Question

Choose the correct statement(s) in context to Ekman spiral from the following:

• A. The balance of Coriolis force and pressure
• B. The balance of Coriolis force, wind shear, and frictional force
• C. Deflection of surface current to the right of the wind direction in the Northern hemisphere
• D. The increase of current velocity with depth

Hint:

Ekman spiral → surface current ~45° to the right (NH), velocity decreases with depth, transport net ~90°.

Answer 1

The Correct Option is B, C

Step 1: Recall Ekman spiral basics.
- The Ekman spiral describes the effect of wind-driven circulation in the ocean surface layer. - It arises due to a balance between: - Wind stress (surface forcing), - Frictional drag between water layers, and - Coriolis force.
Step 2: Check each statement.
- (A) Incorrect → Ekman balance is not between Coriolis and pressure; pressure gradient does not dominate here.
- (B) Correct → Ekman transport is caused by the balance of Coriolis, wind shear, and friction.
- (C) Correct → In the Northern Hemisphere, surface current is deflected about 45° to the right of wind direction.
- (D) Incorrect → Current velocity actually decreases with depth, not increases. Final Answer: \[ \boxed{\text{(B) and (C)}} \]