Physical interaction between air & sea takes a number of forms-
i. Ocean circulation/currents: Current systems aid in the exchange of heat between low & high latitudes & are essential in the sustaining the global heat balance. Currents are set in motion predominantly by prevailing winds. The wind transfer energy by the frictional drag of the air blowing over the water surface.
The conveyor belt of ocean currents is very important in the climate system. Because of its long time scale this cycle provides a stabilizing effect on climate.
ii. Wave & Wave Breaking: Undulation of surface water of sea by alternate crest & trough is called wave.
When air moves over water surface, the kinetic energy of air convert to potential energy in wave & finally when wave break also some kinetic energy release in air.
iii. Salt Water Spray: After breaking waves some salt water molecules spray in atmosphere. It is more dominant phenomena of plunging & surging wave breaking.
iv. Upwelling/Downwelling: The upwelling that takes in the polar areas result from the formation of two cold water masse beneath the ice shelves as water freezes to their undersides. The surface water temperature drops as low as -1.9°C.
Downwelling occurs because of an increase in density. An increase in density can be brought about by pressure & mixing of currents which produce one of the strongest currents.
v. Cyclones: Cyclones is formed over tropical seas. Winds from opposite directions meet. This air is heated by warm seas & so evaporates moisture from the ocean. This warm air rises up rapidly, cools & condenses to form clouds & produces an area of very low pressure. When moisture & air mix, it makes a collection of thunderstorms from which a cyclone can develop.
vi. Storm Surges: Strom surges associated with severe tropical cyclones constitute the world’s worst marine hazard. As a result of the storm winds the massive pilling of the sea water occurs at the coast leading to the sudden inundation & flooding of coastal region.
Storm surges are extremely serious hazards along the east coast of India, Bangladesh, Myanmar.
vii. ENSO ( El Nino-Southern Oscillation ): ENSO is occurs due to interaction between the atmosphere & ocean in the tropical pacific.
viii. Climate Change: Climate change due to interaction between the atmosphere & ocean.
ix. Maintain Ocean Ecological Balance: Maintained ocean ecological balance by interaction between the atmosphere & ocean. Dissolved gasses is very important for plant & organisms living in water. O2 is important for aquatic plants & CO2 important for photosynthesis of algae. Most gases in the air readily dissolve in seawater at the ocean’s surface. Plants & animals living in the ocean require these dissolved gases to survive. Dissolved nitrogen gas is a conservative component of seawater, while biologically active oxygen & dioxide are non-conservative components.
Fig: Air-sea interaction |
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