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

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.

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.

Fledermaus – It’s Like a Video Game for Science

Jonathan Pazol, high school AP science teacher in the Chicago area, onboard through the ARMADA Teachers Program

Every minute spent aboard the Healy during this expedition, we have been collecting data. The multibeam echosounder and the “Chirp” system run 24 hours a day, 7 days a week. Millions of data points have been collected and then processed by the 7 scientists assigned that task during their watches. That data then get uploaded into a computer software program that puts them all together.

This program, called Fledermaus, which Chief scientist Larry Mayer helped to develop, is an interactive three-dimensional (3D) tool that provides a way to prepare, analyze and present data. It was designed for the display of geographic features, such as mountains or ocean floors but has many other uses as well.

The program takes the processed data and can display them as surfaces, images, points, lines or even cross-sections. The bathymetric data can be positioned over a geographic map and looked at from “above” to see the features of a particular area. The picture titled “Multibeam data in Fledermaus in 2D” shows this type of display from multibeam data in an area of the Arctic Ocean called the Alpha Ridge.

Fledermaus can also take the data, color-band the surface features according to their height, and then display them in a 3D format on a map, such as the International Bathymetric Chart of the Arctic Ocean (IBCAO) map. The picture titled “Fledermaus image of multibeam data in 3D” shows a map of the Northwind Ridge – the western edge of the Chukchi Borderland. Areas based on imported data points are displayed in color. Areas that appear as a black grid are areas where there is no multibeam data to overlay on the IBCAO map.

Furthermore, seismic data can be imported and displayed simultaneously along with the multibeam data. One of the most amazing features of the software is that all of the displays can be rotated in 3D to look at a location from any angle, including underneath. And, there is a 3D “flight mode,” where the user can “fly” through a map to see various geographic changes. It’s like a video game for scientific purposes.

In addition to mapping, Fledermaus has been used to show before and after images of dredging for shipping channels, the positioning of pipelines, chemical reactions, and crop growth rates. It has even been used to map the locations of ships, caissons (temporary docks/breakwaters), and tanks off the coast of Normandy left over from the D-Day invasion of WWII.

The Otherworldly Sights and Sounds of the Arctic

Petty Officer Patrick Kelley, U.S. Coast Guard

I am a photographer, videographer and journalist in the U.S. Coast Guard. During this mission, I am onboard Healy to document this historic voyage to map the ocean floor and define the outer reaches of our continental shelf.

If you are reading this, you most likely have an infinitely greater understanding of the complexities of what the science team is doing to accomplish its goals than I do.  You probably know better than I what the significance of 12khz multi-beam sonar is to the oceanographers.  You probably know why pockmarks on the Chukchi Cap are relevant to the geologists.

What you might not have, however, is an idea of what we aboard Healy are seeing and experiencing.  This region is amazingly unique, awesome, and striking. So instead of offering a feeble attempt to explain the very complicated scientific research underway, I am simply providing you a description of our temporary environment.

We are a little more than two weeks into our journey into the Arctic Ocean, and I am still amazed by what I see each day.  We have seen four polar bears, a few rare birds and many seals.  However, the most incredible feature of the Arctic, in my opinion, is the ice itself.

As we move through the Arctic Ocean, the ice changes from one location to the next. The change is not just the thickness, as I had anticipated, but also the color, density, and texture.  In some areas, the ice looks harsh and unwilling to yield to the weight of Healy, and in other spots it appears that the ice attempts to flee before the ship gets to it. Sometimes when you look out you feel like you are cruising through a snow-covered prairie. The next day, it’s as though you have landed on a rocky, frozen planet and the ship has to blast its way through.

When it comes to color, you might think only of blue and white as the prevailing colors of the extreme north. While those are the most common colors, just calling them blue and white is not sufficient. I have seen more shades of blue here than any home improvement store paint department could hope to produce, and until I got here, I didn’t even realize there was more than one shade of white.  The frozen pools that form on top of the multi-year ice floes create the most astonishing shade of blue I have ever seen.  The white ice background creates an intense contrast, which makes the blue stand out even more.

When the fog clears enough for the sun to make an appearance, gold becomes an important player in the color scheme of the Arctic. When the sun is out, the ocean water appears to be a deep shade of black. When we are not completely surrounded by ice, the sun reflects off the black water and the bright white of the ice and creates a brilliant golden haze that runs along the horizon. And at this time of the year, the sun does not drop below the horizon; instead, you have a lasting sunset or sunrise.

If you are out on deck while the ship is breaking ice, you can actually hear the ice strain under the weight of the hull and snap when the load is too much for the sheet to bear. From inside the ship, you hear a deep rumble when Healy confronts large sheets of ice. The sound of the ship colliding with a smaller chunk of ice is more of a loud bang.

Having spent the majority of my career on boats and cutters, I am still struggling to wrap my mind around the fact that one of Healy’s primary purposes is to go out to sea and run into a major navigational hazard, over and over again.  I guess at some point I won’t flinch when the ship rocks, rolls, and shakes through an eight-foot-thick sheet of ice.

