All questions of Climatology for BPSC (Bihar) Exam

All statements are correct; hence answer is (d). There are six major controls of the climate of any place. They are latitude, altitude, pressure and wind system, distance from the sea (continentality), ocean currents and relief features.

Inter-tropical Convergence Zone (ITCZ)

The Inter-tropical Convergence Zone (ITCZ) is a significant belt of low pressure around the Earth's equator where the northeast and southeast trade winds converge. It is characterized by rising air, unstable weather conditions, and abundant rainfall. Let's evaluate each statement:

Statement 1: It is an area near the Equator where northeast and southeast trade winds meet.
This statement is correct. The ITCZ is formed by the convergence of the northeast trade winds from the Northern Hemisphere and the southeast trade winds from the Southern Hemisphere. As these trade winds converge, they ascend due to the low-pressure system, resulting in the formation of clouds and precipitation.

Statement 2: The zone is referred to as the doldrums because of its erratic weather patterns with stagnant calms and violent thunderstorms.
This statement is also correct. The region of the ITCZ is often referred to as the doldrums because of its unpredictable and erratic weather patterns. The convergence of trade winds creates areas of calm or light and variable winds, which can lead to stagnation and little to no wind movement. Additionally, thunderstorms are common in this area due to the convective activity caused by the rising warm air.

Statement 3: If ITCZ is north of the equator, the southeast trade wind changes to a southwest wind as it crosses the equator because of the Coriolis effect.
This statement is correct as well. The Coriolis effect, caused by the Earth's rotation, influences the wind direction. As the southeast trade winds approach the ITCZ from the Southern Hemisphere, they are deflected to the left (westward) in the Northern Hemisphere due to the Coriolis effect. Therefore, as they cross the equator, the southeast trade winds change direction and become southwest winds.

In conclusion, all three statements are correct. The ITCZ is an area near the equator where northeast and southeast trade winds converge. It is referred to as the doldrums due to its erratic weather patterns with stagnant calms and violent thunderstorms. The Coriolis effect causes the southeast trade winds to change direction to southwest winds as they cross the equator.

Assertion and Reasoning

Assertion: The annual range of temperature is greater in the Northern Hemisphere than that in the Southern Hemisphere.

Reasoning: Northern Hemisphere has more land area than Southern Hemisphere.

Explanation

The correct option is A, i.e., A is correct, and R is an appropriate explanation of A.

The annual range of temperature refers to the difference between the maximum and minimum temperatures recorded in a year. The Northern Hemisphere has more land area than the Southern Hemisphere. Land areas heat up and cool down faster than water bodies. As a result, the temperature changes are more drastic and the annual range of temperature is greater in the Northern Hemisphere.

For instance, in the Northern Hemisphere, the annual range of temperature in some regions can be as much as 50-60°C. In contrast, the annual range of temperature in the Southern Hemisphere is comparatively lower, with some regions having an annual range of 20-30°C.

Conclusion

Thus, the assertion is correct, and the reasoning is an appropriate explanation of the assertion. The difference in land area between the Northern Hemisphere and Southern Hemisphere is responsible for the difference in the annual range of temperature.

Zero Coriolis force at the equator:
- The Coriolis force is responsible for the deflection of winds in the Northern and Southern Hemispheres.
- At the equator, the Coriolis force is nearly zero due to the minimal effect of the Earth's rotation on the winds.

Presence of roaring forties:
- The roaring forties are strong westerly winds found in the Southern Hemisphere, generally between 40 and 50 degrees latitude.
- These winds are located much farther from the equator and do not directly impact the deflection of winds at the equator.

A large number of land breaks and bays:
- Landmasses and bodies of water, such as bays, can influence the direction and speed of winds.
- At the equator, there are a large number of land breaks and bays that can disrupt the flow of winds, leading to less deflection.

In conclusion, the winds are not deflected with great force at the equator primarily due to the zero Coriolis force at the equator. The presence of the roaring forties and a large number of land breaks and bays also play a role, but they are not as significant as the absence of the Coriolis force at the equator.

The correct answer is option 'C' - 1 and 2 only.

Explanation:
The Roaring Forties are strong westerly winds found in the Southern Hemisphere. These winds are primarily caused by two factors:

1. Air being displaced from the Equator towards the South Pole:
The Earth's rotation and the difference in temperature between the equator and the poles create a pressure gradient, causing air to flow from the equator towards the poles. This flow of air is known as the Ferrel cell. In the Southern Hemisphere, the air is deflected to the left due to the Coriolis effect, resulting in the westerly winds known as the Roaring Forties.

2. Earth's rotation:
The rotation of the Earth also plays a significant role in the formation of the Roaring Forties. The Coriolis effect, which is caused by the rotation of the Earth, causes the moving air to be deflected to the left in the Southern Hemisphere. This deflection is what creates the westerly winds.

However, the other options mentioned in the question are not directly responsible for the formation of the Roaring Forties:

3. Equatorial counter-currents:
Equatorial counter-currents refer to the eastward flowing currents found near the equator. While these currents do influence the ocean currents and atmospheric circulation patterns, they are not the main cause of the Roaring Forties.

4. Thermal dipole created in the Pacific Ocean:
A thermal dipole refers to the contrast in sea surface temperatures between two regions. While temperature differences can affect atmospheric circulation, a thermal dipole in the Pacific Ocean does not directly cause the Roaring Forties.

