Avery Marvin: Is it an Island or Just an Ink Blot? July 16, 2013

NOAA Teacher at Sea
Avery Marvin
Aboard NOAA Ship Rainier (NOAA Ship Tracker)
July 8 — 25, 2013 

Mission: Hydrographic Survey
Geographical Area of Cruise: Shumagin Islands, Alaska
Date: July 16, 2013

Current Location: 54° 55.8’ N, 160° 09.5’ W

Weather on board: Overcast skies with a visibility of .5 nautical miles, South wind at 18 knots, Air temperature: 10°C, Sea temperature: 7.2°C, 1-2 foot swell

Science and Technology log: Shoreline Verification

When you think of a shoreline, you might think of a straight or curved “edge” made of sandy beaches that gradually retreat into deeper and deeper water.  In the Shumagin Islands, a sandy cove is a rare occurrence and a place for a beach party! Towering, jagged cliffs patched with Artic moss and blanketed by a creeping fog are the typical “edges” here.  Below the cliffs in the water, lie sporadic toothed rocks and beds of dense rooted bull kelp, swaying with the current. As I sit on the edge of the skiff (small dingy-like boat), which gently trudges along the outside of the protruding rocks, I think to myself “Is this what Ireland is like?” or is this a world unto its own-untouched and solitary? Whatever it is, this place evokes an ethereal mood and you really feel like you are in one of the most remote places in the world.

Rocky shoreline of Nagai Island

Rocky shoreline of Nagai Island

Navigating through Bull Kelp bed

Navigating around Bull Kelp bed

Picture of skiff offshore

Picture of skiff offshore

Remote it is and that is why we are here. These are for the most part, uncharted or poorly documented waters and shorelines and in this post, I am going to talk about the shoreline aspect.  Besides taking bathymetric data (depth data), hydrographic ships like the Rainier must also verify that the shorelines of various land-masses are portrayed accurately and that all necessary “features” are documented correctly on nautical charts.  Features include anything that might be a navigational hazard such as rocks, shoals, ledges, shipwrecks, islets (small islands) and kelp beds. For shoreline verification, a 19 foot skiff is used for maneuverability and shallow water access. This boat will go out during the “shoreline window”, when the tide is the lowest, with the hopes that if there is a dangerous feature present, it will be visible above the water. In the best case scenario, we can investigate the shoreline fully with the skiff before sending in the bigger launches to survey the area with the sonar, so that we know they won’t hit anything.

Shoreline verification crew


Shoreline verification crew. From left: Randy (Coxswain), John (NOAA Corps. Officer), Chief Jacobson (Chief Survey Tech), Avery (Teacher at Sea)

Shoreline verification crew hard at work

Shoreline verification crew hard at work. From left: Randy (Coxswain), John (NOAA Corps. Officer), Chief Jacobson (Chief Survey Tech), Steve (NOAA Corps. Officer)

The main goal of the scientists aboard the skiff is to establish a “navigational area limit line” (NALL). This is a boundary line delineating how far off shore the launch boats should remain when they are surveying.  This boundary line is obtained in one of three ways:

1) presence of a navigational hazard such as a dense kelp bed or several protruding rocks

2) a depth of 4 meters

3) distance of 64 meters to shore

Whichever of these is reached first by the skiff will be the navigational area limit line for the launches.  Here in the Shumagins, kelp beds and rocks have been the boundary line determinant and often these hazards are in water that is deeper than 4 meters because we have been encountering these before we get within 64 meters of the shoreline.

While scientists are determining the NALL, they are also verifying if certain features portrayed on older charts are in fact present and in the correct location. Using navigational software on a waterproof Panasonic Toughbook, they bring up a digitized version of the old chart of a specific survey area. This chart depicts features using various symbols (asterisk=rock above water, small circle=islet). This software also overlays the boat’s movement on top of the old chart, allowing the boat to navigate directly to or above the feature in question.

Shoreline map 1

Shoreline map showing course of skiff, shoreline buffer, and feature for examination.

