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March 1998

A SHEBA photo gallery--brought to you by IDC


Last fall, members of the Atmospheric Technology Division and UCAR's Joint Office of Science Support trekked to the Arctic to set up instrumentation and networking for the Surface Heat Budget of the Arctic Ocean (SHEBA) project. Below are some of the images they brought back. The print version of the pictures are provided here was provided in color with assistance from the NCAR Imaging and Design Center and its new high-speed, high-quality color copier.

See below for more details on the February ice realignments at the SHEBA base camp.•

Four little Flux-PAMs all in a row: Aboard individual transport sleds, the portable automated mesonet units (white containers in foreground) head out for their October deployment, flanked by SHEBA's two Canadian ships. (All photos courtesy of ATD unless otherwise noted.)

ATD's Kurt Knudson braves the rime to work on one of the Flux-PAMs.

Boreal beauty: A sundog adds some light to the wan Arctic sky.

Home away from home for the SHEBA team, the Des Groseilliers shimmers in this nighttime view from base camp. (Photo courtesy of Marty Mulhern, NOAA.)

A miniature portrait of the Arctic's water-and-sea-ice mélange presents itself from the deck of the Des Grosseilliers. (Photo by Jim Moore.)

A radiometer attached to one of the Flux-PAMs looms larger than life. (Photo by Jim Moore.)

On the Web

An unexpected icebreaker at the SHEBA party

The science is solid, but the base camp for the SHEBA project is on thin ice--literally. The NSF-sponsored project is designed to monitor a year's worth of growing and melting of the sea ice near the center of the Beaufort gyre. The gyre, several hundred miles beyond the northern coast of Alaska and Canada, contains some of the Arctic's oldest, most compact sea ice. After only four months, it's become clear that something unusual is happening--perhaps a long-term shift toward a different sea-ice regime. The crew had its hands full keeping the base camp intact during February as sections of the ice broke up and realigned, putting the squeeze on one of NCAR's portable automated mesonet (PAM) stations.

The SHEBA base camp--separated into three floes by ice breakups in February--is pictured here in October as seen from the nearby Des Grosseilliers . (Photo by Lia Pennington.)

Two Canadian ships went to the middle of the Beaufort gyre last October to establish a base camp. The Louis St. Laurant departed while the Des Grosseilliers remained, to be frozen into the ice pack for a year of measurement and analysis. Supply flights from Prudhoe Bay every few weeks have been shuttling equipment and fresh food and rotating the staff, who work at the base camp next to the Des Grosseilliers and sleep aboard the ship. Since an ATD/JOSS team helped with set-up in October, several NCAR and UCAR staff have visited the site, including ATD's Steve Semmer in early January and Tony Delany and Ned Chamberlain (also from ATD) in late February.

Surprises from the initial SHEBA data gathered in October are outlined in a paper recently published on the Web. Salinity measurements in the upper 100 meters (330 feet) of the water column imply a net summertime influx of about 2 meters of fresh water. In contrast, only 0.8 meters of freshwater input were deduced in the same region in a 1975 sea-ice project.

"We were struck [in October] by the lack of thick ice," write the authors, led by Miles McPhee (McPhee Research Company). "Where we expected the mean thickness to be between 2 and 3 meters, we were hard-pressed to find floes more than 1.5 meters thick." Changes in local precipitation, river runoff, and even warming elsewhere in the Arctic between 1975 and 1997 appear unlikely to have triggered these changes. Scientists are thus exploring the idea that changes in atmospheric circulation might have stepped up a positive feedback between ice melt and albedo to accelerate the usual seasonal melting.

With the Des Grosseilliers in position through the fall of 1998, "the SHEBA project is well poised to investigate if and how the ice pack will reestablish equilibrium. The possibility that the ice is thinning rapidly lends a sense of urgency to our measurements over the next melt season."

A more tangible urgency reached the camp this past month. On 29 January, a crack formed through the central camp area. Initially a few inches wide, by 4 February it was more than four feet across and growing. All but one of the power lines from ship to camp were severed by the movements, and the camp buildings were dispersed on three separate floes. Power has since been restored to most buildings, and the camp is being reconfigured.

Meanwhile, a shifting ice ridge put the crunch on one of the four Flux-PAM stations on 12 February. The PAM's tripod and radiometers were damaged by the moving mass of ice, but the data system and most of the sensors were unharmed, notes Flux-PAM manager Tom Horst (ATD). The hapless station had already incurred some cable damage earlier in the project, thanks to a visit from a local polar bear. On the bright side, the sun came back in February for the first time since early November. •BH

New convenience for your color-copying dollar at IDC

This two-page Staff Notes Monthly insert was printed in-house on the Imaging and Design Center's new Canon CLC 1000 color copier (pictured at right with imaging specialist Pam Hale and designer Mike Shibao). The machine is a fast, easy, and cost-effective way to brighten up documents and viewgraphs, says imaging coordinator Collen Ertle. "This machine is fully networked," notes Colleen; this allows it to print directly from the World Wide Web. It's also equipped to work directly from various Macintosh word-processing and presentation software, such as WordPerfect and PowerPoint. PC capability arriving in March. The 1998 IDC calendar, featuring a spectacular Carlye Calvin photo of flying-saucer-type wave clouds, was printed on the CLC 1000. The in-house team of IDC designers--including Carlye, Mike, and the newest member, Penny Sadler--is ready to bring your documents from design to print stage. Color-copy prices start at $1.20 per copy for NCAR accounts and $1.49 for UCAR (due to varying overhead rates) and drop to as low as 55 cents per copy with quantity. Transparencies start at $2.10 (NCAR) and $2.29 (UCAR), with quick turnaround time, typically the same day. For details on how IDC can help you, check with Colleen or Pam at ext. 1168 for printing and Carlye, Mike, or Penny at ext. 1186 for design. "No job is too small or too big," Colleen emphasizes. "Please call us for an estimate and keep your job in house for fast turnaround, excellent quality, and personalized service!" See the IDC Web page.•


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Edited by Bob Henson, bhenson@ucar.edu

Prepared for the Web by Jacque Marshall