At sea breezes they are air currents that arise in coastal regions and have two possible directions: from the sea to the sand (during the day) and from the sand to the sea (at night). This difference in the directions of sea breezes is related to the differences between the specific heats of water and sand and the phenomenon of convection.
Why do breezes occur?
During the day, the heat radiated by the sun increases the temperature of sand and water. As the specific heat of sand is lower than that of water, it heats up and cools more easily. Therefore, the temperature near the sand will be higher than the temperature near the water, and the air over the sand will be hotter than the air over the water, which causes a decrease in air pressure. Therefore, we can conclude that the air pressure on the sand is lower than the air pressure on the water, which causes a displacement of air from the sea to the beach.
During the night, the process is reversed: sand has a lower temperature than water, and the air in this region, consequently, is cooler. Thus, the air pressure is greater on the sand, and the breeze moves from the beach to the sea.
Note in the figure above the direction of displacement of the air masses during the day to the beach and during the night to the sea. This movement of air masses motivated by temperature differences is what characterizes the phenomenon of convection.
By Joab Silas
Graduated in Physics
Source: Brazil School - https://brasilescola.uol.com.br/fisica/conveccao-brisas-maritimas.htm
