Eric Koser: Hydrography 101 – and the Tools to Make it Happen, June 28, 2018

NOAA Teacher at Sea

Eric Koser

Aboard NOAA Ship Rainier

June 22 – July 9, 2018

Mission: Lisianski Strait Survey

Geographic Area: Southeast Alaska

Date: June 28, 2018: 0900 HRS

Weather Data From the Bridge
Lat: 57°52.59′ Long: 133°38.7′
Skies: Broken
Wind 1 kt at variable
Visibility 10+ miles
Seas: calm
Water temp: 5.6°C

Science and Technology Log

Long Line Boat

A typical longline fishing boat. The fishing lines get spread out behind the boat from the large booms on either side.

The ultimate focus of Rainier is to assure accurate navigational charts are available to all mariners. This task is critical to the safety of many industries. About 80% of all the overseas trade in the US (by weight) is moved over water. Here in SE Alaska, it appears the largest industry is commercial fishing. Many boats fish both with nets and long lines to catch halibut, rockfish, cod, and several varieties of salmon.

Another major industry here is certainly tourism. As we conduct our work, we often see very large cruise ships. It’s an interesting juxtaposition to be in a narrow inlet surrounded by mountains, ice, and wildlife and then come across a large ship.  We passed the brand new ship Norwegian Bliss around 11 PM on our transit to Tracy Arm. This ship is 1,082 feet long, carries a crew of 2,100 people and has a guest capacity of 4,004 people! The safe navigation of all of these vessels depends upon the accuracy of charts produced by NOAA.

Norwegian Bliss

The cruise ship Norwegian Bliss as we passed her port to port in the evening.

The freely available charts offered by NOAA are created with three essential steps. First, the bulk of the depth data in this area is measured with MBES (Multi-Beam Echo Sounder). This creates a three-dimensional digital image of the bottom.

Secondly, important features to navigation that are shallow are best identified by our launches which travel along the shorelines and inspect for rocks, ledges, and other potential dangers. The locations of features are identified by GPS location and charted digitally by hydrographers on each launch.

Thirdly, bottom samples are collected by launch crews to confirm the type of material present on the bottom.

The MBES systems aboard Rainier and the launches come from Kongsberg Maritime. Two transducers (devices that transmit and receive) work in tandem. The transducer that is oriented front to back sends out an array of sound signals in a wide beam. The width of the beam on the sea floor depends directly on the depth – deeper water allows the beam to spread farther before reflecting. The transducer that is oriented side to side in the water receives a narrow swath of the ‘pings’ of sound that were transmitted. The time it takes any ping to get to the bottom and reflect back to the ship is recorded. The greater the time, the larger the depth.

MBES on a launch

This shows the position of the MBES on the bottom of one of several launches.

MBES transducers

This is the pair of MBES transducers on a launch, looking from the bow towards the stern.

Hydro Sonar

This image, courtesy of NOAA, depicts an MBSS beam below the ship and the mapped results off the stern.

A couple of issues provide challenges to this technique. One, the speed of sound in water depends on several factors. The salinity (concentration of salt in the water),  the conductivity (how easily electricity passes through the water), and the temperature each fluctuate as the depth changes and affect the speed of the sound waves. As hydrographers receive data, the system has to account for these changes in speed to produce an accurate depth measurement. One way to do this is with a static CTD sensor. This device is lowered from the launches all the way to the bottom as it measures the speed of sound in the water.  It provides a set of three charts as the depth changes which are used to adjust the time data from the MBES accordingly. There is also a version of the CTD, called a MVP (Moving Vehicle Profiler or ‘fish’), that can be pulled behind Rainier as we are moving and take dynamic data.

Here is a NOAA article on hydrographic surveying.  Here is further explanation of MBSS.

Deploying Depth Profiler

Here the crew lowers the profiler “fish” into the water.

Speed Profiler Data

These three plots represent the speed of sound, temperature, and salinity (from left to right) vs. depth (on the vertical axis).

