Hydrographic survey – Page 81 – NOAA Teacher at Sea Blog

April 7, 2005March 18, 2021

Melissa Fye, April 7, 2005

NOAA Teacher at Sea
Melissa Fye
Onboard NOAA Ship Hi’ialakai
April 4 – 25, 2005

Mission: Coral Reef Ecosystem Survey
Geographical Area: Northwest Hawaiian Island
Date: April 7, 2005

Location: Latitude:43.0 N, Longitude: 20.0 W

Weather Data from the Bridge
Visibility: 10 miles
Wind Direction: 120
Wind Speed: 12 kts
Sea Wave Height: 2-3 feet
Swell Wave Height: 3-5 feet
Sea Water Temperature: 23.5
Celsius Sea Level Pressure: 1022.0
Cloud Cover: 7/8 Cumulonimbus, Ac, Ci

Science and Technology Log

Early this morning the HI’IALAKAI arrived at Shark Island to conduct a 500 m CTD, (Conductivity, Temperature, and Depth) measuring device, at a location of 50.2 N and 24.8W for about 1 hour. The ship then traveled on towards a launch site for the AHI research boat. In the afternoon the AHI research vessel was lowered into the water so that the chief scientist, Scott Ferguson, and other scientists could run engineering tests on it before using it for a sonar mission. By mid-afternoon the AHI, which stands for Acoustic Habitat Investigator, was once again lowered into the ocean to begin running survey lines closer into the more shallow, shoal areas surrounding the French Frigate Islands. The surveys were run at 7 knots. The AHI boat looks much like an orange lifeboat but has a metal cabin on top which houses a range of computer monitors and a sonar system to take in data about the ocean floor.

That data was then transported back onto the HI’IALAKAI to be processed. Inside the ship, GIS, or Geological Information Systems scientists, like Emily Lundblad, process saved data on the computers in the drylab on board. They take one swath of data at a time (think of a swath of data as a line of data -the ship basically runs lines across the ocean much like a lawnmower mows a lawn-trying not to leave any gaps) and edit it on their monitors. The scientists are looking for errors in data which show up as points or scatters of “dots” for lack of a better word, on the swath. The swath is 3 dimensional on the screen and the scientists put 4 different vantage points of the data on the monitor. Carefully, outliers of data, or tiny dots of color that lie outside of the more solid path, are deleted. The outliers, or errors, in this case are usually due to noise pollution. A school of fish, drilling, or a boat engine can cause extra noise which is picked up by the sonar system, and needs to be edited out of the data. The ship continued to run its own survey lines with its sonar system attached to the hull of the ship.

Personal Log

Today I awoke after a good night’s sleep. My stateroom is on the lowest level towards the back of the ship. It is the noisiest room because it is near the cranes that operate, the mess, and engines, but it rides the smoothest. This means that it rocks the least out of any of the rooms on board because of its location. Good news to me! The higher up and more forward you go on the ship, the more the boat sways. There are handrails in all the hallways, bathrooms, decks, etc. so you can hold on while walking on the ship. I spent the day interviewing more members of the ship, to include the Executive Officer, a deck hand, and a scientist. I stationed myself on the upper deck to watch the AHI research vessel being deployed into the ocean for tests, stood on the bridge for awhile and looked out at La Perouse Pinnacle (23 degrees 46’N, 166 degrees 16’W) a volcanic rock that rises out of the Pacific that is so steep and rugged that it is practically inaccessible. Later, I situated myself in the drylab to observe the scientists editing data.

Then, right before dinner, I gave a presentation to the officers, crew, and scientists in the forward mess about the Teacher At Sea Program and what it entails. I presented a picture of my class, which is posted on board the HI’IALAKAI, and received a lot of feedback. Finally, after dinner, I visited the ship’s store for the first time, run by ENS Amy Cox and spent the evening typing logs and watching video from a previous diving cruise, whereas the scientists were studying the ecosystem below the ocean.

