ctd cast – Page 2 – NOAA Teacher at Sea Blog

July 9, 2009April 5, 2021

Scott Sperber, July 9, 2009

NOAA Teacher at Sea
Scott Sperber
Onboard Research Vessel Kilo Moana
July 9-17, 2009

Mission:Woods Hole Oceanographic Institution Hawaii Ocean Time series Station; Albert J. Plueddemann, Chief Scientist
Geographical area of cruise: Central Pacific, north of O’ahu
Date: July 9, 2009

Weather Data from the Bridge
Temperature: 23.9 c

The WHOTS-6 buoy getting prepared to be placed on the ship

Science and Technology Log

As a first log I would like to explain a little about this project. Much of what you will be reading will be directly from correspondence I have received from NOAA themselves prior to the expedition. The following is the cruise plan that the chief scientist, Al Plueddemann sent me before the cruise:

Overview

The R/V Kilo Moana (KM) will participate in mooring operations associated with the WHOI Hawaii Ocean Timeseries Station (WHOTS) project. The primary intent of the WHOTS mooring is to provide long-term, high-quality air-sea changes and upper ocean temperature, salinity and velocity at a specific location in the central Pacific Ocean.

Receiving tower for the weather balloon information

The first WHOTS mooring was deployed in August 2004, and the site has been continuously occupied since that time by means of annual mooring service cruises. The KM will depart from the UH Marine Center at Sand Island on 9 July 2009 to the WHOTS site. The cruise will include participants from WHOI, U. Hawaii, NOAA ESRL, U. Colorado CIRES, and possibly a NOAA Teacher at Sea (ME). The WHOTS moorings are a design utilizing wire rope, chain, nylon and polypropylene line. The surface buoy is a 2.7-meter diameter foam buoy with a watertight electronics well and aluminum instrument tower. Instruments are attached to the mooring line in the upper 150 m. An acoustic (sound) release is placed above the 9300 lb anchor, and 80 glass balls above the release provide backup flotation.

These receive information from the sun. The temperature skimmers.

Two meteorological systems will be deployed aboard the KM in addition to the ship’s standard sensors. The first system is one developed at WHOI to meet the need for more accurate meteorological observations from volunteer observing ships. The configuration on Kilo Moana will include five main components: a splash-proof housing with sensors for AT/RH (Atmospheric temperature and relative humidity), SWR (short wave radiation) and LWR (long wave radiation), a second housing with a BP (barometric[atmospheric] pressure sensor and central data logger, a rain gauge, a wind sensor, and a GPS) global positioning system) logger. Data are made available in real-time using a computer kept temporarily in the ship’s chart room.

Cruise Plan

Staging/Destaging: Preparation of the WHOTS-6 buoy and mooring equipment will take place at the UH Marine Center during 1-6 July. Loading and staging of scientific equipment on the KM will be done on 7 July (or earlier as the situation permits). As part of the preparation, the two meteorological systems described above will be mounted on the KM. One will be mounted on the bridge mast. Others will be installed on a 30′ high tower on the port bow, and the instrumentation and computers for theses will be kept on the port (left) side of the ship There will also be an installation along the railing for a boom that will support a sea surface temperature skimmer device and mounted on the port side of the bridge.

Operations: The cruise involves four principal operations, as listed below. These operations are expected to require 9 ship days.

1. Deployment of the WHOTS-6 mooring. The buoy will be deployed through the A-frame, after which the ship will proceed slowly ahead. The remainder of the mooring will be deployed over the stern using the mooring winch, capstan, air tuggers, and crane as necessary. Acoustic ranging from three stations will allow the mooring anchor position, to be determined by triangulation.

2. Sensor comparison period. During a period of approximately 4 days between release of WHOTS-6 and recovery of WHOTS-5, the KM will establish and hold position, with bow into the wind. During the comparison period satellite transmissions from the buoys will be monitored using equipment supplied by the scientists. A series of shallow (200 m) CTD (conductivity, temperature and depth) casts will be done at approximately 4 hr intervals using a CTD and rosette supplied by the science party.