In conclusion, the Roaring Forties are primarily caused by the displacement of air from the Equator towards the South Pole and the Earth's rotation. Other factors such as equatorial counter-currents and thermal dipoles may influence the atmospheric circulation patterns but are not the primary causes of the Roaring Forties.

The general distribution of winds throughout the lower atmosphere is known as planetary winds. Confined within some latitudinal belts, these winds blow rather regularly throughout the year and are basically controlled by the latitudinal pressure belts.

The main planetary winds are (i) the North-east and the South-east Trade winds, (ii) the Temperate Westerlies and (iii) the Polar Easterlies, which blow from the polar high-pressure area to the temperate low-. Pressure area.

All of them are affected by Coriolis force (Earth's rotation on its axis), and migration of pressure belts apart from how heat patterns vary across the Earth (creating pressure difference).

Explanation:

Absolute Humidity:
Absolute humidity refers to the actual amount of moisture present in the air, regardless of temperature. It is a measure of the total water vapor content in a given volume of air and is usually expressed in grams per cubic meter (g/m3) or grams per kilogram (g/kg).

Relative Humidity:
Relative humidity is the ratio of the actual amount of moisture present in the air to the maximum amount of moisture the air can hold at a particular temperature. It is expressed as a percentage and provides a measure of how close the air is to saturation. Relative humidity is dependent on both the temperature and the absolute humidity.

Specific Humidity:
Specific humidity is a measure of the actual amount of moisture present in the air on a mass basis. It is the ratio of the mass of water vapor to the total mass of the air parcel. Specific humidity is expressed in grams per kilogram (g/kg) and is not dependent on temperature.

Analysis of the Statements:
1. Absolute humidity is the water content of the air.
This statement is correct. Absolute humidity refers to the actual amount of moisture present in the air.

2. Relative humidity, expressed as a per cent, measures the current absolute humidity relative to the maximum for that temperature.
This statement is correct. Relative humidity is a measure of the current absolute humidity relative to the maximum amount of moisture the air can hold at a particular temperature.

3. Specific humidity is a ratio of the water vapor content of the mixture to the total air content on a mass basis.
This statement is incorrect. Specific humidity is a ratio of the water vapor content of the mixture to the total mass of the air parcel, not the total air content. It is not dependent on temperature.

Conclusion:
Based on the analysis, statement 3 is incorrect, while statements 1 and 2 are correct. Therefore, the correct answer is option 'D' - None of the above.

Rotation of earth on its axis gives rise to Coriolis force.

Temperature inversion is most common in Mountain valleys.

Explanation:

Temperature inversion refers to a reversal of the normal atmospheric temperature gradient, where the temperature increases with altitude. In other words, instead of the temperature decreasing as we go higher in the atmosphere, it actually increases. This phenomenon is caused by the trapping of cool air near the surface of the Earth by a layer of warm air above it.

Inversions can occur in various locations, but they are most common in mountain valleys. Here's why:

1. Geographic Features:
- Mountain valleys are characterized by their topography, with high mountains surrounding a narrow valley floor.
- This topography plays a crucial role in the formation of temperature inversions.
- During the day, the sun heats up the valley floor, causing the air near the surface to warm and rise.
- However, at night, the valley floor cools rapidly due to radiative cooling, causing the air near the surface to become colder than the air above it.

2. Cold Air Drainage:
- In mountain valleys, cold air tends to drain down the slopes and accumulate in the valley bottom.
- This cold air becomes trapped beneath a layer of warmer air, leading to the formation of a temperature inversion.
- The surrounding mountains act as barriers, preventing the cold air from mixing with the warmer air above.

3. Stable Atmospheric Conditions:
- Temperature inversions are more likely to occur when the atmosphere is stable.
- In stable atmospheric conditions, there is little vertical mixing of air masses, allowing the inversion layer to persist.
- Mountain valleys often experience stable atmospheric conditions, especially during calm and clear nights when radiative cooling is most effective.

4. Local Climate:
- Mountain valleys tend to have specific climatic conditions that favor the formation of temperature inversions.
- The cool air trapped in the valley can lead to the accumulation of pollutants, such as smoke or fog, which further enhance the inversion layer.
- This can result in poor air quality and reduced visibility in these areas.

In conclusion, temperature inversions are most common in mountain valleys due to the geographic features, cold air drainage, stable atmospheric conditions, and local climate characteristics associated with these regions.

Insolation over continents and oceans at the same latitude

Insolation refers to the amount of solar radiation that reaches a specific area. It plays a significant role in determining the climate and weather patterns of a region. In this context, we are comparing the insolation over continents and oceans at the same latitude.

1. Oceans are cloudier:
- Oceans have a higher potential to be cloudier compared to continents. This is because water bodies have higher evaporation rates, leading to increased moisture content in the atmosphere.
- The presence of clouds can significantly affect the amount of solar radiation reaching the surface. Clouds can reflect or absorb solar radiation, reducing the amount that reaches the surface.
- Therefore, due to the higher likelihood of cloud cover over oceans, the insolation is generally lower compared to continents at the same latitude.

2. Continents have varied relief:
- Continents are characterized by varied relief features such as mountains, plateaus, and plains. These relief features can influence the distribution of solar radiation.
- Mountains, for example, can intercept the path of incoming solar radiation, causing shadows and reducing the amount of insolation reaching the surface. This phenomenon is known as the orographic effect.
- In contrast, plains and low-lying areas tend to receive more direct solar radiation as there are no significant barriers to block or divert the incoming solar radiation.
- Therefore, the varied relief of continents can lead to differences in the distribution of insolation at the same latitude compared to oceans.

