Seagoing sensor sends climate data.

One of the most elusive pieces of the climate and weather puzzle soon may be made available by a simple oceangoing package of sensors the size and shape of a Frisbee. While scientists long have known that climate and weather in large measure are driven by the flow of heat from the ocean to the atmosphere, reliable measurements of this "heat flux" have been almost impossible to obtain, explains John R. Anderson, professor of atmospheric and oceanic sciences, University of Wisconsin-Madison, and associate director of the school's Space Science and Engineering Center.

A drifting ocean heat flux sensor could provide important clues to long-term climate issues as well as insight into seasonal weather events such as hurricanes and the winter storms that frequently lash the eastern U.S. "Most storms that strike the East Coast are driven by ocean heat fluxes. Heat flux is also an important part of the climate system. And while these measurements are critical, they are extremely difficult to get and they are often inaccurate."

For the planet as a whole, the measurements are crucial because most of the energy or heat directed at the Earth by the sun is soaked up and stored in the oceans. Eventually, that heat is transferred to the...