eddies, because the ring of current has es- sea surface temperature (SST) or sea sur-
sentially lassoed a core of warmer water face height (SSH). The satellite mapping
from south of the Stream. Similarly, eddies of sea surface height is not looking for the
generating south of the Stream are known same information as weatherfax forecasts
as cold eddies. Warm eddies flow clockwise of wave conditions. The stream actually
and cold eddies flow counter clockwise. It is bulges above the mean sea level. Addition-
quite possible for boats to be within sight ally, current velocity is modeled from satel-
of each other while being driven in oppo- lite data.
site directions by either side of an eddy. Because much of this data is for use by
Cold eddies tend to display stronger cur- oceanographers, it is often averaged over a
rents. Once established, eddies will tend to three- or seven-day period. While this al-
drift in the general direction of the Stream as lows scientists to get a better view of overall
they dissipate. An eddy maintains a distinct trends, it does little for the sailor trying to
temperature difference that makes it possible take advantage of conditions at a specific
to track on satellite imagery. time and location. When using images from
Satellite Imagery: A great deal of effort the Internet, be certain to double check the
goes into tracking Gulf Stream eddies, effective dates of the imagery.
which serve as important biological and en- Another important thing to remember
ergy transport mechanisms and can have an is that much of this is the result of various
effect on weather. As a result, there is a con- computer interpretations of data.
stant stream of satellite imagery available. Perhaps the most sophisticated of these is
Most data is focused on recording either the Modular Ocean Data Assimilation System.
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When the Gulf Stream enters the Gulf of Mexico from between Cuba and the Yucatan Peninsu-
la it forms a huge loop, with confused currents in the center and very strong currents as it pass-
es between the two land masses. Its course is very evident from the temperature differences.
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