The link of PDF of this Geography Class-5 Types of Inversion and Humidity is given below the explanation of the class, you can download the PDF by going below.
Geography Class-5 Types of Inversion and Humidity
In this Geography Class-5 Types of Inversion and Humidity, we will discuss about the Types of Inversion, Effects of temperature inversion, Humidity, and types of humidity etc.
Topics to be covered in this Article :-
Types of Inversion
Effects of Temperature Inversion
Humidity
Types of Humidity
Types of Inversion
Temperature inversion refers to a deviation from the normal atmospheric temperature profile, where temperatures increase with height rather than decrease. In a normal atmospheric temperature profile, as you climb up through the atmosphere, the temperature usually decreases due to decreasing pressure and decreasing density of air molecules.
However, in inversion, the opposite occurs: temperature increases with altitude. This reversal of the normal temperature profile can have significant impacts on weather conditions, air quality and the dispersion of pollutants. Here are some common types of temperature inversions:
1. Radiation Inversion:
Description: Radiation inversions occur due to the radiative cooling of the Earth’s surface, particularly during clear, calm nights.
Cause: As the ground loses heat through radiation, the air near the surface cools rapidly, leading to a temperature inversion where the temperature increases with altitude.
Effects: Radiation inversions can lead to reduced vertical mixing of air, trapping pollutants near the surface, and affecting air quality, especially in urban areas.
Description: Advection inversions occur when warm air moves over a colder surface, such as a warm air mass moving over a cold ocean or snow-covered ground.
Cause: The warm air cools as it moves over the colder surface, leading to a temperature inversion.
Effects: Advection inversions can influence local weather patterns, leading to the formation of fog, low clouds, or stable atmospheric conditions.
Description: Valley inversions occur in mountain valleys where cold, dense air settles at lower elevations while warmer air resides above.
Cause: During clear, calm nights, the cooler, denser air near the valley floor sinks and becomes trapped by the surrounding terrain, leading to a temperature inversion.
Effects: Valley inversions can result in temperature variations within the valley, with colder temperatures near the valley floor and warmer temperatures at higher elevations. This can lead to the trapping of pollutants and fog in the valley, affecting air quality and visibility.
Each type of temperature inversion has unique characteristics and effects on weather conditions, air quality, and atmospheric stability. Understanding these different types of inversions is crucial for meteorologists, environmental scientists, and policymakers, as they play a significant role in weather forecasting, air quality management, and climate studies.
Effects of Temperature Inversion
Temperature inversions can have various effects on weather, air quality, and the environment. Understanding these effects is crucial for assessing the impact of inversions on local conditions and for developing strategies to mitigate potential problems. Here are some of the key effects of temperature inversions:
Air Quality Degradation:
Trapping of pollutants near the surface.
Buildup of pollutant concentrations.
Decrease in air quality and visibility.
Weather Stability:
Suppression of vertical air mixing.
Hindering the formation of clouds and rainfall.
Long periods of clear skies and less rainfall.
Temperature Variations:
Temperature gradient within different atmospheric layers.
At temperature extremes, surface temperatures are cold and above are hot.
Impacts on Agriculture:
Increased risk of frost formation.
Temperature fluctuations affecting crop growth and development.
Aviation and Transportation:
Reduced visibility due to trapped pollutants or fog.
Wind shear risks during takeoff and landing.
Health Impacts:
Increase in respiratory problems.
The risk of respiratory infections and diseases increases.
Due to extreme temperatures, the risk of heat-related illnesses is higher.
Understanding these impacts is important to assess the impact of temperature inversions on local conditions and to implement strategies to mitigate potential problems.
Practice Question
Ques. What do you understand by the phenomenon of “temperature inversion” in meteorology? How does it affect the weather and the habitants of the place? (100 Words)(UPSC CSE, 2013)
Humidity
Humidity refers to the amount of water vapor present in the air. It is an essential component of the atmosphere and plays a significant role in weather and climate. Humidity can influence various weather phenomena, such as cloud formation, precipitation, and temperature regulation.
Types of Humidity
Here are the types of humidity:
1. Absolute Humidity:
Description: Absolute humidity refers to the actual amount of water vapor present in a unit volume of air, typically expressed in grams per cubic meter (g/m³).
Measurement: It is usually measured using devices such as hygrometers.
2. Relative Humidity (RH):
Description: Relative humidity is the ratio of the amount of water vapor present in the air to the maximum amount of water vapor the air could hold at that temperature, expressed as a percentage.
Calculation:Â
Importance: Relative humidity gives an indication of the air’s moisture content relative to its capacity to hold moisture at a particular temperature. A relative humidity of 100% indicates that the air is fully saturated with water vapor and cannot hold any more moisture, leading to the possibility of precipitation.
3. Specific Humidity:
Description: Specific humidity refers to the mass of water vapor present in a unit mass of moist air, typically expressed in grams of water vapor per kilogram of air (g/kg).
Calculation:Â Â Â
Importance: Specific humidity provides a measure of the actual moisture content of the air, unaffected by changes in temperature or pressure.
Understanding the different types of humidity and their characteristics is essential for meteorologists, climatologists, and anyone interested in weather and climate science. Humidity plays a crucial role in shaping weather patterns, affecting human comfort, and influencing various natural processes in the atmosphere.
