moving vessel profiler – NOAA Teacher at Sea Blog

July 18, 2023July 20, 2023

Elli Simonen: Data, Calibrating Data and Surveying, July 15, 2023

NOAA Teacher at Sea

Elli Simonen (she/her)

Aboard NOAA Ship Fairweather

July 10, 2023 – July 28, 2023

Mission: Hydrographic Survey of the Pribilof Islands

Geographic Area of Cruise: Pribilof Islands, Alaska

Date: July 16, 2023

Weather Data

Location: 55’21.02° N, 161’02.02° W

Outside temperature: 11°C

Water temperature: 10°C

True Winds: 337°, 6.5 kts

Skies: Overcast and Cloudy

Science and Technology Log

What is Surveying?

I was in port with the NOAA Ship Fairweather for a little under a week but right now we are en route to the Pribilof Islands. During the time at port, the survey team surveyed surrounding areas, calibrated equipment and practiced troubleshooting survey systems. The goal of surveying is to gather the bathymetry data of the seafloor, or the depths and shape of the seafloor.

Surveying equipment is located on NOAA Ship Fairweather as well as four smaller boats called survey launches, which each get deployed from the ship. Depending on the mission, sea conditions and the project plan, the ship or launches may both be used, or a combination of both.

Global Positioning System (GPS) records position. The Inertial Measurement Units (IMU) measures the motion of the ship. Multibeam Echosounder (MBES) is when sound is pinged from a vessel to the seafloor and the time lapse is used to determine the depth of the seafloor. MBES is a type of sonar that uses multiple beams to get a more complete picture of the seafloor with depths and characteristics. After the data is pinpointed to a specific location, variability associated with tides is also taken into account by transforming the data vertically to the mean lowest low tide. Bathymetry data taken on NOAA Ship Fairweather as well as its four survey launches appears as strips on a map, as the ship or boat moves.

Data is measured to the mean lowest low tide because that level of water is on average the lowest of any tide for a given area. Using the lowest depth in navigation is conservative, thus allowing vessels to navigate safely through mapped waters.

photo of two adjacent computer monitors with different views of the collected survey data imposed on charts or maps

Survey Data shown as green strips.

a small boat (a survey launch) mounted on the port side of NOAA Ship Fairweather, as seen from the deck in front of another mounted launch (only partially visible). Beyond the side of the ship, the still water of a bay extends toward the steep green hill that lines the far side. Another launch, already deployed, is visible on the water at a distance.

Survey launches being stored on NOAA Ship Fairweather as well as one deployed in the harbor

Elli stands on the deck of a small boat. She's wearing a life vest and her Teacher at Sea hat. We have a partial view of the launch's wheelhouse to her left and an electronic winch to the right. Behind Elli the waters are calm, and we can see mountains in the distance.

TAS Elli Simonen aboard one of the survey launches.

Calibrating the Data

During our time in port we took out some of the survey launches to perform a patch test; that is, calibration procedures to ensure the data we collect is as accurate as possible. A correctly calibrated system will show the same mapping of the seafloor in repeated tests, without the influence of confounding variables – speed, direction and ship motion. In a patch test, time delay, pitch, roll and heading are calculated multiple times over different depths, obstructions and slopes on the seafloor and compared to known data. The obstruction we surveyed was a shipwreck.

view of two computer monitors, two keyboards, and two computer mice on a desk

Planning the Patch Test

photo of a computer screen; it is difficult to see what is being displayed, but Elli has circled one area and added the label "shipwreck"

Map of the planned surveys for the Patch Test.

photo of a computer screen displaying bathymetric data. much of the area appears flat (colored teal blue) but there is a small, raised, orange portion in the shape of a ship lying on its side

Survey Data showing the Wreck

To correct for how the speed of sound changes in ocean water, during surveying every four hours Conductivity, Temperature and Depth (CTD) is measured. The CTD measures Salinity and Pressure of the Water Column, aspects that can change the speed of sound. The CTD is used to further calibrate data because different depths have different levels of salinity and temperature, and therefore distort how fast the sound travels. CTD data is used in post-processing to correct for any distortions.

a conductivity, temperature, an depth probe stored in front of a computer tower inside the survey launch's wheelhouse. the probe looks like a white cylinder strapped inside a metal frame that tapers at the top

CTD on the survey launches.

three crewmembers, wearing orange life vests and white hard hats, stand around a piece of equipment mounted at the corner of the aft deck of NOAA Ship Fairweather. a computer is mounted in a blue frame; above extends a blue boom and pulley. a coil of rope hangs on the side. Beyond the ship, the waters are gray with some caps, distant mountain ranges appear in shades of dark blue, and a cloudy, gray-white sky tops the picture.

Moving Vessel Profiler (MVP), a type of CTD that can be used while the ship is in motion, being deployed on NOAA Ship Fairweather by members of the surveying team.

Where does the data go?

