chukchi sea – Page 2 – NOAA Teacher at Sea Blog

August 18, 2009April 6, 2021

Christine Hedge, August 18, 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: August 18, 2009

Weather Data from the Bridge
Lat: 80⁰ 32’N
Long: 154⁰ 04’ W
Temp: 28.72⁰ F

Science and Technology Log

Twice each day, AG1 (Aerographers mate 1^st class) Richard Lemkuhl launches a weather balloon. Today, at 6 AM I assisted with the launch. The balloon is filled with helium and attached to a device powered by a 9-volt battery. The weather balloon sends back temperature, pressure, and humidity data along with GPS derived winds to a radio receiver on the bridge of the Healy. This profile of the atmospheric conditions can be injected into global weather models to help predict the weather. On the Healy we use this information for flight operations (the helicopter). Helicopters, ships, and planes all need current weather conditions to navigate safely. Data from weather balloons can help determine if there might be icing, turbulence, wind driven ice or the possibility of thunderstorms.

FOR MY STUDENTS: All kinds of scientists use models to help explain, predict, and understand the world around them. Can you think of a model you have used in science?

Radio Receiver on the bridge of the Healy

AG1 Lemkuhl works for the Naval Maritime Forecast Center in Norfolk, Virginia. He is part of a group of U. S. Navy personnel on board the Healy to better understand how to operate Navy vessels in the Arctic. The dynamic weather patterns he experienced as a child in Oklahoma sparked his interest in meteorology. His very first weather balloon was launched in 8^th grade under the watchful eyes of Mrs. Stevens, his science teacher in Clarksville, Tennessee. AG1 enjoyed learning about Earth Science as a middle school student, which lead to studying geography and climatology in college. The Navy has added to his education and after a year of school he is currently an Assistant Operational Meteorologist.

FOR MY STUDENTS: What have you studied in school that has sparked your interest?

Personal Log

AG1 Lemkuhl holding the weather balloon instrument

Yesterday the sun came out and the sky was blue. What a difference that blue sky made! There isn’t much color in the Arctic – especially when it is foggy. The inside of the ship is tan. The ice and sky are white. Blue sky brought more people out on deck just to enjoy the color change. We also saw more seals out on the ice. Could it be that they like to bask in the sun as well?

Today, as we backed and rammed through 2.5 meters of ice, I saw my first fish! They were small, about the size of my palm. Could these be the Arctic Cod I have read about??

FOR MY STUDENTS: Look at my current latitude. What day will the sun finally set at this latitude???

AG1 Lemkuhl shows Mrs. Hedge how to launch a weather balloon.

Blue Sky in the Arctic! This is the CCGS Louis S. St. Laurent. The Healy is breaking ice for her.

August 13, 2009April 6, 2021

Christine Hedge, August 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: August 13, 2009

Weather Data from the Bridge
Long: 148⁰9.54199W
Lat: 78⁰17.31641N
Air Temp: 31.08 ⁰F

Science and Technology Log

A CTD, above, is much bigger than an XBT, which I’m holding in the picture below.

Sound waves travel at different speeds through different substances. If you look up the speed of sound in air you will find it to be about 300 meters/second, in water 1500 meters/second. But these numbers are not constants. In water, the temperature, the amount of salt, and the pressure can all impact how fast sound waves travel. In other words, all water is not created equal. Our mapping mission depends on data collected from bouncing sound waves off the sea floor. In order to get an accurate image of what the sea floor looks like and how deep it is – we need to measure precisely how fast the sound waves are traveling. This means we need to have a handle on any variable that might change the speed of the sound waves. Measuring the speed of sound in the water column is an important part of data collection for accurate mapping.

So, how does the Healy measure the speed of sound? Sometimes we use a Conductivity-Temperature-Depth instrument (CTDs). The ship needs to be stationary to deploy these instruments so they don’t happen very often while we are cruising. CTD measurements record conductivity of the water, which gives us the salinity (how much salt is in the water), temperature, and the depth at which these measurements were taken. Four times a day instruments called Expendable Bathythermographs (XBTs) are deployed off the moving ship. These XBTs measure the temperature as the device travels through the water. As pressure increases, (the deeper you go) the speed of sound increases. As temperature decreases, the speed of sound decreases. Four times a day the Healy science crew gets new data so that they can determine more precisely the speed of sound and therefore interpret what the sound waves are telling us.

