Generally northern hemisphere winds at 5000 FT/AGL are south-westerly while most of the surface winds are southerly. What is the primary reason of difference between these two wind directions?

Question

Question ATPL - Airline Transport Pilot license - Meteorology

QuizVDS · Accepted Answer

Friction between the wind and the surface.

QuizVDS · Answer

The influence of warm air at the lower altitude.

QuizVDS · Answer

Stronger Coriolis force at the surface.

QuizVDS · Answer

A strong pressure gradient at higher altitudes.

Id 511 - ATPL - Generally northern hemisphere winds at 5000 FT/AGL are south-westerly while most of the surface winds are southerly. What is the primary reason of difference between these two wind directions?