MEV 012: Unit 05 - Elements of Climate

-

 UNIT 5: ELEMENTS OF CLIMATE

5.0 Introduction

Climate plays a vital role in shaping the physical and human environment. This unit introduces the key elements of climate, how they interact, and their spatial and temporal variations. It also explores global pressure systems, wind belts, humidity, precipitation, and the Earth’s radiation balance.

5.1 Objectives

By the end of this unit, you will be able to:

  • Understand the basic elements and controls of climate.
  • Explain the Earth’s radiation balance and the role of insolation.
  • Describe global pressure systems and wind circulation.
  • Understand the hydrological cycle and various forms of precipitation.
  • Analyze the concept of water balance in climate systems.

5.2 Elements and Controls of Climate

Elements of Climate include:

  • Temperature
  • Precipitation
  • Humidity
  • Pressure
  • Winds
  • Cloudiness
  • Sunshine duration

Controls of Climate are factors influencing these elements:

  • Latitude
  • Altitude
  • Land and water distribution
  • Ocean currents
  • Mountain barriers
  • Wind and pressure systems

5.3 Earth’s Radiation Balance

The Earth receives energy from the Sun in the form of shortwave radiation (insolation) and emits longwave radiation (terrestrial radiation).

  • Incoming Solar Radiation (Insolation): Varies by latitude and time of year.
  • Albedo: Reflectivity of Earth’s surface; higher for snow/ice, lower for forests/water.
  • Greenhouse Effect: Traps terrestrial radiation, warming the Earth.

Balance: The equilibrium between incoming and outgoing radiation ensures a stable climate.

5.4 Latitudinal and Seasonal Variation of Insolation

  • Latitudinal Variation: Equator receives maximum insolation; poles receive the least.
  • Seasonal Variation: Caused by Earth’s tilted axis (23.5°) and revolution around the Sun.
  • Solstices and Equinoxes define the solar seasons and variation in day length.

5.5 Global Pressure and Wind Belts

The uneven heating of the Earth causes variations in air pressure and creates distinct wind systems.

Global Pressure Belts:

  • Equatorial Low (ITCZ)
  • Subtropical High
  • Subpolar Low
  • Polar High

Global Wind Belts:

  • Trade Winds: Blow from subtropical highs toward the equator.
  • Westerlies: From subtropics to subpolar zones.
  • Polar Easterlies: From poles toward subpolar regions.

These winds influence climate zones and ocean currents.

5.6 Humidity and Precipitation

Humidity is the amount of water vapor present in the air. It plays a major role in cloud formation and precipitation.

5.6.1 The Hydrological Cycle

Describes the continuous movement of water on, above, and below the surface of the Earth:

  • Processes: Evaporation, condensation, precipitation, infiltration, runoff.
  • Storage: Atmosphere, oceans, glaciers, groundwater.

5.6.2 Precipitation and Its Forms

Precipitation occurs when water vapor condenses into water droplets or ice and falls to the ground.

Main Forms:

  • Rain: Liquid drops
  • Snow: Ice crystals
  • Hail: Hard ice balls
  • Sleet: Partially frozen rain

5.6.3 Types of Precipitation or Rainfall

  • Convectional Rainfall: Due to intense heating and rising of moist air.
  • Orographic Rainfall: Caused by moist air forced up by mountains.
  • Cyclonic (Frontal) Rainfall: Associated with cyclones and low-pressure areas.

5.7 Water Balance

The water balance equation summarizes the input, output, and storage of water in a region:

P = E + R ± ΔS
Where:

  • P = Precipitation
  • E = Evapotranspiration
  • R = Runoff
  • ΔS = Change in Storage

Understanding water balance helps in agriculture, hydrology, and climate modeling.

5.8 Let Us Sum Up

This unit examined key elements of climate—temperature, pressure, humidity, wind, and precipitation—along with controls that influence them such as latitude and altitude. It explained the Earth's energy balance and the variation in insolation that governs seasons and climate types. The global wind systems, hydrological cycle, types of rainfall, and concept of water balance were discussed as central aspects of climatic dynamics.

5.9 Keywords

·         Climate-Average weather conditions of a place over a long period (30+ years).

·         Weather-Short-term atmospheric conditions like temperature and precipitation.

·         Insolation-Incoming solar radiation received by Earth’s surface.

·         Albedo-Reflective property of Earth’s surface; high for snow, low for water.

·         Greenhouse Effect-Warming effect due to trapped outgoing terrestrial radiation by gases.

·         Humidity-Amount of water vapor present in the air.

·         Hydrological Cycle-Continuous circulation of water in Earth’s system through various processes.

·         Precipitation-Water falling from the atmosphere in various forms (rain, snow, hail).

·         Trade Winds-Prevailing winds blowing from subtropical high to equatorial low pressure.