QUESTION OF THE DAY for my fourth grade students: After reading the information under the science log, you need to better understand what an outlier is in data collection. Ask everyone in the class to write their age on the chalkboard. Also, include the teacher(s) age in the data, or information, collected on the chalkboard. Make a graph of the data (remember to include a title, x & y coordinates). When you are finished you should notice most of the data is close together but a few pieces of data are much different, or lie outside of most of the other ages. What data is the outlier(s) in the class graph of ages? How can outlier data affect an experiment?

PICTURES OF THE DAY: Scientists processing and editing data on a computer in the drylab/ Research vessel AHI

April 6, 2005March 18, 2021

Melissa Fye, April 6, 2005

NOAA Teacher at Sea
Melissa Fye
Onboard NOAA Ship Hi’ialakai
April 4 – 25, 2005

Mission: Coral Reef Ecosystem Survey
Geographical Area: Northwest Hawaiian Island
Date: April 6, 2005

Location: Latitude: 28.5 N, Longitude: 49.3 W

Weather Data from the Bridge
Visibility: 10 nautical miles
Wind Direction: 42
Wind Speed: 16 kts
Sea Wave Height: 3 feet
Swell Wave Height: 3-4 feet
Sea Water Temperature: N/A
Sea Level Pressure: 1021 mb
Cloud Cover: 3/8 SC, AS, Ci

Science and Technology Log

Today’s plan involved running sonar survey lines in a westerly direction en route to Necker Island (14.5 hours). Run at sea speed. CTD casts were conducted as needed, and I attended one at 1230. The senior surveyor informed me that CTDs are usually cast at least every 12 hours. I also spent the day interviewing various persons onboard to include the senior survey scientist, a deck hand/surveyor/, and the chief medical officer. At 1530, we arrived at our first point of reference, Necker Island, and the proceeded to continue survey lines westerly towards the French Frigate shoals for the next 9.5 hours.

The scientists on board are creating benthic habitat maps to support the Coral Reef Ecosystem Integrated Observing System under the direction of the Pacific Islands Fisheries Science Center and the National Marine Fisheries Service. Basically, several different plans have been laid out to determine fishing and no fishing zones around the island chain. The additional data collected on this cruise will hope those organizations determine the best plan for unrestricted and restricted fishing areas. Mapping boundaries may help to decide what fathoms (depths) to fish at or a longitudinal system may be used. Currently, lobster fishing is not allowed at all because they were all but wiped out in the past. The area around Necker, Brooks Bank, the French Frigate Shoals may eventually be entirely closed to fishing because evidence collected leads scientists to believe that that area may be a genetic gateway for species to the south.

Personal Log

I woke up around 6:30 am and proceeded to eat breakfast and to establish some times to interview people for the day, in between observing CTD casts and popping into the dry lab. Soon after lunch I interviewed the Chief Medical Officer and got a tour of the on board hospital which is equipped to handle many kinds of emergencies. The chief medical officer is LTJG Mike Futch. While on board he is in charge of handling any emergencies that may occur. Most common emergencies include sea sickness and if someone needs treated for that he can prescribe medication, administer shots, and treat dehydration that may occur from people regurgitating. He likened sea sickness to the feeling you would get if you were stuck on an elevator going up and down continuously until you got sick. LTJG Futch is authorized to do any lifesaving technique, but he is also in charge of handling medical questionnaires for members of the ship, weekly sanitation and safety checks, and handling inventory in the medical lab. Proximity to a port determines if a ship is assigned a medical officer (if more than 2 days from a port, then a med. officer is assigned), otherwise other members of the ship are trained for medical emergencies as well.

LTJG Futch recommends anyone who would like a job like his to major in chemistry or biology in college, attend physician’s assistant school, and specialize in emergency programs. He is an employee of the United States Public Health Service (the Surgeon General is the leader of this group) which deploys medical personnel to all federal agencies including NOAA, Coast Guard, prison system, Indian affairs, to just name a few. He will spend roughly 200 days at sea this year and he comments that the best part of his job is getting see parts of the world that many others don’t see, the pay is good, and you get to function almost like your own boss because there is usually only one or two at most medical officers assigned to a ship.

