Tag: XBT

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Karen Matsumoto, April 27, 2010

NOAA Teacher at Sea: Karen Matsumoto
Onboard NOAA Ship Oscar Elton Sette
April 19 – May 4, 2010

NOAA Ship: Oscar Elton Sette
Mission: Transit/Acoustic Cetacean Survey
Geographical Area: North Pacific Ocean; transit from Guam to Oahu, Hawaii, including Wake Is.
Date: Friday, April 27, 2010

Science and Technology Log

In addition to the deployment of the acoustic sonobouys and monitoring of the towed hydrophone array, we also do “XBT” drops three times a day, at sunrise, noon, and sunset. The Expendable Bathythermograph (XBT) has been used by oceanographers for many years to obtain information on the temperature structure of the ocean. The XBTs deployed by the Sette research team measures temperature to a depth of 1000 meters.

The XBT is a probe which is dropped from a moving ship and measures the temperature as it falls through the water. Two thin copper wires transmit the temperature data to the ship where it is recorded for later analysis. The probe is designed to fall at a known rate, so that the depth of the probe can be inferred from the time since it was launched. By plotting temperature as a function of depth, the scientists can get a picture of the temperature profile of the water. It is amazing to think that over 1000 meters of thin copper wire is packed into that small tube! When I first launched an XBT, I was expecting to shoot it off like a rifle, but it actually just falls out of the unit by gravity. I was relieved that I didn’t experience “kick-back” from the probe unit when I pulled the lynch pin!

Chief Scientist Marie Hill preparing to launch the XBT unit.
XBT deployed and falling to a depth of 1000 feet.
Marie cutting the copper wire ending the connection to the probe and computer.

Bellow: Temperature and depth information is sent to the computer from the probe attached to the XBT unit by thin copper wires. The wires are cut when the unit reaches a depth of 1,000 meters, and the unit falls to the ocean floor. The researchers on the Sette use XBTs to obtain information on the temperature structure of the ocean, as seen on the computer screen at bellow.

We are continuing to conduct visual observations on the “Flying Bridge.” I had a chance to take a shift on the “Big Eyes” which are 25 x 150 magnification binoculars. The person at each of the Big Eye stations does a slow 90 degree sweep toward the bow and then back again, searching the ocean from horizon to ship to spot whales. I have a renewed appreciation for the skill it takes to use binoculars, especially one that weighs over 40 pounds! I had to use stacked rubber mats to be able to reach the Big Eyes at its lowest height setting, and even then it was a struggle to keep them steady every time we hit a wave! I think the Big Eyes were designed by the same people that made the huge Norwegian survival suits!

Karen on the “Big Eyes.”

Personal Log

The more I learn about sperm whales, the more I want to see one! I heard sperm whale clicks this morning, which was super exciting. John Henderson, a member of our science team sent me a cool website that shows an MRI of a juvenile sperm whale. I’ve included it below. Sperm whales are still on my wish list for whale sightings on this trip!

QuickTime™ and a decompressorare needed to see this picture.

MRI Image of a juvenile sperm whale. © 1999 Ted W. Cranford.
See website at: http://www.spermwhale.org/SpermWhale/spermwhaleorgV1.html

Question of the Day: How do sperm whales make their vocalizations? Sperm whale clicks are produced when air is passed between chambers in the animals’ nasal passages, making a sound that is reflected off the front of the skull and focused through the oil-filled nose. It has been suggested that powerful echolocation clicks made by sperm whales may stun their prey. Recent studies have shown that these sounds are among the loudest sounds made under water by animals (they can travel up to six miles despite being fairly high frequency).