3. Recovery of the WHOTS 5 mooring. The WHOTS-5 mooring is presently on station at another location not far from the new buoy. The WHOTS mooring release will be fired and recovering of the old buoy will begin with the glass balls (lower end) and proceed to about 50 m below the buoy while the ship moves ahead slowly. The work boat will be used tograb the glass balls and pass a leader line to the KM. The work boat will be lowered again and used to connect a line to the buoy and pass the line to the stern of the ship. The buoy will be recovered through the A-frame. Recovery operations will use the A-frame, the mooring winch, capstan, air tuggers, and crane as necessary.

4. Deep CTD casts and CTD Survey. At certain times during operations,several deep (1000 m) CTD casts will be made. The fifth WHOTS WHOI-Hawaii Ocean Timeseries Site (WHOTS) buoy was deployed from the Kilo Moana at 03:24:39 UTC June 5, 2008.

The R/V Kilo Moana will be deploying the WHOTS-6 mooring and will for a number of days be used in the comparison of real time data between the new mooring, the WHOTS-5 mooring and that of the ship. After which the WHOTS-5 mooring will be recovered via the A-frame on the stern.

Real Time Data

Hourly averaged meteorological data for the current deployment of the WHOI Hawaii Ocean Time Series Station are received via Service Argos four times daily. Hourly averages are also being transmitted for an engineering study using the Iridium Satellite service. Preliminary data is displayed in unedited form as time series plots, and is available for download as ASCII files.

Personal Log

Wow. That is a lot of scientific jargon and acronyms which I will try to clear up in the next week. As for my responsibilities they will include but not be limited to:

During this expedition I will try to match the NOAA goals of which are:

Short-term Goals

I will:

Understand how NOAA oceanic and atmospheric research is linked to National Education Science Standards and Ocean Literacy Principles.
Understand the education and training paths that lead to NOAA-related careers.

Mid-term Goals

I will:

Use NOAA data and resources in classroom activities. (oh boy)
Use NOAA-related career information in classroom activities, when mentoring students and when working with colleagues.

Why am out here in the middle of the ocean?

The vision of NOAA’s Teacher at Sea program is to be NOAA’s main provider to teachers of opportunities to participate in real-world scientific research and maritime activities.

Tasks and Responsibilities

I will have a defined set of tasks and responsibilities before, during, and after the mission. During the mission, I will be under the ultimate command of the ship’s Commanding Officer. AYE, AYE CAPTAIN. However, I will also be considered a member of the science party, And will also be under the direction of the mission’s Chief Scientist and will be expected to take part in the tasks assigned by the Chief Scientist.

MICROCat sensor to be located at 155 meters

Everyone here is very accommodating of the new guy. I am going to quietly sit back and observe for a while, there is so much going on I do not want to get in the way. From my berth window, I look directly out on the A-frame, great cautious way to observe the deployment without stepping on anyone’s toes. I am watching the crew assemble the line of MICROCat and other monitoring devices. Lengths of chain, shackles and hitches are laid over the deck in what seems like a chaotic mess but I have been assured that it will all flow out nicely when the deployment of the system begins. You can see how the MicroCATs are labeled with their respective depths.. There is also another device, the Seabird, that will be the one that bobs (yo-yo’s) up and down for daily data regarding, temperature, conductivity and depth.

Words of the day: deployment, winch, capstan, crane, acoustic, triangulation, comparison, bow, stern, A-frame

June 24, 2009April 5, 2021

Mary Patterson, June 24, 2009

NOAA Teacher at Sea
Mary Patterson
Onboard NOAA Vessel Rainier
June 15 – July 2, 2009

Mission: Hydrographic Survey
Geographical area of cruise: Pavlov Islands, AK
Date: June 24, 2009

Weather Data from the Bridge
Overcast
Wind Light
6 mi visibility
Pressure 1009.1 mb
Dry Bulb Temp 6.7˚ C Wet bulb 6.7˚ C
Seas 0-1 ft.
Water temp 6.1˚ C 42˚ F