I then proceeded to the science lab to get a first hand look at the computer system where data is filtered into from the onboard sonar systems. The senior surveyor and another surveyor spoke to me about the details aforementioned. I next interviewed Joyce Miller, Senior Survey Scientist, about her background and duties. Her job is to plan surveys, train new surveyors, and process data. She is at sea for 60-150 days a year depending on the projects she is working on. She comments that her most important piece of equipment is the computer and that any students who might be interested in this type of career should study oceanography (physics, biology, chemistry, geology) and heavily concentrate in computers. She feels a surveyor should be flexible, because things often don’t go according to plan, and that this job offers a lot of challenges and movement.

Eventually I attended the launch of another CTD cast and ate lunch. The ship hasn’t stopped, except for the occasional CTD cast for 30-40 minutes, because our late start has put us behind and there are 2 contractors aboard who need to be dropped off by a certain date at one of the islands to catch a plane. The afternoon was spent writing logs and lesson plans. Finally, I will go up on the bridge to interview the Operations officer and other officers employed by NOAA so I can give my fourth grade students a sense of the various jobs and people needed aboard a research ship to make it run smoothly. I am happy to report I don’t seem to be sea sick at all, which makes me very happy, because many of the people on board are still trying to get their “sea legs!” To this point the seas have not been very rough though!

QUESTION OF THE DAY for my fourth grade students: The scientists on board are compiling data to create benthic habitat maps. What does the word benthic mean? What could maps like these be used for in the future?

April 5, 2005March 18, 2021

Melissa Fye, April 5, 2005

NOAA Teacher at Sea
Melissa Fye
Onboard NOAA Ship Hi’ialakai
April 4 – 25, 2005

Mission: Coral Reef Ecosystem Survey
Geographical Area: Northwest Hawaiian Island
Date: April 5, 2005

Location: Latitude: 28.5 N, Longitude: 49.3 W

Science and Technology Log

Today’s scientific goals involve running survey lines at Nihoa. Survey lines will begin at the 12:00 position and run counterclockwise one and a quarter times at Nihoa. The ship will be using its multibeam sonar equipment to do this and it will in turn fill in missing data to complete benthic habitat maps of this area. A formal in-service was given by senior surveyor, Joyce Miller, on multibeam sonar equipment. Some of the interesting facts from that presentation are provided below. There are 3 multibeam sonar devices available for use on the HI’IALAKAI. Sonar concepts from the in-service: An echo sounder sends sound down to the sea floor and then back up. A single beam echo sounder sends a pulse out that comes back to 1 point on the ship. The center of the beam right under the ship, or swath, is termed nadir.

Nadir is the shortest distance between the sensor and the location of the beam. Ensonification is energy within the main part of the beam pattern which radiates toward the sea floor. Decibel is a unit used to measure the relative strength of a signal. Beam width is an angle that defines the main part of the energy that is radiated within a 3db solid angle. The footprint size beneath the sonar beam changes as the water gets deeper because it comes out of the ship at an angular direction. The deeper the water, the less accurate the information will be from the beam because the footprint pattern below the beam gets larger. A narrow beam echo sounder ensonifies a smaller area, so it gets more accurate information because of its narrower angle. A transducer is a device that converts electrical energy into sound energy and vice versa. The “ping” is the sound going down the beam. The frequency is the number of times per second that the same waves of sound repeat itself (vibrations per second). The pulse length, or duration of outgoing pulses of the sonar equipment, in part determines the system’s resolution.

