Diana Griffiths, June 24, 2006

NOAA Teacher at Sea
Diana Griffiths
Onboard UNOLS Ship Roger Revelle
June 22 – June 30, 2006

Mission: Hawaiian Ocean Timeseries (WHOTS)
Geographical Area: Hawaiian Pacific
Date: June 24, 2006

Weather Data from Bridge 
Visibility:  10 miles to less than 25 miles
Wind direction:  065°
Wind speed: 06 knots
Sea wave height: small
Swell wave height:  4-6 feet
Sea level pressure: 1014.5 millibars
Cloud cover:  3, type:  stratocumulus and cumulus

Buoy Technician, Sean Whelan, contacting the Acoustic Releases on WHOTS-2.

Buoy Technician, Sean Whelan, contacting the Acoustic Releases on WHOTS-2.

Science and Technology Log 

Today was very busy because it was the day that WHOTS-2 mooring, which has been sitting out in the ocean for almost a year, was recovered.  At around 6:30 a.m., Sean Whelan, the buoy technician, tried to contact the Acoustic Release.  (The Acoustic Release is the device that attaches the mooring to the anchor. When it receives the appropriate signal, it disengages from the anchor, freeing the mooring for recovery.  There are actually two releases on WHOTS2.) He does this by sending a sound wave at 12 KHz down through the ocean via a transmitter, and when the release “hears” the signal, it returns a frequency at 11 KHz. The attempt failed, so the ship moved closer to the anchor site and the test was repeated.  This time it was successful.  Based on the amount of time it takes the acoustic signal to return, the transmitter calculates a “slant range” which is the distance from the ship to the anchor. Because the ship is not directly over the anchor, this slant range creates the hypotenuse of a right triangle. Another side of the triangle is the depth of the ocean directly below the ship.  Once these two distances are known, the horizontal position of the ship from the anchor can easily be calculated using the Pythagorean theorem.

Recovery of WHOTS-2 buoy aboard the R/V REVELLE.

Recovery of WHOTS-2 buoy aboard the R/V REVELLE.

After breakfast, the buoy recovery began. A small boat was lowered from the ship and driven over to the buoy, as the ship was steamed right near the buoy. A signal was sent down to activate the Acoustic Releases. Ropes were attached from the buoy through a pulley across the A-frame, located on the stern of the ship, to a large winch.  With Jeff Lord leading the maneuvering of the 3750-pound buoy, it was disengaged from the mooring and placed safely on deck.  This was a bit of a tense moment, but Jeff did a wonderful job of remaining calm and directing each person involved to maneuver their equipment to effectively place the buoy. Once the buoy was recovered and moved to the side of the deck, each instrument on the mooring was recovered.  The first to appear was a VMCM, (Vector Measuring Current Meter) located just 10 meters below the buoy.

Jeff Lord, engineering technician, directing the recovery of a Vector Measuring Current Meter (VMCM).

Jeff Lord, engineering technician, directing the recovery of a Vector Measuring Current Meter (VMCM).

Then two microCATs were pulled up, located 15 and 25 meters below the buoy, followed by a second VMCM. This was followed by a series of eleven microCATs located five or ten meters apart, an RDI ADCP (Acoustic Doppler Current Profiler), and two more microCATs.  As each instrument was recovered, the time it was removed from the water was recorded and its serial number was checked against the mooring deployment log.  Each instrument was photographed, cleaned off and sent to Jeff Snyder, an electronic technician, for data upload. Each of these instruments has been collecting and storing data at the rate of approximately a reading per minute for a year (this value varies depending on the instrument) and this data now needs to be collected. Jeff placed the instruments in a saltwater bath to simulate the ocean environment and connected each instrument to a computer by way of a USB serial adaptor port. The data from each instrument took approximately three hours to upload. Tomorrow, these instruments will be returned to the ocean alongside a CTD in order to compare their current data collection with that of a calibrated instrument.

