Question

Which one of the following statements is correct regarding the dominant energy balance in the troposphere in a tropical convergence zone?

• A. Shortwave heating balances longwave radiative cooling.
• B. Compressional heating balances radiative cooling.
• C. Radiative cooling balances heating due to viscous dissipation of kinetic energy.
• D. Condensational heating balances adiabatic cooling.

Hint:

In the tropical convergence zone, the dominant energy balance is controlled by condensational heating (due to condensation of water vapor) and adiabatic cooling (due to expansion of rising air).

Answer 1

The Correct Option is D

In the tropical convergence zone, the dominant energy balance is primarily associated with condensational heating and adiabatic cooling. This zone is characterized by strong convective activity, where warm, moist air rises, and cooling occurs as the air ascends. As the air rises, condensation releases latent heat, which helps to counterbalance the cooling that occurs due to the expansion of air in the lower pressure regions at higher altitudes.
- Option (A) Shortwave heating balances longwave radiative cooling:
This is not correct because in the tropical convergence zone, radiative processes (like shortwave and longwave radiation) play a lesser role compared to convective processes, such as latent heat release and adiabatic cooling.
- Option (B) Compressional heating balances radiative cooling:
Compressional heating is more relevant in processes like subsidence and in the lower layers of the atmosphere, not in the tropical convergence zone where convective processes dominate.
- Option (C) Radiative cooling balances heating due to viscous dissipation of kinetic energy:
This is also not correct, as radiative cooling is not the dominant process in the tropical convergence zone. The primary driver is latent heat release, not dissipation of kinetic energy.
- Option (D) Condensational heating balances adiabatic cooling:
This is the correct option. In the tropical convergence zone, the ascent of warm moist air leads to condensation, which releases latent heat, counteracting the cooling that occurs as the air expands (adiabatic cooling). This balance is crucial for maintaining the vertical convection currents in this region.
Thus, (D) is the correct answer.