Shoreline map 2

Shoreline map showing charted location of islet and the actual location of islet determined by the skiff.

If the feature is not visually seen by the human eye or the single beam sonar on the skiff, it will be “disproved” and a picture and depth measurement will be taken of the “blank” location. If the feature IS seen, more data will be recorded (height of feature above the water, time of day observed, picture) to document its existence.  This same verification procedure is used for newfound features that are not present on the old charts.  All of this data is written on a paper copy of the chart and then back in the “dry lab”(computer lab), these hand-written notes are transferred to a digital copy of the chart.

Section of shoreline showing data and notes about specific features in question

Section of shoreline showing data and notes about specific features in question

Digitized version of notes and data taken at field site Note: Kelp buffer are the large shaded red areas and the smaller red circle is the actual position of the islet

Digitized version of notes and data taken at field site. The black box corresponds to the area from the previous picture above.
Note: Kelp buffers are the large shaded red areas and the smaller red circle is the actual position of the islet. The three southernmost rocks (marked by red asterisks) inside the black box were disproved.

On the two shoreline verification adventures I went on, many rocks and islets were disproved and several new features were found. Most of the new features were rocks, islets or large kelp beds.  It is important to note that if scientists find a new feature which is a serious present navigational hazard (ex. Shipwreck, huge jutting rock or shoal far offshore) it will be marked a DTON (Danger to Navigation) and communicated to mariners within a short time frame. Other less significant features take 1-2 years to appear on updated nautical charts.

For some survey areas, the Rainier uses aircraft-acquired LiDAR (Light Detection And Ranging) to get an initial idea of various features and water depths of a shoreline area. (This is a service that is contracted out by NOAA.) LiDAR data is obtained by a plane flying over an area at 120 mph, emitting laser beams to the water below. Like SONAR, LiDAR measures the time it takes for the laser beam to return to its starting point. Using this measured time and the speed of light, the distance the light traveled can be obtained, using the equation distance = speed*time, accounting for the fact that it travels through air and then water.  Because light travels much faster than sound, the plane can travel significantly faster than a boat and a large area can be surveyed faster.  Unfortunately LiDAR can only be used in clear, calm water because light is easily reflected by various solids (silt in the water, floating wood), specific color wavelengths (ex. White foam on ocean surface) and absorbed by biological specimens for photosynthesis (ex. Surface bull kelp).  LiDAR surveys do reduce the time hydrographers spend at a shoreline site thus increasing the safety and efficiency of an operation.  As with any data acquisition method, it must be cross-checked by another method and in this case because of the obvious downsides, it is used as a guide to shoreline verification.

Map of island showing LIDAR data.

Map of island showing LiDAR data. The skiff does shoreline verification outside the orange line that outlines the island. Everything inside this orange island was surveyed by the LIDAR airplane. The three orange features circled in red on the southeast section of the island, need to be re-surveyed by the skiff. Different colors show various depths. (Green is more shallow than light blue.)

After spending several days “disproving” a lot of rocks and islets that were clearly not present in their identified location, we started to wonder why someone would have thought there was a specific feature there. One possibility is that it was just an ink blot on the original chart, made by accident (from a fountain pen), and then interpreted as a rock or islet in the process of digitizing the chart. It’s better to be safe than shipwrecked! Another possibility is that these features were “eyeballed” in their documented location, and thus were present but just in the wrong spot.  Lastly because of limitations previously mentioned, LiDAR occasionally mis-reports features that are not present. Fortunately, our current survey methods use sophisticated navigational technology and several cross-checks to minimize data errors.