This for me is a once in a lifetime trip that I hope to someday tell my grandkids about. If you are ever offered the opportunity to make your way to the top of the world, do not pass it up. I would hate for you to miss out because no one ever told you how amazing the Arctic Ocean is.

Surveying Unexplored Features

Andy Armstrong, NOAA Office of Coast Survey, Co-chief scientist about USCGC Healy

Today we did some multibeam bathymetric mapping over areas of high seafloor relief on the Alpha-Mendeleev Ridge complex, 625 miles north of the Arctic coast of Alaska. We are still breaking through 9/10 ice (90% of the sea surface covered by ice) in front of the Canadian Coast Guard Ship Louis S. St-Laurent. Although the ice is often 1-2 meters thick, we are generally breaking it fairly easily.

This part of the track is designed to obtain multichannel seismic reflection profiles over seafloor areas from which we dredged rock samples last year (see photos of scientists examining these rocks at http://continentalshelf.gov/newsroom.html). The dredge samples and seismic profiles will help us analyze the geology of the Arctic region and delineate the extended continental shelf.

Our planned route has also taken us within a few miles of an unsurveyed feature that is vaguely depicted on Russian contour maps of the area, and is represented as a single circular contour on the International Bathymetric Chart of the Arctic Ocean. These representations are indistinct probably because they are based on one or two isolated soundings.

So, in an exploratory deviation from our planned track, we are running a bathymetric survey to precisely locate and define the feature. We began mapping a north-south trending, 14-nautical-mile-long ridge that rises abruptly out of the seafloor and stands at least 500 meters tall. Having mapped the eastern flank on our first pass, our path over the next two hours will take us along the spine of the feature and back to our originally planned track line (see image). As we turned to run the northbound leg of our survey, we saw a hint of some additional seafloor relief to the south – but that will have to wait for next year!

Two days ago, over the abyssal plain, we also had an opportunity to pass over another potential feature: an area shown as a deeper spot on Russian bathymetric maps. As we passed over the area, however, we found no change in the depth. We are again reminded that the existing maps and charts of the Arctic are based on very sparse soundings from a wide variety of sources, and depth contours reflect the very subjective judgment of the compiler.

Forecasting Arctic Weather

Jonathan Pazol, high school AP science teacher in the Chicago area, onboard through the ARMADA Teachers Program

We’re still heading north at about 4.5 knots (nautical miles per hour), which, if you don’t know ships, is very slowly. It is still foggy and when the wind picks up, it is very cold.  Whose idea was it to go to the Arctic in August when it’s 90^◦ F in Chicago?

One of the other science activities that occurs on board is the collection of weather data.  Twice daily, at 6 a.m. and 6 p.m., members of the Navy launch a weather balloon off the flight deck.  AG1 (Aerographers Mate 1^st Class) Richard Lehmkuhl is in charge of the operations.  He is based in Norfolk, Virginia at the Naval Meteorology and Oceanographic Center, and in his 14 years of service has traveled the world.  Supervising AG1 is Navy Commander William Sommer from the Naval Oceanographic Office in Stennis, MS.  The Navy has formed a task force on climate change and is onboard Healy to work with and learn from the Coast Guard about Arctic surface operations and engineering, including navigation through the ice, polar communications, weather forecasting, and developing ice prediction systems.

AG1 Lehmkuhl is responsible for preparing the balloons. It’s more than a balloon, really — a battery-powered radiosonde, which is a small white box containing a transmitter, hangs suspended from the balloon.  The radiosonde contains sensors that collect information about wind direction, temperature, humidity, and air pressure, and a GPS transmitter that sends the data back to Healy.

In the helicopter hangar, the balloon is filled with helium, and then the radiosonde is attached. Then it is carried carefully to the edge of the flight deck and released. This can be a tricky operation because handling an almost five-foot diameter balloon in strong winds is difficult.  AG1 Lehmkuhl and Commander Sommer have to be careful that the equipment does not bang into the flight deck, and that the balloon flies off the ship without becoming entangled in any of the equipment on board.

The balloon will gather data as it travels up almost 6 kilometers (3.6 miles). At that point, the air pressure drops to about 50 millibars, causing the balloon to expand so much it pops.  If it doesn’t reach this altitude, the batteries will stop transmitting data after about 2 hours.

Once AG1 Lehmkuhl receives the data, he forwards it along so it can be used to provide weather forecasts for the Navy, Coast Guard, other Department of Defense groups, and NATO units.

Straightening Out The Gear And Heading Toward More Interesting Seafloor

Andy Armstrong, NOAA’s Office of Coast Survey, Co-chief scientist aboard USCGC Healy

Today began on the same northwestward track as yesterday, with Healy multibeam echo sounding in the lead and CCGS Louis S. St-Laurent towing their multichannel seismic reflection gear astern. Although we had expected ice conditions to remain about the same, the ice actually got a little more closely packed, with more ridges and thick areas. On a couple occasions we had to back up and ram the ice to break through and make a path for Louis S. St-Laurent. Without a clear path through the ice, the towed seismic equipment on the Louis S. St-Laurent would be destroyed in short order.