Practice Question
Ques. Out of many expressions of humidity, relative humidity is the most useful for atmospheric analysis. Discuss. (Answer in 150 Words)
Class Quiz
Q1. What is the primary cause of a radiation inversion? a) Movement of warm air over a cold surface
b) Sinking air in high-pressure systems
c) Clear, Calm nights
d) Associated with the movement of air masses
Q2. Match the given phenomenon with their effects of temperature inversion:- Codes: a) A-2, B-3, C-1, D-4 b) A-1, B-4, C-3, D-2 c) A-1, B-4, C-2, D-3 d) A-1, B-3, C-4, D-2
Q3. During a temperature inversion, what typically happens to visibility? a) Visibility improves due to reduced humidity
b) Visibility remains unaffected
c) Visibility worsens due to trapped pollutants
d) Visibility improves due to increased cloud cover
Q4. Match the types of humidity with their characteristics:- Codes: a) A-1, B-2, C-3 b) A-3, B-2, C-1 c) A-2, B-1, C-3 d) A-2, B-3, C-1
Q5. Which factor primarily determines the capacity of air to hold water vapour? a) Temperature
b) Pressure
c) Wind Speed
d) Cloud Cover
This is all about the Geography Class-5 Types of Inversion and Humidity. In next class, we will discuss about the Condensation, Precipitation, Types of Rainfall etc.
The link of PDF of this Geography Class-4 Temperature is given below the explanation of the class, you can download the PDF by going below.
Geography Class-4 Temperature
In this Geography Class-4 Temperature, we will discuss about the Temperature, Factors affecting temperature, Distribution of temperature, temperature inversion etc.
Topics to be covered in this Article :-
Temperature
Process of Heat transfer in the Atmosphere
Factors affecting Temperature
Distribution of Temperature
Range of Temperature
Temperature Inversion
Temperature
Temperature is a measure of how hot or cold something is. It indicates the level of thermal energy present within a substance or system. Temperature is typically measured using instruments like thermometers and expressed in units such as Celsius, Fahrenheit, or Kelvin. It’s an essential concept in science and everyday life, influencing various physical and chemical properties of materials and affecting how they interact with each other.
Important Points:-
Measure of Hotness/Coldness: Temperature is a measure that tells us how hot or cold something is.
Representation of Thermal Energy: It represents the amount of thermal energy present within a substance or a system.
Average Kinetic Energy: Temperature is related to the average kinetic energy of the particles within the substance or system.
Measured with Instruments: Temperature is typically measured using devices such as thermometers.
Expressed in Units: It is expressed in various units such as Celsius (°C), Fahrenheit (°F), or Kelvin (K).
Influences Physical and Chemical Properties: Temperature affects numerous physical and chemical properties of materials, including their state (solid, liquid, gas), conductivity, and reaction rates.
Important in Science and Everyday Life: Understanding temperature is crucial in fields like physics, chemistry, engineering, and meteorology. It also impacts daily activities such as cooking, weather forecasting, and maintaining comfortable environments.
Process of Heat transfer in the Atmosphere
The atmosphere is involved in various processes of heat transfer, which play a crucial role in shaping weather patterns and climate. Here’s an overview of the main processes of heat transfer in the atmosphere:
Radiation: Radiation is the transfer of heat energy through electromagnetic waves. The Sun emits radiant energy, which reaches the Earth’s atmosphere and surface. Some of this energy is absorbed by the atmosphere, while the rest is absorbed by the Earth’s surface. The absorbed energy heats up the atmosphere and surface, contributing to temperature differences and driving weather systems.
Conduction: Conduction is the transfer of heat energy through direct contact between molecules. Near the Earth’s surface, conduction plays a role in transferring heat from warmer surfaces to cooler ones. For example, during the day, the ground absorbs heat from the Sun and warms up. This warmth is then conducted to the air layer directly above the surface.
Convection: Convection is the transfer of heat energy through the movement of fluids (liquids or gases). In the atmosphere, convection plays a significant role in redistributing heat vertically. Warm air near the Earth’s surface becomes less dense and rises, carrying heat upward. As it rises, the air cools and eventually sinks back down to the surface, completing a convection cycle. This process is responsible for the formation of clouds, thunderstorms, and other weather phenomena.
Advection: Advection is the horizontal movement of air, carrying heat energy with it. It occurs when air masses with different temperatures come into contact and exchange heat. For example, warm air moving from the tropics toward the poles (warm advection) or cold air moving from polar regions toward the equator (cold advection) can influence temperature patterns and weather conditions over large areas.
These processes of heat transfer interact with each other and with other factors such as humidity, pressure, and Earth’s rotation to create the complex weather patterns observed in the atmosphere. Understanding these processes is essential for meteorologists to forecast weather accurately and for scientists studying climate dynamics.
Latitude refers to the distance of a location from the equator, measured in degrees north or south.
Areas near the equator receive more direct sunlight throughout the year, leading to higher temperatures. This is because the Sun’s rays are more concentrated near the equator.
As you move away from the equator towards the poles, the angle at which sunlight hits the Earth’s surface becomes less direct, resulting in lower temperatures.
Consequently, locations near the equator experience tropical or warm climates, while those closer to the poles have colder climates.
2. Altitude:
Altitude, or elevation, refers to the height of a location above sea level.
As altitude increases, atmospheric pressure decreases, and the air becomes less dense. This causes a decrease in temperature with increasing altitude.
At higher altitudes, the air expands and cools due to the decrease in pressure, leading to cooler temperatures compared to lower elevations.
For example, mountainous regions often have cooler temperatures than low-lying areas at the same latitude.
The distance of a location from large water bodies, such as oceans or seas, affects its temperature variability, a concept known as continentality.
Coastal areas experience maritime climates characterized by milder temperatures and lower temperature variations throughout the year. This is because water has a higher heat capacity than land, meaning it can absorb and release heat more slowly.
Inland areas, or continental regions, tend to have more extreme temperature variations, with hotter summers and colder winters, due to the land’s lower heat capacity.
The moderating effect of water results in coastal areas having a more stable and temperate climate compared to inland regions.
The nature of the surface, such as land cover and land use, influences how much heat is absorbed and retained.
Dark-colored surfaces, such as asphalt and forests, absorb more sunlight and heat up quickly, leading to higher temperatures. This is because dark surfaces have lower albedo, meaning they reflect less sunlight and absorb more.