After shoreline verification has been completed, launches can survey the ocean floor (using SONAR) outside the boundary (NALL) that was established by the skiff. Each launch will be in charge of surveying specific polygons (labeled by letters and names). The picture above shows the polygon areas which are outlined in light orange (most are rectangles). I will talk more about SONAR and surveying on the launch in my next post. 🙂

Personal log:

I have been on the skiff two times now helping with the shoreline verification process. After the second time around and a chat with the XO Mike Gonsalves, my understanding of this process is more fine-tuned. It feels good to reach this point and it reminds me of the need to be patient, diligent and okay with the unknown when learning something new. I, like my students, often seek answers and a deep understanding of complex topics immediately and if this doesn’t happen I can get frustrated with myself. I have been more self-forgiving aboard the Rainier because I know I will be exposed to the same topic or process once again either in a different format or with a different set of crew members. I am also surrounded by a group of tolerant people who continually answer my questions with grace and peak my interest with new ideas.  This repetition of content and supportive network is crucial for any learning environment, whether it be on a ship or in a classroom.  Additionally, I have been given several small but important tasks which make me feel like a part of this group and complex operation.  This empowerment inspires me to learn more and continue contributing. Building a successful classroom community is no different than what is going on here on the Rainier. All students need to have a stake in their learning and a purpose for coming to class each day.

One of my small tasks aboard the skiff during the shoreline verification was to take pictures of the various features (rocks, islets etc.) that needed to be examined.  In some cases, it was important to photograph specific biological features that had an effect on navigation.  For example, when rounding the SE side of Chernabura Island we came across a large Stellar Sea Lion rookery inhabiting a small rocky islet. The male proudly stood in the center, surrounded by about 50 females.  As seen in the picture, this was a hefty male who easily weighed upwards of 1200 pounds. (Males can get as big as 2,500 pounds.)  During the breeding season (June-August), the male will fast and often won’t leave his reproductive rookery site. His primary focus is to defend his territory and spread his genes! Even though male Stellar Sea Lions are polygamous, they do not force the females into a harem but rather control the boundaries around their physical territory where within, the females reside.  The most successful rookery territories, not surprisingly are small rocky islands which can remain stable and productive for up to two months.

Stellar sea lion reproductive rookery

Stellar sea lion reproductive rookery

After researching about the Stellar Sea Lion, I learned that the western stock which resides in the Aleutian Islands is listed as an endangered species (since the 1970’s populations have declined by 70-80%). The cause for this is complex and has been attributed to a range of factors including: overfishing of sea lion prey (ex. Herring, Pollock), predation by Orca whales, shooting by fisherman, and disease.  Interestingly, a few native Alaskan communities are still permitted to hunt Stellar Sea Lions for subsistence (survival) purposes.

Stellar Sea Lion Range   Note, the two different stocks (Western and Eastern)

Stellar Sea Lion range

Fun factoid: The Stellar Sea Lion was named after the naturalist, George Wilhelm Stellar who first discovered the species in 1741 while part of Bering’s tragic voyage across the uncharted North Pacific.

Jacquelyn Hams: 14 November 2011

NOAA Teacher at Sea
Jackie Hams
Aboard R/V Roger Revelle
November 6 — December 10, 2011

Mission: Project DYNAMO
Geographical area of cruise: Leg 3, Eastern Indian Ocean

Date: November 14, 2011

Weather Data from the R/V Revelle Meteorological Stations

Time: 1045
Wind Direction: 262.60
Wind Speed (m/s): 135.8
Air Temperature (C): 28
Relative Humidity: 79.7%
Dew Point: (C): 24.20
Precipitation (mm): 42.4

PAR (Photosynthetically Active Radiation) (microeinsteins): 1101.5
Long Wave Radiation (w/m2): 410.3
Short Wave Radiation (w/m2): 192.5

Surface Water Temperature (C): 29.8
Sound Velocity: 1545.1
Salinity (ppm): 34.8
Fluorometer (micrograms/l): 0.2
Dissolved Oxygen (mg/l): 2.8
Water Depth (m): 4637

Wave Data from WAMOS Xband radar

Wave Height (m) 1.3
Wave Period (s): 13.2
Wavelength (m): 236
Wave Direction: 2800

Science and Technology Log

Ocean Mixing

All about CTDs

A CTD is a standard instrument used on ships to measure conductivity, temperature and depth. Three CTD systems are being used during Leg 3 of Project DYNAMO to measure CTD.

