NOAA Teacher at Sea
Lauren Wilmoth
Aboard NOAA Ship Rainier
October 4 – 17, 2014
Mission: Hydrographic Survey
Geographical area of cruise: Kodiak Island, Alaska
Date: Tuesday, October 7, 2014
Weather Data from the Bridge
Air Temperature: 0.77 °C
Wind Speed: 12 knots
Latitude: 60°07.098′ N
Longitude: 149°25.711′ W
Science and Technology Log
Our departure from Seward was originally scheduled for today, but the ship is having some repairs done, so our expected departure is now Wednesday or Thursday. In case you were wondering, this doesn’t delay my return date. Regardless of the fact that we are not underway, there is still so much to learn and do.
Yesterday, I met with Christie, one of the survey techs, and learned all about the Rainier’s mission. The main mission of the ship is to update nautical charts. Up-to-date charts are crucial for safe navigation. The amount of data collected by Rainier if vast, so although the main mission of the Rainier is updating nautical charts, the data are also sent to other organizations who use the data for a wide variety of purposes. The data have been used for marine life habitat mapping, sediment distribution, and sea level rise/climate change modeling among other things. In addition to all of that, Rainier and her crew sometimes find shipwrecks. In fact, Rainier and her crew have found 5 shipwrecks this season!
Simplified, hydrographic research involves sending multiple sonar (sound) beams to the ocean floor and recording how long it takes for the sound to come back. You can use a simple formula of distance=velocity/time and divide that by two because the sound has to go to the floor and back to get an idea how deep the ocean is at a particular spot. This technique would be fine by itself if the water level weren’t constantly fluctuating due to tides, high or low pressure weather systems, as well as, the tilt of the ship on the waves. Also, the sound travels at different speeds according to the water’s temperature, conductivity and depth. Because of this, the data must be corrected for all of these factors. Only with data from all of these aspects can we start to map the ocean floor. I have attached some pictures of what data would look like before and after correction for tides.
I was also given a tour of the engine room yesterday. Thanks, William. He explained to me how the ship was like its own city. In this city, there is a gym, the mess (where you eat), waste water treatment, a potable (drinkable) water production machine, and two engines that are the same type of engines as train engines. Many of my students were interested in what happens to our waste when we are aboard the ship. Does it just get dumped into the ocean? The answer is no. Thank goodness! The waste water is exposed to bacteria that break down the waste Then, salt water is used to produce chlorine that further sterilizes the waste. After those two steps, the waste water can be dumped. The drinking water is created by evaporating the water (but not the salt) from salt water. The heat for this process is heat produced by the engine. William also explained that there are two of everything, so if something fails, we’ll still be alright.
Personal Log
Sunday, I drove from Anchorage to Seward. The drive was so beautiful! At first, I was surrounded by huge mountains that were vibrant yellow from the trees whose leaves were turning. Then, there was snow! It was actually perfect, because the temperature was at just the right point where the snow was melted on the road, but it had blanketed the trees. Alaska is as beautiful as all of the pictures you see. The drive should have been about 2.5 hours, but it took me 3.5 hours, because behind each turn the view was better than the previous turn, so I had to stop and take pictures. I took over 100 pictures on that drive. Once I arrived in Seward, I was given my first tour of the ship and then I had some time to explore Seward.
Yesterday (the first official day on the job), I learned so much. Getting used to the terminology is the hardest part. There are acronyms from everything! Immersion is the best way to learn a foreign language, and I have been immersed in the NOAA (National Oceanic and Atmospheric Administration) language. There is the CO (Commanding Officer), XO (Executive Officer), FOO (Field Operations Officer), TAS (Teacher at Sea or Me!), POD (Plan of the Day) and that is just the tip of the iceberg. I also had to learn all of the safety procedures. This involved me getting into my bright red survival suit and learning how to release a lifeboat.
Today, I am going on a dive launch. The purpose of this launch is to help some of the divers get more experience in the cold Alaskan waters. I will get to ride on one of the smaller boats and watch as the Junior Officers scuba dive.
Did You Know?
NOAA Corps is one of the 7 branches of the U.S. uniformed services along with the Army, Navy, Coast Guard, Marine Corps, Air Force, and the Public Health Service Commissioned Corps (PHSCC).
We love your red suit! You look adorable! Can you bring it back with you? We’d also like for you to bring us back some whale. Haha!
How many sound waves are received each minute by the equipment?
We miss you!
Sincerely,
1st Period
1) I don’t think I can bring home the suit. Thanks for the complement though. If I end up in the water, it will be comforting to know that I look adorable.
2) Congrats! You have stumped not just me, but the scientists as well. The number of sound waves received is equal to the number put out, but when you produce a sound, you don’t know how many sound waves are in that sound. They do know the frequency of the sound waves 200 kilohertz (kHz) for deeper water and 400 kHz for shallower water. Also, they adjust the pulse rate which is how often the sound is made, and they adjust the pulse width which is the duration of the sound pulse.
You probably shouldn’t talk about the tip of icebergs while you’re in Alaska! You look very #teamswole in the gym!
Have you done anything yet that would require special training?
Do you have to correct the sonar data for the tide manually or does a computer do it? Is there a big, long equation that you could show us?
Love,
Your “Favorite” Class
3rd Period
1) I have done some special training for safety procedures. I was taught what my role is if their is a man-overboard, a fire, or if we need to abandon the ship. My assignment mostly is to follow orders at that point. Other people have more specific tasks, but since I am new, they don’t want to put too much on me, because I have had less training than everyone else. I was taught how to plug a hole that is spewing water and how to pump water out of the ship if the ship is taking on water.
2) For tide corrections, the tide gauges must be set manually by divers. That is why we did the practice dive. Also, the computer must be told manually what to correct for and in what order. There are different ways you can apply correctors, so the computer must be told to do that manually. However, the computer does the fancy math when it comes to data processing using a computer program. I will be learning more about this process soon, so I should be able to give you more details next week.
You da best!
What do the different colors on the graph of hydrographic data mean? Do you process the data aboard the ship or do you just store the data and process it on land? How many sonar signals are sent to get an accurate measurement of a location? POP QUIZ: How fast does sound travel (you can’t look it up!) 🙂
Love,
Your percolating cohort
1) The different colors represent different lines, which means it’s data from different times that the ship passed by. All together you can get a pretty good idea of what the ocean floor looks like.
2) All of the data processing takes place on the ship. A report is written. Once that report is sent off it gets checked for anything abnormal. Although, it has already been checked several times before it gets sent off in the report. If a major DTON (Danger to Navigation) is found, then that information will be sent out immediately to ensure no one crashes on it while the data is still going through the process of being checked.
3) 15 to 20 pings (sound pulses) are sent out per second, and there are 258 beams that are sending the pings each time. So if we do a little math, we can figure out approximately how many pings are recorded per second. For example, 15 pings/sec X 258 beams = 3870 pings/sec.
4) Your pop quiz is a trick question, because sound travels at different speeds depending on the medium it is traveling through. In the ocean water, they must take into account water temperature, salinity, and conductivity, because this changes the speed that the sound travels through water.
What keeps the Rainier from crashing on the DTONs?
Prior data and cautious navigation keep Rainier from crashing. In general, Rainier stays in deeper waters, because she is a large ship. There are not going to be as many DTONs in this deep water. The launch boats are where it can be a little more dicey. The launch boats go where Rainier can’t, because it is too shallow. They are, therefore, more likely to find a DTON. The crew has talked about some close calls when surveying, but going slow in these areas can help with safety.