Sperm whale clicks are heard most frequently when the animals are diving and foraging. These sounds may be echolocation (“sonar”) sounds used to find their prey, calls to coordinate movement between individuals, or both. Clicks are heard most frequently when the animals are in groups, while individual sperm whales are generally silent when alone. Most of the sounds that sperm whales make are clicks ranging from less than 100 Hz to 30 kHz

New Term/Phrase/Word of the Day: Expendable Bathythermograph or the XBT was developed in the 1960s by former The Sippican Corporation, today Lockheed Martin Sippican. Over 5 million XBT’s have been manufactured since its invention. The XBT is used by the Navy and oceanographic scientists to provide an ocean temperature versus depth profile. Some XBTs can be launched from aircraft or submarines, and have been used for anti-submarine warfare. How many XBTs do you think are on the bottom of the ocean?

Something to Think About:

“Thar she blows!” was the cry of the whaler!

Whale researchers can identify many whales by their “blows,” when the whale comes to the surface to breathe. Observers look for the direction and shape of the blow. For example, sperm whale blows are almost always directed at a low angle to the left, as their single nostril is located on the left side.

Grey whales, on the other hand, have two blowholes on the top of their head, and have very low heart-shaped or V-shaped blows, with the spray falling inwards. What do you think are you seeing when you see whale blows?

Animals Seen Today:

• Flying fish

Did you know?

Cetaceans evolved from land mammals in the even-toed ungulates group. The hippopotamus is most likely their closest living relative!

Picture of the Day

Abandon ship drill on the Sette!
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Jennifer Fry, July 26, 2009

NOAA Teacher at Sea
Jennifer Fry
Onboard NOAA Ship Miller Freeman (tracker)
July 14 – 29, 2009 

Mission: 2009 United States/Canada Pacific Hake Acoustic Survey
Geographical area of cruise: North Pacific Ocean from Monterey, CA to British Columbia, CA.
Date: July 26, 2009

Weather Data from the Bridge 
Wind speed: 10 knots
Wind direction: 100° [from the east]
Visibility: fog
Temperature: 13.5°C (dry bulb); 13.5°C (wet bulb)
Sea water temperature: 10°C
Wave height: 1ft.
Swell direction: 315° Swell height:  6 ft.

Here I am checking HAB samples.
Here I am checking HAB samples.

Science and Technology Log 

We conducted a number of HAB, Harmful Algal Bloom sample tests. The Harmful Algal Bloom test takes samples at predetermined location in our study area. The water is filtered to identify the presence of toxic plants (algae) and animals (zooplankton). The plankton enter the food chain specifically through clams and mussels and can be a possible threat to human health.

We also conducted XBTs, Expendable Bathythermograph; and one  fishing trawl net. The trawling was successful, catching hake, squid, and Myctophids.  Fishery scientist, Melanie Johnson collected specific data on the myctophids’ swim bladder.  The swimbladder helps fish regulate buoyancy.  It acts like a balloon that inflates and deflates depending on the depth of the fish. Sharks on the other hand have no swim bladder. They need to swim to maintain their level in the water. Marine mammals such as dolphins and whales have lungs instead of a swimbladder.  Most of the sonar signal from the fish comes from their swimbladder.  The study of the swimbladder’s size helps scientists determine how deep the fish are when using the sonar signals and how strong their sonar signal is likely to be.

Commander Mike Hopkins, LTjg Oliver Brown, and crewmember John Adams conduct a marine mammal watch on the bridge before a fishing trawl.
Commander Mike Hopkins, LTjg Oliver Brown, and crewmember John Adams conduct a marine mammal watch on the bridge before a fishing trawl.

The scientists tried to conduct a “swim through” camera tow, but each time it was aborted due to marine mammals in the area of the net. During the “Marine Mammal Watch” held prior to the net going in the water, we spotted humpback whales. They were observed breeching, spouting, and fluking. The humpback then came within 30 feet of the Miller Freeman and swam around as if investigating the ship.

Animals Seen Today 
Fish and animals trawled: Hake, Squid (Cephalopod), and Myctophids.
Marine Mammals: Humpback whale.
Birds: Albatross, Fulmar, and Shearwater.