  • The Revelle deploys the ship’s CTD twice a day to a depth of 1,000 m. The CTD measurements can be viewed on a monitor in the computer room.
Ship's CTD

Ship's CTD

Ship's CTD in water

Ship's CTD in water

Ship's CTD data display

Ship's CTD data display

Data obtained from the ship's CTD

Data obtained from the ship's CTD

  • The Ocean Mixing group is using a specialized profiling instrument that was designed, constructed, and deployed by the microstructure group at the College of Oceanic and Atmospheric Sciences, Oregon State University. The instrument, called “Chameleon”, measures CTD and turbulence. Chameleon takes continuous readings to a depth of 300 m as it is lowered through the water column. The top of the instrument has brushes to keep the instrument upright in the water and make it hydrodynamically stable so that very precise measurements of turbulence can be achieved. These measurements allow computations of mixing, hence the name Ocean Mixing Group. The instrument freely falls on a slack line to a depth of 300 m after which it is retrieved using a winch. The Chameleon has been taking continuous profiles at the rate of about 150/day since we have been on station and will continue taking measurements for the next 28 days.
Photograph of Chameleon

Photograph of Chameleon

Close-up of Chameleon's sensors

Close-up of Chameleon's sensors

Data obtained from the Chameleon
  • The T Chain CTD aboard the ship was also designed by the microstructure group at the College of Oceanic and Atmospheric Sciences, Oregon State University. This instrument measures CTD in the near-surface (upper 10 m) using bow chain-mounted sensors (7 Seabird microcats + 8 fast thermistors). The T Chain takes data every 3 seconds, and although that is not very fast, the data is extremely accurate (within 1/1000th of a degree – 3/1,000th of a degree). The T Chain is mounted on the bow and has been taking measurements continuously since we have been on station. These measurements focus on the daytime heating of the sea surface and the freshwater pools created by the extreme rainfall we have been observing and which is associated with the MJO.
Photograph of T Chain

Photograph of T Chain

Data obtained from T Chain

Data obtained from T Chain

NOAA High Resolution Doppler LIDAR (Light Detection And Ranging) Group

A Brief Introduction to LIDAR

The following introduction to LIDAR systems was provided by Raul Alvarez.

In LIDAR, a pulse of laser light is transmitted through the atmosphere. As the pulse travels through the atmosphere and encounters various particles in its path, a small part of the light is scattered back toward the receiver which is located next to the transmitter. (You may have seen similar scattering off of dust particles in the air when sunlight or a laser pointer hits them.) The particles in the atmosphere include water droplets or ice crystals in clouds, dust, rain, snow, aircraft, or even the air molecules themselves. The amount of signal collected by the receiver will vary as the pulse moves through the atmosphere and is dependent on the distance to the particles and on the size, type, and number of particles present. By keeping track of the elapsed time from when the pulse was transmitted to when the scattered signal is detected, it is possible to determine the distance to the particles since we know the speed of the light.

Once we know the signal at each distance, it is now possible to determine the distribution of the particles in the atmosphere. By measuring how the light was affected by the particles and the atmosphere between the LIDAR and the particles, it is possible to determine things such as the particle velocity which can yield information about the winds, particle shape which can indicate whether a cloud is made up of water droplets or ice crystals, or the concentration of some atmospheric gases such as water vapor or ozone. The many kinds of LIDARs are used in many different types of atmospheric research including climate studies, weather monitoring and modeling, and pollution studies.

Typical lidar signal as a funciton of range

Typical lidar signal as a function of range

Photograph of Ann and Raul inside the LIDAR van.

Photograph of Ann and Raul inside the LIDAR van.

Raul explains the inner workings of LIDAR aboard the ship. From left to right: 1st photo shows Raul and the LIDAR system; 2nd and 3rd photos display the optical components of the LIDAR; 4th photo is the rotating scanner base.

Raul explains the inner workings of LIDAR aboard the ship. From left to right: 1st photo shows Raul and the LIDAR system; 2nd and 3rd photos display the optical components of the LIDAR; 4th photo is the rotating scanner base.

The four cone-shaped devices are differential GPS antennae used to correct for the motion of the boat.

