Kelly Dilliard: Sonobuoys and Gliders, June 4, 2015

NOAA Teacher at Sea
Kelly Dilliard
Onboard NOAA Ship Gordon Gunter

May 15 – June 5, 2015

Mission: Right Whale Survey
Geographical area of cruise: Northeast Atlantic Ocean
Date: June 4, 2015

Weather Data from the Bridge:

Air Pressure: 1025.1 mb
Air Temperature: 13.3 degrees C
Relative Humidity: 64%
Wind Speed: 13 knots
Wind Direction: 63 degrees

Science and Technology Log:

The sounds marine mammals make are often used to study them.  Dolphins make clicks and whistles whereas humpback whales mostly sing.  North Atlantic right whales also make sounds with their signature sound being described as an up-call, a rising whoop that lasts for about a second.  Sei whales, on the other hand make a down-call, a sinking whoop.  Right whales also make a variety of other sounds including: 1) eerie moans, 2) shrill screams which often occur when gathered in groups, and 3) a gunshot sound that sounds like a very loud pop and is thought to be an aggressive call towards males.  These sounds are not easily heard, but can be observed on a sound spectrogram.  A sound spectrogram is a graph of frequency (the number of cycles in a second, given as hertz) on the vertical axis and time on the horizontal axis.  Right whale up-calls range in the low hertz levels of 100-300 hertz, while dolphins are much higher in pitch.  The darker the call on the spectrogram, the louder the call is. To listen to a variety of right whale calls go to the Right Whale Listening Network for examples.

Right whale up-call on a spectrogram posted on the Northeast Fisheries Protected Species Branch website. Go to link to actually hear the call of a right whale and several other whale species.

Right whale up-call on a spectrogram posted on the Northeast Fisheries Protected Species Branch website. Go to link to actually hear the call of a right whale and several other whale species.

Close up of a right whale up-call on a spectrogram. Image from the Right Whale Listening Network.

Close up of a right whale up-call on a spectrogram. Image from the Right Whale Listening Network.

Sonabuoy
Sonobuoy tube.

Whale acoustics can be recorded by a variety of methods.  On this cruise we are using two methods: sonobuoys deployed from the ship and autonomous acoustic technology (aka “gliders”).  Let’s talk about sonobuoys first.  The sonobuoys used on this cruise were first designed for the military but have found a second use in scientific research.  They are housed in an aluminum tube about a meter in length and 10 centimeters in diameter.  When the tube hits salt water it starts a chain reaction starting with deployment of the bright orange float.  The sonobouy, with hydrophones, then bobs freely in the ocean and sends radio signals to an antenna high on the ship’s mast.  The signal is then captured by a computer and a spectrogram of the sound is displayed and recorded.  The sonobuoy has about an eight hour life span and a five mile range.

Sonobouy
Close up of the electronics panel of a sonobuoy.
sonobouy
Chris Tremblay, from the Northeast Fisheries Science Center, Passive Acoustic Group, deploying a sonobuoy to listen for sei whales off the stern of the Gordon Gunter.
sonobouy
A defunct sonobuoy out of the aluminum case. You can see the orange float, and the round hydrophone (in the upper left corner) attached to the purple netting.
sonobouy
Chris Tremblay analyzing the signal coming from the sonobuoy that was deployed.
sonobouy
Two sei whales with orange float of the sonobuoy located to the left of the whales.

There are some limits to sonobuoys, namely the five mile (or more depending on model and antenna location) range.  Doctors Baumgartner and Fratantoni at the Woods Hole Oceanographic Institution (WHOI) have developed a means of retrieving real-time detection of whale acoustics from autonomous acoustic gliders.  The particular glider used in the Great South Channel is a Slocum glider.  It looks a bit like a torpedo.  It is programmed to follow a specific track and come to the surface every two hours to send data.  The two researchers also developed a computer program that detects, classifies and reports interesting marine mammal calls otherwise the amount of data coming in would be completely overwhelming.  The Slocum glider also measures fluorescence and other oceanographic conditions, similar to the CTD.


View of the Slocum glider underwater. Photo from NE Fisheries, Protected Species Branch (Dave Fratantoni, WHOI).

How the slocum glider travels and sends data. (Autonomous Real-time Marine Mammal Detections, WHOI)

How the slocum glider travels and sends data.  (Autonomous Real-time Marine Mammal Detections, WHOI)

For more information on acoustics check out the following links:

Personal Log:

Today is the last full day on the ship and it is bittersweet.  I have had a wonderful time and will be sad to go (but also glad to get home).  I have learned so much about whales and the ocean.  I have met some absolutely wonderful people, both scientists and crew.  I am very grateful to all for incorporating me into their family.  I would love to do this again next year.

