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In physical oceanography, Langmuir circulation consists of a series of shallow, slow, counter-rotating vortices at the ocean's surface aligned with the wind. These circulations are developed when wind blows steadily over the sea surface. Irving Langmuir discovered this phenomenon after observing windrows of seaweed in the Sargasso Sea in 1927. [1]
An illustration from an 1866 Japanese book. Mahoraga, who is an incarnation of Bodhisattva Kannon in this scene, gives a sermon to folks. The Mahoraga are one of the eight classes of deities (aṣṭasenā) that are said to protect the Dharma. They are described as huge subterranean serpents who lie on their sides and rotate the earth, which ...
Weather buoys, like other types of weather stations, measure parameters such as air temperature above the ocean surface, wind speed (steady and gusting), barometric pressure, and wind direction. Since they lie in oceans and lakes, they also measure water temperature, wave height , and dominant wave period . [ 14 ]
The tides, the Coriolis effect, changes in direction and strength of wind, salinity, and temperature are the main factors determining ocean currents. The thermohaline circulation (THC) ( thermo- referring to temperature and -haline referring to salt content ) connects the ocean basins and is primarily dependent on the density of sea water .
Due to the Coriolis effect, surface water moves at a 90° angle to the wind current. If the wind moves in a direction causing the water to be pulled away from the coast then Ekman suction will occur. [1] On the other hand, if the wind is moving in such a way that surface waters move towards the shoreline then Ekman pumping will take place. [1]
Because the vast majority of the world ocean's volume is deep water, the mean temperature of seawater is low; roughly 75% of the ocean's volume has a temperature from 0° – 5 °C (Pinet 1996). The same percentage falls in a salinity range between 34 and 35 ppt (3.4–3.5%) (Pinet 1996). There is still quite a bit of variation, however.
Ocean currents can be generated by differences in the density of the water. How dense water is depends on how saline or warm it is. If water contains differences in salt content or temperature, then the different densities will initiate a current. Water that is saltier or cooler will be denser, and will sink in relation to the surrounding water.
An example of a geostrophic flow in the Northern Hemisphere. A northern-hemisphere gyre in geostrophic balance; paler water is less dense than dark water, but more dense than air; the outwards pressure gradient is balanced by the 90 degrees-right-of-flow coriolis force The structure will eventually dissipate due to friction and mixing of water properties.