Question

The zonal gradient of meridional current and the meridional gradient of zonal current is \( -0.3 \times 10^{-3} \, {s}^{-1} \) and \( 0.3 \times 10^{-3} \, {s}^{-1} \), respectively, at a location P (87°E, 15°N). Which one of the following best explains the nature of the flow?

• A. The flow is non-divergent in nature.
• B. The flow is non-rotational in nature.
• C. The flow is counter-clockwise in nature.
• D. The flow is clockwise in nature.

Hint:

The direction of flow in ocean currents can often be determined from the gradients of zonal and meridional currents, which indicate whether the flow is clockwise or counter-clockwise.

Answer 1

The Correct Option is D

The zonal gradient of meridional current and the meridional gradient of zonal current can help determine the nature of the flow in terms of vorticity and rotation. The flow’s rotational direction depends on the sign and magnitude of the gradients of the zonal and meridional currents:
- A positive meridional gradient of zonal current indicates counter-clockwise rotation, while a negative one indicates clockwise rotation.
- The flow will rotate in a direction that compensates for the gradients of the zonal and meridional currents. Since the given gradients are \( -0.3 \times 10^{-3} \, {s}^{-1} \) and \( 0.3 \times 10^{-3} \, {s}^{-1} \), the resulting vorticity leads to a clockwise flow.
Thus, the correct answer is (D) The flow is clockwise in nature.