Land and Sea Breezes

views updated May 23 2018

Land and Sea Breezes

Land and sea breezes are wind and weather phenomena associated with coastal areas. A land breeze is a breeze blowing from land out toward a body of water. A sea breeze is a wind blowing from the water onto the land. Land breezes and sea breezes arise because of differential heating between land and water surfaces. Land and sea breezes can extend inland up to 100 mi (161 km), or manifest as local phenomena that quickly weaken with a few hundred yards of the shoreline. On average, the weather and cloud effects of land and sea breezes dissipate 20-30 mi (32-48 km) inland from the coast.

Land and sea breeze patterns can influence fog distribution and pollution accumulation or dispersion over inland areas. Current research on land and sea breeze circulation patterns also include attempts to model wind patterns that affect energy requirements (e.g., heating and cooling requirements) in affected areas as well as impacts on weather dependent operations (e.g., aircraft operations).

Because water has a much heat capacity than sand or other Earth materials, for a given amount of solar irradiation (insolation), water temperature will increase less than land temperature. Regardless of temperature scale, during daytime, land temperatures might change by tens of degrees, while water temperature change by less than half a degree. Conversely, waters high heat capacity prevents rapid changes in water temperature at night and thus, while land temperatures may plummet tens of degrees, the water temperature remains relatively stable. Moreover, the lower heat capacity of crustal materials often allows them to cool below the nearby water temperature.

Air above the respective land and water surfaces is warmed or cooled by conduction with those surfaces. During the day, the warmer land temperature results in a warmer and therefore, less dense and lighter air mass above the coast as compared with the adjacent air mass over the surface of water. As the warmer air rises by convection, cooler air is drawn from the ocean to fill the void. The warmer air mass returns to sea at higher levels to complete a convective cell. Accordingly, during the day, there is usually a cooling sea breeze blowing from the ocean to the shore. Depending on the temperature differences and amount of uplifted air, sea breezes may gust 15 to 20 miles per hour (13 to 17 knots [nautical miles per hour]). The greater the temperature differences between land and sea, the stronger the land breezes and sea breezes.

After sunset, the air mass above the coastal land quickly loses heat while the air mass above the water generally remains much closer to its daytime temperature. When the air mass above the land becomes cooler than the air mass over water, the wind direction and convective cell currents reverse and the land breeze blows from land out to sea.

Because land breezes and sea breezes are localized weather patterns, they are frequently subsumed into or overrun by large-scale weather systems. Regardless, winds will always follow the most dominant pressure gradient.

The updraft of warm, moist air from the ocean often gives rise to daytime cloud development over the shoreline. Glider pilots often take advantage of sea breezes to ride the thermal convective currents (sea breeze soaring). Although most prevalent on the sea coastline, land breezes and sea breezes are also often recorded near large bodies of water (e.g., the Great Lakes). In general, land breezes and sea breezes result in elevated humidity levels, high precipitation, and temperature moderation in coastal areas.

See also Atmospheric circulation; Atmospheric pressure; Atmospheric temperature; Clouds; Solar illumination: Seasonal and diurnal patterns; Weather forecasting.

Land and Sea Breezes

views updated Jun 08 2018

Land and sea breezes

Land and sea breezes are wind and weather phenomena associated with coastal areas. A land breeze is a breeze blowing from land out toward a body of water . A sea breeze is a wind blowing from the water onto the land. Land breezes and sea breezes arise because of differential heating between land and water surfaces. Land and sea breezes can extend inland up to 100 mi (161 km), or manifest as local phenomena that quickly weaken with a few hundred yards of the shoreline. On average, the weather and cloud effects of land and sea breezes dissipate 20 -30 mi (32-48 km) inland from the coast.

Land and sea breeze patterns can greatly influence fog distribution and pollution accumulation or dispersion over inland areas. Current research on land and sea breeze circulation patterns also include attempts to model wind patterns that affect energy requirements (e.g., heating and cooling requirements) in affected areas as well as impacts on weather dependent operations (e.g., aircraft operations).

Because water has a much higher heat capacity that do sands or other crustal materials, for a given amount of solar irradiation (insolation), water temperature will increase less than land temperature. Regardless of temperature scale, during daytime, land temperatures might change by tens of degrees, while water temperature change by less than half a degree. Conversely, water's high heat capacity prevents rapid changes in water temperature at night and thus, while land temperatures may plummet tens of degrees, the water temperature remains relatively stable. Moreover, the lower heat capacity of crustal materials often allows them to cool below the nearby water temperature.

Air above the respective land and water surfaces is warmed or cooled by conduction with those surfaces. During the day, the warmer land temperature results in a warmer and therefore, less dense and lighter air mass above the coast as compared with the adjacent air mass over the surface of water. As the warmer air rises by convection , cooler air is drawn from the ocean to fill the void. The warmer air mass returns to sea at higher levels to complete a convective cell . Accordingly, during the day, there is usually a cooling sea breeze blowing from the ocean to the shore. Depending on the temperature differences and amount of uplifted air, sea breezes may gust 15 to 20 miles per hour (13 to 17 knots ([autical miles per hour]. The greater the temperature differences between land and sea, the stronger the land breezes and sea breezes.