The four cone-shaped devices are differential GPS antennae used to correct for the motion of the boat.

An integrated motion compensation system is used to stabilize the scanner to maintain pointing accuracy. As you can see from the video below, the scanner maintains its position relative to the horizon while the ship moves.

The slides below represent a Doppler LIDAR data sample from Leg 3 of the Revelle cruise. The images and slides were provided courtesy of Ann Weickmann.

Image credit: Ann Weickmann

Image credit: Ann Weickmann

Image Credit: Ann Weickmann

Image Credit: Ann Weickmann

Image credit: Ann Weickmann

Image credit: Ann Weickmann

Image credit: Ann Weickmann

Image credit: Ann Weickmann

Image credit: Ann Weickmann

Image credit: Ann Weickmann

Personal Log

The R/V Revelle is not a NOAA ship. It is part of the University-National Oceanographic Laboratory System (UNOLS) and part of the Scripps Institution of Oceanography research fleet. A few crew members were kind enough to take time from busy schedules to talk with me about their careers. Students may find these interviews interesting especially if they are exploring career options.

The food aboard the Revelle is very good thanks to our cooks, Mark and Ahsha. They are very friendly crew members and always happy to accommodate the diverse eating schedules of scientists who have to work during meal hours.

Mark Smith, Senior Cook

Mark Smith, Senior Cook

Ahsha Staiger, Cook

Ahsha Staiger, Cook

Meanwhile back on the winch, I am beginning to get the hang of it. I will not say that I am comfortable, because I am always aware that I am in charge of a very expensive piece of equipment. I alternate between operating the winch, operating the computer, standby time (to assist as needed) and free time.

Jackie on the computer in the Hydro lab.

Jackie on the computer in the Hydro lab.

Dramatic cloud formation at sunrise.

Dramatic cloud formation at sunrise.

Kirk Beckendorf, July 31, 2004

NOAA Teacher at Sea
Kirk Beckendorf
Onboard NOAA Ship Ronald H. Brown

July 4 – 23, 2004

Mission: New England Air Quality Study (NEAQS)
Geographical Area:
Northwest Atlantic Ocean
Date:
July 31, 2004

Daily Log

This will be my last day in New England with NEAQS-ITCT. Tomorrow morning I leave my hotel at 3:00 AM to drive to the airport to fly home to Oregon. The past month has been an amazing experience. I have been continually amazed at the complexity, cooperation and coordination involved in this massive air quality study. I have seen that the scientists are an extremely intelligent and hardworking group of men and women. They are truly committed to obtaining a thorough and accurate understanding of our global society’s air pollution problem so that solutions can be obtained.

Today Fred took me onto the WP-3, another of NOAA’s planes being used in NEAQS. Unlike the DC-3 which only has a LIDAR on board, the P3 is packed with many different scientific instruments. To be able to make as many measurements as possible, equipment is also attached underneath the wings, under the fuselage and even sticking out from the tail is a special cloud radar. The windows and body have been modified so that specially designed tubes stick out and suck air from the outside and feed it to the instruments inside the plane. Once we have climbed up the ladder and are inside, we can barely get passed the door.

In a couple of hours the P3 will take off for a night flight, but right now the plane is not only packed with the equipment, it is also packed with scientists making last minute adjustments to their instruments. Because there are so many air quality measurement instruments on board, there is very little room for people during the flight. Therefore the instruments need to be ready to run on their own with very little supervision.

Much of the equipment is similar to that found on the BROWN, but the plane will obviously be taking measurements higher in the atmosphere and over a larger area in a shorter amount of time, than can the BROWN. Also, because the plane is traveling a lot faster than the BROWN, if a measurement is made every 30 seconds and the P3 passes through a narrow plume of pollution the plume may not even be measured. It is therefore important for the measurements to be made very quickly and often.