Conclusion:
Based on the above discussion, it can be concluded that both statements are correct:
a) Oceans are cloudier.
b) Continents have varied relief.
Therefore, the correct answer is option 'A' - both 1 and 2.

Explanation:
The thermal equator is an imaginary circle around the Earth that connects the points where the highest mean annual temperature is recorded at each longitude. The following points explain why the thermal equator is slightly north of the geographical equator:

- Solar insolation is comparatively much higher in the Northern Hemisphere than in the Southern Hemisphere. This is due to the fact that the Earth's orbit is not circular but slightly elliptical. As a result, the Earth is closer to the Sun during the Northern Hemisphere summer than during the Southern Hemisphere summer. This means that there is more solar radiation falling on the Northern Hemisphere, leading to higher temperatures.

- The Northern Hemisphere is dominated by land, which heats up faster than water. Land has a lower heat capacity than water, which means that it takes less energy to raise its temperature. This is why temperatures in the interior of continents can be much higher than temperatures on the coasts. In contrast, the Southern Hemisphere is dominated by ocean waters, which have a higher heat capacity and take longer to warm up. This leads to lower temperatures in the Southern Hemisphere.

Therefore, both factors contribute to the fact that the thermal equator is slightly north of the geographical equator. Option B is the correct answer.

Distribution of land:
- The distribution of land on Earth plays a significant role in the daily weather changes.
- Land heats up and cools down more quickly than water, leading to temperature variations between land and water bodies.
- During January, when the Northern Hemisphere is tilted away from the Sun, the landmasses in the Northern Hemisphere receive less direct sunlight, resulting in lower temperatures compared to the Southern Hemisphere.
- In July, when the Northern Hemisphere is tilted towards the Sun, the landmasses in the Northern Hemisphere receive more direct sunlight, leading to higher temperatures compared to the Southern Hemisphere.
- This temperature difference between land and water influences the formation of pressure systems and wind patterns, which in turn affect daily weather changes.

Atmospheric circulation:
- Atmospheric circulation is driven by the unequal heating of Earth's surface, which is influenced by the tilt of the Earth and distribution of landmasses.
- The Sun's rays heat the equator more than the poles, resulting in warm air rising at the equator and cool air sinking at the poles.
- This creates global wind patterns, such as the trade winds and prevailing westerlies, which play a crucial role in daily weather changes.
- The variation in solar output between January and July affects the strength and position of these wind patterns, influencing the movement of air masses and the distribution of weather systems.
- However, the overall effect of solar variation on daily weather changes is relatively small compared to other factors, such as local topography, proximity to water bodies, and the presence of weather systems like cyclones.

Extra-tropical cyclones:
- Extra-tropical cyclones, also known as mid-latitude cyclones, are large-scale weather systems that occur outside the tropics.
- They are formed by the interaction of warm and cold air masses along the boundary known as the polar front.
- These cyclones are driven by the temperature differences between land and water, as well as the variation in solar output.
- While the variation in solar output between January and July can influence the strength and position of extra-tropical cyclones, their occurrence and daily weather changes are also influenced by other atmospheric factors, such as jet streams, upper-level troughs, and frontal boundaries.
- Therefore, although extra-tropical cyclones are affected by solar variation, they are not solely determined by it, and other factors play a significant role in daily weather changes.

In conclusion, the distribution of land and atmospheric circulation are the primary factors that explain why the variation in solar output between January and July does not have a significant effect on daily weather changes on the surface of the Earth. The variation in solar output influences temperature variations between land and water, which in turn affect pressure systems, wind patterns, and the movement of air masses. However, daily weather changes are also influenced by other factors such as local topography, proximity to water bodies, and the presence of weather systems like extra-tropical cyclones.

Explanation:

1. Climate change is leading to increased frequency and intensity of heatwaves.
Climate change refers to long-term changes in temperature, precipitation, wind patterns, and other aspects of the Earth's climate system. It is widely accepted that human activities, particularly the burning of fossil fuels, have significantly contributed to climate change. As a result, the Earth's average temperature is increasing, leading to various impacts, including an increase in the frequency and intensity of heatwaves. Heatwaves are prolonged periods of excessively hot weather, typically lasting for several days or even weeks. The rising temperatures due to climate change create favorable conditions for heatwaves to occur more frequently and with greater intensity.

2. In India, it is most commonly experienced in North-Western regions.
India experiences heatwaves across various regions, but they are most commonly observed in the North-Western parts of the country. This region includes states like Rajasthan, Gujarat, Punjab, Haryana, and parts of Madhya Pradesh. These areas are known for their arid or semi-arid climate, which makes them more prone to extreme heat conditions. Factors such as geographical location, proximity to deserts, and the absence of significant water bodies contribute to the higher occurrence of heatwaves in these regions.

3. As per NDMA guidelines, when local temperature is constantly above 40°C, heatwaves must be declared by local authorities.
The National Disaster Management Authority (NDMA) is responsible for planning, coordinating, and implementing measures for disaster management in India. The NDMA has issued guidelines regarding the declaration of heatwaves by local authorities. According to these guidelines, a heatwave is declared when the local temperature consistently remains above 40°C for a certain period. This threshold temperature helps authorities in identifying and responding to heatwave situations, ensuring appropriate measures are taken to protect vulnerable populations from the adverse effects of extreme heat.

