Rita Larson

August 19, 2009April 6, 2021

Rita Larson, August 19, 2009

NOAA Teacher at Sea
Rita Larson
Onboard NOAA Ship Rainier
August 10 – 27, 2009

Mission: Hydrographic Survey
Geographical Area of the Cruise: Kasitsna Bay, AK
Date: August 19, 2009

Weather Data from the Bridge
Latitude: 59° 28.339′N Longitude: 151° 33.214′W
Sea Water Temperature: 10°C (50°F)
Air Temperature: Dry Bulb: 11.1°C (52°F) Wet Bulb: 10.0°C (50°F)
Visibility: 5 miles

Science and Technology Log

I would like to give a very brief explanation of how surveying becomes a nautical chart. When all the surveying launches return to the Rainier, a debriefing meeting takes place in the wardroom. All the hydrographersin-charge or “Hicks” give a short discripition of the successes and complications they had during surveying for the day. At least one night processor attends these debriefing meetings to have a good understanding of what to expect as they process this data. Some of the things the night processors are looking for are: How many CTD (conductivity, temperature, depth) casts were made from each launch? Were there any data problems, such as noisy data or gaps in coverage? Then, the night processors collect the Hypack and Hysweep data from the launches and transfer the surveys to the ship’s computers where they will process it with CARIS. The night processors use the program CARIS to convert the “RAW” information from the launches into processed data. This processed data has correctors such as tide and SVP applied to it. This is completed in the plotting room on board the Rainier. The data is then cleaned and examined for problems.

This process produces a smooth image depicting the water depth over the area surveyed for the sheet managers. When this is complete, the sheet manager sets up for the next day’s acquisitions and polygon plans for all of the launches. Then, this information is sent to the Pacific Hydrographic Office to further examine the bathymetric data. After that, cartographers use this information to create nautical charts. The U.S. Coast Guard, U.S. Navy, as well as civilian mariners use nautical charts worldwide. This entire process may takes up to a year to complete.

These are various images of data completed during night processing. (Pictures taken by Nick Mitchell.) — Various images of data completed during night processing. (Pictures by Nick Mitchell.)

Personal Log

I am so amazed in the way the professionals from NOAA work together and share the responsibilities for the purpose of creating safety for others. By creating these nautical charts, it makes the waters of the world a safer place to be. Everyone on the ship has a meaningful purpose and it is clear to me that they take great pride in what they contribute in the mission of the Rainier. I feel like I belong here after such a short time.

Animals I Saw Today
A bald eagle in a tree using the large binoculars nicknamed, “big eyes” from the Rainier. I also saw a sea otter.

Nautical chart of the geographical area the Rainier is surveying at this time. — Nautical chart of the area the Rainier is surveying at this time.

August 15, 2009April 6, 2021

Rita Larson, August 15, 2009

NOAA Teacher at Sea
Rita Larson
Onboard NOAA Ship Rainier
August 10 – 27, 2009

Mission: Hydrographic Survey
Geographical Area of the Cruise: Kasitsna Bay, AK
Date: August 15, 2009

Weather Data from the Bridge
Latitude: 59° 36. 952′N Longitude: 151° 24. 490′W
Sea Water Temperature: 9.4°C (49°F)
Air Temperature: Dry Bulb: 13.3°C (56°F) Wet Bulb: 12.2°C (54°F)
Visibility: 10
Wind: Light

Science and Technology Log

I am deploying and retrieving the CTD. (Picture taken by Asst. Survey Tech. Nick Mitchell)

The one unique feature I witnessed here at Kachemak Bay is a phenomenon called glacial flour, which was mixed in with a very strong tidal rip current. If you can imagine a grayish white top layer almost like foam on a good cappuccino and as soon as you motor through it, you could see the normal clear Alaskan water underneath in its wake. There was a definite line between the outgoing bay waters and the in-coming seawaters. This was really awesome to see up close and for the first time! The Rainier uses specialized sonar systems and equipment, such as the CTD, which collects conductivity, temperature, and pressure samples. This instrument collects the necessary correction factors to aid in the post processing of the sonar data in determining the bottom depth. One factor that is considered while collecting bathymetric data is that fresh water is less dense than salty ocean water, so it will float or suspend on the top of the ocean water. Because these differences in sound speed through the water can have a major impact on the accuracy of the soundings generated by the sonar.

Mid-summer melting from snow capped mountains.