The flight is intentionally leaving late in the day so that most of the flight will be after sunset. Sunlight is necessary for a lot of the chemical reactions that cause pollutants to change once they are in the air. Tonight’s flight is designed largely around a single instrument measuring the specific chemicals that are more likely to be in the atmosphere at night. During the day the sunlight breaks these chemicals down, yet they are a very important part of the pollution problem.

Since the beginning of July until about the end of August, for almost two months, the men and women involved in NEAQS will be making measurements from airplanes, from the BROWN, from satellites, from the top of Mt. Washington and other spots on land. But when I asked Fred what is the one thing my students should know about this project, he said that they need to realize that the real work starts after everyone is out of the field. The “Ah-ha” moments will occur over the next 8 -12 months as the data is being analyzed, that is when the real learning and understanding will happen.

Finally I would like to thank all of the scientists who were so generous, cooperative and patient with my many questions.

Kevin McMahon, July 30, 2004

NOAA Teacher at Sea
Kevin McMahon
Onboard NOAA Ship Ronald H. Brown

July 26 – August 7, 2004

Mission: New England Air Quality Study (NEAQS)
Geographical Area:
Northwest Atlantic Ocean
Date:
July 30, 2004

Weather Data from the Bridge
Lat. 42 deg 37.86 N
Lon. 70 deg 12.37 W
Speed 8.6 kts
Barometer 1018.96 mb
Rel Humidity 93.16%
Temp. 18.9 C

The seas are calm. The skies have a distant haze. The New England atmosphere so common at this time of year. As is usual for the day, at 0700 we sent aloft a radiosonde, and then at 1000 an ozonesonde.

I was lucky enough to see a couple of finback whales; but unfortunately I had left my camera on my bunk, before beginning a discussion with Drew Hamilton about alternative power generation. Many of the scientists lead very diverse lives. Drew has a house in Seattle and wants to get off the electrical grid. He has worked for NOAA for 25 years and has seen much of the world. Thirty years ago he started out at the University of Miami, never in a thousand years dreaming he’d be involved in the kind of research he’s doing.

Ever hear of di-methyl sulfide DMS? As chemistry teacher I’d heard the name but never understood its significance to the atmospheric work the scientist aboard the ship are undertaking. It turns out that di-methyl sulfide is produced by plankton and is part of a planktons waste process. DMS is one of the major contributors of atmospheric sulfur. Overly high levels in the atmosphere can act as a reflective unit not allowing enough sunlight through our atmosphere. As a result, in certain areas the Earth does not receive the needed heat for some of the biological processes to take place.

Weather Data from the Bridge
Lat. 43 deg 17.84 N
Lon. 69 deg 33.83 W
Speed 9.3 kts
Barometer 1018.3 mb
Rel Humidity 86.16%
Temp. 20.65 C

1530 hours and there seems to be a flurry of activity among many of the scientist. A radiosonde is being rapidly readied to be sent aloft. It seems that the ship has reached a position somewhat east of Portland, ME and we have found a plume of ozone. The initial spike on the instrumentation showed 80-85 ppb (parts per billion) but then it jumped again to 101 ppb. This spike in the ozone was enough to request that another ozonesonde be readied and sent aloft. They have also requested a fly over by the DC3 out of Pease. Onboard the DC3 is a LIDAR (Light Radar) which measures atmospheric ozone. I am told that the cost of one ozonesonde is approximately one thousand dollars, so I assume that the readings on the instrumentation are justifying the expense. It will be interesting to see what they all have to say at the evening science meeting which is held each evening at 1930 hours.

We seemed to have found a large plume of ozone. It is as everyone, the science staff at least, had assumed. We have indeed found a large plume of ozone.

1930 hours. We are now heading in a westerly direction for Cape Elizabeth, ME.