A second issue is GPS signal drift. Over time, the location information can shift slightly. To account for this potential problem, the scientists place a HORCON (Horizontal Control) station onshore in the area where they are mapping. I described this tool in my previous post.

Another interesting technology that is currently being developed is called “backscatter” mapping. Here scientists look not only at the time it takes the sound waves to bounce back to the transducer, but also at the quality of the return signal. Different materials on the seafloor reflect the sound differently – hard surfaces like rocks have a sound signature that is much different than soft surfaces like silt or plants. NOAA is continually improving the tools they use to learn!

Here is an example of the chart that we are updating in Tracy Arm.

Personal Log

I had a chance to take the helm yesterday! It’s interesting how sensitive the steering on this large vessel really is. The rudders are able to turn from “amidships” or their center position, up to about 35° to either side. But while traveling at about 8 knots, we tend to use a maximum of about 5° of rudder to alter the ship’s direction. While at the helm, we keep close track of the heading (compass bearing) of the ship as indicated by the gyro compass and magnetic compass on board. Then we provide steering input to hold the ship to the course ordered by the CONN. I had the chance to help steer around several icebergs as we transited into Tracy Arm. Careful attention to detail – and willingness to promptly follow commands make for success!

Helm

My opportunity to take the helm of Rainier.

I also took an opportunity to head out in a kayak from the ship where we are anchored! Two of my new colleagues and I paddled across this bay and had a great chance to look very closely at pieces of ice. The ice is really beautiful and forms many interesting shapes. The quiet of the bay – hearing only the distant waterfalls, birds, and our paddling was beautiful!

Iceberg

This piece of ice drifted through Tracy Arm from the glacier. It was temporarily ‘grounded’ on the bottom by the receding tide.

It’s crazy to consider the ice we were seeing may have been formed thousands of years ago in the glacier – and it just now melting as it floats away.

Did You Know?

President Thomas Jefferson signed a mandate in 1807 ordering a survey of the nation’s coasts. This fundamental task is always ongoing, with 95,000 miles of US Coastline.

About 90% of any floating piece of ice will be submerged below the salt water.  Because the density of frozen fresh water just slightly less than salt water, the ice floats very low in the water!  Read more here!

Who is Onboard?

I’d like you to meet HST (Hydrographic Survey Technician), Amanda Finn! Ms. Finn has been with NOAA since last September – and started working aboard NOAA Ship Rainier in October of 2017. As an HST, Amanda works with the team of hydrographers to collect MBES data from either the ship or any of the launches. Amanda graduated from the University of Connecticut in 2016 with a bachelor of science degree in GeoSciences and a minor in Oceanography. At the end of her college experience, she knew that seafloor mapping was her passion but wasn’t sure how to make that into a job. But it all came together when she found NOAA through a friend of a friend!

HST Amanda Finn

HST Amanda Finn with recently acquired depth data for Lisinaski Inlet!

Amanda was performing at her first harp concert (another skill!) when she met a relation of a hydrographer who works on a NOAA ship! Based on her experience, her advice to students is: “When things don’t seem to be going the way you want, take time to focus on something else you like instead. In good time, things will work out!”

One positive challenge Amanda shares working here on a hydro ship is developing an understanding of systems integration. Many different pieces must come together to create the finished charts. The people aboard Rainier make the experience very positive!  The passion for seeking the unknown is the drive to continue!

 

Mary Cook: Day 4 at Sea, March 22, 2016

NOAA Teacher at Sea
Mary Cook
Onboard R/V Norseman II
March 18-30, 2016

Mission: Deepwater Ecosystems of Glacier Bay National Park
Geographical Area of Cruise: Glacier Bay, Alaska
Date: Tuesday, March 22, 2016
Time: 7:40pm

Data from the Bridge
Temperature:
37.6°F
Pressure: 1013 millibars
Speed: 0.0 knots
Location: N 58°51.902’: W 137°04.737’

Science Log

Happy Birthday to Cheryl!

Cheryl small

This is Cheryl!