Correct Answer:
Based on the given information, the correct answer is option 'A' - 1 and 2 only. The statement that climate change is leading to increased frequency and intensity of heatwaves is supported by scientific consensus. The statement about heatwaves being most commonly experienced in North-Western regions of India is also accurate. However, there is no mention of the NDMA guidelines in the given information, so the statement regarding the declaration of heatwaves by local authorities is not supported.

Gravitational forces acting on air

- The reason why air closer to the Earth's surface is heavier is due to the gravitational forces acting on it.
- Gravity is a force that pulls objects towards the center of the Earth. It is responsible for keeping the atmosphere in place.
- The force of gravity is stronger closer to the Earth's surface and weaker as you move further away from it.
- As a result, the air molecules near the surface experience a greater gravitational force compared to those in the upper atmosphere.

Effect of gravitational forces on air

- The gravitational force causes the air molecules to be pulled towards the Earth's surface, creating pressure.
- This pressure is known as atmospheric pressure and it decreases with increasing altitude.
- The weight of the air above a certain point in the atmosphere creates pressure at that point.
- Therefore, the air closer to the Earth's surface experiences a higher atmospheric pressure compared to the air in the upper atmosphere.

Density and weight of air

- The air near the Earth's surface is denser compared to the air in the upper atmosphere.
- Density is the mass of an object per unit volume. The denser the air, the more mass it contains in a given volume.
- The weight of an object is the force exerted on it due to gravity. The weight of air is determined by its mass.
- Since the air near the Earth's surface has a higher density, it also has a higher mass per unit volume, resulting in a higher weight.

Conclusion

- In conclusion, the air closer to the Earth's surface is heavier because of the gravitational forces acting on it.
- These forces cause the air molecules to be pulled towards the Earth, creating higher atmospheric pressure and denser air near the surface.
- Understanding the effects of gravity on the atmosphere is important for studying weather patterns, air circulation, and other atmospheric phenomena.

Assertion (A): The eastern coasts of continents within the tropics have much heavier rainfall than the interiors of the west coasts.
Reason (R): All western coasts fall in the rain shadow zone.

The correct answer is option 'C', which states that Assertion (A) is correct, but Reason (R) is incorrect.

Explanation:

Eastern Coasts of Continents within the Tropics have Heavier Rainfall:
- The eastern coasts of continents within the tropics, such as the eastern coast of India or the eastern coast of Africa, receive heavier rainfall compared to the interiors of the west coasts.
- This is due to the prevailing wind patterns in the tropics, specifically the trade winds.
- The trade winds blow from east to west in the tropics, carrying moist air from the oceans towards the western coasts of continents.
- As the moist air encounters the landmass, it is forced to rise, leading to the formation of clouds and subsequent rainfall along the western coasts.
- This phenomenon is known as orographic rainfall, where the moist air is lifted over a mountain or elevated terrain, resulting in enhanced precipitation.
- As a result, the western coasts of continents within the tropics receive significant rainfall.

Rain Shadow Zone:
- The rain shadow zone refers to the area that lies on the leeward side of a mountain range or elevated terrain.
- When moist air is lifted over a mountain range, it cools and condenses, leading to rainfall on the windward side of the mountain.
- However, as the air descends on the leeward side, it warms and dries up, resulting in reduced rainfall and arid conditions.
- This creates a rain shadow zone, which is characterized by low precipitation and dry climate.
- The rain shadow effect is prominent on the leeward side of mountain ranges, where the prevailing winds are blocked by the mountains, preventing the moist air from reaching the area.

Reason (R) is Incorrect:
- While it is true that western coasts often experience the rain shadow effect, it is not true that all western coasts fall in the rain shadow zone.
- There are several factors that determine the occurrence of the rain shadow effect, including the direction of prevailing winds, the height and orientation of the mountain range, and the distance from the coast.
- In some cases, the western coasts may not be affected by the rain shadow effect and may receive significant rainfall due to other atmospheric factors or geographical features.

Conclusion:
- The assertion that the eastern coasts of continents within the tropics have heavier rainfall than the interiors of the west coasts is correct.
- However, the reason that all western coasts fall in the rain shadow zone is incorrect, as it does not consider the various factors that determine the occurrence of the rain shadow effect.

Why do rain clouds appear black in colour despite having the Sun above them?

Explanation:
Rain clouds appear black in colour despite having the Sun above them primarily because clouds scatter the light they receive. Let's understand each option given in the question to arrive at the correct answer:

1. Clouds accumulate electrostatic charge:
This option is incorrect as the accumulation of electrostatic charge in clouds does not cause them to appear black in colour.

2. Rain-bearing clouds absorb most of the solar insolation falling on them:
This option is incorrect as rain-bearing clouds do not absorb most of the solar insolation falling on them. Instead, they reflect and scatter a significant portion of the sunlight they receive.

3. Clouds scatter light received by them:
This option is correct. Clouds are made up of tiny water droplets or ice crystals, which act as scattering centers for the incoming sunlight. When sunlight passes through a cloud, the individual water droplets scatter the light in all directions. This scattering of light causes the cloud to appear white or gray to the observer on the ground. However, when rain clouds become thicker and denser, they scatter more light and absorb less, resulting in a darker appearance. The thicker the cloud, the more light it scatters, making it appear darker or even black.

Therefore, the correct answer is option 'D' - 3 only, which states that rain clouds appear black in colour because clouds scatter the light received by them.

