Analyzing Wind Advection with Height

This question examines the relationship between changes in wind direction with increasing altitude (vertical wind shear) and the resulting advection (horizontal transport) of warm or cold air masses in different hemispheres.

Statement A Analysis: Northern Hemisphere

Statement A states that backing of wind with increase of height in the Northern Hemisphere contributes to cold air advection.

• Backing Wind: In meteorology, backing refers to a wind shift in a counter-clockwise direction.
• Northern Hemisphere Dynamics: In the Northern Hemisphere, surface winds are influenced by friction, causing them to blow slightly across isobars towards lower pressure compared to the geostrophic wind aloft. As altitude increases, friction decreases, and the wind direction tends to shift towards the geostrophic wind.
• Advection: When wind direction backs (shifts counter-clockwise) with increasing height in the Northern Hemisphere, it typically signifies that air is being transported from a region of lower temperature towards a region of higher temperature relative to the pressure gradient. This process results in cold air advection.

Therefore, Statement A is true.

Statement B Analysis: Southern Hemisphere

Statement B states that veering of wind with increase of height in the Southern Hemisphere contributes to warm air advection.

• Veering Wind: Veering refers to a wind shift in a clockwise direction.
• Southern Hemisphere Dynamics: In the Southern Hemisphere, the Coriolis effect deflects winds to the left (meaning lower pressure is to the right). Similar to the NH, friction at the surface alters the wind direction. As altitude increases, friction lessens, and the wind direction shifts towards the geostrophic wind.
• Advection: A veering wind with increasing height in the Southern Hemisphere indicates that the wind is shifting clockwise. This typically implies that air is moving from a region of higher temperature towards a region of lower temperature relative to the pressure gradient. This process results in cold air advection, not warm air advection. Warm air advection in the SH with height would typically be associated with backing winds.

Therefore, Statement B is false.

Conclusion

Based on the analysis, Statement A is true and Statement B is false. This corresponds to Option A.