So if on the 17th of May already oil entered the Loop Current, why isn´t it in the Keys or Miami 20 days later?
Because of eddy.
Every 6 - 11 months, the top bulge of the Loop Current cuts off, forming a 250-mile diameter circular eddy in the middle of the Gulf of Mexico. This clockwise-spinning eddy is filled with warm water from the Loop Current, and is called a Loop Current Eddy. The main body of the Loop Current then takes a fairly direct eastward path from the Yucatan Channel to the Florida Keys.
By May 27, this loop had separated, and new oil moving southwards from the spill will now be trapped in the clockwise rotating Loop Current Eddy that is cut off from the Loop Current.
See animation here.
During the first 1 - 2 months that a Loop Current Eddy forms, it is common for the eddy to exchange substantial amounts of water with the Loop Current, and in some cases get re-absorbed into the Loop Current.
It remains to be seen if the deep water currents have followed suit, and a stable Loop Current Eddy cannot exist until the deep water currents also cut off into a clockwise-rotating ring of water at depth.
Read the complete article at Dr. Jeff Masters' WunderBlog
The cycle of forming an eddy from the loop current. Read more about that here.
The warm water of the loop current has a depth from 80 to 150 meter, the cooler up to 300 meter.
I had the fear of the oil plumes hitchhiking from the loop current into the gulf stream, but with this data now, this fear is luckily short lived.
The shallowest oil plume so far detected is at about 2,300 feet (700 m), while the deepest was near the sea floor at about 4,200 feet (1,300 m).
So with this information, I can see the whole east coast from the Florida Keys up to North Carolina cheer:
GO EDDY GO!
GO EDDY GO!
I feel very sorry for you guys on the Gulf of Mexico, because Katrina and Rita got their supercharge from a similar eddy what separated in July. You might be in for much more trouble.
Jonnie will keep you posted what´s going on in that region.
... and the last name of Eddy is "Franklin"