Unbeknownst to Cheryl, Chief Scientist Rhian Waller, even though she was very busy preparing for the cruise, brought balloons, streamers, candles, and noisemakers to celebrate Cheryl’s birthday today.

Birthday Decor small

Surprise Birthday Decor

The ship’s chef is secretly making her a cake. The celebration is slated for tonight at dinner. Shhhhh……

This morning, Chief Scientist Rhian Waller announced that we are steaming toward the end of the west arm of Glacier Bay to Johns Hopkins Glacier. This is a place where cruise ships take tourists in the Fall. But the Park Service has it closed during the Spring and Summertime because it’s a harbor seal nursery. The nightshift workers are trying to catch a few winks of sleep before we get there. No one wants to miss it. We are hoping for clear skies. Johns Hopkins Glacier is one of the few glaciers that is advancing instead of receding. As it advances, it is joining the Gilliman Glacier.

Park Service Map small

Map showing John Hopkins Glacier. Credit: National Park Service

It’s 10:30 am and we’ve arrived sooner than I expected. Johns Hopkins Glacier is really something to see! So massive. Once again everyone is out on deck taking pictures and oohing and aahing.

The glacier has shades of blue and white with streaks of brown and gray. It has a covering of white snow that looks like cake icing. The glassy water is a blue-green color with a multitude of icebergs floating in it. Bob Stone uses a term we all like—“bergy bits”—meaning small pieces of floating ice. He even brought some “bergy bits” onto the ship for us to add to our water or soft drinks. So refreshing!

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While on deck taking pictures we hoped to see the glacier calve and fall into the sea. It sounds like thunder. We waited and we waited and finally a couple of small ones happened. Also, a couple of snow avalanches slid off the mountains into the water leaving dirty brown streaks along the slopes.

Avalanche medium

Occasional avalanches leave dirty streaks in the glacier’s white snow covering

Our scuba divers went down for another exploratory look and came up with a first! They found Primnoa pacifica in the West Arm! This is the first Primnoa pacifica ever found here. They described it as spindly and small in comparison to the others found in the East Arm.

The scuba divers continue their search for Red Tree Coral.

The significance of this Red Tree Coral being in the shallow water is that it has been considered a deep-water coral. There are two broad categories of coral: warm-water coral and cold-water coral. Generally, warm-water coral live in shallow, tropical waters. Cold-water coral live in deep water. The emergence of cold-water corals like Primnoa pacifica in the shallow waters of Glacier Bay has caused scientists to re-evaluate their understanding and descriptions of these organisms.

The third and last scuba dive for today was described as “mud, mud, and more mud”. A bit of a disappointment but they did bring up an interesting little critter.

Sea Peach small

Maybe a sea peach?

This sea squirt is a tan color here in the wet lab, but according to Bob, in its natural habitat it has a bright cherry red color.

Cheryl Birthday Party large

Birthday party for Cheryl!

Well, it’s finally suppertime! That means “Birthday Party Time!” The ship’s chef, Harry served up a delicious meal of salmon, barbeque chicken, steamed kale, baked summer squash, scalloped potatoes and a big salad. For dessert, he prepared a layered chocolate cake with freshly made whipped cream and strawberries. Everyone sang “Happy Birthday” to Cheryl.

After she blew out the candles we went out on the deck and ate cake with new friends in the view of majestic mountains and glaciers.

Eating Cake on the Deck large

A birthday to remember, I’ll say.

Now it’s back to work and the ROV crew is getting ready to deploy Kraken 2 for another night of exploration!

 

Personal Log

Today has been a day of anticipation and inspiring wonder. I’ve tried to stay out on deck watching the glacier. Hoping for calving and avalanches. It’s really neat to me that no one else is here. We haven’t seen anyone else except four Park Service employees who boated out to meet us today. I found out that there are over 1,000 glaciers in Glacier Bay National Park! Some of them aren’t even named. I enjoyed watching a couple of bald eagles sitting on icebergs. And the absolute coolest thing has been the discovery of Primnoa pacifica in the West Arm of Glacier! I could feel the excitement in the air!

