NOAA Teacher at Sea
Aboard NOAA Ship Rainier
June 3 – 14, 2019
Mission: Kodiak Island Hydrographic Survey
Geographic Area of Cruise: Kodiak Island, Alaska
Date: June 12, 2019
Time: 1541 hours
Location: Saltery Cove, Kodiak Island
Weather from the Bridge:
Latitude: 57°29.1009’ N
Longitude: 152°44.0031’ W
Wind Speed: 9.0 knots
Wind Direction: N (10 degrees)
Air Temperature: 12.78° Celsius
Water Temperature: 8.89° Celsius
Science and Technology Log
You may be wondering what role technology plays in a hydrographic survey. I have already written about how modern survey operations rely on the use of multibeam sonar. What I have not described, and am still coming to understand myself, is how complex the processing of sonar data is, involving different types of hardware and software.
For example, when the sonar transducer sends out a pulse, most of the sound leaves and eventually comes back to the boat at an angle. When sound or light waves move at an angle from one substance into another, or through a substance with varying density, they bend. You have probably observed this before and not realized it. A plastic drinking straw in a glass of water will appear broken through the glass. That is because the light waves traveling from the straw to your eye bend as they travel.
The bending of a wave is called refraction. Sound waves refract, too, and this refraction can cause some issues with our survey data. Thanks to technology, there are ways to solve this problem. The sonar itself uses the sound velocity profile from our CTD casts in real time to adjust the data as we collect it. Later on during post processing, some of the data may need to be corrected again, using the CTD cast profiles most appropriate for that area at that general time. Corrections that would be difficult and time-consuming if done by hand are simplified with the use of technology.
Another interesting project in which I’ve been privileged to participate this week was setting up a base station at Shark Point in Ugak Bay. You have most likely heard of the Global Positioning System, and you may know that GPS works by identifying your location on Earth’s surface relative to the known locations of satellites in orbit. (For a great, kid-friendly explanation of GPS, I encourage students to check out this website.) But what happens if the satellites aren’t quite where we think they are? That’s where a base station, or ground station, becomes useful. Base stations, like the temporary one that we installed at Shark Point, are designed to improve the precision of positioning data, including the data used in the ship’s daily survey operations.
Setting up the Base Station involved several steps. First, a crew of six people were carried on RA-7, the ship’s small skiff, to the safest sandy area near Shark Point. It was a wet and windy trip over on the boat, but that was only the beginning! Then, we carried the gear we needed, including two tripods, two antennae (one FreeWave antenna to connect with the ship and a Trimble GPS antenna), a few flexible solar panels, two car batteries, a computer, and tools, through the brush and brambles and up as close to the benchmark as we could reasonably get. A benchmark is a physical marker (in this case, a small bronze disk) installed in a location with a known elevation above mean sea level. For more information about the different kinds of survey markers, click here.
Next we laid out a tarp, set up the antennae on their tripods, and hooked them up to their temporary power source. After ensuring that both antennae could communicate, one with the ship and the other with the satellites, we met back up with the boat to return to the ship. The base station that we set up will be retrieved in about a week, once it has served its purpose.
Career Focus – Commanding Officer (CO), NOAA Corps
Meet Ben Evans. As the Commanding Officer of NOAA Ship Rainier, he is the leader, responsible for everything that takes place on board the ship as well as on the survey launches. Evans’ first responsibility is to the safety of the ship and its crew, ensuring that people are taking the appropriate steps to reduce the risks associated with working at sea. He also spends a good deal of his time teaching younger members of the crew, strategizing with the other officers the technical details of the mission, and interpreting survey data for presentation to the regional office.
Evans grew up in upstate New York on Lake Ontario. He knew that he wanted to work with water, but was unsure of what direction that might take him. At Williams College he majored in Physics and then continued his education at Woods Hole Oceanographic Institution, completing their 3-year Engineering Degree Program. While at WHOI, he learned about the NOAA Commissioned Officers Corps, and decided to apply. After four months of training, he received his first assignment as a Junior Officer aboard NOAA Ship Rude surveying the waters of the Northeast and Mid-Atlantic. Nearly two decades later, he is the Commanding Officer of his own ship in the fleet.
When asked what his favorite part of the job is, Evans smiled to himself and took a moment to reply. He then described the fulfillment that comes with knowing that he is a small piece of an extensive, ongoing project–a hydrographic tradition that began back in 1807 with the United States Survey of the Coast. He enjoys working with the young crew members of the ship, sharing in their successes and watching them grow so that together they may carry that tradition on into the future.
For my last post, I would like to talk about some of the amazing marine life that I have seen on this trip. Seals, sea lions, and sea otters have shown themselves, sometimes in surprising places like the shipyard back in Seward. Humpback whales escorted us almost daily on the way to and from our small boat survey near Ugak Bay. One day, bald eagles held a meeting on the beach of Ugak Island, four of them standing in a circle on the sand, as two others flew overhead, perhaps flying out for coffee. Even the kelp, as dull as it might seem to some of my readers, undulated mysteriously at the surface of the water, reminding me of alien trees in a science fiction story.
Stepping up onto dry land beneath Shark Point, we were dreading (yet also hoping for) an encounter with the great Kodiak brown bear. Instead of bears, we saw a surprising number of spring flowers, dotting the slopes in clumps of blue, purple, and pink. I am sensitive to the smells of a new place, and the heady aroma of green things mixed with the salty ocean spray made our cold, wet trek a pleasure for me.
Word of the Day
Davit – a crane-like device used to move boats and other equipment on a ship
Speaking of Refraction…
Thank you to NOAA Ship Rainier, the Teacher at Sea Program, and all of the other people who made this adventure possible. This was an experience that I will never forget, and I cannot wait to share it with my students back in Georgia!