Light-colored surfaces, such as snow and sand, reflect more sunlight and heat, resulting in lower temperatures. This is because light surfaces have higher albedo, reflecting more sunlight back into the atmosphere.
Urban areas with extensive pavement and buildings tend to experience higher temperatures due to the urban heat island effect, where heat is absorbed and emitted by artificial surfaces.
Wind patterns play a significant role in redistributing heat across the Earth’s surface.
Winds can transport heat from warmer regions to cooler regions, affecting temperature gradients over large distances.
For example, warm winds blowing from tropical regions towards higher latitudes can raise temperatures in cooler areas, while cold winds blowing from polar regions can lower temperatures in warmer areas.
Additionally, local wind patterns, such as sea breezes and mountain breezes, can influence temperature variations in coastal and mountainous regions, respectively.
These factors interact in complex ways to determine the temperature of a particular location, shaping its climate and influencing weather patterns. Understanding these factors is essential for predicting temperature variations and assessing climate variability.
Distribution of Temperature
Horizontal and Vertical Distribution of Temperature is as follows:-
(A). Horizontal Distribution:- Horizontal distribution of temperature refers to how temperatures vary across different regions on Earth’s surface. It is influenced by factors such as latitude, proximity to large bodies of water, wind patterns, and the nature of the surface.
Types of Horizontal Distribution of Temperature are:-
1. Longitudinal Distribution (East-West):
The longitudinal distribution of temperature varies greatly due to the rotation of the Earth and the presence of landmasses and oceans.
Along the equator, temperatures tend to be consistently warm throughout the year due to direct sunlight.
Towards the poles, temperatures decrease significantly, with the polar regions experiencing extreme cold due to minimal sunlight angles.
Landmasses generally experience greater temperature variations compared to oceans due to differences in heat absorption and release.
Isotherms:- It is represented bylines joining places with equal temperature called as isotherms. These are drawn considering temperature at sea level.
Isotherms at a given latitude should be straight and parallel, but due to presence of oceans and continents with differential specific heat, isotherms bend. During winters, isotherms bend towards poles over oceans and towards equator over continents and vice-a-versa. In southern hemisphere, along temperature latitudes, isotherms are parallel and widely spaced.
2. Latitudinal Distribution (North-South):
The latitudinal distribution of temperature shows a gradual decrease from the equator towards the poles.
The equatorial regions experience high temperatures throughout the year due to direct sunlight and minimal variation in day length.
Temperatures decrease towards the poles due to the oblique angle of sunlight and shorter days during certain seasons.
Seasonal variations are more pronounced in mid-latitude regions, with distinct temperature changes between summer and winter.
Thermal Anomaly:- It is a phenomenon or a condition when place or a region has a different temperature than its latitude. If the temperature is less than the latitude, it is called as negative thermal anomaly and if the temperature is higher than the latitude, it is called as positive thermal anomaly. e.g.:- Death Valley (USA), and Al-Aziziya (Libya).
At Poles, temperature is low because of slating sunrays. During winters, temperature is less than 0•C and also experiences long winters. At sub-polar latitudes, temperature is higher than 0•C during summers, but winters are cold and harsh. At temperate latitudes, summer remains moderate and winters record colder temperature i.e. sub-zero. In lower latitudes, temperature is high throughout the year, although hottest or maximum temperature is recorded to the north and south equator. At equator, due to dominance of water and frequent rainfall, temperature is moderated.
(B). Vertical Distribution:- The vertical distribution of temperature refers to the distribution of temperature in the different layers of the atmosphere at the different latitudes from the earth’s surface. The temperature generally decreases due to the elevation from the surface. The decrease in temperature is different in all places and it is not similar anywhere.
The vertical distribution of temperature varies with altitude in the Earth’s atmosphere and within bodies of water.
In the atmosphere, temperatures generally decrease with increasing altitude in the troposphere due to the lapse rate.
In bodies of water, temperature stratification occurs with warmer water near the surface and colder water at greater depths.
Oceanic thermoclines, layers where temperature changes rapidly with depth, play a significant role in marine ecosystems and climate dynamics.
Mountainous regions exhibit a significant vertical temperature gradient, with cooler temperatures at higher elevations due to adiabatic cooling and reduced atmospheric pressure.
Understanding the distribution of temperature across longitudinal, latitudinal, and vertical dimensions is crucial for comprehending global climate patterns, weather systems, and ecological processes.
Range of Temperature
The range of temperature refers to the difference between the maximum and minimum temperatures observed within a specific location, region, or timeframe. It provides valuable insights into the variability and fluctuations in temperature over a given period, which have significant implications for various natural processes, human activities, and ecosystems. Here are the following types of range of temperature:
Diurnal Range: This refers to the variation in temperature within a single day, typically between the daytime maximum and nighttime minimum temperatures. Diurnal temperature ranges can be influenced by factors such as solar radiation, cloud cover, humidity, and wind patterns. In arid regions, where moisture levels are low and skies are clear, diurnal temperature ranges can be particularly wide, with hot daytime temperatures and cool nights.
Seasonal Range: Seasonal temperature ranges encompass the variations in temperature observed between different seasons (e.g., winter, spring, summer, autumn). These variations are driven by changes in solar insolation, atmospheric circulation patterns, and the tilt of the Earth’s axis. Regions at higher latitudes often experience more pronounced seasonal temperature ranges, with distinct contrasts between cold winters and warm summers.
Annual Range: The annual temperature range represents the difference between the highest and lowest temperatures recorded over the course of a year. It reflects the combined effects of diurnal and seasonal temperature fluctuations. In equatorial regions and coastal areas, where temperatures remain relatively stable throughout the year due to the moderating influence of oceans or consistent solar radiation, the annual temperature range tends to be smaller compared to continental interiors.