Once all of the instruments were recovered, over 4000 feet of wire, nylon rope, and polypropylene rope were drawn up using a winch and a capstan. Polypropylene rope is used near the end of the mooring because it floats to the surface.  The last portion of the mooring recovered was the floatation.  This consisted of eighty glass balls chained together and individually encased in plastic. The glass balls, filled with air, float the end of the mooring to the surface when the Acoustic Releases disengage from the anchor.  It takes them about 40 minutes to reach the surface. Recovering the glass balls was tricky because they are heavy and entangled in one another. Once on deck they were separated and placed in large metal bins. After dinner, a power washer was used to clean the buoy (it is a favorite resting place for seagulls and barnacles) and the cages encasing some of the instruments.  The deck was cleaned and organized to prepare for tomorrow.

Recovery of mooring floatation on WHOTS-2, consisting of 80 glass balls encased in plastic.

Recovery of mooring floatation on WHOTS-2, consisting of 80 glass balls encased in plastic.

Personal Log 

The theme that keeps going through my mind during this trip and today especially, is how much of a cooperative effort this research requires. It begins with the coordination between Dr. Weller and Dr. Lukas to simultaneously collect atmospheric data using the buoy and subsurface data with the mooring instruments. In addition, Dr. Frank Bradley, an Honorary Fellow at the CSIRO Land and Water in Australia, is on the cruise working to create a manual set of data points for relative humidity using an Assman psychrometer to further check the relative humidity data produced on the buoy. Within the science teams, coordination has to occur at all stages, from the collection of data to its analysis. This was very evident in physical form today with numerous people on deck throughout the day working to retrieve the mooring, fix machinery as it broke down (the winch stopped twice), and clean the instruments.  In the labs, others were working to upload data and configure computer programs to coordinate all of the data.  In addition to all of this is the quiet presence of the ship’s crew who are going about their duties to be sure that the ship is running smoothly.  Several of the crew did take a break today just after the instruments were collected in order to put out fishing lines!  They caught numerous tuna and beautiful Mahi Mahi that the cook deliciously prepared for dinner.

Diana Griffiths, June 23, 2006

NOAA Teacher at Sea
Diana Griffiths
Onboard UNOLS Ship Roger Revelle
June 22 – June 30, 2006

Mission: Hawaiian Ocean Timeseries (WHOTS)
Geographical Area: Hawaiian Pacific
Date: June 23, 2006

Science and Technology Log / Interview 

Dr. Lukas, aboard the REVELLE collecting water samples from the CTD.

Dr. Lukas, aboard the REVELLE collecting water samples from the CTD.

Dr. Roger B. Lukas Professor of Oceanography Dept. of Oceanography and Joint Institute for Marine and Atmospheric Research University of Hawaii at Manoa.

After taking a CTD sample earlier this afternoon, I spoke with Dr. Lukas, the research scientist on this cruise who is leading the recovery and replacement of the mooring components below the WHOTS-3 buoy.  The following is a summary of our discussion.

Dr. Lukas encouraged to me to communicate to my students how imperative it is to set up means of continually confirming the accuracy of scientific data.  The data from the mooring, for example, is compared with six or seven different profiles in order to verify the accuracy of its data and to determine when an abnormal reading has occurred (i.e. a sensor breaks or fishing lines are caught in an instrument).

Organisms both in the sample and in the surrounding water can shift the conductivity calibration in a CTD (Conductivity Temperature Depth) instrument.  Therefore, the calibration of these instruments must be constantly checked and monitored.  Throughout the day today at two-hour intervals, Dr. Lukas has been sending down CTD’s that provide a continuous profile of the salinity and temperature of the ocean from the surface to the maximum depth of the cast.  There are sampling bottles on the rosette of the CTD that close at a depth of 10 and 200 meters. The water from these samples is brought to the surface and is used to calibrate the conductivity of the CTD.  The conductivity readings (which are used to determine salinity measurements) are compared to readings taken from the sampled water via an analytical instrument called an Autosal.  The Autosal is located in a lab on the ship near the main science lab.  This instrument is contained in a water bath for stabilization and is kept in a temperature-controlled room.  Any atmospheric pressure variations that might occur during the Autosal conductivity tests do not have enough of an effect on the conductivity determinations to create inaccuracies in salinity readings. The Autosal itself is calibrated against standard seawater which is quite expensive ($55 for a small vial) but whose salinity is known to the nearest part per million (ppm).

