Probing the Black Current

Satellites and ocean bottom instruments tell similar stories.


PHYSICAL oceanographer Jae-Hun Park helped steady a pumpkin-sized, plastic-encased glass ball on the deck of the Research Vessel Melville. The ball contained scientific sensors and had been moored to the sea floor off the eastern coast of Japan for two years, collecting data about the rapidly flowing ocean current above it. Forty-two other such glass balls either had been retrieved or were still moored underwater. Park would spend almost a month at sea with other researchers, retrieving these instruments. But he was very excited about the data they would be getting on the eddies, gyres, and meanders that make up the most active region of the Kuroshio Current.

The Kuroshio, one of the three largest of the world’s ocean currents, has long fascinated humans. Early fishermen and explorers took note of these currents because they either sped up their voyages or got them lost. Early Chinese mariners called the Kuroshio Current Wei-Lu, or the current to a world from which no man has ever returned. The Japanese named it Kuroshio, or black current, for its dark, cobalt blue waters. Physical oceanographer Steven Jayne said, “The Kuroshio is the strongest current in the Pacific Ocean, and is also one of the most intense air-sea heat exchange regions on the globe. It influences climate as far as North America.”

Originally published in Sensing Our Planet: NASA Earth Science Research Features. Read the full story here.

Image courtesy N. Kuring, NASA MODIS Ocean Color Team.