What causes valley air to move up surrounding mountains during the day?

Question

The Sun warms the tops of hills and mountains more than it does the valley.

The Coriolis Force moves the winds up the sides of hills and mountains.

The valley air is denser because is of its lower elevation.

The Sun warms the air in the valley more than it does the mountains.

Answer 1

The phenomenon where valley air moves up surrounding mountains during the day is primarily due to the Sun warming the tops of hills and mountains more than it does the valley. This warming causes the air around the mountains to heat up and rise, creating a flow of air from the valley (which is relatively cooler and denser) up the slopes. This process is known as upslope or valley breeze.

Therefore, the correct statement is: The Sun warms the tops of hills and mountains more than it does the valley.