It’s so thrilling to be a part of this scientific exploration and to learn from these world-class researchers!

 

Mary Murrian: Getting Ready to Fly to Alaska, July 1, 2014

NOAA Teacher at Sea

Mary Murrian

(Almost) Onboard NOAA Ship Oscar Dyson

July 19- July 22, 2014

 

Mission:  Annual Pollock Survey

Geographical area of cruise: Bering Sea and Gulf of Alaska

Date: July 1, 2014

Personal Log

Greetings from Dover, Delaware, the first state to ratify the United States Constitution!  My name is Mary Murrian and I teach math and science to a wonderful group of fifth grade students at William Henry Middle School.  My journey will begin early in the morning on Wednesday, July 2, 2014.  My son, Robert–an upcoming junior at the University of Delaware, is driving me to the Philadelphia airport at 3:00 am in the morning.  After transferring planes in Chicago, Illinois and then again in Anchorage, Alaska, I will finally make land at my final destination, Dutch Harbor, Alaska.

disney trip 2014 009

If you are a Deadliest Catch fan you will recognize Dutch Harbor as the home base for the popular television show on the Discovery Channel.  I will be aboard NOAA Ship Oscar Dyson, a NOAA (National Oceanic and Atmospheric Administration) ship.  I have the wonderful opportunity to work  with the crew and scientists aboard the Oscar Dyson to research and determine the abundance and health of walleye pollock, one of the largest fisheries in the world.  If you have ever eaten fish sticks or imitation seafood, most likely you have tried pollock!

Thanks to the NOAA Teacher at Sea program, I am afforded this wonderful opportunity to work hands-on, learning the science involved in research aboard a NOAA ship. I currently teach a unit on ecosystems, where my students learn about the ecosystem around them and the interrelationships between organisms in an environment focusing on food chains, food webs, and environmental factors that play a role in an ecosystem. This experience will enhance my knowledge of marine ecosystems and the important role the fish play in supporting a healthy and sustainable environment.  I look forward to learning and growing through my participation with experts in their field.  I want to gather as much information as possible, in order to bring it back to my classroom and share my real life experience with my students this upcoming school year and years to come.  What a wonderful way to bring real-life data and experiences to my students.

I have been asked numerous times if I am scared or nervous to be aboard a ship sailing on the Bering Sea.  My response, NO!  I am thrilled.  I cannot wait for my journey to begin.  I have cruised to Alaska before, however not as far north as the Dutch Harbor area and I was on a recreational cruise ship. It was beautiful and the scenery was amazing.  I never saw ice as blue as I did when we crossed Tracy Arm fjord.  A fjord is a typically long, narrow valley with steep sides that are created by advancing glaciers (http://oceanservice.noaa.gov/education/kits/estuaries/media/supp_estuar04_fjord.html).  The trip, although freezing, was amazing.  I also found out that glacial ice often appears blue because of years of compression gradually making the ice denser over time, forcing out the tiny air pockets between the crystals.  When glacier ice becomes extremely dense, the ice absorbs a small amount of red light, leaving a bluish tint in the reflected light (http://nsidc.org/cryosphere/glaciers/quickfacts.html).  Super cool!

Sawyer Glacier in Tracy Arm, showing the very blue ice.  Photo provided by personnel of the NOAA ship John N. Cobb

Sawyer Glacier in Tracy Arm, showing the very blue ice.
Photo provided by personnel of the NOAA ship John N. Cobb

I look forward to my upcoming experience, a trip of a lifetime.  There is more to come, I hope you will continue with me on my journey across the Gulf of Alaska and the Bering Sea!  Watch out Alaska, here I come!