The shorter the pulse length, the greater the resolution. Other facts: The transducer range, or how far the sound is effectively transmitting, is determined by a number of factors, including; frequency, transmit power, beam width, transmit pulse length, received bandwidth, absorption, ocean floor composition, and noise level (heavy rain). In summary, high frequency sonars with narrow beam widths provide the highest vertical resolution. If you need both range and resolution, pick a medium frequency sonar to do the job. What is being measured then? The 2-way travel time of a sound wave and this information is converted to distance. The speed of sound in water ranges from 1450 meters/sec to 1550 m/sec. CTDs, or Conductivity, Temperature/Depth devices are dropped at intervals off the side of the ship daily because the information they gather are the most accurate way to get sound velocity data and is needed when multibeam error sources are being defined. Multibeam concepts: Side scan sonars are sonars that are towed behind a boat. Backscatter is the term for when the sonar signal provides information about the character of the sea bottom (smoothness, roughness, etc). Multi-beam sonars were first designed to provide information on depths and they just happen to also give information on backscatter.

Benthic habitat maps are maps pf the sea floor, so backscatter information is extremely useful and the goal of this expedition. To get good backscatter data, many factors need to be kept constant. The ship should be driven in straight lines and kept at a constant speed. Some of the area around the Hawaiian Island chain has already been mapped using this technology but there are many gaps to be filled in. The cruise aims to fill in more of that missing information for the benthic habitat maps. Three multibeams are being utilized on this trip. Finally, it is important to understand sources of error in multibeam use. They consist of sound velocity or physical oceanographic parameters that influence the sound velocity structure. These include temperature, salinity, depth, and density, which are all recorded and gathered during CTD drops. Changes in these parameters affect the multibeam because they are used to create a sound velocity profile.

Personal Log

I awoke to the hustle and bustle of the ship, as my stateroom is located a few doors down from the mess. After eating (I eat better here than I do at home) I attended a formal inservice presentation by the senior surveyor, Joyce Miller, on Multibeam Training. I took notes during her PowerPoint slideshow, to try to better understand the type of sonar equipment they are using onboard. The transducer on the sonar equipment turns electrical energy into sound energy and is sent down to the ocean floor. It bounces and scatters and provides data which is used to create a map of the ocean floor (a benthic habitat map). I also learned some new vocabulary words like nadir, ensonification, and beam width. We broke for lunch and after lunch I attended my first CTD cast on the deck and took some pictures. After noon the scientists met back in the forward mess lounge to finish the multibeam training. The rest of the evening was just left to typing logs, watching a movie, and resting. I am not assigned a watch schedule so I have been sleeping normal hours of 10 to 6am.

QUESTION OF THE DAY for my fourth grade students: Locate the ship using the latitude and longitude coordinates above. Remember “latitude” lines are fat (horizontal) and longitude lines are long (vertical). What are the 5 major Islands of Hawaii? What does the word salinity mean? Would the Pacific Ocean or the Potomac River be measured for salinity, and why?

April 4, 2005March 18, 2021

Melissa Fye, April 4, 2005

NOAA Teacher at Sea
Melissa Fye
Onboard NOAA Ship Hi’ialakai
April 4 – 25, 2005

Mission: Coral Reef Ecosystem Survey
Geographical Area: Northwest Hawaiian Island
Date: April 4, 2005

Science and Technology Log

The HI’IALAKAI is equipped to perform many operations while sailing the area around the Northwest Hawaiian Island Chain. This mission will involve the use of multibeam sonar equipment to map the nature of the sea floor around the island chain, scuba divers will replace a buoy system which measures many things including the occurrence of photosynthesis in the water, and CTD drops will occur multiple times. A CTD, or Conductivity, Temperature, Depth device measures the depth, salinity, and temperature of ocean water. The boat is stopped in order to drop the device from a crane so it can measure the levels of these categories and that information is used to support multibeam sonar operations.

I will be observing scientists at work and interviewing members of the HI’IALAKAI throughout the next 3 weeks. I will be trying to relate the knowledge I gain to my students’ science and math standards in Virginia. The information I gather on board will be available to NOAA and my 4th grade students at Ashburn, Elementary in Ashburn, VA.

