Oceanography (2+1)

Gradient current

Gradient current:

Is the current which is defined by assuming that the horizontal pressure gradient in the sea is balanced by the sum of the coriolis and bottom frictional forces. At some distance from the bottom the effect of friction becomes negligible and above this the gradient and gcostrophic currents are equivalent which is also known as slope current. These are currents originating in oceans and seas as a result of differences in water column pressure. These differences in pressure are caused by the driving force of winds on the water, the unequal distribution of the waters density in a basin or the atmospheric pressure above it and the influx of continental waters or waters from other soruces, and so forth. Under the action of the coriolis force, gradient currents are deflected from the direction of the pressure gradient to the right in the northern hemisphere and to the left in the sourthern hemisphere.