Julia Harvey: Calibration in Sea-Otterless Sea Otter Bay, August 7, 2013

NOAA Teacher at Sea
Julia Harvey
Aboard NOAA Ship Oscar Dyson (NOAA Ship Tracker)
July 22 – August 10, 2013 

Mission:  Walleye Pollock Survey
Geographical Area of Cruise:  Gulf of Alaska
Date: 8/7/13 

Weather Data from the Bridge (as of 21:00 Alaska Time):
Wind Speed:  10.42 knots
Temperature:  13.6 C
Humidity:  83%
Barometric Pressure:  1012.4 mb

Current Weather: A high pressure system is building in the east and the swells will increase to 8 ft tonight.

Science and Technology Log:

Before I begin, I must thank Paul for educating me on the calibration process.  Because calibration occurred during the day shift, I was not awake for some of it.

The EK60 is a critical instrument for the pollock survey.  The calculations from the acoustic backscatter are what determines when and where the scientists will fish.  Also these measurements of backscatter are what are used, along with the estimates of size and species composition from the trawling, to estimate fish biomass in this survey.  If the instruments are not calibrated then the data collected would possibly be unreliable.

Calibration of the transducers is done twice during the summer survey.  It was done before leg one in June, which began out of Dutch Harbor, and again now near Yakutat as we end leg three and wrap up the 2013 survey.

As we entered Monti Bay last night, Paul observed lots of fish in the echosounder.  This could pose a problem during calibrations.  The backscatter from the fish would interfere with the returns from the spheres.  Fortunately fish tend to migrate lower in the water column during the day when calibrations were scheduled.

This morning the Oscar Dyson moved from Monti Bay, where we stopped last night, into Sea Otter Bay and anchored up.  The boat needs to be as still as possible for the calibrations to be successful.

Monti and Sea Otter Bays Map by GoogleEarth

Monti and Sea Otter Bays
Map by GoogleEarth

Site of calibration: Sea Otter Bay

Site of calibration: Sea Otter Bay

Calibration involves using small metal spheres made either of copper or tungsten carbide.

Chief Scientist Patrick Ressler with a tungsten carbide sphere

Chief Scientist Patrick Ressler with a tungsten carbide sphere

Copper sphere photo courtesy Richard Chewning (TAS)

Copper sphere
photo courtesy Richard Chewning (TAS)

The spheres are placed in the water under transducers.  The sphere is attached to the boat in three places so that the sphere can be adjusted for depth and location.  The sphere is moved throughout the beam area and pings are reflected.  This backscatter (return) is recorded.  The scientists know what the strength of the echo should be for this known metal.  If there is a significant difference, then data will need to be processed for this difference.

The 38 khz transducer is the important one for identifying pollock.  A tungsten carbide sphere was used for its calibration. Below shows the backscatter during calibration, an excellent backscatter plot.

Backscatter from calibration

Backscatter from calibration

The return for this sphere was expected to be -42.2 decibels at the temperature, salinity and depth of the calibration  The actual return was -42.6 decibels.  This was good news for the scientists.  This difference was deemed to be insignificant.

Personal Log:

Calibration took all of the day and we finally departed at 4:30 pm.  The views were breathtaking.  My camera doesn’t do it justice.  Paul and Darin got some truly magnificent shots.

Goodbye Yakutat Bay

Goodbye Yakutat Bay

As we left Yakutat Bay, I finally saw a handful of sea otters.  They were never close enough for a good shot.  They would also dive when we would get close.  As we were leaving, we were able to approach Hubbard Glacier, another breathtaking sight.  Despite the chill in the air, we stayed on top getting picture after picture.  I think hundreds of photos were snapped this evening.

The Oscar Dyson near Hubbard Glacier

The Oscar Dyson near Hubbard Glacier

Location of Hubbard Glacier.  Map from brentonwhite.com

Location of Hubbard Glacier. Map from brentonwhite.com

Many came out in the cool air to check out Hubbard Glacier

Many came out in the cool air to check out Hubbard Glacier

I even saw ice bergs floating by

I even saw ice bergs floating by

Lots of ice from the glacier as we neared

Lots of ice from the glacier as we neared

Nearby Hubbard Glacier with no snow or ice

Near Hubbard Glacier

And there it is: Hubbard Glacier

And there it is: Hubbard Glacier

Hubbard Glacier

Hubbard Glacier

Hubbard Glacier

Hubbard Glacier

Did You Know?