Once the survey technicians gather bathymetry data, they still need to edit it before passing it along to National Centers for Environmental Information (NCEI), who package it for public view and is the data repository for environmental data in the U.S. and the U.S. Office of Coast Survey who create navigational charts. Editing the data involves rejecting spurious noise that MBES picked up that is out of range or incorrect. This data then is transformed into charts and more standardized bathymetry data.

two people look at a computer screen in the computer lab. The survey tech, seated at the computer station, points toward multicolored swaths against a black background on the right monitor. Elli stands be hind him to view over his shoulder. On the desk are messy folders and papers, a small potted plant, and an action figure.

Survey Technician showing TAS Elli Simonen the process of cleaning survey data

Personal Log

Members of the survey team are all smart, respectful and patient and take the time to explain to me the science at play no matter how many questions I have. I spend the majority of my day with the survey team but also explore other areas of the ship. I have now been onboard for over a week and things are beginning to feel routine. The sun does not set here until about 10:30pm and rises around 6am. Meals are served at regular times and more importantly, at least to me, coffee is available 24/7.

a view of Elli's stateroom. To the left is a metal warddrobe and a metal sink. To the right is a filing cabinet, a simple bed, and the edge of a metal chest of drawers. There's an open porthole along the back wall, and light shines through it onto the wall, forming a bright circle above the bed.

This is TAS Elli’s room aboard NOAA Ship Fairweather at 9:45pm

view through a sea-sprayed porthole of water and mountains. the sun is low in the sky.

View out my window in the Gulf of Alaska.

Did you know?

The USA offers their bathymetric data for free; Not all countries do this. (https://www.opencpn.org/OpenCPN/info/chartsource.html)
75% of the ocean floor has not been mapped

screenshot of a political map of the continents of the world, with North America at the center. Neon green lines color the North American coastline and extend in webs throughout the rest of the ocean. the map is titled "Data Centre for Digital Bathymetry Viewer."

This map shows, in green, the areas of the world that have bathymetry data, from NCEI, https://www.ncei.noaa.gov/maps/iho_dcdb/

Animals Seen

an otter floats on its back in the water.

Otter swimming near NOAA Ship Fairweather

July 10, 2022July 10, 2022

Laura Grimm: Most Valuable Player? July 9, 2022

NOAA Teacher at Sea

Laura Grimm

Aboard NOAA Ship Thomas Jefferson

July 4 – July 22, 2022

Mission: Hydrographic Survey of Lake Erie

Geographic Area of Cruise: Lake Erie

Date: July 9, 2022

Weather Data from the Bridge

Latitude: 42ᵒ 08’3N

Longitude: 080ᵒ 16’2W

Sky Conditions: Few clouds

Wind Speed: 23.0 knots

Wind Direction: 030ᵒ NNE

Lake Temperature: 21.4 ᵒC

Wave Height: 4 -6 feet

Dry Bulb: 19.7 ᵒC

Wet Bulb: 16.6 ᵒC

Calculated Relative Humidity: 74%

Visibility: 10+ miles

screenshot of software displaying a nautical chart and many parallel colored lines — An Electronic Chart Display and Information System (ECDIS) display of our current hydrographic survey progress. ECDIS is a system used for nautical navigation that serves as an alternative to paper nautical charts. The colorful lines indicate where we have used the Multibeam Echo Sensor (MBES) to measure the depth and physical features of the lake bottom.

Science and Technology Log

As explained in a previous blog, hydrographic survey uses sound energy. NOAA hydrographers use various tools to measure the speed of sound from the time it is sent out to the time it is received as an echo. Sound waves traveling through water of different density cause refraction (or bending) of the energy wave. The density of water is affected by the salinity, temperature, and depth of the water. Scientists need to measure these parameters (things) and then use this knowledge to correct the data depending upon the properties of the water the sound is traveling through. (If you have been following this blog, nothing so far is new.)

Today’s question is how is the temperature and salinity of a column of water measured? Hydrographers use different types of tools to measure the temperature, salinity, and water depth. As a group, these tools are called “sound velocity profilers”. A conductivity, temperature, and depth sensor (CTD) can measure these three things in a column of water and then it calculates the speed of sound in water using a formula called the Chen-Millero equation. (I do not claim at all to understand this equation!)

To make matters more interesting, there are two (I’m sure there are more than two, however, to simplify things, we will assume that there are only two) types of CTDs. One type is sent overboard when the ship is not moving. The other type can be used when the ship is moving. Using a CTD while the ship is moving is a great thing, because to get good data, CTD data must be taken frequently (every 1-4 hours) and this big ship is difficult to stop!

a digital illustration of an award ribbon reading "MVP" — Most Valuable Player Award

NOAA Ship Thomas Jefferson has both types of CTD sensors. They rely heavily on the type that can be used when the ship is moving. In fact, it is so important that we call it our MVP. This does not stand for Most Valuable Player – although it is extremely important! A moving vessel profiler (MVP) can be used to measure the water column when the ship is moving at regular survey speeds (8-10 knots). It kind of looks like a torpedo. The MVP system can be set up to drop to a given depth determined by the hydrographers in charge of the project – not to shallow & not too deep . . . just right.