Overall, the range of temperature serves as a fundamental indicator of climate dynamics and variability, providing valuable information for scientific research, policy-making, and community resilience efforts.
Inversion of Temperature
Temperature inversion refers to a meteorological phenomenon where the normal vertical temperature profile of the atmosphere is inverted, meaning that temperature increases with altitude instead of decreasing as it typically does. This reversal of the normal temperature gradient can have significant impacts on weather conditions, air quality, and the dispersion of pollutants.
Q1. Discuss thermal anomaly. Illustrate with few examples.
Q2. Give reasoned account on vertical and horizontal variation in atmospheric temperature.
Class Quiz
Q1. Match the following processes of heat transfer in the atmosphere (List-I) with their descriptions (List-II):- Codes: a) A-1, B-2, C-3, D-4 b) A-3, B-4, C-2, D-1 c) A-3, B-4, C-1, D-2 d) A-4, B-3, C-1, D-2
Q2. Diurnal temperature variation refers to:- a) Temperature variation throughout the day b) Temperature variation throughout the year c) Temperature variation along lines of latitude. d) Temperature variation along lines of longitude
Q3. Match the following factors affecting temperature (List-I) with their descriptions (List -II): Codes: a) A-4, B-2, C-1, D-3 b) A-4, B-3, C-1, D-2 c) A-4, B-1, C-3, D-2 d) A-4, B-1, C-2, D-3
Q4. Which of the following term correctly match with their characteristic:- Select the correct answer from the options given below:- a) 1 only b) 2 only c) Both 1 and 2 d) Neither 1 nor 2
Q5. The process of trapping heat within the Earth’s atmosphere is primarily associated with:- a) Convection
b) Greenhouse effect c) Thermal inversion
d) Albedo effect
Q6.Which of the following factors does NOT affect temperature? a) Latitude
b) Altitude c) Humidity d) Longitude
Q7. Match the following temperature ranges (list-I) with their corresponding descriptions (list-II):- Codes: a) A-2, B-1, C-4, D-3 b) A-1, B-2, C-4, D-3 c) A-2, B-1, C-3, D-4 d) A-1, B-2, C-4, D-3
This is all about the Geography Class-4 Temperature. In next class, we will discuss about the Temperature Inversion, Types of Inversion, Humidity etc.
The link of PDF of this Geography Class-3 Atmosphere is given below the explanation of the class, you can download the PDF by going below.
Geography Class-3 Atmosphere
In this Geography Class-3 Atmosphere, we will discuss about the Atmosphere, Primordial Atmosphere, Origin of Atmosphere, Structure of Atmosphere, AQI, NCAP etc.
Topics to be covered in this Article :-
Atmosphere
Primordial Atmosphere
Origin of Atmosphere
Structure of Atmosphere
Temperature of Atmosphere
Air Quality Index (AQI)
National Clean Air Program (NCAP)
Atmosphere
The atmosphere is a layer of gases that surrounds a planet, like Earth. It’s held in place by gravity and extends outward from the planet’s surface. The atmosphere is essential for life on Earth as it provides the air we breathe, shields us from harmful radiation from the sun, and regulates the planet’s temperature. It’s composed of various gases, primarily nitrogen (about 78%) and oxygen (about 21%), with traces of other gases such as carbon dioxide, argon, and water vapor. The atmosphere is divided into several layers based on temperature and composition, each with its own unique characteristics and functions.
Important Points:-
The envelope of gases surrounding the Earth is called the atmosphere.
It plays a crucial role in sustaining life on Earth.
It’s made up of different gases, like oxygen, nitrogen, carbon dioxide, and others.
It protects us from the Sun’s harmful rays and regulates temperature.
Primordial Atmosphere
The primordial atmosphere refers to the very early atmosphere of the Earth. It was formed billions of years ago when the Earth was still in its infancy. This atmosphere was mostly made up of gases like hydrogen and helium.
Originated around 4.6 billion years ago during Earth’s formation.
Mostly composed of hydrogen and helium gases.
Origin of Atmosphere
Primordial atmosphere formed from gases released during Earth’s formation.
Secondary atmosphere developed from volcanic outgassing, releasing gases like carbon dioxide and water vapor.
The atmosphere of the Earth was formed over billions of years through various processes such as volcanic activity, outgassing from the Earth’s interior, and the impact of comets and asteroids. These processes released gases like nitrogen, oxygen, carbon dioxide, and water vapor into the atmosphere.
Structure of Atmosphere
The Earth’s atmosphere is a complex and layered system composed of several distinct layers, each with its own unique characteristics. These layers are defined primarily by changes in temperature with altitude, as well as by the composition of gases within them. From the surface of the Earth upwards, the atmosphere is generally divided into five main layers: the troposphere, stratosphere, mesosphere, thermosphere, and exosphere. Each layer has distinct characteristics and properties.
1. Troposphere:
Altitude Range: Surface of the Earth up to 8 km at the poles and up to 18 km at the Equator.
Temperature Profile: Temperature decreases with increasing altitude.
Key Features:
Most weather phenomena occur here, earning it the title of the “weather-making layer.”
Upper limit is called the tropopause.
Contains about 75-80% of the atmosphere’s mass.
The boundary between the troposphere and the layer above it, known as the stratosphere, is called the tropopause. Above the tropopause, temperature remains relatively constant or may even increase with altitude due to the presence of the ozone layer, which absorbs ultraviolet radiation from the sun.
2. Stratosphere:
Altitude Range: Extends from the tropopause to about 50 km above the Earth’s surface.
Temperature Profile: Temperature increases with increasing altitude, due to ozone absorption of solar ultraviolet radiation.
Key Features:
Often referred to as the ozonosphere due to the concentration of ozone molecules.
