Land and sea breeze pressure system

• As the name clearly suggests these breezes occur along coastal areas or along large lakes and water bodies.
• A breeze is a cool and calm wind.
• There arise as a result of differential heating and cooling between land and adjacent sea areas during the day and at night.
• The resultant pressure differences produce gentle breezes which affect coastal areas during calm clear anticyclonic conditions.

Sea breeze

Sea breeze. Image by Brisbanehotairballooning.

• It occurs during the day.
• The land heats up quickly by conduction and air rises.
• The air moves towards the sea and falls since it is denser.
• The air creates an area of high pressure over the sea while the land has low pressure since it is hotter when compared to the ocean’s surface.
• The sea absorbs heat more slowly during the day and transmits it to greater depth so it remains cool.
• A cool sea breeze moves from the sea towards the land.
• The sea breeze is capable of reducing temperatures by as much as 15°C along coastal areas and may produce fogs.

Land breeze

Land breezes occur at night. Image by Brisbanehotairballooning.

• At night the reverse happens.
• Land quickly loses its heat while the ocean cools at a slower rate because water has a higher heat specific capacity.
• This means air over the water is less dense and begins to rise creating low pressure above the ocean’s surface.
• Cooler dense air from the land begins to move to the water surface to replace the warm rising air.
• A cool gentle breeze blows towards the ocean.
• This is called a land breeze.

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