The Arabian Sea's high salinity is primarily due to high evaporation rates and limited freshwater inflow.
Factors Contributing to High Salinity
Several factors contribute to the Arabian Sea's high salinity:
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High Evaporation Rates: The Arabian Sea experiences significantly high rates of evaporation due to its location in a hot, arid climate. Water evaporates, leaving behind the dissolved salts. This process is intensified by strong surface heat loss. [This is consistent with findings from research on the Persian Gulf, which shares similar characteristics, noting "extremely high evaporation rates, strong surface heat loss"](Bower et al., 2000, Pous et al., 2004a).
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Low Rainfall and River Discharge: The region receives relatively little rainfall, and the inflow of freshwater from rivers is limited. This lack of freshwater input further concentrates the salt content. [Again, mirroring the Persian Gulf's low rainfall and river discharge contributing to its high salinity.](Bower et al., 2000, Pous et al., 2004a)
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Limited Exchange with the Open Ocean: The relatively limited exchange of water with the open ocean restricts the dilution of the concentrated saltwater. [The shallowness of the Persian Gulf also restricts exchange, indicating that similar shallowness may play a role in the Arabian Sea.](Bower et al., 2000, Pous et al., 2004a). The Arabian Sea has a dense, high-salinity top layer reaching 37 ppt due to the high evaporation rates. [Source: UNESCO Ocean Literacy]
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Salt from the Indian Ocean: The Arabian Sea receives some salt from the Indian Ocean, contributing to its overall salinity levels as noted in research on the Persian/Arabian Gulf.
Simplified Explanation
Imagine a bathtub. If you let the water evaporate without adding more, the remaining water becomes more concentrated. The Arabian Sea is similar; the sun's heat evaporates water leaving behind the salt, and the lack of freshwater replenishment maintains this high salinity.
