Coriolis force ocean

As a result of these factors (wind, Ekman transport, Coriolis force) the surface ocean circulation in the mid-latitudes is characterized by clockwise gyres in the northern hemisphere and the counterclockwise gyres in the southern hemisphere. The main surface currents around these gyres for the world s oceans are shown in Fig. 10-6. The regions where Ekman transport tends to push water together are called convergences. Divergences result when surface waters are pushed apart. 

The distribution of chemical components within the ocean is determined by both transportation and transformation processes. A brief outline of oceanic circulation is necessary to ascertain the relative influences. Two main flow systems must be considered. Surface circulation is established by tides and the prevailing wind patterns and deep circulation is determined by gravitational forces. Both are modified by Coriolis force, the acceleration due to the earth s rotation. It acts to deflect moving fluids i.e., both air and water) to the right in the northern hemisphere and to the left in the southern hemisphere. The magnitude of the effect is a function of latitude, being nil at the equator and increasing poleward. 

Currents in the oceans, both surface and deep, are responsible for planetary-scale heat transfer, and thus oceans profoundly impact Earth s climate. The surface currents are driven mainly by wind, with their direction modified by the Coriolis force, which is an inertial force arising from Earth s rotation (see Section 4.3.1 for a detailed discussion). Several of the major oceanic surface currents are shown in Fig. 2.11. These include the well-knovm Gulf Stream, in the Atlantic Ocean, whose heat flux helps warm the climate of northern Europe. 

FIGURE 2.11 Major surface currents in the oceans. Surface currents are mainly wind-driven, but are also influenced by the oceans boundaries and by the Coriolis force. Not illustrated here are deep-water currents, mainly driven by differences in water density. For example, water carried northward by the Gulf Stream sinks after giving up much of its heat, and flows southward in the Atlantic Ocean as a near-bottom current. On the planetary scale, one net effect of ocean currents is to transport large amounts of heat from warm equatorial regions toward the poles (Earth Science Reference Tables, 2011). 

The Coriolis force is particularly important when fluid motion occurs at large scales, as in vast lakes such as Lake Michigan (Fig. 2.6b), in oceans (Fig. 2.11), or in atmospheric circulation (Fig. 4.12). Figure 4.12 explains the origin of the Coriolis force in terms of the radial and tangential components of the velocity of a fluid parcel in a rotating disc of fluid. 

Three forces combine to drive the GHCB. The first is the Coriolis effect, which is caused by the rotation of the globe and results in a faster movement of the ocean s surface near the equator. The second is the level of the Pacific... 

We assume a large-scale wind force acting on the surface of the rotating ocean where x is directed eastward, y is directed northward, and z is directed upward with z = 0 at the sea surface. The Coriolis parameter/= 2 Q sin cp, where Q is the rotation velocity of the earth and cp is the latitude. The corresponding components of the mean current are (m, v) and that of the small scale turbulence are Then the governing equations are... 

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