Here I am deploying the XBT into the Arctic.

Today, MST-2 (Marine Science Technician) Daniel Jarrett let me participate in the deployment of an XBT. As the device travels through the water it sends back temperature data from different depths to a computer on board.

The data travels through a very thin copper wire attached to the instrument. A graph of this data is observed and that information is used to create a profile of the speed of sound in that part of the Arctic Ocean at that moment in time.

Personal Log

All the things I do at home also have to be done on board ship. I eat, sleep, shower, exercise, and do laundry. The food is excellent so far. I love not having to cook or plan meals. There is fresh fruit, a salad bar, and a huge hot breakfast every day. It will be a rude awakening when I return home and have to plan and cook meals again! My daily routine does not involve much physical activity and I worry about gaining weight while on board. In order to stay in shape, it seems everyone uses the gyms or runs on deck. I have been working out on the treadmill or elliptical every day faithfully to avoid a severe weight gain.

Was the data good? Did the deployment work?

The laundry and all other facilities are really nice. I have a 25-year-old washer/dryer at home and was pleasantly surprised to find state of the art, low-water-usage, front-loading washers on board the Healy. From what I can see the United States Coast Guard is working hard to become a “green” organization. Trash is separated and recycled when possible. People are encouraged to reduce their water usage. Extreme care is given to filtering and recycling wastewater and any kind of oil or lubricants. It is great to see the amount of thought and energy that is being put into helping the community on board the Healy to “walk lightly” on the Earth.

The Healy is very careful to treat the arctic with care

August 10, 2009April 6, 2021

Christine Hedge, August 10, 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: August 10, 2009

Science and Technology Log

This trip is all about data collection. In addition to our main seafloor mapping mission, each day there are buoys, sensors, or weather balloons deployed each collecting important data to help us understand the Arctic environment. This ocean is a harsh place. The objects that are placed underwater to collect data (like the HARP instruments that were retrieved earlier this week) need to be able to withstand cold, salt, pressure, and for those on the surface, wind and waves. Designing such a device to work for long periods of time in the Arctic must take great engineering skills.

The pressure of the deep ocean is an amazing force. If you have ever lost your goggles in the deep end of a pool – you know that water pressure increases with depth. Water is much heavier than air (about 1000 times heavier). Any instrument sent to the bottom of the Arctic Ocean is under a column of water that literally squeezes it with massive weight. In fact, the weight of just a 10 meter thick slice of ocean is equivalent to the weight of the entire atmosphere. Of course there is a scientific name for this increase of pressure due to the weight of the water above you. It is called hydrostatic pressure.

A simple experiment to illustrate the type of forces these scientific instruments endure involves Styrofoam cups! In fact, yesterday folks were encouraged to decorate a Styrofoam cup. The cups were gathered into a mesh bag and sent down 3800 meters attached to a device, which measures the conductivity, temperature, and depth of the water as it descends (a CTD).

Styrofoam cups after their trip on the CTD

Styrofoam can be thought of as plastic netting filled with air. This is why it is such a good insulator and so light. If we squeeze it with our hands, we can make the netting tighter and the Styrofoam becomes tight balls of plastic. If we lower the Styrofoam cups to great depths within the ocean – just think of the huge amount of hydrostatic pressure they are under!!!

The cups went to a depth of 3800 meters and shrank from about 4 inches to less than 2 inches! The weight of the water above them squeezed the air from the Styrofoam and gave us teeny cups – the shape didn’t change much – just the size. When engineers build instruments to study the ocean – such forces must be considered carefully.

Something to Think About

Besides diving into a swimming pool, can you think of another place in your world where pressure changes impact the environment?

Personal Log

I’m getting used to the life on board a ship. The crew is very helpful. They point me in the right direction when I get lost (which happens a lot) and help me to find basic comforts such as ice, the gym, and the laundry. I am amazed at how many doors I have to open and close to get from one place to another. The doors, designed to withstand water and fire, are heavy and take some upper body strength when we are in windy conditions.

They can also be very noisy and since someone is always sleeping on a ship that operates 24/7 we need to be considerate and move through them quietly. The further north we go the calmer the water gets. It is a real treat to walk out on deck and see the water smooth as glass, the blue and white ice chunks, and nothing but sky in front of us.