In conclusion, rain clouds appear black in colour despite having the Sun above them because of the scattering of light by the water droplets or ice crystals present in the clouds. The thicker and denser the clouds, the more light they scatter, resulting in a darker appearance.

Explanation:
Rainfall patterns are influenced by various factors, including solar insolation, atmospheric circulation, and temperature gradients. When moving from the equator to the poles, there is a general trend of reducing rainfall. This can be explained by the change in solar insolation.

Change in solar insolation:
Solar insolation refers to the amount of solar radiation or sunlight received at a particular location. The intensity of solar radiation decreases as one moves away from the equator towards the poles. This is mainly due to the curvature of the Earth and the angle at which sunlight reaches the surface.

- At the equator, the Sun's rays are more direct, resulting in higher solar insolation. This leads to warmer temperatures and increased evaporation, which in turn contributes to higher rainfall.
- As one moves towards the poles, the angle at which sunlight reaches the surface becomes more oblique. This reduces the amount of solar radiation received, resulting in lower temperatures and decreased evaporation. Consequently, the amount of moisture available for condensation and rainfall decreases.

Other factors:
While solar insolation is the primary factor influencing rainfall patterns from the equator to the poles, other factors can also play a role:

- Atmospheric circulation: The movement of air masses and prevailing winds can affect rainfall patterns. However, in the context of the given options, it is not the main factor responsible for the reducing rainfall pattern.
- Formation of wavy isotherms at the equator: Isotherms are lines on a map connecting points with equal temperature. The formation of wavy isotherms at the equator can result in localized convective rainfall, but it does not explain the general trend of reducing rainfall when moving polewards.
- Movement of the jet stream along the way: The jet stream is a high-speed wind current in the upper troposphere. It can influence weather patterns, but its movement alone does not explain the reducing rainfall pattern.

In conclusion, the primary reason for the reducing rainfall pattern when moving from the equator to the poles is the change in solar insolation. As the angle of sunlight decreases and the amount of solar radiation received reduces, there is less evaporation and moisture available for rainfall.

Explanation:

Capacity of air to hold moisture and temperature:
- As the air gets warmer, it's capacity to hold moisture increases if all other things are constant.
- This is because warm air has more energy which allows it to hold more water vapor.

White trail left by jets and condensation of moisture:
- The white trail left by jets is due to the condensation of moisture from their engines.
- Jet engines produce water vapor as a byproduct, which then condenses into ice crystals in the cold atmosphere.

Cyclonic rainfall and meeting of warm and cold air:
- Cyclonic rainfall is caused in the meeting of warm and cold air.
- When warm and cold air masses meet, the warm air rises and cools, causing the moisture in the air to condense and form clouds. These clouds then produce rainfall.

Therefore, the correct answer is option 'A' as statements 1 and 2 are true, while statement 3 is false.

During the day, this happens.

• So, if you are facing the sea, the wind will strike your face and continue to land.
• During the night, this happens. So, if you are facing the sea, the wind will strike your back and continue to the sea.

Explanation:

The correct answer is option B: The Earth, in turn, radiates back solar insolation received from the Sun.

Reasoning:

The Earth receives solar insolation from the Sun in the form of electromagnetic radiation. This energy is absorbed by the Earth's atmosphere, land, and oceans. However, the Earth as a whole neither accumulates heat nor loses it due to solar insolation because it radiates back an equal amount of energy into space. This process is known as radiative balance or radiative equilibrium.

Key Points:
- Solar insolation refers to the amount of solar radiation received per unit area on the Earth's surface.
- The Earth's atmosphere plays a crucial role in regulating the amount of solar energy that reaches the Earth's surface. It absorbs some of the incoming solar radiation and reflects or scatters the rest.
- The absorbed solar energy heats up the Earth's atmosphere, land, and oceans. However, this heat is not accumulated indefinitely.
- The Earth radiates energy back into space in the form of longwave infrared radiation. This radiation is emitted by the Earth's surface, the atmosphere, and clouds.
- The rate of energy radiated by the Earth is equal to the rate of energy received from the Sun. This balance between incoming and outgoing radiation is necessary to maintain a stable temperature on Earth.
- If the Earth were to accumulate more energy than it radiates, the temperature would continually increase, leading to a runaway greenhouse effect. Conversely, if the Earth were to lose more energy than it receives, the temperature would continually decrease, resulting in a global cooling effect.
- The maintenance of radiative balance is crucial for the Earth's climate system. It ensures that the Earth's temperature remains relatively stable over long periods.

Therefore, the correct answer is option B: The Earth, in turn, radiates back solar insolation received from the Sun.

Tyndall effect can be observed when sunlight passes through the canopy of a dense forest. In the forest, mist contains tiny droplets of water, which act as particles of colloid dispersed in the air.

Factors that affect the temperature at a particular region include:

1. Circulation of planetary and local winds:
The circulation of winds plays a crucial role in determining the temperature of a region. The movement of air masses through the circulation of winds can bring warm or cold air to a particular area, thereby affecting its temperature. For example, the warm and dry winds blowing from the desert regions can increase the temperature in nearby areas, while the cool sea breeze can lower the temperature in coastal regions.

2. Altitude and terrain of the place:
Altitude and terrain have a significant impact on temperature. As we move higher in altitude, the temperature tends to decrease. This is because the air becomes thinner and cannot retain heat as effectively. Additionally, the presence of mountains or other geographical features can influence temperature patterns by blocking or diverting air masses, leading to variations in temperature.