The CTD cast is used to detect these differences and measures the sound speed at various depths to correct the sonar readings. Another influence while collecting bathymetric data is glacial flour. Glacial flour is known as clay-sized particles of rock, generated by glacial erosion. This material is very small and creates a suspended silty covering over the ocean waters. While collecting data in Kachemak Bay, which is located in Cook Inlet, we experienced a current shift during high tide, which was heavily emerged with glacial flour. More than likely, the flour came from the Kenai Fjords Glaciers, which are located north of Homer, Alaska. Normally, during mid-summer, it is expected to flood and have high standing water in glacial areas. When the glaciers melt, the glacial flour also mixes with glacier till and erodes into the oceans. Since the glacier mix is fresh water, this blanket of glacial flour suspends on top of the ocean water until it becomes sediment on the bottom of the ocean floor.

Less dense fresh water suspended over the denser salty ocean water.

This is during high tide on August 15, 2009 with evidence of glacial till.

This is the same water; two hours later after the tides and currents had changed.

Personal Log

While surveying, it is hard to ignore the beauty that is all around you. When the sun is shining and the wind on your face, Alaska is just breathtaking. It is still hard to believe I am working in Alaska for NOAA all the way from Woodbridge, Virginia. Every day brings wonderful first-time experiences and I am so glad to be a part of it. It is nice to have this opportunity to become the captain of your destiny and navigate towards your own TAS (Teacher at Sea) adventures.

Here I am driving the launch! (Pictures taken by Seaman Surveyor, Steve Foye.)

New Term/Phrase/Word
Sailors use charts, navigational tools, and landmarks, to help find their way around the oceans. While surveying today, we came across a landmark called a “Lighted Day Mark” which signifies, on nautical charts, hazards or changes in the directions of channel patterns.

Did You Know?
Did you know that there are eight active volcanoes around Cook Inlet, Iliamna, Redoubt, Double Glacier, Spurr, Hays, Douglas, Four Peaked, and Mt. Augustine? Today, while we were surveying, Mt. Augustine was venting or letting out steam, gases, and ash. We were able to observe this volcanic activity through the binoculars. If you would like to see it visit the website.

A “Lighted Day Mark” landmark which signifies a hazard or change in the direction of channel patterns.

August 13, 2009April 6, 2021

Rita Larson, August 13, 2009

NOAA Teacher at Sea
Rita Larson
Onboard NOAA Ship Rainier
August 10 – 27, 2009

Mission: Hydrographic Survey
Geographical Area of the Cruise: Kasitsna Bay, AK
Date: August 13, 2009

RA-4 launch, one of the Rainier’s small boats

Weather Data from the Bridge
Latitude: 59° 28.515′N Longitude: 151° 33.549′W
Sea Water Temperature: 9.4°C
Air Temperature: Dry Bulb : 14.4°C (46°F); Wet Bulb: 12.2°C (54°F) (Dew Point)
Visibility: 10 miles

Science and Technology Log

The Rainer deploys launches or small boats such as the RA-4 that have different tasks assigned to them listed on the POD or the Plan of the Day. Today, our mission was to survey a section of the sea floor in Kachemak Bay. Once the survey has been completed, the raw data is processed and then is sent to other NOAA’s National Ocean Service divisions to create nautical charts of the sea floor for either updating for accuracy or created for the first time.

Each launch is equipped with multi-beam sonar devices. The crew is currently collecting bathymetric as well as backscatter data simultaneously. Backscatter data can be analyzed to categorize the bottom type of the sea floor indicating changing sediment types such as rock or mud. This information is of particular use to fisheries biologists, ecologists, and others who are interested in habitat mapping. The lead hydrographers are given a polygon region, which defines the area in which they are going to survey. This is what ours looked like for today:

This was our chart at the beginning of the day.

This is our chart after a hard days work!

Can you see what we surveyed? Yes, you are correct if you said the purple and green-blue mixture. The first step that was taken was putting a cast in the water, which is called a CTD and stands for Conductivity, Temperature, and Depth. The CTD is used to see the changes in sound velocity all the way to the bottom. This process is repeated at least every four hours for readings. This sound velocity data is used to correct the multi beam sonar data. The computer is able to translate the multi-beam sonar data in a 3-D image of the sea floor.

The CTD, which measures conductivity, temperature, and depth.

Personal Log

I am getting used to my routine living on a ship. The main idea is respecting others and their space. Listening to others and following the rules. Asking lots of questions will help you transition easily. Following others advice. Enjoying the company you are with. Having fun on every adventure that is given to you. I am learning so much, and each day I am feeling more and more comfortable here in my new home on the Rainier.

