To understand what causes a land breeze, it’s crucial first to understand the difference in heating of both land and sea.
Land heats and cools more quickly than water. This is because changing the temperature of land takes less energy than changing water.
A land breeze is a warm air blowing off the land. Since water has a higher specific heat capacity, the temperature of the land cools at a slower rate during the night than the seawater. Because of this, it develops lower pressure than the sea. The air over the ocean then flows onto the land to equalize the pressure.
Distinct Features and Characteristics of a Land Breeze
High Humidity at Sea
During the day, land breezes bring a large amount of warm air from inland.
This process draws up cool air from the water and usually causes heavy mist or even fog, known as a sea or lake haze.
As the land heats up, hot air rises and starts winds in the atmosphere.
These winds often cause the air to come together in a system called a “hot spot.”
This hot spot acts as a pivot point for winds circling it.
These winds collide with cold, dry air moving in from an area of low pressure. The collision of cold and hot causes thunderstorms.
Little Rainfall on Land
A land breeze can occur on land when there is a significant vertical pressure gradient between land and water.
This causes air to blow from the water onto land, resulting in dry conditions because little or no rainfall is received.
Heavy Rainfall at Sea
When a warm air mass ascends over the sea, it can be cooled and condensed by contact with a layer of cold air overlying the sea.
This produces cloudy skies and precipitation, a common occurrence that causes a land breeze.
A temperature inversion is a phenomenon that occurs when warm air sits on top of cold air.
Because water has a higher heat capacity than does land, it cannot store as much heat at any given time.
As a result, water cools more rapidly than it can release heat to the atmosphere. This means that a layer of warm air forms over the sea on windy days.
Note: If a temperature inversion occurs over water, it traps pollutants near the surface.
Land breeze formation of fog occurs when warm air over the sea is cooled as cold air from the land moves over it.
The cold air carries moisture, which condenses as it cools. Mist or fog forms, reducing visibility.
Low Temperature Over Sea
A land breeze creates a temperature difference between land and sea.
The cold air from the land blows toward the sea, lowering the over-water temperature.
Stages of Land Breeze Formation
Here are the main steps and processes that lead to a land breeze formation:
Step #1. Rising Air
Air temperatures tend to decline at night. As air warms, it rises.
Rising air creates a low-pressure thermal system at the boundary between land and a water body.
Step #2. Low-Pressure Zone
The rapid loss of heat from the land surface creates a low-pressure zone over the land.
Step #3. High-Pressure Zone
Cool air over the ocean lends itself to the formation of high-pressure zones. This occurs when air is cooled by contact with the ocean’s surface.
Assuming it remains cool and humid, it blows towards land, producing a pressure gradient that results in a high-pressure zone.
Step #4. Land Breeze Creation
As air flows from the ocean to the land, it cools and becomes less dense.
When warm air near the surface rises, it creates a wind coming from high to low pressure, called a land breeze.
During summer, the heat of the day causes land temperatures to rise quickly.
This, in turn, encourages the formation of land breezes, which last longer than they would if temperatures rose slowly and steadily.
Land Breeze Apex
After understanding what a land breeze is, let’s delve deeper to understand what causes a land breeze apex.
The wind formation process during a land breeze involves the difference in temperature between the land and the ocean is more significant than it would typically be because of the sun’s effects on both areas.
The breeze will be stronger when the temperature difference between land and ocean is more significant, thereby causing a land breeze apex.
However, a land breeze is typically shallower than the sea breeze because, during the night, the colder air over land can only cool a few hundred feet beneath the surface.
Convection Currents and Land Breezes
What type of heat transfer causes a land breeze? During the cool of the night, after sunset, the land cools faster than the water.
Consequently, warm air is less dense than cool air and can rise. Over the ocean, which stays warm through the night, this warm air rises like a hot-air balloon.
Cooler air offshore flows in to replace it. This movement of air is called a land breeze. The movement of cool air of the land is caused by convection.
Why Land Breeze occurs at Night
Generally, at night water will retain more heat than land surfaces. This is because water has a higher heat capacity than land.
If a breeze occurs during the night, it is likely to be a land breeze.
A land breeze typically happens at night when the ground cools quickly without the insolation from the sun.
Note: In most cultures worldwide, land breezes are referred to as overnight or early morning wind.
Read Next: How Do Humans Affect the Geosphere?
Land breezes are an essential part of the hydrological and water cycles. The difference in temperature between land and water, resulting in air movement from the sea onto land, is what causes a land breeze.
Air movement over land transports heat and moisture over land. This can be useful in areas with large water bodies, such as lakes and seas, as it keeps them topped up with fresh water.
Areas without such large water bodies will suffer as there is nothing to replace evaporating moisture as it is drawn into the air.