a moving vessel profiler sitting on deck of NOAA Ship Thomas Jefferson. It looks like a small torpedo standing on end. A life preserver ring is mounted on the rail in the background. — *Moving Vessel Profiler (MVP) utilized by NOAA field units.*

close-up of a label on the moving vessel profiler control station, which reads: AML Oceanographic, www.AMLoceanographic.com, +1 250 656 0771, MVP Moving Vessel Profiler — *Here is the information should you want to order a MVP. :o)*

a control panel for the moving vessel profiler: we see buttons, knobs, what looks like a joystick — *After the MVP is put in the water, it can deployed and controlled with a computer in the Plot Room.*

a crane lowers the moving vessel profiler into the water — *The MVP is placed overboard and into the water using a crane.*

It can be controlled remotely with a computer without needing someone to be on deck. Deploying the MVP is called a “cast”. The benefit of deploying a sound speed profiler like the MVP while the ship is moving is significant. It is a real time-saver! Surveyors do not need to stop the ship at regular intervals – this makes their time at sea much more efficient.

Yesterday, I got the opportunity to deploy the MVP. From the acquisition desk in the plot room, one first needs to get permission from the bridge (the “upstairs office” filled with people driving and navigating the ship), to take a “cast”. The conversation over the intercom goes something like this:

Laura: “Bridge, this is Survey.”

Bridge: “Go ahead Survey.”

Laura: “May I please take an MVP cast?”

Bridge: (If the area is clear of small boats and obstructions, they will respond,) “Go ahead Survey.”

Laura: (Once permission is granted, all you need to do is to push the “start” button. A lot of cable attached to the MVP automatically pays out and it drops to a set depth, a few meters above the bottom. Once this started to happen, I informed the Bridge by saying,) “Fish is away.”

Bridge: “Copy.”

Laura: (After reaching the designated depth, the cable drum turns quickly in reverse and hauls the MVP back up to near the surface. I finished by saying,) “Cast complete”.

I was a bit nervous talking to the bridge, but I think I did okay.

screenshot of a computer screen with readout from the moving vessel profiler, including a graph showing the depth over time — This is the computer that controls the MVP. The Hydrographer In Charge (HIC) does this from the acquisition desk in the Plot Room. The blue line above shows the movement of the MVP and its location in the water column. It was sent down to 1.5 meters above the floor of the lake.

Meet the Crew

Sydney peers into a compass mounted on a post on deck — *Sydney Catoire is using a gyro compass to get a visual reading on a prominent antenna near Erie, PA.*

Sydney Catoire is a Lieutenant in the NOAA Corps. (More about the NOAA Corps in a future blog post.) She is an Operations Officer in Training (OPS IT). Sydney comes from a Navy family and grew up on Virginia Beach, VA. Ms. Catoire studied marine biology and mathematics at Old Dominion University in Norfolk, VA. Wanting to combine aspects of the Navy as well as work as a scientist led her to apply to the NOAA Corps. She received her Master of Science in Geospatial Information Sciences (GIS) while working for the Office of Coast Survey.

Why is your work important? The safety of navigation is our primary goal as hydrographers. We use the data to update nautical charts to make it safe to sail. The bathymetric products provided are open source (free for anyone to download and use) and are used for ocean and lake bed mapping. For example, the data can be used for tsunami storm surge modeling, coastal erosion, and habitat mapping. All this data is super critical and is used by a wide variety of scientific organizations and research institutions.

How will your job change once you become an Operations Officer (OPS)? She will still be involved with the day-to-day workings of the hydrographic survey, however, once she becomes an OPS, she will take a leadership role in the survey, assigning sheets (areas to survey), and mentoring sheet managers who develop the line plans (the path that the ship travels to complete the survey). In other words, she will decide on the most efficient methods to “mow the lawn.” She will also help to train junior officers, organize the processing of the data, and work directly with the Office of Coast Survey Hydrographic Division.

What is the thing about your job you like the most? She likes being on the bridge, navigating and driving the ship, as well as looking out the window for marine life – which lately has been very limited since we are sailing on the Great Lakes.

Tell us a few things about yourself outside of being an OPS IT. Sydney and her sister have a dog named, Max. She likes to scuba dive, hike, and hang out with her family and nephews when she is on shore.

Good Luck, Sydney as you strive to become an Operations Officer! For not originally knowing about this career path you sure have excelled and are an example for others with similar interests.

Personal Log

All the people on TJ have been very nice and hospitable. They freely answer my questions and are fun to hang out with during meals. There are three people, however, who are super important to the smooth sailing of TJ. They are the stewards, Ace & Brent and the Chief Steward, Miss Parker. I never imagined that the food would be so varied and tasty! A well-fed crew = a happy crew!