According to the National Park Service, Hubbard Glacier is the largest tidewater glacier in North America.  At the terminal face it is 600 feet tall.  This terminal face that we saw was about 450 years old.  Amazing!

Read More about Hubbard Glacier

Robert Ulmer: Perspectives on a Glacier, June 14, 2013

NOAA Teacher At Sea

Robert Ulmer

(En route from Jacksonville, Florida to NOAA Ship Rainier and at port in Juneau, Alaska)

Will be underway from June 15 to July 3, 2013

At port in Juneau:  N 58⁰17.895’, W 134⁰24.684’

Mission:  Hydrographic survey

Geographical area of cruise:  Southeast Alaska, including Chatham Strait and Behm Canal, with a Gulf of Alaska transit westward to Kodiak

Log date:  June 14, 2013

Weather conditions at port:  19.08⁰C, scattered cumulus clouds with little vertical extent against bright blue skies, 43.05% relative humidity, 1017.36 mb of atmospheric pressure, wind speed of 9.5 knots with a heading of 79⁰

Port of Juneau

A panoramic view of the Port of Juneau with a cruise ship beginning its exit of Gastineau Channel

Explorer’s Log:  Mendenhall Glacier

Flying across the North American continent at an altitude of 34,000 feet is an experience somewhere between looking down upon a held globe and walking across the terrain.  Maybe that’s too obvious a sentence for starting this second blog entry, but the fact of that obviousness is the necessary beginning, I think.

Marker on the trail to Mendenhall Glacier with Ensign Steven Wall

As we walked the few miles through Tongass National Forest and across or around several mountains along the West Trail to Mendenhall Glacier, Ensign Steven Wall and I followed piled stone trail markers called cairns.

Crossing the skies above the glaciers of western Canada and eastern Alaska, I was overwhelmed by the sheer majesty of the sights below me.  Stretching from one horizon to the other, mile after seemingly endless mile of nearly blinding albedo from frozen water reflecting the sunlight of the approaching solstice at the nearly-Arctic latitude, interrupted only occasionally by jutting dark crags of towering mountains with just enough warmth or slope to slough the otherwise boundless field of snow, and dotted here and there by impossibly sapphire pools of today’s meltwaters.  Eons of valleys carved by the almost imperceptibly unhurried slog of ice advancing under the magnitude of its own weight.  Cascades of energy waiting, breathing, crawling, leashed only by the chilly bonds of molecular attraction below a certain thermal mark.  But the hiker in me instantly feels a frostbitten ache in the ankles and knees just from peering downward at the tremendous glaciers from the warmth of the airplane cabin, entirely based on the mere consideration of just one day’s walk across the frozen sheet, thousands of frigid footfalls constituting a single-digit of traversed miles, at best.   Truly, the glaciers are awesome when seen from an airplane.

At the toe of Mendenhall Glacier, just before a calving

These ice formations are at the leading face of Mendenhall Glacier as it slowly creeps along and melts into the lake and river below. Even though they seem small, the rocks beneath the ice are more than twenty-five feet high above the water line in this picture! About an hour after I took this photograph, a chunk of ice calved away from the glacier, making an explosive sound that could be heard for miles.

On a globe in my classroom, though, those magnificent glaciers are mere splotches of white and maybe a bit of texture for the fingertips, an entirely different paradigm, to be sure.  Accurate, proportional, and contextually appropriate on a cardboard sphere that must display the major surface features of an entire planet.  Excellent for showing young people comparative and relative size and location in order to launch discussions about geography, tectonics, Earth’s axial tilt, or the water cycle, but not likely to send shivers through the imaginations of the young students whose travels more often are flights of fancy rather than physical treks to distant lands.