Salinity, or the number of grams of dissolved salts in a kg of seawater, is detected in one part per million (ppm) and is not taken as a direct measurement.  Instead, both the temperature of the sample and its conductivity are measured.  This is because the conductivity of seawater is affected by three variables:  temperature, pressure, and salinity. Temperature affects conductivity ten times more than does salinity.  Basically this means that temperature measurements must be extremely accurate in order to obtain precise salinity measurements.  If a temperature reading were to be off by 1°C this would produce an error in the salinity determination by a factor of ten.  This would render the salinity measurement entirely useless.  Salinity measurements are related to a scale known as the Practical Salinity Scale where, for example, a reading of 35 units would be equivalent to the conductivity of 35 grams of salt in 1 kg of water.  The scale is practical because the ratio of ionic chemical compounds in the ocean remains relatively constant.

Ultimately, the salinity readings produced by the instruments contained in the MicroCATs in the mooring are being compared to numerous measurements taken off of the ship via the CTD’s profiles.  The CTD’s readings are being calibrated against water samples taken by closing bottles on the CTD frame at different depths, which are then measured in the Autosal, which is, in turn, calibrated against standard seawater samples.  The multiple checks on the temperature measurements taken at sea are not a stringent as those of the salinity readings because the temperature instruments do not have nearly the same rate of calibration drift.  Unless they are broken, they will only drift approximately one millidegree per year.

There are different types of oceanographers who study various parameters of the ocean.  Dr. Lukas is a physical oceanographer as opposed to one who studies the biological or chemical aspects of the ocean.  Physical oceanographers study such factors as current, waves, wind, heat content, temperature, and salinity. However, there is overlap amongst the different areas of science. A chemical determination, such as salinity, can actually be quite pertinent to the physical study of the ocean.  Alterations in salinity correlate with changes in density.  Variations in density gradients across the ocean cause flow or ocean currents.  Other factors that affect the ocean currents include the depth of the water; wind, which drags water along; and the rotational motion of the earth.  For example, if a current is moving northward, the rotation of the earth causes an apparent force to affect the water thus drawing it eastward and changing the direction of the current.  Additional smaller factors that affect the current include turbulence in both the air and the sea.  Turbulence is chaotic eddying motions that cause mixing amongst masses of water at different temperatures and salinities.

Dr. Lukas has a Bachelor’s degree in Mathematics, and a Master’s and PhD in oceanography. The work that he has done in earning his PhD gives him the ability to lead a research project, such as the Hawaii Ocean Time-series (www.soest.hawaii.edu/HOT_WOCE). However, Dr. Lukas noted that one does not need a PhD to be a vital part of a research team.  We have people working as part of the science team on this cruise who are at the Master’s, Bachelor’s and Associate’s degree levels.

When asked about what he likes about his work, Dr. Lukas told me that he enjoys several aspects of his job. He enjoys going to sea and the fact that his work leads him to discover new things. He also values the freedom that his occupation affords him.  If he is successful in obtaining funding for a proposal, he has the freedom to carry out a project of his own design. His work has taken him to a variety of places including Papua New Guinea, the Philippines and the Bay of Bengal!

It became very evident in talking with Dr. Lukas that he is devoted to this work that he so enjoys. He puts many hours into his profession.  As he stated, he and Dr. Weller have continual “time and a half” jobs.  His occupation involves many different aspects including being at sea, gathering data and preparing for such science cruises.  He spends large chunks of time working with his research group of eight members.  This work involves managing and training the members of the group as well as dealing with various personnel issues. Approximately 20% of his time is spent teaching at the graduate level.  This is a smaller percentage than many of his colleagues.  Dr. Lukas spends time developing projects and proposals and a significant amount of time completing the science for those that are funded.  This science includes analyzing data, writing papers, attending meetings, etc. Finally, another large aspect of his job is of a more global, community nature. Like many of his colleagues, he reviews the work of other scientists.  He is a member of various committees including those that make recommendations to funding agencies. He has numerous meetings each year, some of which require extensive travel. He travels to Washington D.C. several times a year, and has worked to raise awareness in congress concerning global issues relating to the ocean and our environment.