Kathy Virdin, July 25, 2004

NOAA Teacher at Sea
Kathy Virdin
Onboard NOAA Ship Rainier

July 20 – 28, 2004

Mission: Hydrographic Survey
Geographical Area:
Eastern Aleutian Islands, Alaska
Date:
July 25, 2004

Latitude:55degrees 17.215 N.
Longitude: 160 degrees 32.231 W.
Visibility:1 nautical mile
Wind direction:140 degrees
Wind speed: 10 kts.
Sea wave height: 0-1 ft.
Swell wave height: 2-3 ft.
Sea water temperature:10 degrees C.
Sea level pressure: 997.4 mb.
Cloud cover:Cloudy, light rain

Science and Technology Log

Today we had a visitor from Tenix Lads, Inc. named Mark Sinclair who does LiDAR depth readings for NOAA. LiDAR means light detection and ranging. It is done from a small aircraft, flying at an altitude of 1800-2200 ft. They over fly an area with two laser beams that measure the surface of the water and the depth of the water. They get the difference in these heights, with geometric corrections for tides and other factors, to give them the ocean floor depths. They are able to take an incredible 324 million soundings in an hour! Their information is used for nautical charting, coastal zone management, coastal engineering, oil and gas development, military applications and research and development. They will identify depths, buoys, beacons, lighthouses, kelp areas on digital display (via computers) and on spreadsheets. The benefits of the LiDAR technology is that it is very cost effective, has amazing speed, and greater safety. They do 200% coverage of an area by measuring lines and then taking new lines in between the first lines. They run a swath beam that is 192 meters, which is larger than the ones that the RAINIER does. Each beam of pulsar light is 15 meters with 4 meters in between.

They are finding changes that need to be made on maps that date back to the 1940s. NOAA contracts with this company to do soundings for them and NOAA picks small segments of these areas to do spot checks with the ship to compare accuracy. So far, they have been extremely accurate. At this point in time, they are not comfortable with the greater depth measurements that the RAINIER does, but expect that to change in the future. Various crew members that I’ve spoken with foresee this becoming the depth measurement instrument of the future. Eventually, all depth readings may be done from satellites, which could become very accurate, as well as safe. Right now, NOAA will continue to use both methods.

Personal Log

I spent the day working on the computer, listening to the LiDAR presentation and reading the information about this new system. It’s very interesting to predict how useful this will become in the next 10-20 years. I’d love to see some of my students flying the airplanes that will send back this newer technology. Right now, the RAINIER is anchored while launches go out to do shallow survey each day. It’s fascinating to watch them lower the launches and bring them back onto the boat. They use hydraulic winches that raise and lower the boats. Everyone has to be very careful at this point, wearing hard hats, because it’s a time when equipment failure could bring a dangerous situation. Generally three or four people go out on each day’s launch. They have several more days of launches scheduled, then they must go to the Kodiak Coast Guard base to refuel.

Virdin 7-25-04 screenshot

Kathy Virdin, July 24, 2004

NOAA Teacher at Sea
Kathy Virdin
Onboard NOAA Ship Rainier

July 20 – 28, 2004

Mission: Hydrographic Survey
Geographical Area:
Eastern Aleutian Islands, Alaska
Date:
July 24, 2004

Latitude: 55 degrees 17.194 N.
Longitude: 160 degrees 32.23 W.
Visibility: 3 nautical miles
Wind direction: 100 degrees
Wind speed: 10 kts.
Sea wave height: 1-2 ft.
Swell wave height: 2-3 ft.
Sea water temperature: 10 degrees C.
Sea level pressure: 1002.0
Cloud cover: Cloudy with rain

Science and Technology Log

Today we went out on a launch (my first in the Shumagin Islands). We traveled near the area of Simeon Bight to run lines to check depth measurement. An example of why this is so important is that in one of their launches, they found after an earthquake, a 30 meter drop-off near a fault line. This wasn’t on any charts because it had been caused by the earthquake itself. Before they begin the depth measurements, it’s vital that they take a cast with the salinity, pressure and temperature instrument. This information is then hooked directly into the computer to be calculated into the depth findings, so that the depth can be corrected by these factors. We ran cross lines (lines that cris-crossed each other) as a quality check to be sure that no area had been missed. The transducer (which sends out a multi-beam swath of sound) is lowered into the water by a mechanical arm. This is high-tech stuff! The computers are also recording the GPS (global position system) location of our boat at all times. When we learn the depths of the waters we pass over, we have to know exactly where we are in order to record this on nautical charts. Out of 24 satellites, we need at least 5-7 within range plotting our location to ensure accuracy. The computers divide the screen into sections which show our depth reading, a picture of the ocean floor by sonar calculations and the range our instruments will accurately reflect. We have traveled a range of 88 meters in depth to 6.7 meters in depth. Interestingly, one possible technology that is being tested and may be the best method of the future is called Lidar, which means sonar transmitted from an airplane, which flies over coastal areas and can give a depth reading on land and in the ocean. The RAINIER is testing one area that has been measured by Lidar to compare our measurements with theirs to check their accuracy. This would be a safer method, since lowering the launch boats and retrieving them has a certain amount of risk.