The west side of Mendenhall Glacier, viewed from below

This was our first close-up view of Mendenhall Glacier. The “ramp” of ice that you see on the right is more than one hundred feet high.

The point of this comparison?  A study in perspective.

Where a biologist sees a species of tree (or maybe a whole ecosystem), a painter sees verticality or varieties of green, and a carpenter sees a cabinet.  Importantly, all three observers are valid, correct, and good in their perspectives.  Perhaps more importantly, not one of those perspectives has to be deemed wrong just so that the others can be right at the same moment.  Likewise, the globe and the look-down from the airplane both are meaningful in providing totally different perspectives on the same glaciers.

Ice cave at Mendenhall Glacier

Pressure, temperature, and friction work together to carve holes and caves in glaciers, some of which are big enough to walk through… with safety gear, of course!

Therefore, I was overjoyed to hear on my first morning after boarding Rainier a bit of enthusiastic encouragement (and a quick primer on how to use a can of bear spray!) from the ship’s XO, Holly Jablonski, insisting that Ensign Steven Wall and I should spend the day actually exploring Mendenhall Glacier above the Tongass National Forest, just outside the Juneau city limits.  With snacks and drinks in hand, Ensign Wall and I were dropped at the head of the West Trail, where we hiked through a few miles of verdant evergreens and mosses, over and around a few mountains, and up a rock face before arriving at the toe of Mendenhall Glacier.  Abruptly, here in front of me was a rippled wall of ice with folds so large that singular words of description are insufficient to capture their enormity.  What had appeared from miles across the meltwater lake to be small chunks of ice at the face of the glacier now were towers more than 140 feet tall, and yet their backdrop still showed them to be relatively tiny.  In the river below were chunks of floating ice that had fallen forward from the glacier’s leading edge, seemingly just a few feet wide… until I saw kayaks completely dwarfed next to them like flies next to football stadiums.

Kayaks among the calvings in Mendenhall Lake

If you look closely, you’ll see that the black specks on the lake are kayaks, which will give you some idea of the size of the “small” icebergs adrift in the water below Mendenhall Glacier.

Twenty-foot crevasse in Mendenhall Glacier

What appears to be a small crack really is a crevasse more than twenty feet deep, and its small drainage cave continues downward for more than 150 feet to the lake below the glacier.

Indeed, the ice was cold, but the feelings at the front of my thoughts were more about size and power, awe and beauty.  Nothing in my previous education had prepared me for my sudden inability to appreciate the magnitude of the behemoth.  Crawling through caves of ice and walking on the surface of the ice was both spiritually overwhelming, as I joined something so much larger in size and time than any human experience, and also tremendously frightening, as the sound of every creak and every drip striking a floor hundreds of feet below the edges of the hole served as a reminder of my fragility at the hands of such forces.

Next, though, I surprisingly was struck by exactly the opposite of the feeling that I had expected:  Rather than feeling the tremendous difference between the frozen landscape in front of me and the 90-plus Fahrenheit degrees that I left before dawn just one day earlier in Florida, I was moved instead by an overwhelming sense of unity, sort of a bridge between the airplane view and the globe view about glaciers that already had passed through my mind.  I couldn’t escape the connection between this mountainous ice sheet and the swampy lowlands where I live thousands of miles to the southeast, because ultimately it is the existence of this frozen ocean atop the mountains of Alaska (and its neighboring icecap, extending toward the planet’s pole) that leaves the great liquid oceans of Earth at a lower level, thus exposing the small peninsula of Florida that I call home at the far other corner of the continent.  And then I saw everything around me differently:  The flowing ice around the peaks looks very much like the wind-blown sands at the beginnings of beach dunes, the small deltas in the mud from the trickles of meltwater are shaped identically to the much larger region surrounding the Suwannee River as it crashes into the Gulf of Mexico, and the wetland grasses miles below the glacier are nearly twins of the salty marshes near Florida’s Intercoastal waterway.  While very different, also quite the same in many ways.

