NBP’s Current Path Approaches the Second of Two Low Pressure Systems

text and images by Linda Welzenbach

Waves approaching 15 feet are regularly inundating both the lower and the main deck (where our berth is located).  Viewing the maelstrom from the large windows of the aft winch control room where I’m sitting, I can forget the sea sickness for a bit as I watch the incredible power and beauty of the sea, eyes fixed on the distant horizon as a rocking and rolling NBP slowly but very steadily works its way south.

Large wave on the starboard side of the aft deck.

It is after 12, and I realize I have missed lunch, when a message suddenly comes from the radio telling everyone outside to come in due to heavy seas.  Feeling somewhat normal, and wanting to know how fast or how close the ship is moving into the outer reaches of the severe weather (very cyclonic looking in my opinion), I head to the bridge.  To watch us float about with all the ease of a cork in a bathtub, you wouldn’t know that the NBP is a 6,800-long-tons (15,232,000 pounds) ship with 3,000 (10’ x 40’) steel plates (the bow plates are 1 9/16 inches thick) carrying 425,000 gallons of gas.

 

The image on the left is a computer model of the low-pressure system. The NBP is the red target between 1016 and 1012 pressure contours. Right image shows the ship’s traverse to the Amundsen sea.

 

Meanwhile, below deck, science planning and activities persevere.

 

The monitors show the depth from the multibeam generated sound wave to the seafloor, 4426 meters (13,278 feet) and the reflected signal from two views. The range of color indicate depth-blues are deepest and reds are shallowest. Chris Linden, the NBP multibeam manager and expert, points out the location of the transducers that generate the sound waves and the instruments that will receive the signals that have been reflected off the seafloor.

 

The THOR team and NBP multibeam specialist Chris Linden set up the EM122 multibeam echo sounder to start gathering bathymetry information. As soon as the ship passed beyond the legal border of Chile, they would take advantage of the adjusted ship traverse to gather high resolution seafloor bathymetry from an area that hasn’t been mapped previously. There will be some challenges to acquiring the return signal: the slow ship speed combined with the rough seas that impact the ship’s hull create interference around the receivers (bubbles, for example), affecting the quality of the data.

Other ITGC scientists, whose constitutions are more stalwart than mine, sit at workstations and tabletops that are festooned with pieces of anti-slide fabric (much like rubber carpet pads) utilizing predrilled holes for eye-screws to which bungee cords are tied; these go over top of valued electronics to hold them in place.

 

Author Elizabeth Rush is ready for the rough sea crossing!

 

Tilt-o-meter and barometer on the bridge of the NBP.

 

Back on the bridge of the NBP, I stumble around still developing my sea legs as the motion of the ship is amplified due to its height off the water. The near 360-degree view of the waves is both captivating and hypnotic, helping to subdue some of the seasickness.  In fact, sitting on one of the control chairs is like having an unlimited ticket on the earth’s most incredible amusement park ride.

But as we roll upwards of 20 degrees each way, knowing that the larger sea is coming, the amusement fades for a few moments.  THOR team member and PhD student Victoria Fitzgerald adds, “There is no getting off this ride.” According to Chief Mate Rick Wiemken, there is a buoy in the area that has measured a wave height of 80+ feet. The highest wave ever recorded!

 

 

 

 

NBP pitches forward into a large wave.

One would think TARSAN’s successful deployment of the Hugin AUV would appease Ran (the AUV’s unofficial name), the Nordic goddess of the seas.   The crew of the ship are reassuring: the storm will still pass in front of us.  And while we will see a couple more days of rough seas, the Palmer (with 80 research cruises since coming into service in 1992) will handle it, and we will have gained a deep appreciation and respect for the amazing people who are taking care of us, and the forces of nature around us that we hope to better understand.

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