DAILY CURRENT AFFAIRS QUIZ – 29 November 2024

Ans. b

Explanation:

According to ecosystem, the maximum albedo would be of Tundra, then Taiga, then Tropical Deciduous then Tropical ever green.

Ans. a

Explanation:

The moisture content in the atmosphere correlates with the latitude due to the dependency of temperature on the latitude, which, in turn, influences the atmosphere’s capacity to retain moisture.

Ans. b: Inter-Tropical Convergence Zone seldom occurs

Reasons for the Absence of Cyclone Formation in the South Atlantic:

1. Sea Surface Temperatures

• Slightly Cooler Conditions: The sea surface temperatures in the South Atlantic tend to be cooler, falling slightly below the optimal threshold required for the formation of tropical cyclones.

2. Influence of Vertical Wind Shear

• Consistently High Wind Shear: Throughout the year, the South Atlantic experiences notably high vertical wind shear levels. This condition persists even during summer, posing a barrier to cyclone development.

3. Lack of Vorticity and Pre-existing Rotational Centers

• Insufficient Vorticity: The absence of pre-existing rotation centers within the area contributes to the challenge of cyclone genesis. The region typically lacks the necessary vorticity for cyclone formation.

4. Factors Relating to Tropical Waves and ITCZ

• Absence of Tropical Waves: The area lacks the presence of tropical waves, which are vital elements for cyclone initiation.
• Position of the Intertropical Convergence Zone (ITCZ): The ITCZ, shifting with the seasons, typically remains near or north of the equator during the South Atlantic’s summer. This positioning denies the region the critical convergence zone required for cyclone formation.

5. Effect of Strong Wind Shear and ITCZ Position

• Impact of Wind Shear: The South Atlantic experiences strong wind shear in the tropospheric layers, hampering the generation of tropical cyclones.
• ITCZ Positioning Impact: The ITCZ largely remains near the equator, lacking a southward shift over the South Atlantic or South Pacific regions. This absence denies these areas the crucial ITCZ influence, contributing significantly to the lack of cyclones.

6. Additional Factors: Lower Sea Temperatures

• Cooler Sea Temperatures: Lower sea temperatures in these regions further contribute to the lack of conducive conditions for cyclone development.

Important Insight:

• Cyclone Characteristics: Cyclones typically manifest as large wind systems revolving counterclockwise north of the Equator and clockwise to the south.

Ans. b

Explanation:

The Atlantic Meridional Overturning Circulation (AMOC):

1. Characteristics of AMOC

• Nature of Circulation: AMOC is a part of the broader global ocean conveyor belt, known as Thermo-Haline Circulation (THC), influencing the movement of ocean water due to variations in density caused by temperature and salinity differences. Within the Atlantic Ocean, it encompasses various currents such as the warm Gulf Stream, North Atlantic Drift, and the frigid Southern Ocean current.
• Flow of Warm and Cold Water: AMOC transports warm surface waters from tropical regions toward the Northern Hemisphere, where they cool and sink. Subsequently, this cooled water returns to the tropics and then to the South Atlantic as a lower-level current. From there, it disseminates across all ocean basins via the Antarctic circumpolar current.

2. Correction and Validation of Statements:

• Statement 1 (Incorrect): Contrary to the statement, AMOC, a crucial segment of the global ocean conveyor belt, works to sustain warmer conditions in mid to high latitudes along the eastern coast of America and Western Europe by transporting warm surface waters via the Gulf Stream and North Atlantic Drift.
• Statement 2 (Correct): According to IPCC’s Assessment Report 6 (AR6) and recent articles in Nature Climate Change, human-induced climate change is causing an unprecedented slowdown of the AMOC, attributable to the accelerated melting of Arctic ice shelves, notably in “The Last Ice Area.” This influx of freshwater diminishes water salinity and density, hindering the typical sinking of water and subsequently weakening the AMOC flow.

3. Predicted Implications of AMOC Weakening:

• Projected Consequences: Anticipated impacts of AMOC slowdown include:
  1. Substantially cooler climates in North America and Western Europe.
  2. Reduced rainfall in Europe due to the significant southward migration of rain belts over the tropical Atlantic.
  3. Diminished nutrient transport in the Atlantic Ocean basin, impacting fishing areas like Newfoundland.
  4. Possible influence on El Niño patterns.
  5. Increased sea ice formation over the Greenland-Iceland-Norwegian seas and the southern vicinity of Greenland.

Ans. b

Explanation:

Vertical Pressure Gradient and Atmospheric Dynamics:

1. Vertical vs. Horizontal Pressure Gradients

• Vertical Pressure Gradient: Significantly larger than horizontal pressure gradient but typically counterbalanced by an almost equal, opposing gravitational force. As a result, strong upward winds are generally absent.

2. Pressure Variations with Height

• Vertical Pressure Gradient or Variation: In the lower atmosphere, pressure diminishes swiftly with altitude. This vertical pressure variation, often known as the vertical pressure gradient, decreases at an approximate rate of 34 millibars for every 300 meters in height.

3. Pressure-Driven Air Motion

• Cause of Air Motion: Atmospheric pressure variances drive air movement, leading winds to flow from areas of high pressure toward regions of low pressure.

4. Pressure Changes and Weather Indicators

• Weather Indicators: Rising pressure signifies stable, clear weather conditions, while falling pressure indicates potential instability and cloudy weather.

5. Pressure Variability and Altitude

• Altitude and Pressure Relations: At higher elevations, such as at the summit of Mt. Everest, air pressure is significantly lower, approximately two-thirds less than at sea level.
• Variable Factors Affecting Pressure: Pressure decrease with altitude isn’t constant due to changing factors influencing air density—temperature, water vapor content, and gravity. This variability prevents a simple, direct relationship between altitude and pressure.

6. Gravity, Density, and Pressure

• Gravity’s Influence on Pressure: At the surface, denser air due to gravity results in higher pressure. As air pressure is contingent on both density and temperature, alterations in either temperature or density bring about corresponding pressure changes.