IMG_2503
NOAA Corps on this cruise. Back row: Operations Officer Ensign David Wang, Junior Officer Ensign Pete Gleichauf, Executive Officer Lieutenant Commander Colin Little, Augmenting Officer Lieutenant Junior Grade P.J. Klavon. Front row: Navigation Officer Ensign Kristin Johns, Junior Officer Ensign Melissa Mathes, Commanding Officer Captain Donn Pratt.

Even though we did not see the as many of the right whales that we wanted to, we did see several species including: humpbacks, sei whales, fin whales, minke whales, and Pete saw a sperm whale.  Yesterday (June 4th) we were deploying plankton nets encircled by a few dozen feeding humpback whales.  It was a spectacular show.

humpbacks
Two humpbacks feeding. Images collected under MMPA research permit #17355
humpback
Humback whale feeding. Images collected under MMPA research permit #17355.
Two humpbacks.  Images collected under MMPA research permit #17355.
Two humpbacks. Images collected under MMPA research permit #17355.
Humpbacks.  Images collected under MMPA research permit #17355.
Humpback feeding. Images collected under MMPA research permit #17355.
Humpback.  Images collected under MMPA research permit #17355.
Humpback. Images collected under MMPA research permit #17355.

And I will end with a sunset photograph.

Sunset
Sunset off the stern.

Christine Hedge, September 13, 2009

NOAA Teacher at Sea
Christine Hedge
Onboard USCGC Healy
August 7 – September 16, 2009 

Mission: U.S.-Canada 2009 Arctic Seafloor Continental Shelf Survey
Location: Chukchi Sea, north of the arctic circle
Date: September 13, 2009

Weather Data from the Bridge 
Latitude: 720 44’N
Longitude: 1560 59’W
Temperature: 350F

A Seasonal Ice buoy with a thermistor chain is deployed from the Healy. This buoy starts in open water and later may
A Seasonal Ice buoy with a thermistor chain is deployed from the Healy. This buoy starts in open water and later may freeze into the ice. This instrument collects ocean and air temperature data, barometric pressure data, and location data.

Science and Technology Log 

Buoys and Moorings And Gliders, Oh My!!! 
Exploring the oceans has a lot in common with exploring space.  NASA can send manned or unmanned missions into space.  Sending manned vehicles into space is more complicated than launching a probe or a telescope. The same is true for exploring the Arctic Ocean.  We can collect data on an icebreaker, manned with Coast Guard and science personnel or use instruments that can send back data remotely.  On this mission, many instruments have been deployed to send back data about the conditions in the Arctic. These instruments continue to do their work after the crew and scientists from the Healy have moved on.  Ice buoys, which float or freeze into ice floes, are one example.  The HARP instruments (High-frequency Acoustic Recording Package), which sit on the sea floor, are another.

A United States Navy team, under the supervision of Navy Commander William Sommer, has launched a very interesting instrument from the Healy called the Seaglider. We have been tracking its movements since it was launched on August 8th. The Seaglider collects information about the salinity, temperature, and optical clarity of the ocean. The Navy is interested in how sound travels through the oceans and this glider is an important tool for doing just that.

CDR Bill Sommer, AG1 Richard Lehmkuhl, and MST3 Marshal Chaidez deploy a Seaglider from the Healy in the Chukchi Sea. Data from the Seaglider will improve the performance, and aid in the evaluation, of the effectiveness of the ocean models in the Arctic. Photo courtesy of PA3 Patrick Kelley, USCG.
CDR Bill Sommer, AG1 Richard Lehmkuhl, and MST3 Marshal Chaidez deploy a Seaglider from the Healy in the Chukchi Sea. Data from the Seaglider will improve the performance, and aid in the evaluation, of the effectiveness of the ocean models in the Arctic. Photo courtesy of PA3 Patrick Kelley, USCG.

What makes the Seaglider unique is that instead of just drifting, it can be driven.  In fact, this instrument is directed via satellite from a computer lab in Mississippi!  The glider moves up and down in the water column and like an air glider it uses this up and down motion to move forward. It has a GPS and a radio so that it can communicate its location. The Seaglider deployed from the Healy in August was picked up today.

Final check of the Seaglider before it was launched.
Final check of the Seaglider before it was
launched.
The green dots indicate the path of the Navy Seaglider as it collected data in the Chukchi Sea.
The green dots indicate the path of the Navy Seaglider as it collected data in the Chukchi Sea.
Coast Guard and Navy personnel work together to retrieve the Seaglider on September 13.
Coast Guard and Navy personnel work together to retrieve the Seaglider on September 13.