Our survey and mapping progress was also slowed a bit by some of the inevitable problems that arise in any major project like this. Louis S. St-Laurent was experiencing intermittent problems with their seismic gear and decided to haul the gear in for service. Louis S. St-Laurent’s helicopter was sent aloft to find open water where the sled and streamer could be safely retrieved, and the two ships steamed about seven miles east of our track to the opening. With Louis S. St-Laurent temporarily out of service, Healy took advantage of this time to do some equipment repair of our own. About a week ago during the first CTD cast of the cruise, the CTD winch level-wind malfunctioned and mis-wrapped some of the wire on the drum. The result of that mishap was that the wire was jammed at about 1300 meters out. The Coast Guard engineers and science technicians have spent the past few hours carefully paying out wire and clearing the jam.

We should be on our way back to the track in about an hour. Because we want continuous lines of seismically determined sediment thickness, we will return to where we left off on our original track before heading northwestward again.

We should complete this leg of the track sometime tomorrow morning, and turn eastward to cross some of the bathymetric features on the margin of the Alpha-Mendeleev Ridge complex. The multibeam will have a more interesting task there than it had just a few days ago. In a part of the Beaufort Sea we mapped on August 13, the multibeam data hardly varied from about 3800 meters of depth, either across the 5-nautical mile wide swath or along the day’s 75 nautical mile track. That part of the Beaufort Sea is one of the flattest seafloors in the entire world; sediment has been drifting down and settling evenly in this basin for millions of years.

How to Map the Seafloor When You Can’t See Bottom

Rachael Soraruf, NOAA’s Office of Coast Survey

For millennia, people have been navigating the seas and waterways for commerce and transportation. However, lack of knowledge of shoals and hazards on the seafloor resulted in the loss of human life, as well as damage to ships and cargo. To safely traverse waters, mariners began measuring the depths of navigable waters and developing nautical charts.

Until the early 1930s, depths were determined by lead-line sounding techniques.  Lead-line sounding involves dropping a lead weight on a graduated line (rope) until it hits the seafloor, and then reading the depth from the line.  While fairly accurate for measuring seafloor depths, especially in shallow waters, this technique is extremely labor intensive and results in gaps between measurements.  These gaps in coverage of the bottom could conceal the discovery of dangerous obstructions on the seafloor.

During the early 20^th century, naval requirements contributed to the development of the single beam echo sounder, which became the primary means of depth measurement for charting by the 1940s.  Although the single beam echo sounder was more efficient than lead-line sounding techniques, it still did not provide continuous coverage of the seafloor.

In the 1970s, the multibeam echo sounder was developed to cover large areas of the seafloor.  Unlike lead-line and single beam echo sounders, multibeam echo sounders collect data in a series of adjacent swaths that provide complete seafloor coverage, eliminating the chance of missing an obstruction or dangerous feature. The technology rapidly improved through the 1980s and 1990s, and is now the standard instrument for surveying the seafloor.

However, the majority of depths found on nautical charts in United States coastal waters remain those captured by lead-line and single beam surveys pre-dating the mid-1980s. Why? Planning and executing hydrographic surveys is time and money-intensive, and there is a lot of seafloor to cover: including the Exclusive Economic Zone (EEZ), the U.S. is responsible for 3.4 million square nautical miles of seafloor. At the current rate of seafloor mapping, it will take over century of continuous surveying to completely chart. Still, it is the aim of NOAA’s Office of Coast Survey (OCS) to provide complete and accurate charts for navigation of all vessel traffic within U.S. coastal waters.

An Icy CTD Cast

Andy Armstrong, NOAA’s Office of Coast Survey, Co-chief scientist aboard USCGC Healy

USCGC Healy continues to break ice for the Canadian Coast Guard Ship Louis S. St-Laurent, which is following astern of us. We are obtaining valuable multibeam bathymetry in parts of the Arctic Ocean that have never been mapped, but multichannel seismic profiling from the Louis S. St-Laurent remains the primary goal for now. On Friday and Saturday, we were on an eastward upslope track toward the Canadian shelf. Last night we reached the end of that track and turned southwestward to profile and sound back down the slope. Tomorrow we expect to turn northwestward toward the areas of more interest to the U.S.

At the end our eastward line last night, we stopped briefly for engineering maintenance on both ships, and some maintenance on the seismic equipment. While stopped, we were able to complete a CTD cast – a deployment of an instrument that measures the conductivity (salinity), temperature, and depth. The readings from the CTD create a sound speed profile, which we compare to the multibeam echosounder depth results. This CTD cast through the ice was a first for me, but is one of the things Healy does fairly routinely.

One of the remarkable aspects of this cruise is the cooperation and collaboration between the U.S. and Canada. Both nations need these seismic profiles for our respective Extended Continental Shelf projects, but they are almost impossible to obtain with the single icebreaker each of us has available. By operating jointly, we can both get the data we need.

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• About the Blog

  The 2009 U.S.-Canada Arctic Continental Shelf Survey is underway from August 7 - September 16. Blog posts from sea are authored by the various agencies collaborating during the expedition. More information on the U.S. Extended Continental Shelf Project can be found at continentalshelf.gov.

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