Meteorology · Ocean Currents — Climate Effect
Why is fog (advection fog) especially common over a cold ocean current lying next to warm, moist air, such as off the Grand Banks?
- ACold water increases the air's capacity to hold moisture
- BThe cold current generates its own wind
- CWarm moist air flowing over the cold current is chilled below its dewpoint, condensing into widespread fog✓ Correct
- DThe current raises the air temperature
Explanation
Where warm humid air (e.g., over the Gulf Stream) drifts across a cold current (the Labrador Current near the Grand Banks), the air cools to saturation and dense advection fog forms — one of the foggiest areas in the world.
Authority: Bowditch (Pub. No. 9), ocean currents and fog; WMO
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