Wednesday, July 21, 2010
Navy subs help scientists expand study of Arctic thaw
Scientists who study the Arctic's icy cap now have a new weapon at their disposal -- nuclear-powered Navy submarines.
Civilian researchers have signed an agreement with the Navy to revive a dormant program that uses the vessels to collect information on parts of the Arctic's ice and ocean that normally lie beyond scientists' reach.
Called SCICEX -- short for "Science Ice Exercise" -- the program began in 1993 when the USS Pargo carried five civilian scientists to the Arctic on a test cruise.
But after six years and five additional dedicated science cruises to the far north, project SCICEX sputtered.
"When the Cold War ended, the Department of Defense really turned its attention to lower latitudes," said Jackie Richter-Menge, a sea ice expert at the Army Corps of Engineers' Cold Regions Research and Engineering Laboratory in Hanover, N.H. "There wasn't really the support to continue that level of support to the scientific community."
Instead of providing submarines for planned science missions to the Arctic, the Navy conducted four "scientific accommodation missions" between 2000 and 2005 -- collecting information during brief pauses in classified submarine exercises.
For the last five years, the submarines -- part of a force stretched thin by conflicts in Afghanistan and Iraq -- have not gathered any data. At the same time, the Arctic has seen dramatic warming that led to a historic low in summer sea ice in 2007, when its areal cover dropped roughly 40 percent below the 30-year average. Scientists have also documented shortening of the region's snow season, rising land surface temperatures and warmer permafrost, and changes in the population and habitat of polar bears, walruses, seabirds and other Arctic wildlife.
A deeper look at a transforming region
Now, with the Arctic's transformation in mind, scientists and the Navy are collaborating to restart the SCICEX program -- with constraints.
Richter-Menge heads a scientific advisory committee that just released a detailed wish list for Arctic data, ranging from measurements of "ice draft" -- how much of the region's sea ice cover lies submerged below the ocean's surface -- to measurements of ocean chemistry, maps of the ocean floor and information on marine microbes.
The idea is to provide a prioritized list for the Navy, which will collect data as time allows on otherwise classified submarine missions. Security concerns prevent advance planning of science activities aboard the subs.
"The goal was to carve out some small amount of time on those planned missions," Richter-Menge said. "There was a general understanding, both from the military standpoint and the scientific standpoint, that you still have to understand the environment."
Reviving the SCICEX effort fits in the with Navy's renewed interest in the Arctic. The region's continuing thaw has positioned the region as a potential future hotbed of tourism, shipping, energy and mineral exploration -- and an emerging military frontier.
With scientists predicting Arctic summers could be ice-free by the 2030s, the ensuing resource grab could increase the potential for competition and conflict between nations, the Navy's Task Force Climate Change warned in its Arctic strategy, released last fall.
'Ground truth' for the satellites
"We really want to understand when changes will be significant enough to provide for increasing access to shipping, resource exploitation and future increased engagement in that region," said Capt. Tim Gallaudet, the task force's deputy director.
In the Arctic, "the players are a little more dynamic now," he saaid. "We're seeing non-Arctic players now. China has an ice-strengthened research vessel."
For scientists, the advantage of SCICEX lies in harnessing submarines that can travel at high speed and operate even in areas that are covered by ice -- missions that would otherwise require use of icebreaking ships, which are in short supply.
And though satellites can cover more ground and easily document multiple snapshots in time, Richter-Menge said the submarine data would be invaluable to help "ground-truth" measurements collected high in the sky.
"The submarine has the advantage of looking up at the ice from underneath," she said, "When they take an ice draft measurement, they're measuring nine-tenths of the ice cover, and they're more accurate."
Exploring the missing nine-tenths
With satellite measurements, scientists must apply a mathematical formula to convert the portion of sea ice that sits above the water line -- roughly one-tenth of total ice volume -- to determine how much ice bobs in the Arctic Ocean.
The submarines can also collect data on ocean chemistry that satellites cannot.
"What it does is gives us a great validation point for [computer] models that are being built to make sea ice forecasts," Richter-Menge said. "Those models, our ability to do that, are important for a variety of reasons: global climate change, the role that sea ice plays in the climate, the whole issue of operations with ships traversing the Arctic, be that for tourists or trade or anything like that."
The renewed SCICEX program will operate under a memorandum of understanding inked in 2000 between the National Science Foundation and parts of the Navy.
The new science plan calls for collection of baseline data on the Arctic's ice canopy and seafloor and the physical, chemical and biological properties of Arctic seawater.
Navy technicians will gather the data using instruments already installed on the submarines during direct transits across the Arctic Basin, from the Atlantic to the Pacific or vice versa. The submarines will also have an opportunity to collect data during biennial exercises in the southern Beaufort Sea, called ICEX, for which the Navy establishes an ice camp.
Subscribe to: Post Comments (Atom)
Post a Comment