Menu for Monday 5 July 2022: Breakfast: Egg to Order, etc. Lunch: Chicken Cordon Blue, Soft Shell Crab Portabella Mushroom, etc. Dinner: Prime Rib w / Au Jus, Baked salmon w/ brown sugar glaze, fried tofu, etc. — *Each day the menu is posted outside of the galley. Just look at Tuesday’s offerings!*

plate of food and place settings — *Roasted duck, grilled vegetables, and wild rice. Just a normal meal on the TJ.*

*Beautifully decorated three-layer cake with strawberry icing and filling.*

three stewards stand in the galley behind a serving line. Ms. Parker and Ace wear aprons. — *The Heroes of the Galley (from left to right): Brent, Miss Parker, and Ace.*

For the little Dawgs . . .

Q: Where is Dewey today? Hint: it is the back of the ship.

Dewey the beanie monkey perches on a rail of some sort, with a pole behind him, and the wake of the ship visible in the water — *Be careful, Dewey! We don’t want you to fall into the water!*

A: Dewey is sitting on the stern of the ship. The propellers are under the stern.

Dewey the beanie monkey sits on the rail on the ship's stern, and the wake of the ship is visible behind — *Dewey is sitting on the stern of the ship. “Stern” rhymes with “learn”. We are learning the different parts of the ship.*

Well, that’s all for today. Spending time aboard NOAA Ship Thomas Jefferson has been a terrific learning experience. I am so thankful for the opportunity!

June 24, 2022

Oktay Ince: Happy Summer Solstice Day and World Hydrography Day! June 21, 2022

NOAA Teacher At Sea

Oktay Ince

Aboard NOAA Ship Thomas Jefferson

June 20- July 1, 2022

Mission: Hydrographic Survey

Geographic Area of Cruise: Lake Erie

Date: Tuesday, June 21, 2022

Latitude: 41° 31′ 52 N

Longitude: 82° 12′ 00 W

Altitude: 138 m

Weather Data from Bridge

Wind Speed: 21 kts

Surface Water Temperature: 22 °C

Air Temperature (Dry Bulb Temperature): 23.5 °C

Wet Bulb Temperature: 22.9 °C

Relative Humidity: 55 %

Barometric Pressure: 25.5 in

Science and Technology Log

Learning is in full swing on NOAA Ship Thomas Jefferson. Previously, I talked about the multibeam sonar that the ship uses to map the bottom of Lake Erie. I also talked about how this technology related to other real-world applications. I hope I inspired you there.

Now, I am going to talk about another technology that Thomas Jefferson uses- side scan sonar. The technology basically detects and creates images of objects on the lake/ocean floor. The ship concurrently uses both technologies. Side scan sonar technology takes images of the bottom of Lake Erie and multibeam sonar records the depth; the seafloor/lakebed data is also known as bathymetry. For instance, if there is a big obstacle or a shipwreck in Lake Erie, side scan sonar would show an image. Then, multibeam sonar would be used to get the depth of the obstacle.

How does side scan sonar work differently than multibeam sonar?

If you remember from my previous post, multibeam sonar sends sound waves down towards the lake bottom. Side scan sonar also sends out sound waves, but from both sides of its transducer, sweeping the seafloor like a fan-shaped beam of a flashlight. So, the data needs to be composed of both the image and depth which allows a more comprehensive map of the seafloor.

A third technology used with the multibeam and side scan sonars is called “moving vessel profiler (MVP)”. The MVP is similar to a conductivity, temperature, depth (CTD) cast as it collects electrical conductivity, temperature, and pressure (to get depth) of water. The benefit of the MVP is that the ship can continue moving and receive sound speed information, rather than coming to a complete stop to deploy a CTD. This improves efficiency, allowing the ship to collect more data.

The MVP is a metal structure that looks like a big fish- also known as a towfish- located at the tail of the ship. As the ship moves, the instrument trails behind it, about a meter below the water’s surface. Sensors to collect sound speed information are located inside the towfish. When the MVP is deployed, the towfish free falls to the lake/sea bottom, before being automatically brought to the surface by the ship’s winch. Then, the ship receives a profile of the water column’s salinity and temperature, and can apply the sound speed measurements to the multibeam data. This information is critical for ensuring acquired depth measurements are in the proper location on the lakebed/seafloor. For the sake of Thomas Jefferson’s mission, CTD data is enough to process multibeam. However, other research vessels could have additional sensors within the MVP including some that measure chemical and biological parameters such as dissolved oxygen and chlorophyll fluorescence, etc.

The MVP Training; Deployment of Towfish

Geared up to learn about the Moving Vessel Profiler (MVP)
MVP instructions
Learning to operate the MVP
Navigating the MVP
On the radio

Let’s elaborate a few science concepts here. Conductivity is a measure of water’s capability to pass electrical flow. It does that based on how many ions are in the water. Therefore, the more ions present, the higher the conductivity of water. Ions are mainly coming from dissolved salts and inorganic materials such as alkalis, chlorides, sulfides, and carbonate compounds. These ions (positive/negative charges) in the water create electric current, so it conducts electricity.