3. Distance of the region from poles or equator:
The distance of a region from the poles or equator is a crucial factor in determining its temperature. The equatorial regions receive direct sunlight throughout the year, resulting in higher temperatures. On the other hand, the polar regions receive oblique sunlight, leading to lower temperatures. The regions located in between experience moderate temperatures.

4. Movement of ocean waves:
The movement of ocean waves, particularly ocean currents, can significantly influence the temperature of coastal regions. Ocean currents can transport warm or cold water from one region to another, thereby affecting the temperature of the coastal areas. For example, the Gulf Stream current brings warm water from the tropics to the eastern coast of North America, resulting in relatively higher temperatures in that region.

Therefore, the correct answer is option 'B' (1, 2, and 3 only). The circulation of winds, altitude and terrain, and the distance of the region from poles or equator are the factors that affect the temperature at a particular region. The movement of ocean waves, while important for coastal regions, is not a factor that affects the temperature at a broader regional scale.

Meteorological drought:
Meteorological drought refers to a prolonged period of significantly below-average precipitation. It is characterized by a lack of rainfall or snowfall, which leads to a deficit in water supply. However, meteorological drought alone does not necessarily indicate a depletion of water resources, as it focuses solely on the lack of precipitation.

Hydrological drought:
Hydrological drought occurs when the availability of water in different storages and reservoirs, such as aquifers, lakes, and reservoirs, falls below what the precipitation can replenish. It considers the overall water balance, taking into account both inflows and outflows of water sources. Hydrological drought reflects the impact of meteorological drought on water resources and can have severe consequences on water availability for human and environmental needs.

Agricultural drought:
Agricultural drought specifically relates to the impact of water scarcity on agricultural activities. It occurs when the water deficit affects crop growth and production, leading to reduced yields and potential agricultural losses. Agricultural drought is closely linked to hydrological drought, as it depends on the availability of water for irrigation and other agricultural purposes.

Ecological drought:
Ecological drought refers to the impact of water scarcity on ecosystems and the natural environment. It occurs when the water deficit affects the health and functioning of ecosystems, including vegetation, wildlife, and aquatic habitats. Ecological drought can result in habitat degradation, loss of biodiversity, and disruptions in ecosystem services.

Explanation of the correct answer:
The correct answer is option 'B', which is hydrological drought. This is because hydrological drought considers the availability of water in different storage and reservoirs, taking into account both inflows and outflows, which directly relates to the depletion of water resources. When the availability of water falls below what the precipitation can replenish, it indicates a deficit in water supply and reflects the impact of meteorological drought on water resources. Therefore, hydrological drought is the appropriate term to describe the situation described in the question.

Explanation:

Statement 1: The air pressure is highest at sea level and decreases with height.

This statement is correct. The air pressure at sea level is the weight of the air above a unit area at sea level. As we move up in the atmosphere, the weight of the air decreases, and hence, the air pressure also decreases. Thus, air pressure is highest at sea level and decreases with height.

Statement 2: Low air pressure is generally associated with cloudy skies and wet weather.

This statement is also correct. Low air pressure is associated with unstable weather conditions and the formation of clouds. When the air pressure is low, the air rises, cools, and condenses to form clouds. The condensation of water vapor in the air leads to the formation of precipitation, which can result in wet weather.

Conclusion:

Both statements 1 and 2 are correct. The air pressure is highest at sea level and decreases with height. Low air pressure is associated with unstable weather conditions and the formation of clouds, which can lead to wet weather.

Polar Vortex

The polar vortex is a persistent, large-scale cyclone that circles either of the planet's geographical poles. Here is a detailed explanation of what the polar vortex is:

Definition
The polar vortex is a low-pressure system that is located in the upper atmosphere, typically in the stratosphere, and is centered on the Earth's poles. It is strongest in the winter months and weakens or breaks down in the summer.

Nature
The polar vortex is a natural phenomenon that has always existed, but it has gained more attention in recent years due to its impact on weather patterns and extreme cold outbreaks in certain regions.

How It Forms
The polar vortex forms and is maintained by the temperature difference between the polar regions and the mid-latitudes. This temperature difference creates a strong wind pattern that circles the poles.

Impact on Weather
When the polar vortex weakens or shifts, it can lead to disruptions in the jet stream and result in extreme weather events such as cold outbreaks, heavy snowfall, and even heatwaves in some regions.

Conclusion
In conclusion, the polar vortex is a persistent, large-scale cyclone that plays a crucial role in shaping weather patterns around the world, particularly during the winter months. Understanding the polar vortex is essential for predicting and preparing for extreme weather events.

Explanation:

Local Winds and Their Areas of Prevalence:

Mistral: North African desert
The Mistral is a strong, cold, northwesterly wind that blows through the Rhône Valley in southern France and into the Mediterranean Sea. It is not prevalent in the North African desert.

Foehn: Southern slopes of Alps
The Foehn is a warm, dry wind that flows down the leeward side of a mountain range, such as the southern slopes of the Alps. It is not prevalent in North African desert or Appalachian mountains.

Sirocco: Appalachian mountains
The Sirocco is a hot, dry wind that originates in the Sahara Desert in North Africa and blows across the Mediterranean Sea into southern Europe. It is not prevalent in the Appalachian mountains.

Therefore, the correct answer is option 'D' - None of the above, as none of the matches provided are accurate.