Finally, I asked Dr. Lukas if he had any advice for students interested in oceanography.  He replied that, “There is no such thing as too much math or science!”  One of his team members was nearby and commented that although math might seem boring in high school it becomes so important later on.  Dr. Lukas confirmed that it is a tool that allows scientists to accomplish a lot.  This is clearly evidenced by the work that he is able to complete.

Diana Griffiths, June 22, 2006

NOAA Teacher at Sea
Diana Griffiths
Onboard UNOLS Ship Roger Revelle
June 22 – June 30, 2006

Mission: Hawaiian Ocean Timeseries (WHOTS)
Geographical Area: Hawaiian Pacific
Date: June 22, 2006

Weather Data from Bridge 
Visibility:  10 miles to < 25 miles
Wind direction:  080°
Wind speed:  12 knots
Sea wave height: small
Swell wave height: 2-4 feet
Sea level pressure:  1016 millibars
Cloud cover: 5
Cloud type: cumulus, stratocumulus

 WHOTS –3 buoy during transfer from 2nd to 1st deck.

WHOTS –3 buoy during transfer from 2nd to 1st deck

The Cruise Mission 

The overall mission of this cruise is to replace a mooring anchored north of the Hawaiian island of Oahu. It’s called the WHOTS buoy: The Woods Hole Oceanographic Institution (WHOI) Hawaii Ocean Timeseries (HOT) Site (WHOTS). The mooring consists of a buoy that contains numerous meteorological sensors that collect data on relative humidity, barometric pressure, wind speed and direction, precipitation, short and long wave solar radiation, and sea surface temperature.  The buoy serves as a weather station at sea, one of few such stations in the world.

There are two of each type of sensor on the WHOTS-3 buoy to ensure that data collection will continue should a sensor break down.  The buoy is equipped with a GPS unit. The buoy also serves as a platform for observing the ocean. Hanging below the buoy are four different types of instruments.  These include SeaCATs, MicroCATs, an ADCP and NGVM. The SeaCATs and MicroCATs take salinity and temperature measurements.  The MicroCATs, in addition to salinity and temperature, also take depth measurements. There are several of each instrument attached to the mooring and they are located approximately 5 meters apart down to a depth of 155 meters.  (The WHOTS-2 mooring only contains MicroCATs). The ADCP or Acoustic Doppler Current Profiler is an instrument that allows the scientists to measure the velocity of the current at a set of specific depths. The NGVM is a New Generation Vector Measuring device that measures the velocity of the current at fixed points using propeller sensors located at 90° to one another. Finally, two Acoustic Release Devices are attached to the anchor that is holding the mooring in place.

 SeaCATs being prepared for mooring.

SeaCATs being prepared for mooring.

These instruments allow the scientists to determine the location of the anchor and will also mechanically release the mooring from the anchor when sent a specific acoustic signal. (More about how these work in a later log).  The WHOTS-2 mooring has been sitting in the ocean for a year collecting data.  It is powered by 4000 D-cell batteries and is capable of running off of them for about 16 months.  I asked Jason Smith, the lead instrument calibration technician, why solar panels weren’t used on the buoy and he told me that they are susceptible to being shot at or stolen.  Evidently anything that looks valuable in the middle of the ocean is vulnerable to theft!

Personal and Science Log 

R/V REVELLE’s resident technician, Cambria Colt, operating the crane used to move the WHOTS-3 buoy to the main deck of the ship.

R/V REVELLE’s resident technician, Cambria Colt, operating the crane used to move the WHOTS-3 buoy to the main deck of the ship.

After arriving in Hawaii on the afternoon of Monday, June 19th, it feels good to be at sea on a moving vessel.  I spent the remainder of Monday meeting the science crew from WHOI (Woods Hole Oceanographic Institution) led by the Chief Scientist, Dr. Robert Weller, having a nice dinner and falling asleep after a long day of travel.

Tuesday brought my first view of the REVELLE, a working science vessel owned by the SCRIPPS Institution of Oceanography in La Jolla, California. Go here for diagrams, pictures and statistics describing this ship. The ship has two platforms below the main deck and three decks above, not including the bridge. The main deck contains heavy equipment consisting of several winches, a crane, an electric winding cart and other machinery designed to move heavy objects. All of this equipment operation is run or overseen by Cambria Colt, the resident technician, who knows the ship like the back of her hand.  It is her primary job to act as a liaison between the ships’ crew and the scientists, making sure that the needs of the science team are met. We were at the ship by 7:30 a.m. and the team started working, preparing for the cruise.