·         Water Balance-Equation showing input and output of water in a system.

·         Convectional Rainfall-Caused by rising heated air carrying moisture.

·         Orographic Rainfall-Rainfall caused by moist air rising over mountains.

·         Frontal Rainfall-Rainfall caused by meeting of warm and cold air masses.

·         Latitudinal Variation-Differences in insolation and climate with latitude.

·         Seasonal Variation-Changes in weather patterns across different times of the year.

 

Comments

Post a Comment

Popular Posts

Jcert Class 8 Daffodil Chapter 1a: The Naive Friends Solutions

-
Chapter 1a : The Naive Friends Answer the following questions: 1. Which questions made Keshav and Shyama curious about the egg? Ans.         How did the chick come out? How big would the eggs? How many? What colours would they? What did they eat? Such types of questions made Keshav and Shyama curious about the egg. 2. What three things did the children do to protect the eggs? Ans.         The children done three things are: (i)          Adjustment of food. (ii)        Adjustment of water. (iii)      Adjustment of roof. 3. Why did Keshav think of making a cushion for the eggs? Ans.         When Keshav saw the egg on direct sun light, he thaught making a cushion for the eggs. 4. What excuse did Keshav give for not showing the eggs to Shyama? Ans.     ...
Read more

Jcert Class 8 भाषा मंजरी Chapter 3 मित्रता Solutions

-
अध्याय - 3 : मित्रता 1. आप किस प्रकार कह सकते हैं कि मित्रों के चुनाव की उपयुक्तता पर हमारे जीवन की सफलता निर्भर करती है? उ. मित्रों के चुनाव की उपयुक्तता पर हमारे जीवन की सफलता निर्भर करती है क्योंकि संगति का गुप्त प्रभाव हमारे आचरण पर पड़ता है और यदि हमें अच्छी संगति, अच्छे मित्र मिलते हैं तो वे हमें सफलता की ओर ले जाते हैं जबकि बुरी संगति हमारे जीवन को खाक में मिला देती है।  2. 'विश्वासपात्र मित्र जीवन की एक औषध है।' आशय स्पष्ट कीजिए। उ. 'विश्वासपात्र मित्र जीवन की एक औषध है'- ऐसा इसलिए कहा गया है कि यदि हमें विश्वासी मित्र मिल गया तो हम अपने जीवन में चाहे जैसा भी कदम उठाएँ, उस कदम की आलोचना करके वह हमें सही दिशा की ओर उन्मुख करेगा। हम अपनी गलती रूपी बीमारी को उसकी आलोचना रूपी औषधि से दूर कर सकेंगे।  3. मित्र का चुनाव करते समय हमें किन बातों का ध्यान रखना चाहिए? उ. मित्र का चुनाव करते समय हमें निम्नलिखित बातों का ध्यान रखना चाहिए हमारे अच्छे विचारों (संकल्पों) को दृढ़ करने वाला हो। हमें दोषों और त्रुटियों से बचाए। हमारे सत्य, पवित्रता ...
Read more

Jcert Class 8 भाषा मंजरी Chapter 8 अमरूद का पेड Solutions

-
अध्याय - 8 : अमरूद का पेड 1. लेखक को क्यों लगता है कि इन सब पिछड़े खयालातों का हमारे घर में गुजर नहीं हो सकेगा। उ. अमरूद के पेड़ को देखकर सबसे पहले बाबू कन्हैयालाल की बूढ़ी पत्नी ने एक दिन टोका कि पश्चिम की तरफ अगर मकान का मुखड़ा हो और सामने ही अमरूद का पेड़ तो 'राम-राम बड़ा अशुभ होता है और माँ के चेहरे पर थोड़ा-सा भय दिखा पर लेखक को विश्वास था कि इन सब पिछड़े खयालातों का हमारे घर में गुजर नहीं हो सकेगा क्योंकि उसके घर के लोग आधुनिक विचारधारा के थे उसकी माँ सत्याग्रह के दिनों में अजमेर में लम्बा जेल कर चुकी है। पिताजी खुद राजनैतिक सामाजिक उदारता वाले आदमी थे। बुआ ने विवाह नहीं किया था, पढ़ने-लिखने में ही अपनी सम्पूर्ण जिन्दगी लगा दी और समाज कोई चुनौती देने का साहस नहीं कर सका। साथ ही परिवार के सभी लोगों में पिछड़ेपन के प्रति भर्त्सना का भाव था। 2. अमरूद के पेड़ की छाया किस प्रकार लेखक को उनके भाई-बहनों के साथ जोड़ती है ? उ. अमरूद के पेड़ की छाया लेखक को उसके भाई-बहनों के साथ जोड़ती है। वे सभी अमरूद की छाया में बेंत की कुर्सियों पर बैठ चर्चाएँ करते थे जिससे उनके बीच...
Read more