Personal Log

Sunday evening: I arrived at the HI’IALAKAI on Sunday late afternoon and met a few of the hands, including the Chief Engineer and Medical Officer. Next, I met the Executive Officer who helped assign me a room onboard. I simply unpacked and grabbed something to eat with the Medical Officer. Later that evening, I met the Chief Scientist on board and then I retired for the evening. I had a hard time sleeping, in anticipation of the next day’s events! It was soon dark so I planned on touring the vessel the next day in the daylight hours. It is much larger than I anticipated and a little daunting to someone who’s not familiar with ships.

Monday: Our departure was delayed (originally set for 9 AM) and pushed back to 4:30 PM due to problems with a boat generator needed for a small research vessel that is vital to the studies of the scientists. Throughout the day I helped the scientific crew pack equipment for the trip. We tied down computer equipment in the dry lab, packed foam pieces around monitors, and cut non slip mats to put under other equipment. Everything that is not bolted down to the ship needs tied down to brackets on the wall. The Executive Officer debriefed us on rules and drills for the cruise. Much of the day was just spent waiting for departure from Honolulu.

QUESTION OF THE DAY for my 4th grade students: What are the names of all the oceans on our planet and which ocean is the largest?

July 14, 2004March 18, 2021

Leyf Peirce, July 14, 2004

NOAA Teacher at Sea
Leyf Peirce
Onboard NOAA Ship Rainier
July 6 – 15, 2004

Mission: Hydrographic Survey
Geographical Area: Eastern Aleutian Islands, Alaska
Date: July 14, 2004

Time: 10:00
Latitude: N 55°17.24
Longitude: W 160°32.17
Visibility: 6 nm

Wind direction: 060
Wind speed: 1 knots
Sea wave height: 0 – 1 foot
Swell wave height: —
Sea water temperature: 10.0 °C
Sea level pressure: 1009.3 mb
Air temperature: 11.7 °C
Cloud cover: 7/8

Science and Technology Log

This morning I went out on launch boat 1 to conduct shoreline hydrography. Shoreline research differs very much from the other research I have seen so far, for it does not require “mowing the lawn” lines. Instead, it is a technique that is used to check the data collected from the LIDAR (airplane) labs. As I learned earlier this week, the data collected using a laser from the airplane primarily focuses on the shoreline and depths up to 30 meters. Today, we went along the shoreline checking questionable data points such as rocks and shoals that may have been confused with kelp or other variances in data collection. In order to do this checking, the survey technicians and officers conducting the research look at the LIDAR chart the day before launching and determine where rocks might be misplaced or not including at all. During surveying, which is what we did today, the researchers take a boat with a single beam echo sounding system and go to the places of concern. With some one on the bow to look out for uncharted rocks, the captain then drives over the areas where there might or might not be a rock. Because all of this is done very close to shore, it is very important to drive slowly. There is also a lot of kelp that can get in the way. Once the boat has past over the area a few times, the true depth is recorded as well as the position and a note is made on the chart where any changes need to be made to the chart. A relatively simple procedure, this type of shoreline research is critical for anyone planning to go on shore on any of these islands. Once again I was able to see how important this work is!

Personal Log

My morning was spent on the launch boat doing shoreline surveying. While the technology used was fascinating, I still did not hesitate to wonder at the naturally beauty of these islands. Almost completely uninhabited, these islands host wildflowers, puffin, gulls, and an occasional seal basking on a sandy or rocky beach. The green slopes are sharply cut by dramatic cliffs, creating a feeling of comfort and adventure at the same time. With the clouds dancing across these islands, I almost felt like I was about to see a dinosaur emerge from one of the cliffs—this looks very much like Hollywood’s rendition of “Jurassic Park”! This afternoon I plan on working on more lesson plans as well as a possible journey on another shoreline survey boat.