Science and Technology Log

Once the data has been collected by the survey boats, it needs to be processed into meaningful information. The data from the boats is called raw data and it is saved onto a thumb drive. The assistant survey tech takes the thumb drive and loads the data into the computers on the ship. From here, the raw data is imported into a software program called CARIS Hips and Sips. CARIS is the primary hydrographic data processing software. It is used to:

Merge all sensor data into a common reference frame
Apply various correctors to sounding data
Edit sounding data in both time and spatial domain
Create gridded surfaces (BASE. CUBE)
Review side scan data and select contacts
Prepare data deliverables for the hydrographic branches

The night processors apply correctors for variables that can affect the data such as tides, sound velocity, true heave and TPE (total propagated error). Then they can generate a surface of the sea floor. Finally, they must look for flyers; data points that are inconsistent with the statistical model. This is where the technology is so cool! The software enables you to view the surface in 3D. Using your mouse, you can literally fly over and under your surface. The night processors add their comments to the acquisition log and create a tiff file to show the sheet managers the coverage for the day. A detailed report about the area surveyed (DR) is written and submitted. The Descriptive Report (DR) is the written record of the survey work completed in an area. It accompanies and complements the digital data. Our survey area will not be completed during this leg of the trip. After some import time in Seward, AK for the Fourth of July, the Rainier will return to the Pavlof Islands to continue their survey. After data acquisition is complete and data has been reviewed aboard the ship to ensure it meets requirements, it is signed off by the Captain, the Chief Survey Tech, the Sheet Manager, and the FOO (Field Operations Officer). When the sheets are completed, they are sent to the Pacific Hydrological Branch in Seattle, WA.

There, they will complete quality control analysis of the data and either accept or reject the survey sheet. They look for any data that is inconsistent with the required Specification and Deliverables. If the data does not meet specification, the area will likely need to be surveyed again. When the data is accepted by the branch they will further process the data to highlight important features and then send the survey sheet to the cartographers at the Marine Charting Division (MCD). The cartographers use the data submitted to place additional soundings and navigation hazards onto the US Navigation charts. A navigational hazard is generally defined as anything 1 meter shoaler than surrounding depths in water less than 20 meters deep. Currently, it may take years for a survey to be charted and reach the mariner. Critical corrections (such as DToNs -Danger to Navigation) or high priority areas can be updated more quickly.

Personal Log

I’ve noticed that marine measurements are not consistent in their use of one system. Some measurements are in meters, some in feet, some in fathoms and some in ancient mariner terms such as shots. Since we “speak only metric,” in my class, I asked why mariners don’t stick to just one system of units. The explanation I received makes sense. Navigation of the seas is a world-wide occurrence. Crews aboard vessels are often multi-national. Using a system that is accepted world-wide makes sense.

Each day I go out on the launch, I feel more a part of the team. I can comfortably cast and log data on the launch computers. I am starting to understand more about running the sonar. Each day, I get to practice my boat driving skills. Thanks especially to coxswain Foye, I have even completed a starboard side pick up for a man overboard drill! As always, safety is a key component. We practice drills on board as well as on the launches. On the launches, we do radio and iridium phone check-ins periodically. You can keep track of where we are by using Shiptracker.

Word of the Day Shot: 90 feet of chain; used to describe how much anchor chain to let out.

June 19, 2009April 5, 2021

Mary Patterson, June 17-19, 2009

NOAA Teacher at Sea
Mary Patterson
Onboard NOAA Vessel Rainier
June 15 – July 2, 2009

Mission: Hydrographic Survey
Geographical area of cruise: Pavlov Islands, AK
Date: June 17-19, 2009

Weather Data from the Bridge
Overcast
Wind 15 kts
8 mi visibility
Pressure 999.5 mb
Dry Bulb Temp 6.7^◦ C Wet bulb 5.6^◦ C
Seas 0-1 ft.
Water temp 6.7^◦C, 44^◦ F

Here I am getting ready to cast the CTD.