Commercial jet planes typically fly in this layer.
Altitude Range: Extends between 50 km and 80 km above the Earth’s surface.
Temperature Profile: Temperature decreases with increasing altitude, reaching lows of around -90°C.
Key Features:
Radio waves transmitted from Earth are reflected back from this layer.
Most meteors nearing Earth’s horizon burn up in this layer.
Uppermost limit is called the mesopause.
4. Thermosphere:
Altitude Range: Extends from the mesopause up to about 500 km above the Earth’s surface.
Temperature Profile: Temperature increases significantly with increasing altitude.
Key Features:
Contains the ionosphere, where ionization of gases occurs due to solar radiation.
Satellite orbits and auroras occur in this layer.
Despite the high temperatures, the density of the thermosphere is very low.
5. Ionosphere:
Altitude Range: The ionosphere extends from about 60 kilometers above the Earth’s surface to roughly 1,000 kilometers and is a region where the Earth’s atmosphere merges with space.
Temperature Profile: Within the ionosphere, there is no distinct temperature profile as seen in other layers of the atmosphere. Temperatures can vary widely depending on factors such as solar activity and altitude within the ionosphere.
Key Features:
This region overlaps with the upper mesosphere, thermosphere, and exosphere.
The ionosphere is divided into several layers, including the D layer, E layer, F layer, and sometimes the G layer. These layers vary in altitude and ionization density depending on factors such as solar activity, time of day, and geographic location.
(i) First layer (i.e. low layer) is called as D-layer. D-layer reflects low frequency radio waves and dissociates after sunset. (ii) Second layer is called as E-layer (also called as Kennelly and Heaviside layer). E-layer reflects medium frequency radio waves and also dissociates after sunset. (iii) Next layer is F-layer (also called as Appleton layer). F-layer reflects high frequency radio waves and partially dissociates after sunset. (iv) Above this, there is G-layer also. G-layer doesn’t dissociates after sunset and doesn’t play important role in radio waves.
The ionosphere plays a crucial role in radio communications and navigation. It reflects and refracts radio waves, allowing long-distance communication beyond the line of sight. This property of the ionosphere is utilized in technologies such as shortwave radio communication, over-the-horizon radar, and global navigation satellite systems (GNSS) like GPS.
Altitude Range: The outermost layer of Earth’s atmosphere. Begins around 500 km above the Earth’s surface and extends indefinitely into space.
Temperature Profile: No distinct temperature profile; temperatures can vary widely.
Key Features:
Transition zone between Earth’s atmosphere and outer space.
Gas molecules in this layer are so sparse that they can travel long distances without colliding with each other.
Satellites orbit within this layer.
Overall, the structure of the Earth’s atmosphere plays a crucial role in regulating the planet’s climate, weather patterns, and the distribution of life. Each layer has its own unique characteristics and importance in maintaining the delicate balance that supports life on Earth.
The temperature of the Earth’s atmosphere varies with altitude and location. In general, the atmosphere’s temperature decreases with increasing altitude in the troposphere, remains relatively stable in the stratosphere, increases in the mesosphere, and can reach extremely high temperatures in the thermosphere.
Carbon dioxide (CO2) concentration in the atmosphere has been increasing due to human activities, primarily burning fossil fuels and deforestation. Too much of it can make Earth warmer.
The amount of carbon-dioxide in the atmosphere has increased along with human emissions since the start of the Industrial Revolution in 1750. CO2 emissions rose slowly to about 5 billion tons a year in the mid-20th century before skyrocketing to more than 35 billion tons per year by the end of the century.
Present State [Global Atmospheric Methane {ppb}]
Methane (CH4) concentration in the atmosphere has also been rising due to agricultural activities, landfills, and fossil fuel production. Too much methane can also make Earth warmer.
Methane is another greenhouse gas, albeit less abundant than CO2.
Its levels have also been rising due to human activities like agriculture and fossil fuel extraction.
The concentration of Methane has increased significantly in 21st century from 1775 ppb (2000) to 1840 ppb presently.
Contribution : 50% of the pollution or carbon-dioxide has comes from Industries, 27% from Vehicles, 17% from crop residues and 7% by domestic cooking etc.
AQI is a measure of how clean or polluted the air is.
It takes into account pollutants like ozone, particulate matter, carbon monoxide, sulfur dioxide, and nitrogen dioxide.
Different levels of AQI indicate different health risks.
It is an index includes 8 major pollutants. A cumulative index is calculated to represent air quality for which a colour is assigned.
PM10 (Particulate Matter → 10)
PM2.5 (Particulate Matter → 2.5)
NO2 (Nitrous Oxide)
O3 (Ozone)
CO (Carbon Monoxide)
SO2 (Sulphur Dioxide)
NH3 (Ammonia)
Pb (lead)
National Clean Air Programme (NCAP)
NCAP is a government initiative to tackle air pollution in India.
It aims to reduce air pollution levels in 131 cities across the country.
Strategies include improving monitoring, reducing emissions, and promoting cleaner technologies.
Previous Year Questions
Q1. The jet aircrafts fly very easily and smoothly in the lower atmosphere. What could be the appropriate explanation? (i) There are no clouds or water vapour in the lower stratosphere. (ii) There are no vertical winds in the lower stratosphere. Which of the statements given above is/are correct in this context? a) i only b) ii only c) Both i and ii d) Neither i nor ii
Explanation: The stratosphere is free from water vapour and dust particles. Absence of clouds and any other factors which may contribute to turbulence in the air makes it a perfect layer fare flying jet aircrafts.
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Q2. The formation of ozone hole in the Antarctic region has been a cause of concern. What could be the reason for the formation of this hole? a) Presence of prominent tropospheric turbulence; and inflow of Chloro-fluoro carbons. b) Presence of prominent polar front and stratospheric clouds; and inflow of chlorofluorocarbons.
c) Absence of polar front and stratospheric clouds; and inflow of methane and chlorofluorocarbons.
d) Increased temperature at polar region due to global warming.