We’ve just seen some lazy puffins that are swimming on top of the water, which makes them look like sitting ducks. As we return to the RAINIER in the late afternoon, we bring back a lot of data that the survey technicians will assess and correct to be submitted to the cartographers.

Personal Log

We had a rainy, foggy afternoon on the water while we were surveying, with clouds that hovered over the green, craggy cliffs. It makes a beautiful sight. We felt we got a lot accomplished and returned with some good data. In talking with various members of the crew, I’ve gotten some good ideas to use in my lesson plans as they help me think of ways to explain their operations that will simplify it, such as flashlights taped together to represent a multi-beam sonar swath. I’m going to catch up tonight on correspondence, and refine my lesson plan ideas tomorrow. I can’t wait to take all these ideas back to the classroom!

Leyf Peirce, July 14, 2004

NOAA Teacher at Sea
Leyf Peirce
Onboard NOAA Ship Rainier

July 6 – 15, 2004

Mission: Hydrographic Survey
Geographical Area:
Eastern Aleutian Islands, Alaska
Date:
July 14, 2004

Time: 10:00
Latitude: N 55°17.24
Longitude: W 160°32.17
Visibility: 6 nm

Wind direction: 060
Wind speed: 1 knots
Sea wave height: 0 – 1 foot
Swell wave height: —
Sea water temperature: 10.0 °C
Sea level pressure: 1009.3 mb
Air temperature: 11.7 °C
Cloud cover: 7/8

Science and Technology Log

This morning I went out on launch boat 1 to conduct shoreline hydrography. Shoreline research differs very much from the other research I have seen so far, for it does not require “mowing the lawn” lines. Instead, it is a technique that is used to check the data collected from the LIDAR (airplane) labs. As I learned earlier this week, the data collected using a laser from the airplane primarily focuses on the shoreline and depths up to 30 meters. Today, we went along the shoreline checking questionable data points such as rocks and shoals that may have been confused with kelp or other variances in data collection. In order to do this checking, the survey technicians and officers conducting the research look at the LIDAR chart the day before launching and determine where rocks might be misplaced or not including at all. During surveying, which is what we did today, the researchers take a boat with a single beam echo sounding system and go to the places of concern. With some one on the bow to look out for uncharted rocks, the captain then drives over the areas where there might or might not be a rock. Because all of this is done very close to shore, it is very important to drive slowly. There is also a lot of kelp that can get in the way. Once the boat has past over the area a few times, the true depth is recorded as well as the position and a note is made on the chart where any changes need to be made to the chart. A relatively simple procedure, this type of shoreline research is critical for anyone planning to go on shore on any of these islands. Once again I was able to see how important this work is!

Personal Log

My morning was spent on the launch boat doing shoreline surveying. While the technology used was fascinating, I still did not hesitate to wonder at the naturally beauty of these islands. Almost completely uninhabited, these islands host wildflowers, puffin, gulls, and an occasional seal basking on a sandy or rocky beach. The green slopes are sharply cut by dramatic cliffs, creating a feeling of comfort and adventure at the same time. With the clouds dancing across these islands, I almost felt like I was about to see a dinosaur emerge from one of the cliffs—this looks very much like Hollywood’s rendition of “Jurassic Park”! This afternoon I plan on working on more lesson plans as well as a possible journey on another shoreline survey boat.