Using the concept of electrical properties of dissolved salts, scientists measure the electrical conductivity of water so that they know the amount of salt present in the water (salinity). As you would expect, Lake Erie is freshwater so salinity is essentially zero.

Conductivity is one of the most useful and commonly measured water quality parameters. Knowing changes of dissolved solids in the water is an indicator of change in a water system. Different life forms adapted to different salt concentrations in the water. Even a slight change to this parameter could have a disastrous effect on life forms in water which creates a cascade of effects in other systems.

Personal Log

It was my second day on ship, and also the summer solstice. Today, sunrise was at 5:55 am and sunset was at 9:07 pm. It was the longest day for Lake Erie, indeed! It was also World Hydrography Day, yay! I am honored and humbled to be a part of Thomas Jefferson’s crew and to be the first Teacher at Sea on Great Lakes, especially on the longest day of the year and on World Hydrography Day in Lake Erie!

After eating my breakfast, I headed to MVP training. It sounded complicated but once I was on it, it was easy to navigate the instrument at sea. Then, I was called for my first boat ride. The ship has several “small” boats to assist in data collection, and they are beneficial for transiting and collecting bathymetry in more shallow places on the water. We had three people on the boat, doing side scan data collection closer to the shorelines. We also did several CTD casts, for nearshore sound speed profiles! On the ship the MVP can collect CTD data more frequently, whereas on the boat, we had to manually put it in the water every 4 hours. The boat was amazing, and I felt like I was on a private vacation boat! However, in this case, I was not only having fun, but also doing citizen science. I learned so much about the side scan, why it is used, and how the data helps the overall mission of Thomas Jefferson.

Deployment of our launch vessel

Oktay wears a helmet and poses for a selfie in front of the launch vessel that crewmembers are prepping to deploy — Getting ready to launch our boat

the coxswain, wearing a helmet and life vest, drives the launch vessel — Getting ready to launch our boat

Recovery of our launch vessel

In this personal blog, instead of just including all the cool things I have done on the ship, I want to share some of my opinions about what I feel about my experience so far.

I would say about one-third of the crew on the ship are women in their twenties and thirties. Many of them are NOAA Corps officers and survey technicians/scientists. What an inspiring environment for women in STEM! They are involved in everything from navigating the ship to collecting data, from driving the boat to doing hands-on activities. I strongly believe that our female crew members are such an inspiration for future generations who will make things better!

Another feeling I have is how people are passionate about what they do. For example, I never thought a Commanding Officer (CO) and Executive Officer (XO) would be so friendly and approachable . I’m glad Thomas Jefferson has a great executive team. I’ve been having great conversations during lunch or any place I go on the ship. In one of our lovely conversations, both CO and XO strongly encouraged me to bring my students to visit the ship to give a tour. I said “This is exactly what I am here for!” I want to bring back my experiences to my school and community, and I can’t wait to bring them to the ship! They will absolutely love it.

In my last note, I should say that people who choose their careers based on their passion, are the ones who are successful, and also constantly inspire others to follow their footsteps. I have seen this in many professions across different fields. It is especially obvious when you have a public service job like educators, officers, doctors… You always have to do more than what your job asks you to do. If this is not something you are passionate about then the job becomes torture rather than enjoying.

Here, on Thomas Jefferson, seeing these men and women on a research vessel, working tirelessly around the clock, collecting data, once again proved to me that you have to be passionate about what you do.

Anyway, I think it is enough for me to stop talking about what I feel. But, you should know this – always follow your passion. That’s when you will find your real purpose in life.

The stewards (cooks) wearing aprons, gloves, and head coverings, wave from the galley (kitchen) — Stewardship department- Two amazing chefs

view down the staircase to the engine room — Stewardship department- Two amazing chefs

Do you know?

The National Oceanic and Atmospheric Administration Commissioned Officer Corps, known as the NOAA Corps, is one of the eight federal uniformed services of the United States. Those officers are made up of scientifically and technically trained officers. It is one of two U.S. uniformed services (the other being the U.S. Public Health Service Commissioned Corps) that consists only of commissioned officers, with no enlisted or warrant officer ranks.

To become a NOAA Corps officer, applicants must hold a baccalaureate degree, preferably in a major course of study related to NOAA’s scientific or technical activities. When selected for appointment, officer candidates must satisfactorily pass a mental and physical examination. For more information check out NOAA Corps eligibility requirements here.