Explanation:
The westerlies are prevailing winds that blow from west to east in the mid-latitudes. They originate from the subtropical high-pressure belts known as the horse latitudes and move towards the poles. In the Northern Hemisphere, the westerlies are strong due to the presence of large land masses, while in the Southern Hemisphere, they are weaker due to the dominance of oceans.

Therefore, the correct statements are:

1. Westerlies originate in the horse latitudes and move towards the poles.
2. Westerlies move from west to east.

Hence, the correct answer is option A (1 and 2 only).

Katabatic winds are downslope winds that occur due to density differences in the wind at different altitudes. These winds are commonly found in mountainous regions and can have significant impacts on local weather patterns and ecosystems.

Explanation:

Density Differences in the Wind at Different Altitudes:
Katabatic winds occur when there is a difference in air density between higher and lower altitudes. This density difference is typically caused by variations in temperature and pressure. As air near the mountaintop cools, it becomes denser and begins to flow downhill, creating a katabatic wind.

Formation of Katabatic Winds:
Katabatic winds are primarily formed at night when the air near the mountaintop cools faster than the air at lower elevations. As the cool air sinks, it gains momentum and accelerates downhill, resulting in strong winds. The process is similar to how cold air sinks and flows down a valley or slope.

Effects of Katabatic Winds:
1. Local Weather Patterns: Katabatic winds can significantly influence local weather patterns. As the cool air descends, it can displace warmer air masses, leading to changes in temperature and humidity. These winds can also enhance orographic lifting, which can result in the formation of clouds and precipitation on the windward side of mountains.

2. Ecological Impact: Katabatic winds can have a significant impact on the local ecosystem, especially in mountainous regions. These winds can cause rapid changes in temperature and moisture, affecting vegetation growth and distribution. They can also create microclimates and influence the behavior of wildlife.

3. Transportation and Aviation: Katabatic winds can create challenging conditions for transportation and aviation. The strong, gusty winds can make driving difficult, especially for high-profile vehicles. In aviation, katabatic winds can affect takeoffs and landings, as well as the stability of aircraft in flight.

In conclusion, katabatic winds occur due to density differences in the wind at different altitudes. These winds are formed when cool, dense air descends from higher elevations, resulting in strong downslope winds. The impact of katabatic winds includes changes in local weather patterns, ecological effects, and challenges for transportation and aviation.

Introduction:
Coastal places like Kolkata and Mumbai experience humid and moderate weather due to the flowing of sea and land breezes. This phenomenon is influenced by various factors such as proximity to the coast, sea surface temperatures, and prevailing wind patterns.

Sea and Land Breezes:
Sea and land breezes are the primary factors responsible for the humid and moderate weather in coastal places like Kolkata and Mumbai. These breezes occur due to the differential heating and cooling of land and water surfaces.

- Sea Breeze: During the day, the land heats up faster than the sea, causing the air above the land to rise. This creates a low-pressure zone over land. Simultaneously, the sea remains relatively cooler, leading to the formation of a high-pressure zone. As a result, cooler air from the sea moves towards the land, creating a sea breeze. This sea breeze brings moisture from the sea, leading to humid conditions.

- Land Breeze: At night, the situation reverses. The land cools down faster than the sea, causing the air above the sea to rise. This creates a low-pressure zone over the sea and a high-pressure zone over land. Consequently, cooler air from the land moves towards the sea, forming a land breeze. This land breeze carries the moisture from the land, resulting in moderate weather conditions.

Other Factors:
While sea and land breezes play a crucial role in shaping the weather patterns of coastal places like Kolkata and Mumbai, other factors also contribute to their humid and moderate weather.

- Proximity to the Coast: Being located near the coast, Kolkata and Mumbai are influenced by the maritime climate. The presence of large water bodies helps in maintaining moderate temperatures and moisture content in the atmosphere.

- Sea Surface Temperatures: The temperature of the sea surface affects the air temperature and moisture content in coastal areas. Higher sea surface temperatures contribute to the evaporation of water, leading to increased humidity.

- Prevailing Wind Patterns: The direction and strength of the prevailing winds also influence the weather conditions in coastal areas. The interaction between the sea and land breezes and the prevailing winds further enhances the humid and moderate weather experienced in places like Kolkata and Mumbai.

Conclusion:
In conclusion, the flowing of sea and land breezes is the primary reason why coastal places like Kolkata and Mumbai experience humid and moderate weather. The differential heating and cooling of land and water surfaces, along with other factors like proximity to the coast, sea surface temperatures, and prevailing wind patterns, contribute to the overall weather patterns observed in these regions.

Explanation:
Cirrus clouds are formed at high altitudes, typically between 8,000 and 12,000 meters. They are thin and detached clouds that have a feathery appearance. These clouds are always white in color.

Characteristics of Cirrus clouds:
- High altitude: Cirrus clouds form at high altitudes in the troposphere, which is the lowest layer of the Earth's atmosphere.
- Thin and detached: Cirrus clouds are thin and wispy in appearance. They are often seen as individual strands or patches rather than a continuous layer.
- Feathery appearance: Cirrus clouds have a characteristic feathery or fibrous appearance. They have a delicate and ethereal quality, resembling the tail of a horse or a mare's tail.
- White color: Cirrus clouds are always white in color. This is because they are composed of ice crystals, which scatter and reflect sunlight, giving them a bright and white appearance.

