The first planned observation of a spiral eddy took place during the first space
shuttle flight of the Columbia. An eddy in the Gulf of Oman had been seen several
times on National Oceanic and Atmospheric Administration (NOAA) infrared
satellite imagery that was enhanced by technicians at the Scripps Institution of
Oceanography in La Jolla, California. While doing the oceanographic interpretation
from that imagery, the Scripps scientists concluded that what appeared to be thermal
gradients were actually the result of sea-surface slicks. They reasoned that an eddy
should be visible, therefore, and briefed the crew of STS- 1 to look out for it.
During an orbit on the first day of the mission, the
commander of the Columbia observed a series of eddies through the Gulf of Oman
and managed to photograph most of them. The largest, shown in this illustration,
was exactly in the location of the rotating system seen on the infrared imagery.
The entire series observed from the spacecraft could be laid one-on-one with a NOAA
infrared image obtained just hours after the shuttle's orbit.
Because of the configuration of the shoreline,
oceanographers believed that the cyclonic spiral was influenced by the coastal
topography. The information of most interest at the time was the coincidence of the
visible eddy with that in the thermal infrared imagery.
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