July 23, 2018

David Tourtellot: Draggin’ The Line, July 21st, 2018

NOAA Teacher at Sea

David Tourtellot

Aboard NOAA Ship Thomas Jefferson

July 9-26, 2018

Mission: Hydrographic Survey – Approaches to Houston

Geographic Area of Cruise: Gulf of Mexico

Date: July 21^st, 2018

Weather Data from the Bridge

Latitude: 29° 11.6357’ N

Longitude: 093° 55.9746’W

Visibility: 10+ Nautical Miles

Sky Condition: 6/8

Wind: Direction: 224° Speed: 8.5 knots

Temperature:

Seawater: 30.4°C

Air: Dry bulb:31.5°C Wet bulb: 28.5°C

Science and Technology Log

In my previous post, I discussed the ship’s sonar. This time, I’ll go into more detail about the tools the Thomas Jefferson is using to complete its mission. The sonar that the ship uses is multi-beam echosounder sonar, which sends the pings down to the seafloor and receives echoes in a fan shape, allowing the ship to survey a wide swath beneath the ship.

In addition to the multi-beam sonar, NOAA Ship Thomas Jefferson utilizes two towfish, or devices that are towed in the water behind the ship.

The first is the side scan sonar. Like the multi-beam, this device uses pings of soundwaves to create images of its surroundings. However unlike the multi-beam, the side scan doesn’t capture any data from the area underneath it. Instead, it collects data to its sides. The side scan is connected to the ship via a cable, and is dragged through the water 6-15 meters above the seafloor. It is great for measuring the intensity of the return of the ping, which provides insights into the makeup of the seafloor.

The second towfish that the Thomas Jefferson is using is the MVP (like many things on the ship, MVP is an acronym, for Moving Vessel Profiler). The MVP truly gives the ship some of its most valuable data. As I discussed in my previous blog post, in order for us to accurately calculate the distance that the sonar’s pings are traveling, we need to know the amount of time it takes them to travel, as well as the velocity, or the speed, at which they’re moving. The singarounds I mentioned in my last post measure sound velocity, but only at the face of the sonar. Water conditions are not uniform – at the surface, water tends to be warmer, with less salinity. As you get deeper, however, the water tends to be colder and saltier. This means that the velocity of sound changes the deeper you get. Most of the time, the MVP rides just under the surface of the water, but periodically it will get cast down, to approximately 1 meter above the seafloor. It measures the water conditions of the entire water column from the surface to the seafloor, allowing us to calculate sound velocity all the way down.

The MVP towfish as it is being lowered into the water

The MVP measures the same water qualities as the CTD (a device I discussed in an earlier blog post), however, the MVP has a distinct advantage over the CTD. In order to use a CTD, the ship has to come to a stop while the CTD is lowered into the water. The MVP, however, can be used while the ship is in motion, which greatly increases productivity.

When surveying, many on the crew say it’s like mowing the lawn. The ship will capture a long stretch of data, called a line, and then turn around, and capture another stretch. 4% of these lines are cross lines, which run perpendicular, across a wide swath of lines of captured data. Cross lines allow the survey department to double check that the data they’ve captured is accurate.

Personal Log

TJ Bridge Daylight — The bridge of NOAA Ship Thomas Jefferson in the daylight

A couple of days ago, I went up to the bridge shortly after sunset, and I was surprised what I saw. All the lights were off, and the screens of the various instruments had been covered by red filters. I was told that this is for maintaining night vision when on watch. Red light interferes least with our night vision, so anything that gives off light is switched to red.

Bridge at night — The bridge of NOAA Ship Thomas Jefferson at night

While on the bridge, I had the opportunity to ask ENS Garrison Grant (who had recently been selected for a promotion to Lieutenant Junior Grade – congratulations Garrison!) a little about the NOAA Corps. I must admit that I was largely unfamiliar with them before joining the Thomas Jefferson.

The NOAA Corps as we know it today began in 1970, though its roots are much older. As president, Thomas Jefferson (for whom NOAA Ship Thomas Jefferson is named) created the United States Survey of the Coast, which would later evolve into the United States Coast & Geodetic Survey. Their early operations were not unlike the survey work that NOAA Ship Thomas Jefferson is doing today, though their tools were more primitive: surveyors wanting to determine the depths of America’s bodies of water didn’t have the benefit of sonar, and instead used lead lines – lead weights tied to the end of ropes. These surveyors would also play a vital role in our military history. They would often assist artillery, and survey battlefields. This is what led to the United States Coast & Geodetic Survey (and later, the National Oceanic and Atmospheric Administration) to gain a commissioned uniformed service. Due to the rules of war, captured uniformed service members could not be tried as spies.

To join the NOAA Corps today, you need to first have a bachelor’s degree. ENS Grant received his degree from Stockton University in Marine Sciences, but he says that it isn’t a requirement that the degree be in a maritime field. He says that some of his classmates had degrees in fields such as English or Communications. After getting a degree, you then apply to join the NOAA Corps (anyone interested should check out this website: https://www.omao.noaa.gov/learn/noaa-corps/join/applying). If selected, you would then complete the Basic Officer Training Class (BOTC), which generally takes about 6 months. After that, you’d be given your first assignment.

