’s surface?
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Discuss the processes through which the earth-atmosphere system maintains heat balance.
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Compare the global distribution of temperature in January over the northern and the southern hemisphere of the earth.
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Additional Practice Questions
Explain how conduction and convection contribute to the heating of the atmosphere.
mediumAnswer: Conduction involves the transfer of heat through a substance without the movement of the substance itself. It primarily heats the air in contact with the ground. Convection, on the other hand, involves the movement of particles, transferring heat by rising warm air currents, effectively heating the atmosphere.
What role does albedo play in the Earth's climate system?
mediumAnswer: Albedo refers to the reflectivity of a surface, where surfaces with high albedo, like ice, reflect most solar energy back into space. This affects the Earth's energy balance and climate, as areas with high albedo remain cooler compared to those with lower albedo.
Identify the factors leading to variation in insolation received at different places on Earth.
hardAnswer: Factors influencing insolation include the Earth's rotation, revolution around the sun, the angle of solar rays, duration of sunlight, atmospheric conditions, and the geographical location, especially latitude.
Discuss how ocean currents can influence climate.
mediumAnswer: Ocean currents, both warm and cold, play a significant role in climate regulation. Warm currents raise the temperature of the air above them influencing nearby lands' climates, while cold currents can lower coastal temperatures.
How does the Earth's atmosphere facilitate the greenhouse effect?
easyAnswer: The Earth's atmosphere contains greenhouse gases like carbon dioxide and methane which trap heat. While sunlight enters the atmosphere freely, greenhouse gases absorb and emit infrared radiation, warming the Earth's surface.
Why do higher altitudes generally have cooler temperatures?
mediumAnswer: At higher altitudes, the atmosphere is less dense and the air is thinner, leading to lower pressure and temperatures. The thin atmosphere is not as effective at trapping and retaining heat as denser air closer to sea level.
Explain how seasonal changes affect temperature distribution.
mediumAnswer: Seasonal changes are driven by the tilt of the Earth's axis and its orbit around the Sun, causing varying sunlight angles and daylight duration, leading to temperature variations.
What is the significance of the heat budget in relation to global temperature regulation?
hardAnswer: The heat budget is the balance between incoming solar energy and outgoing terrestrial radiation. Maintaining this balance is crucial for the Earth's climate stability, ensuring the planet does not overheat or cool excessively.
How do human activities potentially alter the heat balance of the Earth?
hardAnswer: Human activities, such as deforestation, industrial emissions, and pollution, increase greenhouse gases, enhancing the greenhouse effect, potentially disturbing the natural heat balance, leading to climate change.
What processes are involved in the latitudinal variation of temperature?
hardAnswer: The tilt of the Earth's axis, differential heating of the land and sea, ocean currents, and atmospheric circulation all contribute to temperature differences across latitudes.