New Discovery: An Underwater Mountain
On August 25, scientists aboard the Coast Guard Cutter Healy discovered an underwater mountain, known as a seamount, protruding from the Arctic’s seafloor. The yet-to-be-named seamount is the first known to be discovered in the Arctic since 2003, when scientists discovered a seamount later named Healy. Underwater features are generally considered seamounts if they reach a height of at least 1,000 meters above the seafloor.
The discovery was made while Healy was en route to map seafloor features targeted for investigation. The ship took a slight detour to map a small contour that appeared on a 2002 Russian map. As the ship traveled toward the new target, watchstander Christine Hedge, a teacher from Indiana onboard the Healy as part of the NOAA’s Teacher at Sea Program, noticed something much more significant beginning to appear on the shipboard monitors. She alerted the scientific team in time to redirect the ship, which enabled the Healy’s high-tech 12kHz multibeam echosounder mapping system to reveal the full extent of the seamount.
Details on the seamount, about 700 miles north of Alaska, are below.
- 81_31.57N 134_28.80W
- Shallowest depth 2622 m
- Depth at base 3710 m
- Approximately 14 nautical miles long, 4 nautical miles wide, oriented N-S
For more information on this seamount, check out the below blog sites.
U.S. Coast Guard
http://cutterhealy.wordpress.com/2009/09/03/healy-science-team-makes-seamount-discovery/
Captain Andy Armstrong from the National Oceanic and Atmospheric Administration and Co-Director of the Joint Hydrographic Center
http://www.ccom-jhc.unh.edu/index.php?p=31|32|33|34|0|1|34&page=outreach/projects/healy0905/HE0905_blog.php
Christine Hedge, NOAA’s Teacher at Sea
http://teacheratsea.noaa.gov/2009/hedge/hedge_log12.pdf
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- 3-D view of newly discovered seamount. Click image for details.
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- 3-D image of newly discovered seamount. Click image for details.
Unmanned Vehicles Gliding Undersea
CDR William Sommer, U.S. Navy
In the early hours of August 8, a U.S. Navy detachment aboard U.S. Coast Guard Cutter Healy launched a SeaGlider into the Chuckchi Sea. The SeaGlider is one model of a class of Unmanned Undersea Vehicles used to sense and report ocean characteristics, including optical properties as well as conductivity (salinity), temperature and depth, also known as CTD. Gathered data are used to evaluate the performance of its oceanographic forecasts.
As the name suggests, this undersea vehicle “glides” through the water column as it moves from location to location. A small pump and motors adjust the buoyancy (weight) and balance of the vehicle causing it to rise and fall through the water. As it rises or falls, the wings convert some of the vertical motion to a forward thrust just as an aero-glider trades altitude for air speed. When the glider completes a full dive and surfacing cycle, it will point an antenna skyward and “phone home” to its pilot at the Glider Operations Center (GOC) at the Naval Oceanographic Office at Stennis Space Center in Mississippi. During this communications period, it sends the recently sensed data, receives a new set of instructions from the pilot, and then begins the next cycle.
The glider is not fast-it is designed to conserve power through gliding. The lack of an active propulsion system conserves enough power to allow the glider to remain at sea for upwards of six months. It is this persistence which makes the glider so useful. Once deployed from a ship, it provides high-quality observations for months, all the while unattended. A single operator at the GOC can manage several gliders simultaneously. In the case of the glider launched from Healy, it will remain at sea for six weeks before it is recovered.
CDR Sommer prepares glider for launch. Click image for details.
The glider also offers a superior quality of data since the vehicle’s small shape does not disturb or mix the water column as a ship’s hull and propellers do. Complex and often very small scale ocean features remain largely undisturbed by the gliders transit. The glider is portable and can be assembled, launched, and recovered easily by a two-man team with just a few hours of training.
Gliders are also a very cost effective tool for observing the ocean. It can cost upwards of $40,000 a day to keep a ship at sea. To complete a CTD cast to 1000 meters depth, it might take two hours or almost $3,400 not including the cost of the instrument itself or the cost to move the ship to the site being studied. While conducting a CTD cast, a ship is also stopped in the water and cannot conduct most other research operations. Costing in the low $100,000s, the glider effectively pays for itself through the recovered ship time in a matter of days. Use of a glider frees the ship to conduct research more appropriate to the ship’s design, such as hydrographic and bathymetric survey operations.
As mentioned, all of the data from the glider and others like it world wide are sent to the Naval Oceanographic Office. There, the Navy operates a supercomputing facility producing daily oceanographic forecasts for the nation’s maritime forces (Navy and Coast Guard) and other key government partners and agencies. These forecasts serve both scientific research and U.S. Navy operational concerns. The observations gathered by the glider will both improve the quality of the ocean forecasts and aid in determining the quality of those modeled forecasts.
What Happens to the Data? Archiving and Distribution
Jennifer Henderson, CIRES/NOAA-NGDC
I was quite excited about the opportunity to sail on the US Coast Guard Cutter Healy since I am a newly hired seismic data manager for NOAA’s National Geophysical Data Center (NGDC) in Boulder, Colorado. In a job that entails archiving and distributing geophysical data to the public, it is extremely beneficial to also be a part of the collection and processing of that same data.
NGDC is a nationally and internationally designated archive, integration, and distribution point for public marine geological and geophysical data, including data collected with US National Science Foundation funds. Data archiving means to preserve data so future generations can both access and understand the data. This involves secure on- and off-site copies of data, migrating to new media every five to seven years, describing the data so it can continue to be understood even 50 years after collection, maintaining current formats and technology, and keeping data accessible.
Data management and archiving must continuously change to keep pace with technology, scientific campaigns, and research needs. In 2006, our total archive of marine geophysical data was less than six terabytes. Today, NGDC stewards over 14 terabytes of new data every three months. A terabyte is 1,024 gigabytes, an allocation of data storage capacity applied most often to hard disk drives.
Examples of the specific data types we maintain and archive are bathymetric, seismic, gravity, magnetic, and data from ocean drilling and seafloor sediment and rock samples. However, data centers not only archive original data and information describing that data but also the derived products (visualizations, assessments, and compilations) that may be generated at the data center for multiple communities and users. Examples of these products include sediment thicknesses, coastal relief models, and hazard assessments, especially related to tsunamis caused by earthquakes and volcanic eruptions. We also work with scientists and science centers to automate data description and quality assurance, to develop common formats, and to develop and implement various tools.
NGDC is one of many agencies involved with the ongoing Extended Continental Shelf (ECS) project that has previously been explained on this blog. NGDC has been given the responsibility from the United States ECS Task Force to establish and maintain a system to manage ECS-related data, track changes made to that data, support ECS data analysis and finally to archive all data and related projects and information.
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