Did you know? Before NOAA Ship Thomas Jefferson was operated by the National Oceanic and Atmospheric Administration, it belonged to the U.S. Navy and was known as the U.S.N.S. Littlehales

June 29, 2018

Vickie Obenchain: Starting a Hydrographic Survey, June 28, 2018

NOAA Teacher at Sea

Victoria Obenchain

Aboard NOAA Ship Fairweather

June 26 – July 6, 2018

Mission: Arctic Access Hydrographic Survey

Geographic Area of Cruise: Northwest Alaska

Date: June 28th, 2018

Weather from the Bridge

Latitude: 54^o 25.5’ N
Longitude: 134^o13.7’ W
Wind Speed: 13 Knots
Wind Direction: South, Southwest
Temperature: 12.2^oC
Visibility: 10 nautical miles
Wave Height: 1 foot
Current Sky Conditions: Overcast

Science and Technology Log

This morning I spent some time on the bridge with the officers. NOAA Ship Fairweather is manned day and night with men and women making sure we are safely on course. While the ship is equipped with GPS, the ship is also full of experienced mariners who plot our position on paper nautical charts to help guarantee the technology is working correctly and helps the officers orient themselves with the area. Every 15 minutes, an officer plots our position either by using GPS coordinates, radar returns, or fixed land triangulation using an alidade. This last mode of determining our coordinates, at least to me, is the most difficult. You must use 3 fixed land points on either side of the ship, determine their direction using the compass on the alidade and then using sliding protractors plot our triangulated position on the chart. Both Executive Officer (XO) Michael Gonsalves and ENS Cabot Zucker have been incredibly helpful in teaching me these different plotting techniques.

XO Gonsalves in the foreground and ENS Zucker in the back plotting our course.

Today we are headed to the Queen Charlotte-Fairweather Fault System. This is a strike slip fault line extending 746 miles off shore of Vancouver Island to the Fairweather range in southeast Alaska. USGS has partnered with NOAA Ship Fairweather to help to create part of a comprehensive map of one of the fastest moving underwater tectonic plates in the world, moving of a slip rate of 2 inches a year. Over the next 24 hours they will survey the area using multibeam sonar to help complete the mapping which as taken almost 4 years to complete.

To start this, the survey team had to deploy a Moving Vessel Profiler (MVP) into the water. The MVP follows behind the ship and by detecting water temperature and salinity of the water, the MVP can then determine the speed of sound in water needed to accurately detect the sea floor. With this knowledge the survey team can correctly calibrate their sonar to map the sea floor. Below you will see Sam Candio and Simon Swart of the survey team deploying the MVP.

MVP, Moving Vessel Profiler

Sam and Simon deploying the MVP

Survey technicians Sam Candio and Simon Swart view the MVP controls

Next blog will cover the amazing people working with the sonar, all times of day and night to make the sea floor maps! (Stay tuned!!)

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Another short term visitor on this ship is a college student from Loyola University Chicago, Paul Campion, who is on board doing an internship with NOAA. Each year NOAA accepts approximately 130 college sophomores into their two-year-long Hollings internship program to give students an opportunity to take part in research, gain job experience and see what NOAA does. While on board, Paul has been working with the survey team to learn how they do their work, as well as create his own project. Paul has been looking at the electronic navigational charts (ENC) used today by most mariners which show the depth of the sea floor. As NOAA Ship Fairweather surveys an area, these ENC’s can then be updated with more accurate and up to date data. While some areas may remain the same, some areas may show changes or even characteristics which may not have been mapped prior and need to be highlighted. Paul has been working to help create an efficient way to show where the ENCs are different to the new NOAA Ship Fairweather data and may need to be altered or updated.

Personal Log

Since we are out in the sea, and do not have neighboring island chains around us, the boat has been tossed around a bit more and is definitely rolling around in the waves. Luckily, I have not been sick… yet. I have been taking sea sickness pills, and making sure I get plenty of fresh air, but the boat is definitely more difficult to work in. You find yourself moving both with the boat’s inertia and then having to fight against it to move. Walking uses walls and railings, sitting requires holding on to the closest counter top or nailed down object and to get into rooms you need to shove doors away from you to open them, yet hold on so they don’t swing completely away from you and slam the opposite wall. It is kind of challenging and yet amusing.

After lunch today, I went to take a shower. I was given some good advice since I had not done this when the boat was in open water. These words of advice included: Use the walls, kind of squat down to lower your center of gravity, don’t take a razor with you (nothing good will come of that), and if the soap drops be especially careful! All things I took to heart and I am glad to report I am clean, unscratched and ready for another day.

June 14, 2018June 21, 2018

Heather O’Connell: Sound in Seawater and Sleeping at Sea, June 8, 2018

NOAA Teacher at Sea

Heather O’Connell

NOAA Ship Rainier

June 7 – 21

Mission: Hydrographic Survey

Geographic Area of Cruise: Seattle, Washington to Southeast, Alaska

Date: 6/8/18

Weather Data from the Bridge: Latitude: 48.15° N, Longitude: 122 ° South 58.0’ West, Visibility: 8 nautical miles, Wind: 24 knots, Temperature: 14.2° C

Science and Technology Log

I was fortunate enough to sit in on a survey orientation for new survey technicians and junior officers with Lieutenant Steven Loy. He was on Rainier as the Field Operations Officer, F.O.O., in the past and is currently here as an augmenter filling the role of Senior Watch Officer since he has navigated through the Inside Passage several times. In his two hour orientation, he shared a wealth of knowledge and discussed how multibeam sonar and ultrasounds are two opposite ends to the ultrasonic pulse spectrum.

