Guest blogger Karen Romano Young aboard the icebreaker Healy, June 26, 2010.
Say it ain’t so. My time with ICESCAPE aboard the jolly red icebreaker Coast Guard Cutter Healy has come to an end. Kathryn Hansen, NASA’s cryosphere writer, joins the ship via helicopter from Barrow on Monday, June 28. Then the helicopter takes me back to that small town on the edge of the Beaufort Sea, the northernmost point in North America and home to our community observer, Benny Hopson.
Benny has told me a lot about Barrow, told me about some whale scientists to talk to, and advised me to attend the Nalukataq, the celebration that marks the spring whaling hunt. If I’m lucky I’ll meet Harry Brower, Jr., a whale researcher who brought in the first bowhead of the whaling season -- and I might even get thrown into the air at the blanket toss that’s the hallmark of Nalukataq.
I’ll be busy in Barrow, but I’ll be sad too, regretful about having to leave this wonderful group of scientists and “coasties”, which is what we affectionately call the men and women who look after the research needs of our country so well -- and who have done each of us aboard ICESCAPE so many good turns. I’m grateful to the scientists, too, for their patience and forebearance in the face of my efforts to understand their work. This has been a crash course in Arctic ocean science for me, and it has been full of difficult concepts and surprises.
One thing that is not a surprise is the continued confirmation that the Arctic ice is melting due to climate change, and that the climate change is due to global warming, and that the melting of the Arctic ice is a sign of the averse effects of human activities on our planet. Scientists, Coast Guard, and everyone who spends time in the Arctic is in agreement about the decrease in the sea ice that supports a vital and rich food chain, and which contributes to the circulation of water throughout the planet.
I’m glad that NASA cared enough to send the scientists to study the Arctic ecosystem in an effort to get new evidence to support and strengthen their satellite surveillance of the area. And I’m grateful that they sent me along to help cover it. I appreciate all three of my blog hosts, and to Ann Downer-Hazell, host of the Science + Story blog: hey Ann, I kept my promise. I found you an eddy chaser!
His name is Bob Pickart, a physical oceanographer from Woods Hole Oceanographic Institution. Pickart and his technician, Frank Bahr, are here measuring the circulation and water types throughout this cruise, using an instrument called the Acoustic Doppler Current Profiler, which emits sound signals from the Healy’s hull. “It emits sound that reflects off the particles (plankton and other substances) in the water. If the bugs are moving, that tells you how the water’s moving relative to the ship.” Pickart uses the ADCP together with the CTD to link the character of the water with the currents and the sea floor, and supplies data about it to the other ICESCAPE scientists. As the cruise moves north (without me!) of Barrow and into a particularly volatile area, Pickart will shift gears, taking a more active role in guiding the ship’s path -- and maybe getting the chance to chase an eddy or two.
Pickart’s images from an expendable probe called the XBT reveals temperature at different depths. Can you spot the eddy? (top left)
Eddies form near the boundary of two different water types where there is often a strong current running parallel to the boundary. The current begins to “wiggle” and eventually pulls water from one side of the boundary to the other in the form of a lens (or eddy in oceanographic jargon). Bob Pickart provided this animation of eddy formation.
In the Arctic these eddies are tiny, often only 10 miles across. If Pickart can find an eddy, the Healy may attempt to stay with it, giving Pickart and the rest of the ICESCAPE team the chance to examine one up close. “It can be like finding a needle in a haystack,” says Pickart. But it’s a worthwhile needle, one that could reveal the mechanism that carries cold Pacific water from the shelf into the central Arctic, where it helps maintain the halocline, the salty barrier layer that keeps the deep, warm Atlantic water from rising to the top of the water column, where it could melt the Arctic ice sheet.
Oceanographers know the Pacific waters get there, but not how. Pickart’s focus haystack is the shelf break jet, formed at the boundary of the Pacific water and the central Arctic water. This jet is known to be unstable, and the hope is that it will be spinning off eddies of cold Pacific winter water at this time of year.
The original plan had been for ICESCAPE to run transects (paths of stations) in lines radiating out from Barrow, using the instruments we’ve been using since Dutch Harbor -- finding out what sorts of organisms live in the water, what they live on, and what their health is. As a group, the scientists understand the vitality of Barrow Canyon -- a deep canyon north of the town of Barrow -- and are eager to see what is happening here. Enter Bob Pickart to run quick stations using the CTD and ADCP only to measure salinity temperature and velocity in hope of finding one of these cold spirals down deep.
What they find by chasing an eddy may contribute greatly to the understanding of how water, and other vital properties, moves through the Arctic -- and that, in turn, will make it easier to see how the Arctic will be affected by climate change.
Thank you for reading my ICESCAPE blogs at Science + Story. For more on ICESCAPE, please see my blog posts at Climate Central and NASA What on Earth? and