Explanation: The severe depletion of stratospheric ozone in late winter and early spring in the Antarctic is known as the “ozone hole”. The formation of the Antarctic ozone hole is due to abundant reactive halogen gases, temperature’s low enough to form Polar Stratospheric Clouds (PSCs), isolation of air from other stratospheric regions and sunlight. Presence of prominent polar front and stratospheric clouds; and inflow of chlorofluoro carbons (CFC) accelerates the ozone layer formation in Antarctica.
Class Quiz
Q1. What does the Air Quality Index (AQI) measure? a) Humidity levels in the atmosphere b) Concentration of greenhouse gases c) Pollution levels in the air d) Atmospheric pressure variations
Q2. Match the layers of Earth’s atmosphere (List-I) with their altitudinal ranges (List-II): Codes: a) A-2, B-4, C-3, D-1 b) A-2, B-4, C-1, D-3 c) A-4, B-2, C-1, D-3 d) A-4, B-2, C-3, D-1
Q3.Match the components of the primordial atmosphere (List-I) with their approximate proportions (List-II):-
Codes: a) A-1, B-2, C-3, D-4 b) A-1, B-2, C-4, D-3 c) A-3, B-2, C-4, D-1 d) A-2, B-3, C-4, D-1
Q4. Match the column: Codes:
a) A-4, B-3, C-1, D-2
b) A-4, B-3, C-2, D-1
c) A-3, B-4, C-1, D-2
d) A-1, B-2, C-3, D-4
Q5. What role did the escape of lighter gases like hydrogen and helium play in shaping Earth’s early atmosphere? a) They contributed to the formation of the ozone layer b) They influenced the development of early life forms c) They led to the loss of water vapour from the atmosphere d) They facilitated the formation of volcanic eruptions
Q6. Match the components of the National Clean Air Program (List-1) with their objectives (List -II):- Codes: a) A-2, B-3, C-1 b) A-2, B-1, C-3 c) A-3, B-2, C-1 d) A-1, B-2, C-3
Q7. Match the following pollutants with their impact on air quality:- Codes: a) A-2, B-4, C-3, D-1 b) A-2, B-4, C-1, D-3 c) A-3, B-4, C-1, D-2 d) A-3, B-4, C-2, D-1
Q8. Which atmospheric layer is characterized by the presence of the ozone layer? a) Troposphere b) Mesosphere c) Stratosphere d) Thermosphere
This is all about the Geography Class-3 Atmosphere. In next class, we will discuss about the Temperature, Factors affecting temperature, Distribution of temperature etc.
The link of PDF of this Geography Class-2 is given below the explanation of the class, you can download the PDF by going below.
Geography Class-2
In this Geography Class-2, we will discuss about the Geography, Shape of Earth, Reasons for occurring Seasons etc.
Topics to be covered in this Article :-
Introduction to Geography
Shape of the Earth
Reasons for occurring Seasons
Zones of Earth
Geography
The word “Geography” is derived from two Greek words :- “Geo” and “Graphy”. Geo means Earth and Graphy word comes from
the word “Graphine” – means “to describe”.
∴ Geography means “the description of Earth”.
In simple terms, Geography is all about learning and understanding our planet Earth—its land, water, weather, and the people and animals that live on it. It’s like exploring a big puzzle, figuring out where things are and why they are there. Geography helps us know more about our world and how we interact with it every day.
Father of Geography : Eratosthenes
Shape of the Earth
The shape of the Earth is best described as an oblate spheroid (Geoid Shape). This means that it’s mostly spherical, like a ball, but slightly flattened at the poles and slightly bulging at the equator. Imagine a ball that’s been squished a bit on the top and bottom. This shape is due to the Earth’s rotation, which causes a slight outward force at the equator and flattens the poles. So, it’s kind of like a slightly flattened ball. That’s why it’s called an oblate spheroid.
1. Revolution of Earth: Imagine Earth as a passenger on a giant merry-go-round, with the sun as the center. This merry-go-round doesn’t just spin in one place; it travels around the sun in a big loop. This journey is what we call Earth’s revolution. It takes about 365 days for Earth to complete one full trip around the sun.
As Earth moves along its path, different parts of it receive varying amounts of sunlight. When one part is closer to the sun, it gets more direct sunlight, making it warmer. This is what we experience as summer. Meanwhile, when that part moves away from the sun, it receives less direct sunlight, leading to cooler temperatures – that’s winter.
Equinoxes and Solstices: There are four main points in the Earth’s orbit that mark the beginning of each season. These are called the equinoxes and solstices.
Spring Equinox: Around March 21st, the tilt of the Earth is such that both hemispheres receive about the same amount of sunlight. This marks the beginning of spring.
Summer Solstice: Around June 21st, the hemisphere tilted towards the sun receives the most sunlight, making it the longest day of the year and the beginning of summer.
Autumn Equinox: Around September 22nd, the tilt of the Earth is again such that both hemispheres receive about the same amount of sunlight, marking the beginning of autumn.
Winter Solstice: Around December 21st, the hemisphere tilted away from the sun receives the least sunlight, making it the shortest day of the year and the beginning of winter.
2. Axial Tilt of Earth: Now, let’s imagine Earth as a spinning top that’s slightly tilted to one side. This tilt is what we call Earth’s axial tilt. It’s like if you were to lean a top slightly as you spin it. Earth’s axis is an imaginary line that runs through its North and South Poles, and this tilt causes different parts of the planet to be angled towards or away from the sun as it revolves.
