Ice core isotopes may reveal more than temperature

Since the 1960s, scientists have used natural isotopes — versions of the same atom that vary slightly in weight — as scientific fingerprints. Carbon isotopes help archeologists date ancient human remains, for example. And in ice cores extracted from layers of compacted snow, oxygen and hydrogen isotopes have long been understood to speak to the temperature at the time.


Climate clues locked in icy isotopes could give researchers a high-definition view of Arctic climate.

"We know that's kind of right, in a general sense," says CIRES Fellow and Associate Professor David Noone, emphasizing the adjectives. But it could be that isotopes say as much about patterns of sea ice or clouds as temperature, Noone said. "Nobody has checked this with modern techniques."

So he's about to. With a four-year, $2-million grant from the National Science Foundation, Noone and his colleagues will set up a unique combination of advanced, laser-based instruments in Summit, Greenland; Reykjavik, Iceland; and Eureka, Canada. They plan to track how various factors — evaporation from oceans, creation of clouds, patterns of moist air movements, the settling of snow into compacted layers, and temperature — affect isotopes in the snow layers.

If Noone's team can unravel those factors and how they create isotopic signatures in Greenland snow, then other scientists will be able to use the results to extract more information about past climates. Perhaps ice core data — which Noone calls "underutilized" — will help climate researchers better understand changing patterns of cloudiness and sea-ice cover in the Arctic, as well as temperature.

The project could fill in the picture much as corrective lenses can help a near-sighted person see more than just the broad outline of a distant tree, Noone said. With glasses, branches and leaves suddenly appear. "And there's a chance," he said, "that when we hold up our lens we'll discover 'Oh, it's a shrub!' or 'That's two trees.' "

Tracking Europe's "weather machine"

Greenland Climate Network (GC-Net) will leap into public service in 2011, providing up-to-the-hour weather and ice-sheet information to the Danish office of the World Meteorological Organization. The data provided by the weather stations deployed on the Greenland's Ice Sheet should boost Europe's weather prediction capabilities.

"The Greenland Ice Sheet is the weather machine for Europe," said CIRES Director Konrad Steffen. "Any changes of circulation in Greenland, such as cyclone frequency, have a large effect on weather in Central and Northern Europe."

To improve predictions, weather forecasters need more accurate pressure readings, temperature, and wind velocity information. "The GC-Net provides this basic information on time to be part of an hourly worldwide distribution of standard meteorology data," said Steffen.

These forecasts will also be helpful closer to home, he said. "GC-Net will improve local forecasts for Greenland, which are essential for transport and the fishing industry."