Question

Sea breezes occur along coastlines and consist of cool air moving toward the shore from the ocean. However, this only occurs during the day and is a stronger effect when the air temperature on the land is greatest and the air temperature above the water is coldest. At night, the breezes are reversed, moving from the land toward the ocean. Taking into consideration the specific heat capacities of water and sand (which is about the same as that of concrete), explain how sea breezes form during the day and change direction at night.

Answer 1

Starting from the first law of thermodynamics, we know that heat travels from a hot recess to a cold enclosure. Extrapolating this to the movements of the earth, the air travels in the direction where the lowest heat concentration is found. Winds originate as a result of differences in atmospheric pressure and these differences are caused by different temperatures in the air. Cold air tends to move down, while hot air moves up. This displacement in the coasts because of the temperature difference generates that to reach the thermal equilibrium, the coldest air travels towards the hot air. The sea breeze travels to the land.

In the case of the night the process is inverse since the water serves as a thermal sink by accumulating more heat than the earth can accumulate. In this way the direction is changed and the breeze travels to the sea.