I just realized that the Loop Current (LC) is unique in the sense that the velocity does not taper off to zero on the right-hand side. Most ocean currents have maximum velocity near their respective center lines and zero velocity at both edges. This is true of the Gulf Stream where it runs freely in the Atlantic Ocean. The LC enters the Gulf of Mexico (GoM) via the Yucatan Channel and eventually exits the Gulf via the Florida Straits, which lie to the right. Also entering the GoM, are clockwise rotating eddies that originate in the North Brazil Current. There are also counter clockwise eddies but these have sea surface depressions at their respective centers and I am speculating that they don't get trapped by the LC. They can sort of sneak under the LC.
However, a clockwise eddy flows around a hill of warm water that drifts into the GoM. The gravitational constant times the slope of the surface is the acceleration of the water down the surface of the hill. This is balanced by the Coriolis acceleration due to the velocity of the water circulating around the hill. The eddy is on the Cuba side of the channel, to the right of the LC. The LC wraps itself around the eddy as it makes the right turn into the Florida Straits. Sea surface height (SSH) contours from 0 cm to 35 cm pretty much belong to the LC, while SSH contours from 35 cm to (on Dec. 6, 2011) 75 cm belong to the eddy. There is appreciable velocity where the LC blends into the eddy. On this date there appear to be two eddies trapped in the LC: one near Cuba, and a second which is almost detached from the Cuba eddy. There is a saddle point at the 12 cm SSH contour. LC water below this SSH flows around both eddies. LC water above this SSH takes the short cut around the Cuba eddy.
Less than half of the LC water is flowing around both eddies on Dec. 6. Most of it is taking the short-cut path. At some future time the almost-detached eddy may disconnect and drift westward. Then again, it may become more tightly bound and the saddle point will fill in. These altimeter maps are available for every day since January 1993. There is an endless variety of LC paths, and oceanographers have been trying to figure out what makes the darn thing tick since way before 1993. At one time I thought that the length of the LC intrusion into the Gulf had to do with excess hydraulic driving power. Fortunately, this has not proved to be correct, so humanity is spared from the temptation to build impossible arrays of floating turbines that were supposed to shorten the LC path and thereby trap less warm water and reduce hurricane intensity.
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