Because of this tilt, the sunlight hits the Earth’s surface at different angles throughout the year. When one hemisphere (half of Earth) is tilted towards the sun, it gets more direct sunlight and experiences warmer temperatures. This is summer for that hemisphere. Meanwhile, the other hemisphere is tilted away from the sun, receiving less direct sunlight and experiencing cooler temperatures – this is winter for that hemisphere.
The occurrence of seasons on Earth is a result of the combined effects of Earth’s revolution around the Sun and its axial tilt. These two factors work together to create variations in sunlight intensity and day length throughout the year, shaping the climate and natural rhythms of life on our planet.
Zones of Earth
The Earth is divided into several distinct climatic zones based on latitude and other geographical factors. These zones play a crucial role in determining the weather patterns, biodiversity, and ecosystems across the planet. These zones are as follows:-
1. Polar / Frigid Zones:
Located near the North and South Poles, extending from approximately 66.5 degrees to the respective poles.
Characterized by extremely cold temperatures, with long winters and short, cool summers.
Vegetation is sparse, consisting mainly of mosses, lichens, and small shrubs. Animal life includes species adapted to cold conditions, such as polar bears, seals, and penguins.
2. Tropical / Torrid Zone:
Situated near the equator, between the Tropic of Cancer (23.5 degrees north) and the Tropic of Capricorn (23.5 degrees south).
Experiences consistently high temperatures throughout the year, with little variation between seasons.
Rich biodiversity, with lush rainforests, diverse plant species, and a wide array of animal life including tropical birds, monkeys, and reptiles.
3. Temperate Zones:
Found between the tropics and the polar regions, roughly from 23.5 to 66.5 degrees north and south of the equator.
Moderate temperatures with distinct seasons: warm summers and cool winters.
Diverse vegetation including deciduous and coniferous forests, grasslands, and mixed forests.
Supports a wide range of wildlife including deer, bears, wolves, and various bird species.
4. Subtropical Zones:
Located adjacent to the tropical zones, roughly between 23.5 and 35 degrees north and south of the equator.
Characterized by warm to hot temperatures year-round, with relatively mild winters.
Vegetation includes a mix of tropical and temperate species, with areas of grasslands, shrubs, and scattered trees.
Wildlife is diverse, with species adapted to both tropical and temperate conditions.
These zones play a crucial role in shaping the Earth’s climate, weather patterns, and ecosystems. They influence everything from the distribution of plant and animal species to human activities and cultures. Understanding these zones is essential for comprehending the complex dynamics of the Earth’s biosphere.
Q1. On 21st June, the sun (2019) a) does not set below the horizon at the Arctic circle. b) does not set below the horizon at the Antarctic Circle. c) shines vertically overhead at noon on the Equator. d) shines vertically overhead at the Tropic of Capricorn.
Explanation: 21st June is the longest day in the Northern Hemisphere, technically this day is referred to as “Summer Solstice”. On 21st June, the Tropic of Cancer is tilted towards the sun i.e. the sun is always above the horizon and does not set below the horizon at the Arctic Circle. After the summer solstice, the sun starts to sink towards the horizon. As the rays of the sun fall directly on the Tropic of Cancer, the northern hemisphere experience more heat.
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Q2. Variations in the length of daytime and night-time from season to season are due to (2013) a) the earth’s rotation on its axis. b) the earth’s revolution round the sun in an elliptical manner. c) latitudinal position of the place. d) revolution of the earth on a tilted axis.
Explanation: Variations in the length of daytime and night-time from season to season are due to the “revolution of the Earth on a tilted axis”. Our earth is revolving around the sun in on elliptical orbit, and one complete revolution around the sun takes the time period of one year. During this one year long revolution process, the distance between the earth and sun changes continuously, because there is no constant diameter of the elliptical orbit and this changes of distance are the main reason behind the change of day time and night-time expansions. The above 3 options (a), (b) and (c) does not directly affect the variations in the length of daytime and night- time from season to reason.
Class Quiz
Q1. The Earth is best described as which of the following shapes? a) Perfect sphere b) Oblate spheroid c) Cube d) Cylinder
Q2. Match the column: Codes: a) A-1, B-2, C-3 b) A-2, B-3, C-1 c) A-3, B-1, C-2 d) A-1, B-3, C-2
Q3. Which geographic zone is characterized by cold temperatures year-round and long periods of darkness in winter? a) Tropical Zone b) Temperate zone c) Polar Zone d) Equatorial zone
Q4. Match the column: Codes:
a) A-3, B-4, C-1, D-2
b) A-3, B-4, C-2, D-1
c) A-4, B-3, C-1, D-2
d) A-4, B-3, C-2, D-1
Q5. The shape of the Earth was first determined by: a) Aristotle b) Nicolaus Copernicus c) Galileo Galilei d) Eratosthenes
This is all about the Geography Class-2. In next class, we will discuss about the Atmosphere, Origin of Atmosphere, Structure of Atmosphere etc.
The link of PDF of this Geography Class-1 is given below the explanation of the class, you can download the PDF by going below.
Geography Class-1
In this Geography Class-1, we will discuss about the Syllabus of Geography for Prelims and Mains, UPSC Geography Trend Analysis for Prelims and Mains, Some Previous Years UPSC Geography Questions for Prelims and Mains etc.
Syllabus for UPSC Prelims (Geography):-
Indian and World Geography – Physical, Social, Economic geography of India and the World.
Syllabus for UPSC Mains (Geography):-
Salient features of the world’s physical geography.
Distribution of key natural resources across the world (including South Asia and the Indian sub-continent); factors responsible for the location of primary, secondary, and tertiary sector industries in various parts of the world (including India).
Important Geophysical phenomena such as earthquakes, Tsunami, Volcanic activity, Cyclone, etc., geographical features and their location changes in critical geographical features (including water-bodies and ice-caps) and in flora and fauna and the effects of such changes.