Many of the team members had already been here for a week unloading and working with the instruments.  The team works well together – everyone keeps busy and seems to know what to do without a lot of discussion. I helped Jason to string up two GPS units on an upper deck of the stern of the ship as well as an antenna.

GPS units set up by science team on stern of R/V REVELLE.

GPS units set up by science team on stern of R/V REVELLE.

The antenna is used to transmit all of the data from the mooring and from the ship to a satellite, which then directs it to WHOI.  I also recorded measurements as Sean Whelan, the buoy technician, measured the distances from the top of the buoy to all of the instruments located on the buoy. He also wrapped bird wire repellant along the top of the tower of the buoy in an attempt to keep birds from landing on the instruments.  The bird wire is spiky wire that jets out in various directions and can be quite treacherous to work with!  Along the deck, Jeff Lord, an engineering technician, and Scott Burman, an undergraduate volunteer, worked on bolting down numerous winches to the deck that will be used to pull the buoy out of the water.  Several winches are used on all sides to maintain maximum control over whatever is being maneuvered into or out of the water.

I also met the captain of the ship, Tom Desjardins, in the afternoon.  I had no idea he was the captain when I first saw him, he was working hard on deck with the rest of the crew, clad in a T-shirt and shorts.  He is quite affable, calm, and willing to put in a hand where it is needed. In a quick discussion with him I learned that security has become much tighter on the ship since 9/11. There are always two people on watch at the entrance to the ship when it is in port making sure that everyone who enters and leaves is accounted for. We all wear badges when we are on ship when it is in port.  I also asked him about potable water use on the ship. The ship can hold 12,000 gallons of water and up to 3,000 gallons more can be distilled per day.  Heat from the ship’s engines is used to distill the water.

I had Wednesday free to do a bit of sightseeing and that leads me back to today.  We packed our clothes onto the ship early this morning and made up our berths (beds).  The staterooms (bedrooms) are larger than I had expected.  I have my own room and share a head (bathroom) with Terry Smith, another member of the team.  Terry is also an undergraduate who won the NOAA Hollings Scholarship to participate on this cruise.  Currently working towards a second career, Terry was a chef for 20 years before making the plunge to study science. She is working towards a degree in geo-oceanography.  During the day I was able to get a computer set up and mostly watched and asked a few questions as more work was being done. The ship left port at 4:00 p.m.  After taking a few pictures and watching the beauty of the coast slip away, I went back inside to attend a meeting led by Cambria and Dr. Weller.

Life Aboard Ship 

Cambria talked about safety and reviewed some basics about living on the ship.  We wear closed toed shoes at all times (except in our rooms), preferably steel-toed.  When we are working on deck during the scientific operations we will wear hard hats and safety vests.  Tomorrow there will be a safety drill at some point to be sure we all know where to “muster” and how to proceed should a fire or other problem occur on the ship.  We separate our trash here – anything plastic and non-biodegradable has a separate bin.  All of the paper and food waste, etc, has its own bin and is eventually tossed into the sea.  Meals are at specific times during the day (and they are quite good!) but we are asked to “eat and run”, as the galley crew needs to get on with their work of cleaning up and preparing for the next meal or just getting some time off.  The ship is equipped with a laundry and an exercise room.  Evidently on long cruises members of the crew can be seen running laps around the main deck.

Vocabulary – Weather Data 

Wind direction: Wind direction is measured in degrees, which follow the readings on a compass.

Wind speed:   Measured in knots. A knot is 1 nm/hr.  A nautical mile is the distance required to travel 1° longitude.  It is equivalent to 1.85 km.

Sea wave height: This is the height of waves produced by the wind.  This is logged in the ships log as either small or slight.  The technical formula for sea wave height is .026 x (speed of wind)2.

Swell wave height: This is the height of the swells produced by distant weather patterns. Swells form a wave pattern as opposed to sea waves, which are more random.  Swell wave height is measured in feet.