After sunset, the air mass above the coastal land quickly loses heat while the air mass above the water generally remains much closer to it's daytime temperature. When the air mass above the land becomes cooler than the air mass over water, the wind direction and convective cell currents reverse and the land breeze blows from land out to sea.

Because land breezes and sea breezes are localized weather patterns, they are frequently subsumed into or overrun by large-scale weather systems. Regardless, winds will always follow the most dominant pressure gradient.

The updraft of warm, moist air from the ocean often gives rise to daytime cloud development over the shoreline. Glider pilots often take advantage of sea breezes to ride the thermal convective currents (sea breeze soaring). Although most prevalent on the sea coastline, land breezes and sea breezes are also often recorded near large bodies of water (e.g., the Great Lakes). In general, land breezes and sea breezes result in elevated humidity levels, high precipitation , and temperature moderation in coastal areas.

See also Atmospheric circulation; Atmospheric pressure; Atmospheric temperature; Clouds; Solar illumination: Seasonal and diurnal patterns; Weather forecasting.

Land and Sea Breezes

views updated Jun 11 2018

Land and sea breezes

Land and sea breezes are wind and weather phenomena associated with coastal areas. A land breeze is a breeze blowing from land out toward a body of water . A sea breeze is a wind blowing from the water onto the land. Land breezes and sea breezes arise because of differential heating between land and water surfaces. Land and sea breezes can extend inland up to 100 mi (161 km) or manifest as local phenomena that quickly weaken with a few hundred yards of the shoreline. On average, the weather and cloud effects of land and sea breezes dissipate 2030 mi (3248 kph) inland from the coast.

Because water has a much higher heat capacity that do sands or other crustal materials, for a given amount of solar irradiation (insolation ), water temperature will increase less than land temperature. Regardless of temperature scale, during daytime, land temperatures might change by tens of degrees, while water temperature change by less than half a degree. Conversely, water's high heat capacity prevents rapid changes in water temperature at night and thus, while land temperatures may plummet tens of degrees, the water temperature remains relatively stable. Moreover, the lower heat capacity of crustal materials often allows them to cool below the nearby water temperature.

Air above the respective land and water surfaces is warmed or cooled by conduction with those surfaces. During the day, the warmer land temperature results in a warmer (therefore less dense and lighter) air mass above the coast as compared with the adjacent air mass over the surface of water. As the warmer air rises by convection, cooler air is drawn from the ocean to fill the void. The warmer air mass returns to sea at higher levels to complete a convective cell. Accordingly, during the day, there is usually a cooling sea breeze blowing from the ocean to the shore. Depending on the temperature differences and amount of uplifted air, sea breezes may gust 1520 mph (2432 kph). The greater the temperature differences between land and sea, the stronger the land breezes and sea breezes.

After sunset, the air mass above the coastal land quickly loses heat while the air mass above the water generally remains much closer to it's daytime temperature. When the air mass above the land becomes cooler than the air mass over water, the wind direction and convective cell currents reverse and the land breeze blows from land out to sea.

Because land breezes and sea breezes are localized weather patterns, they are frequently subsumed into or overrun by large-scale weather systems. Regardless, winds will always follow the most dominant pressure gradient.

The updraft of warm, moist air from the ocean often gives rise to daytime cloud development over the shoreline. Glider pilots often take advantage of sea breezes to ride the thermal convective currents (sea breeze soaring). Although most prevalent on the sea coastline, land breezes and sea breezes are also often recorded near large bodies of water (e.g., the Great Lakes ). In general, land breezes and sea breezes result in elevated humidity levels, high precipitation , and temperature moderation in coastal areas.

See also Adiabatic heating; Clouds and cloud types; Convection (updrafts and downdrafts); Seasonal winds; Weather forecasting methods

land and sea breezes

views updated Jun 11 2018

land and sea breezes Circulations of air, common along coasts, which are caused by a low-level pressure gradient owing to the differential heating of land and sea. On summer days solar radiation warms the land surface more strongly than the adjacent sea: a pressure gradient from sea to land results in a gentle, cooling, landward ‘sea breeze’ whose maximum strength is usually developed by late afternoon. Upward movement of warm air over the land and movement towards the sea at greater height, followed by subsidence, produces a shallow convection cell. At night and in early morning cooler land and relatively warmer sea produce a reverse-flow convection cell, with a seaward ‘land breeze’. The horizontal extent of well-developed land and sea breezes is typically limited to about 40 km from the coast, but associated air movements can often be detected over a much wider coastal belt.

land and sea breezes

views updated May 08 2018

land and sea breezes Circulations of air common along coasts, caused by a low-level pressure gradient due to the differential heating of land and sea. On summer days, solar radiation warms the land surface more strongly than the adjacent sea: a pressure gradient from sea to land results in a gentle, cooling, landward ‘sea breeze’ whose maximum strength is usually developed by late afternoon. Upward movement of warm air over the land and movement toward the sea at greater height, followed by subsidence, produces a shallow convection cell. At night and in early morning cooler land and relatively warmer sea produce a reverse-flow convection cell, with a seaward ‘land breeze’. The horizontal extent of well-developed land and sea breezes is typically limited to about 40 km from the coast, but associated air movements can often be detected over a much wider coastal belt.