Multibeam sonar sends out sound and measures the time it takes to return to calculate the depth of the ocean floor. The accuracy of the depth data generated from the multibeam sonar relies on the sound speed profile of the water. The combined effects of temperature, salinity and pressure generate a sound speed profile. Because of the inherent importance of this profile, there are several different ways to measure it. The sound velocity profiler measures this right at the interface of the multibeam sonar. C.T.D.s., or conductivity temperature and depth machines, measure water profile while the ship is stopped. M.V.P.s, or moving vessel profilers, take the water profile as the vessel is moving. Lastly, XBTs are expendable bathythermographs that measure temperature while the ship is in motion.

Sound is affected by different variables as it is energy that travels through a medium as a wave. Lieutenant Loy shared an informative website, The Discovery of Sound in the Sea, where I was able to enhance my understanding. Sound can travel through a liquid, such as water, a gas like air, or a solid like the sea floor. On average, sound travels about 1500 meters per second in sea water. However, the rate changes at different times of day, various locations, changing seasons and varying depths of the water. By looking at sound speed at one particular place in the ocean, you can determine how the different variables affect this sound. Usually, as depth increases, temperature decreases, while salinity and pressure increase.

A multi-beam sensor has a metal plate receiver and a transmitter perpendicular to one another. This array geometry enhances sound. The sound velocity profiler is next to the receiver and measures right at the interface. To determine the speed of sound right where the beam is generated, sonar is used to measure speed sound across a known distance. This information is then utilized in the overall determination of the depth of the ocean floor. Once this cast is taken, the Seafloor Information System (SIS), can adjust sonar measurements accordingly.

Another way to measure the sound profile of water includes a C.T. D. This device measures the conductivity, temperature and depth of the water. Conductivity measures the electrical current of the water. The more dissolved salt, or ions in solution, the greater the conductivity and salinity of the water. The depth of the water is directly related to the pressure of the water. Salinity, temperature and pressure affect the sound speed profile of water. This machine has a high data rate that goes up and down the water column. The titanium C.T.D. operates at a high pressure and costs about forty thousand dollars. This accurate technology can only be utilized when the boat is stopped and is used on the smaller survey launches.

C.T.D. used for sound speed profile of water

A third method of measuring sound profile is the M.V.P., moving vessel profiler, which takes the data when the ship is moving. These are calibrated before a survey begins and are an efficient way to collect data. An expansive crane lowers the metal torpedo with the sensor off the fantail, the overhanging back part of the ship, into the water to collect the data. The fish is programmed to stop twenty meters above the ocean floor, at which point it returns to its docked position. On ship Rainier, the deck department deploys the fish with a cable wire and the plot room with the survey technicians controls the sensor.

Boatswain Kinyon and Survey Technicians Finn and Stedman releasing the torpedo of the M.V.P. into the water

Another way to collect the sound profile of water with a moving vessel is to use an expendable probe. As temperature decreases, the sound speed decreases. Since temperature is the most important factor affecting the speed of sound, an X.B.T., Expendable Bathythermograph, or expendable probe created by the military. With bathy relating to depth and thermo meaning heat, this measures the temperature of the water at a cost of about one hundred dollars. These probes descend at a known rate, so, depth is a function of time.

Sources – Discovery of Sound in the Sea

Personal Log

We left port yesterday at 16:30, which has been a highlight of my NOAA Teacher at Sea Experience thus far. Before leaving port, all hands were assigned a different assignment to help with the launch. I watched the crew bring in the gangway that connects the ship to the port then disassemble it. The crew with hard hats and orange work vests took down poles and neatly tied up different sections by knotting ropes. We slowly progressed out of the port after a cargo ship passed us.

Once the ship picked up speed and the ocean breeze was in my hair, I felt a new kind of freedom. With the Seattle skyline behind us and the beautiful green peninsulas in front of us, I was content to be moving forward. Everyone seemed to feel relieved once we were underway. I felt gratitude as I enjoyed watching the sunset from the flying bridge, the area of the ship above the bridge at the front of the ship.

After sunset, I returned to my berth, or sleeping quarters, located in the bow of the ship on the C-deck. I heard the constant white noise of the propellers that got much louder when the pitch, or angle, of them changed. This sound of seawater combined with the rocking motion of the ship lulled me to sleep on our first night at sea.

Did You Know?

Juneau, the American capital of Alaska, can only be entered by plane or boat. It is inaccessible by roads due to large mountain ranges on either side.