Taking the Ocean's Temperature

Scientists find a better way to gauge the high seas.

By Mark Schrope

June 28, 2002

Even though over seventy percent of the earth's surface is ocean-more than one billion-billion tons of water-oceanographers still know very little about it. Compared to the sophisticated data collection and information technologies used for atmospheric research, science's ability to forecast, or even record, ocean conditions remains antiquated.

An international collaborative effort, called the Global Ocean Data Assimilation Experiment, last month announced plans to improve the process. The group intends to tie together a world-wide army of oceanographic floats and satellites in order to get an unprecedented daily view of the high seas. Organizers say these new space and water-based systems will fill the longstanding gap in ocean monitoring abilities that has prevented our ability to better understand the ocean and forecast its constantly changing face.

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According to Neville Smith, chair of the project's international steering team, plans began to form in 1998 as a number of satellites that would provide a wealth of needed ocean data got ready to launch. The satellite Jason-1, launched by NASA last December, uses an altimeter to precisely measure aspects of ocean-surface topography, such as surface conditions, circulation and sea levels. Satellites soon to launch will measure surface winds and other phenomena.

But satellites alone are not enough, says Phil Sharfstein, the data manager for the U.S. component of the assimilation experiment, based at the Navy's Fleet Numerical Meteorology and Oceanographic Center in Monterey, CA. "The main problem is that there's just not that much data out there," he says. For example, satellites can measure current sea levels, but predicting future levels requires information that a satellite can't collect, such as salinity and deep-sea temperatures.