New Term/Phrase/Word

Wow, I am a student here on the Rainier! I am learning new words and terms everyday. Just today I found out a FISH is not an animal, but an instrument that is towed behind a boat on a cable and “swims” through the water. One example is a Moving Vessel Profiler or a MVP. This apparatus collects the same information as the CTD; however, it collects the information in real time. It is smart to have the CTD and the MVP on the launch to compare the same data to make sure it is correct.

This is a screen that is read by the hydrographers that shows the 3-D sonar images of the bottom of the sea floor. Today, some of our readings were more than 500ft deep. WOW!

When we survey a section of the sea floor that was previously surveyed that is called junctioning, or overlapping. Holidays are not the days on a calendar, but stands for “holes in the data”. That means after you survey a section of the sea floor, if there is a missed section on the computer screen you must go back and re-survey that area.

August 12, 2009April 6, 2021

Rita Larson, August 12, 2009

NOAA Teacher at Sea
Rita Larson
Onboard NOAA Ship Rainier
August 10 – 27, 2009

Mission: Hydrographic Survey
Geographical Area of the Cruise: Kasitsna Bay, AK
Date: August 12, 2009

Weather Data from the Bridge
Latitude: 59° 28.515′N Longitude: 151° 33.54′W
Sea Water Temperature: 9.4°C
Air Temperature: Dry Bulb: 14.4°C (58°F); Wet Bulb: 12.2°C (55°F)
Visibility: 10 miles
Wind: 06

The skiff RA-8 being launched from NOAA Ship Rainier.

Science and Technology Log

Last night (Aug 11, 2009) the P.O.D (Plan of the Day) was posted and I found out that I was assigned to work with the Survey Team. We would go out on the skiff identified as RA-8. We had a special guest that came with us today, Mr. Randall, from the NOAA Headquarters located in Silver Spring, Maryland was in Homer Alaska, so we drove RA-8 to Homer, Alaska to pick him up. Then we proceeded to Bear Cove to complete our main mission, which was to observe the tides and complete the leveling of the remote tide gauge. NOAA uses tide gauges to verify long-term assessment of sea level changes and establishes the vertical datum, or frame of reference, for their nautical charts. Mr. Randall was retrieving a GPS (Global Positioning System) unit that was planted in Bear Cove the previous day to collect data.

Our crew consisted of Matt Abraham, our coxswain, was responsible for driving the open skiff (RA-8). Our hydrographer in charge was ENS Schultz; she surveyed Bear Cove and retrieved the data from the tide gauge. Manuel Cruz and Tony Lukach were responsible for holding the leveling rods to help complete the survey. My responsibility was to write the data given to me and record it on the leveling sheets and find the difference between each measurement. Mr. Randall also worked with us throughout the day. While surveying we used a three-wired level that sits on a tripod, level rods, measuring tape, turtles, pencil, and a calculator.

Personal Log

I was so excited about this mission since it was my first one. I was very cold in the morning since we were a little bit wet from the spray of the ocean, even though I was dressed very warmly. By the afternoon I was only wearing a t-shirt and jeans. The scientists were telling me the last time they were at Bear Cove they actually saw a bear. So, I was looking around constantly to keep an eye out for them. At one point of the day I went with ENS Schultz to collect the initial tide measurements from the tide gauge and check the flow of the nitrogen gas to make sure it was operating smoothly. Little did I know that I had to climb a wooded hill to help collect this data. One has to be in great physical shape to perform these types of tasks. It was unbelievable to see such sophisticated equipment in such a remote area.

After observing these remarkable scientists doing their jobs in the middle of a mosquito-infested area, I applaud everything they do. I felt comfortable and I felt safe in their care. They are all so knowledgeable in their fields. One can really sense the teamwork that is needed for all the missions NOAA expects from them. I am proud and honored to be a part of the project called Hydropalooza, which provides a deeper understanding of Alaska’s Kachemak Bay.

New Term/Phrase/Word: Turtles in surveying are not animals. They are used as half way marks from the benchmark item to the surveyor. The ones we used were round and heavy with a silver handle on them. They are heavy for a reason, so they do not move once they are placed on the ground. Surveying is very important to this mission since the measurements must be within 2.5mm.

Animals Seen Today
Puffins and Sea Otters

Collecting data from the tide gauge in Bear Cove

As we were bringing Mr. Randall back to Homer we saw this glacier in the distance.