Science and Technology Log

While the weather holds, we head out on the launches to survey areas that are not charted or were last charted probably back in the time of Captain Cook. After the boats are lowered using gravity davits, 4 boats head out to survey. Upon reaching the survey area, the first thing that gets done is a casting. This consists of lowering the CTD (Conductivity, Temperature and Depth) unit into the water at the surface for 2 minutes for calibration. Then it’s lowered to the sea floor (taking measurements as it goes) and brought back up to the surface with a winch and a pulley system. The sensor unit is cabled to the computer and the data is downloaded. This is a vital step in interpreting the sonar data. Since saltwater conducts electricity differently based on the salt concentration, using the CTD gives the hydrographer information about sound velocity at different depths.

Velocity of sound is most affected by temperature, which is also measure by the CTD. Next, the hydrographer decides whether to use the high or low frequency transmitter depending on the depth. The hydrographer uses a lower frequency for deeper water. Casting is often done again after lunch since temperatures can change, especially at the surface. Alaska is known for the confluence of fresh and salt water at the surface due to melting glaciers and fresh water runoff. The MVP (moving vessel profile), is another device used for sound velocity. It looks like a torpedo and it’s towed behind the boat allowing for continuous casting.

The shape of a plane has more points than a boat so is a good way to use points to line up a survey transect.

The plane you see on the picture is used instead of a boat because of the position of the GPS sensor relative to the shape. The coxswain can make the plane pivot on a point as they line up on a line to survey. On the survey, the map is broken down into polygons. Each sheet manager gets a sheet with their polygons to survey. Surveying consists of the coxswain driving the boat as they watch the computer screen. As they drive, the screen shows in real-time a swath of color indicating the swath of the beams. After surveying, the boats return to the ship and are hoisted back up onto the davits. All survey techs meet in the wardroom to discuss what happened on their survey. The Captain and FOO (Field Operation Officer) ask questions about what was surveyed and any problems they had with any equipment. This is a true community of scientists who share data and knowledge.

Personal Log

We load the launches at 8:00 am and complete surveys until noon. We break for lunch and unpack the ice chest packed by the cooks for us. It’s always a surprise to see what we have! Then we continue surveying until about 4:00 pm when we return back to the ship. I have had the opportunity to cast the CTD unit into the water, drive the launch and collect the data on the computers. The coxswains make driving the boat following the lines on the computer look so easy! Especially in rough seas, the coxswains do an amazing job of helping the survey techs collect data. Again, good communication is a key! I’ve also seen how the techs have to problem- solve on a daily basis.

One day we got into the launch and the engine wouldn’t start and the coxswain had to troubleshoot the problem. Another day, several boats had problems with their CTD units and they had to repeat trials several times. When you are 12 miles away from the nearest help, it’s crucial to have good problem-solving skills. After dinner, there’s time to finish writing journals, do laundry, fish off the fantail, watch a movie, play guitar hero or exercise in the gym area. Then, it’s time for bed and the day will start over again. If you are not on a survey launch, you work in the night processing lab compiling the data collected by the survey techs during the day’s launch. This includes applying various filters to clean up the “noise” or fuzziness from the sonar. The coolest part is seeing the data in three dimensions. After the data is cleaned up, the sheet managers write up a descriptive report that gets sent to Pacific Hydrographic Branch. This ship is a great example of a system: there are many separate parts that when combined with other parts, complete a task.

Pavolf and Pavlof’s Sister are active volcanoes.

Each night at 10 pm, fellow Teacher at Sea –Jill Stephens and I go to the bridge and collect weather data that is transmitted directly to NOAA. Although the days have started off hazy and grey, by evening we often see sunshine that lasts until 11:00 pm. This part of Alaska is breathtaking! I love watching the volcanoes, Pavlov and Pavlov’s sister, in different types of light.

Animals Seen

Whales, Puffins, and Sea gulls.

New Word of the Day

Cavitation: The sudden formation and collapse of low-pressure bubbles in liquids by means of mechanical forces, such as those resulting from rotation of a marine propeller.