UPSC Geography Trend Analysis (Prelims)
UPSC Geography Trend Analysis (Mains)
Some Previous Years’ UPSC Prelims Questions (Geography)
Q1. The jet aircrafts fly very easily and smoothly in the lower stratosphere. What could be the appropriate explanation?(2011) 1. There are no clouds or water vapour in the lower stratosphere. 2. There are no vertical winds in the lower stratosphere.
Which of the statements given above is/are correct in this context? a) 1 only b) 2 only c) Both 1 and 2 d) Neither 1 nor 2
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Q2. Consider the following crops of India: (2012) 1. Groundnut 2. Sesamum 3. Pearl Millet
Which of the above is/are predominantly rainfed crop/crops? a) 1 and 2 only b) 2 and 3 only c) 3 only d) 1, 2 and 3
Q3. Variations in the length of daytime and night-time from season to season are due to (2013) a) the earth’s rotation on its axis b) the earth’s revolution round the sun in an elliptical manner c) latitudinal position of the place d) revolution of the earth on a tilted axis
Q4. The seasonal reversal of winds is the typical characteristic of (2014) a) Equatorial climate b) Mediterranean climate c) Monsoon climate d) All of the above climates
Q5. Tides occur in the oceans and seas due to which among the following? (2015) 1. Gravitational force of the Sun 2. Gravitational force of the Moon 3. Centrifugal force of the Earth
Select the correct answer using the code given below: a) 1 only b) 2 and 3 only c) 1 and 3 only d) 1, 2 and 3
Q6. Which of the following is/are tributary / tributaries of Brahmaputra? (2016) 1. Dibang 2. Kameng 3. Lohit
Select the correct answer using the code given below: a) 1 only b) 2 and 3 only c) 1 and 3 only d) 1, 2 and 3
Q7. Consider the following statements: (2017) 1. In India, the Himalayas. are spread over five states only. 2. Western Ghats are spread over five states only. 3. Pulicat Lake is spread over two states only.
Which of the statements given above is/are correct? a) 1 and 2 only b) 3 only c) 2 and 3 only d) 1 and 3 only
Q8. Consider the following statements: (2018) 1. The Barren Island volcano is an active volcano located in the Indian territory. 2. Barren Island lies about 140 km east of Great Nicobar. 3. The last time the Barren Island volcano erupted was in 1991 and it has remained inactive since then.
Which of the statements given above is/are correct? a) 1 only b) 2 and 3 c) 3 only d) 1 and 3
Q9. On 21st June, the Sun (2019) (a) does not set below the horizon at the Arctic Circle. b) does not set below the horizon at the Antarctic Circle. c) shines vertically overhead at noon on the Equator. d) shines vertically overhead at the Tropic of Capricorn.
Q10.Siachen Glacier is situated to the (2020) a) East of Aksai Chin b) East of Leh c) North of Gilgit d) North of Nubra Valley
Q11. Consider the following rivers: (2021) 1. Brahmani 2. Nagavali 3. Subarnarekha 4. Vamsadhara
Which of the above rise from the Eastern Ghats? a) 1 and 2 b) 2 and 4 c) 3 and 4 d) 1 and 3
Q12. Consider the following pairs: (2022)     Peak            Mountains 1. Namcha Barwa – Garhwal Himalaya 2. Nanda Devi    – Kumaon Himalaya 3. Nokrek        – Sikkim Himalaya
Which of the pairs given above is/are correctly matched? a) 1 and 2 b) 2 only c) 1 and 3 d) 3 only
Q13. Consider the following pairs: (2023)       Port                    Well Known as 1. Kamarajar Port       : First major Port in India registered as a company 2. Mundra Port         : Largest privately owned port in India 3. Vishakhapatnam Port : Largest container port in India
How many of the above pairs are correctly matched? a) Only one pair b) Only two pairs c) Only three pairs d) None of the pairs
Some Previous Years’ UPSC Mains Questions (Geography)
Q1. Major hot deserts in the northern hemisphere are located between 20-30 deg N latitudes and on the western side of the continents. Why? (200 Words) [10 Marks](2013)
Q2. Tropical cyclones are largely confined to South China Sea, Bay of Bengal and Gulf of Mexico. Why? (250 Words) [10 Marks](2014)
Q3. Explain the factors responsible for the origin of ocean currents. How do they influence regional climates, fishing and navigation? (250 Words) [12.5 Marks](2015)
Q4. “The Himalayas are highly prone to landslides.” Discuss the cause and suggest suitable measures of mitigation. (200 Words) [12.5 Marks](2016)
Q5. What characteristics can be assigned to monsoon climate that succeeds in feeding more than 50 percent of the world population residing in Monsoon Asia? (250 Words) [15 Marks](2017)
Q6. Defining blue revolution, explain the problems and strategies for pisciculture development in India. (Answer in 250 Words) [15 Marks](2018)
Q7. What is water stress ? How and why does it differ regionally in India? (Answer in 250 Words) [15 Marks](2019)
Q8. The process of decertification does not have climatic boundaries. Justify with examples. (Answer in 150 Words) [10 Marks](2020)
Q9. How do the melting of the Arctic ice and glaciers of the Antarctic differently affect the weather patterns and human activities on the Earth? Explain. (Answer in 250 Words) [15 Marks](2021)
Q10. Troposphere is a very significant atmospheric layer that determines weather processes. How? (Answer in 250 Words) [15 Marks](2022)
Q11. Why is the South-West Monsoon called ‘Purvaiya’ (easterly) in Bhojpur region? How has this directional seasonal wind system influenced the cultural ethos of the region? (Answer in 150 Words) [10 Marks](2023)
This is all about the Geography Class-1. In next class, we will discuss about the Introduction of Geography, Shape of the Earth, Reasons for occurring of seasons etc.