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Jennifer Fry, July 19, 2009

NOAA Teacher at Sea
Jennifer Fry
Onboard NOAA Ship Miller Freeman (tracker)
July 14 – 29, 2009 

Mission: 2009 United States/Canada Pacific Hake Acoustic Survey
Geographical area of cruise: North Pacific Ocean from Monterey, CA to British Columbia, CA.
Date: July 19, 2009

The XBT (Expendable Bathythermograph)
The XBT (Expendable Bathythermograph)

Weather Data from the Bridge 
Wind speed: 42 knots
Wind direction: 350°from the north
Visibility: clear
Temperature: 11.4°C (dry bulb); 10.4°C (wet bulb)

Science and Technology Log 

The seas are still very rough with 40 knot winds. No fishing trawls due to the high waves and heavy seas. However, despite the rough seas, we were able to conduct an XBT, which stands for Expendable Bathythermograph.  An XBT is a measuring apparatus consisting of a large lead weight connected to a very thin copper wire. The function of the XBT is to measure the temperature throughout the water column.  It is launched off the stern (back) of the ship. As it sinks to the sea floor, temperature data is transmitted to an onboard computer.

Biologist Chris Grandin prepares to launch an XBT
Biologist Chris Grandin prepares to launch an XBT

Personal Log 

The Miller Freeman is an NOAA research vessel.   Here’s a bit of information about the Miller Freeman…For more information go here. The Miller Freeman is a 215foot fisheries and oceanographic research vessel and is one of the largest research trawlers in the United States. Its primary mission is to provide a working platform for the study of the ocean’s living resources. The ship is named for Miller Freeman (1875-1955), a publisher who was actively involved in the international management of fish harvests. The ship was launched in 1967, but not fully rigged until 1975. The vessel was again re-rigged in 1982. Its home port is Seattle, Washington.  It is capable of operating in any waters of the world. The ship has 7 NOAA Corps officers, 27 crew members, and maximum of 11 scientists.

Following is a “tour” of the ship.  It has many nice amenities for extended life at sea.

The Laundry Room - Here’s where we do our laundry. The laundry room is located in the bow/front of the ship which bounces up and down a lot, so you can feel pretty sea sick if you’re up there too long.
The Laundry Room – Here’s where we do our laundry. The laundry room is located in the bow/front of the ship which bounces up and down a lot, so you can feel pretty sea sick at times.
The Kitchen - Our 3 amazing cooks, Bill, Larry, and Adam, work hard preparing 3 meals a day for over 30 people. They have quite a difficult and detailed job.
The Kitchen – Our 3 amazing cooks, Bill, Larry, and Adam, work hard preparing 3 meals a day for over 30 people. They have quite a difficult and detailed job.
The Galley - This is where we enjoy deliciously prepared meals.
The Galley – This is where we enjoy deliciously prepared meals.
The Library - Pictured here is the ship’s library where crew members can read and check e-mail.
The Library – Pictured here is the ship’s library where crew members can read and check e-mail.
The Lounge - Here’s the lounge where movies and video games can be watched.
The Lounge – Here’s the lounge where movies and video games can be watched.
The Gym - The gym is located on the lowest level of the ship. This is where you can work off the great food that you’ve eaten.
The Gym – The gym is located on the lowest level of the ship. This is where you can work off the great food that you’ve eaten.

The Gift of Patience 
Wending our way through the North Pacific Ocean,
The massive waves crash against our hull with Herculean strength
As high as a one story building, their tops are dolloped with luscious whipped cream
They take their turn crashing against the ships sturdy hull, as gale force winds whip wildly past.
We play a waiting game. We practice the ancient art of patience.
When will we have hake, the silvery, slender fish that evades our sonar?

As the winds blow, cold sea spray stings my face.
I watch as the never ending line of waves wait their turn to hit the ship’s hull.
The waves wait patiently as do we.
The sea teaches us serenity.
We must not show greed or impatience.
The sea will provide.
One should lay empty and open waiting for the gifts from the sea.

~Inspired by Anne Morrow Lindberg’s Gifts from the Sea

NOAA Ship Miller Freeman
NOAA Ship Miller Freeman