Other types of clouds:
a) Cumulus clouds: Cumulus clouds are large, puffy clouds that have a flat base and a rounded top. They are often associated with fair weather, but can also develop into cumulonimbus clouds, which are associated with thunderstorms.
c) Cumulonimbus clouds: Cumulonimbus clouds are large and vertically developed clouds that can reach high altitudes. They are associated with thunderstorms, heavy rain, lightning, and sometimes hail.
d) Stratus clouds: Stratus clouds are low-lying clouds that form in a uniform layer. They often cover the entire sky and can be gray or white in color. Stratus clouds are typically associated with overcast weather and light precipitation.

In conclusion, the description provided in the question matches the characteristics of Cirrus clouds, which are thin, detached, feathery clouds that form at high altitudes and are always white in color. Hence, the correct answer is option 'B' - Cirrus.

The correct answer is option 'D', None of the above. Let's discuss why.

1. They blow mainly in the Northern Hemisphere near the equator:
This statement is incorrect. The South-East trade winds do not blow mainly in the Northern Hemisphere near the equator. In fact, they blow primarily in the Southern Hemisphere near the equator. The trade winds are a global wind system that blows from the subtropical high-pressure belts towards the equator. In the Southern Hemisphere, the trade winds blow from the southeast towards the equator, while in the Northern Hemisphere, they blow from the northeast towards the equator.

2. The winds are deflected towards the East by the Coriolis Effect:
This statement is also incorrect. The South-East trade winds are not deflected towards the East by the Coriolis Effect. The Coriolis Effect is a phenomenon that is caused by the rotation of the Earth. It causes moving objects, including wind, to be deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. As a result, the South-East trade winds are actually deflected towards the West in the Southern Hemisphere, not towards the East.

In summary, both statements given about the South-East trade winds are incorrect. The trade winds blow primarily in the Southern Hemisphere near the equator and are deflected towards the West by the Coriolis Effect. Therefore, the correct answer is option 'D', None of the above.

Not Related to Formation or Modification of Present Atmosphere

Differentiation is not related to the formation or modification of the present atmosphere.

Explanation:

Formation and modification of the present atmosphere involve various processes that have occurred over millions of years. Some of the significant processes that have led to the formation or modification of the atmosphere are:

1. Solar winds: Solar winds are streams of charged particles that originate from the sun. These solar winds have contributed to the formation of the atmosphere by stripping away the outer layer of the early atmosphere.

2. Degassing: Degassing refers to the release of gases from the Earth's interior. Volcanic eruptions and other tectonic activities have contributed to the release of gases such as carbon dioxide, nitrogen, and water vapor.

3. Photosynthesis: Photosynthesis is the process by which plants convert carbon dioxide and water into oxygen and organic compounds. This process has led to the increase in the concentration of oxygen in the atmosphere.

However, differentiation is not related to the formation or modification of the present atmosphere. Differentiation refers to the process by which the Earth's interior became separated into distinct layers, with the heaviest materials sinking to the core and the lighter materials rising to the surface. This process occurred early in the Earth's history, and it did not have a significant impact on the formation or modification of the atmosphere.

The troposphere is thicker at the equator than at the poles because the equator is warmer. The convection currents of air expand the thickness of the troposphere (atmosphere) at poles. Thus, the simple reason is thermal expansion of the atmosphere at the equator and thermal contraction near the poles.

Movement of Inter-tropical convergence zone:
The movement of the Inter-tropical convergence zone (ITCZ) is one of the factors that affect the generation and flow of Equatorial Westerlies.

The ITCZ is a low-pressure belt that encircles the Earth near the equator. It is characterized by the convergence of trade winds from the Northern Hemisphere and Southern Hemisphere. The zone moves northward during summer in the Northern Hemisphere and southward during summer in the Southern Hemisphere.

1. During the summer in the Northern Hemisphere, the ITCZ moves northward, resulting in the convergence of trade winds from the Northern Hemisphere and the Equatorial Westerlies. This convergence leads to the generation of Equatorial Westerlies.

2. Similarly, during the summer in the Southern Hemisphere, the ITCZ moves southward, resulting in the convergence of trade winds from the Southern Hemisphere and the Equatorial Westerlies. This convergence also leads to the generation of Equatorial Westerlies.

Coriolis force caused due to the rotation of Earth:
The Coriolis force, which is caused due to the rotation of the Earth, is another factor that affects the generation and flow of Equatorial Westerlies.

The Coriolis force is an apparent force that deflects the motion of objects, including air masses, on the rotating Earth. In the Northern Hemisphere, the deflection is to the right, while in the Southern Hemisphere, it is to the left.

1. The Coriolis force deflects the trade winds from the Northern Hemisphere towards the right, resulting in the formation of Equatorial Westerlies.

2. In the Southern Hemisphere, the Coriolis force deflects the trade winds towards the left, also resulting in the formation of Equatorial Westerlies.

Both 1 and 2:
Therefore, both the movement of the Inter-tropical convergence zone and the Coriolis force caused due to the rotation of the Earth play a role in the generation and flow of Equatorial Westerlies. The movement of the ITCZ leads to the convergence of trade winds, while the Coriolis force deflects these winds to form the Equatorial Westerlies. Hence, option C, "Both 1 and 2," is the correct answer.

As the evaporation is high and moisture content is lesser in the subtropical and temperate areas compared to equatorial and polar regions, winds are dry; and dust particles are more. Where the moisture is high they fall back to the ground.