In the study of atmospheric circulation and global wind systems, which of the following forces balances the horizontal pressure gradient force in the upper troposphere to produce geostrophic winds blowing parallel to straight contour lines?

💡 Solution & Explanation

Geostrophic wind flow in the upper atmosphere represents a balance between the pressure gradient force pushing air from high to low pressure and the Coriolis force deflecting moving air to the right in the Northern Hemisphere. Friction disrupts this balance close to the Earth's surface, causing winds to cross isobars toward lower pressure. Centrifugal force becomes significant in curved gradient wind circulation around intense cyclones and anticyclones. The Coriolis force acts perpendicular to the wind velocity vector.