Delta beneath a rivulet near the toe of Mendenhall Glacier

A delta is formed when running water meets the friction of an obstacle in its path (often a larger body of water) and spills leftward and rightward of its banks, making a triangular shape (like the shape of the Greek letter delta) in the nearby land when seen from above. This tiny delta is at the end of a rivulet at the base of Mendenhall Glacier, but it has the same basic form as larger river deltas all over the world.

As my students and friends hear me say so often, we are the sum of our stories, and every story is interesting if told from a meaningful or exciting perspective.

If I simply had described the past few days of my life as a series of long and uneventful flights followed by a walk among some trees and ice chunks, it wouldn’t have been untrue; it just would have been less interesting.  We all know that the best stories often come from places of familiarity, but spun with unfamiliar points of view.  During the next three weeks, I look forward to hearing and sharing ideas and insights with scientists, mariners, stewards, and technicians aboard Rainier as together we explore the same scenery along the waterways of Alaska, but from our own different perspectives… and then sharing those stories with you here.

Hikers on Mendenhall Glacier

By finding the ice features along the left wall of this picture on other photos in this blog may give you some additional perspective about the tremendous size of Mendenhall Glacier, as here you can see a group of hikers along the edge of a meltwater stream.

In our hurried world of expediency, cell phones, and paved highways, perhaps we too often put on blinders to see our travels from only one frame of reference.  As you walk your own paths, I challenge you – as I again challenge myself – to look at each new thing in several ways before closing any doors of possibility or windows of perspective.  Keep exploring, my friends.

Explorer’s Supplemental Log:  Juneau, Alaska

Tlingit totem pole and wall painting on Village Drive in Juneau

The native Tlingit people carve and paint totem poles and other images to tell stories, record events, and celebrate or worship. Central to their totemic imagery is the great raven, a powerful bird of the local skies. The items in this photograph are at the entry to Village Drive, where many members of the Tlingit Tribe still live just a few blocks from the water in downtown Juneau.

Before my excursion to Mendenhall Glacier, I first was taken to the ship port in Juneau, where NOAA Ship Rainier has been at port for two weeks.  Despite the late hour of my arrival, the sun at this northern latitude so near the beginning of summer remained far above the horizon, and so I decided to explore the local city on foot.

Blooming flowers in Juneau

Many colorful flowers bloom in the warming air in and around Juneau as summer approaches.

Juneau, the Alaskan state capital, is nestled among several evergreen-rich yet white-capped mountains on both banks of the mighty Gastineau Channel, which carries its glacial headwaters eventually to the distant Gulf of Alaska in the North Pacific Ocean.  While Juneau has served as host for my shipmates during their hours of liberty in the past several days, the city traces its history both to the discovery of gold in the nearby mountains and waters and to the native Tlingit people who moved from nearby Auke Bay.  During the past century and a half, those beginnings have laid a strong foundation for commercial ventures in mining, exploration, and government alongside a rich cultural heritage that still is seen in the stories told by the totem poles at the entry to Village Drive.  Further, those roots have since grown as other visitors and new residents have brought their own religions, cultures, and curiosities, resulting in a small and beautiful city of varied flavors and voices, a city whose shopkeepers, fisherman, sailors, citizens, and guests mingle their perspectives into a lovely harmony with those of the soaring eagles, boisterous ravens, playful otters, and hungry gulls.

Juneau movie theater building

Downtown Juneau has many beautiful older buildings, like this one, which houses the movie theater (a favorite evening site for ship crews ashore).

Alaska Senate Chambers

Senators represent their home districts as they debate, negotiate, and legislate in the Alaska Senate Chambers in the state capital city of Juneau.

Russian Orthodox church in Juneau

This is the oldest Russian Orthodox church in North America, constructed in the 1800’s to educate and convert the local Tlingit people.

Did you know?

Like other living things, languages grow, ingesting new ideas and experiences, and then converting them into written or spoken symbols called words.  The study of vocabulary often reveals another important lesson in perspective, as word roots give us clues about how the inventors of those words saw the items and events in their own worldviews.

For example, a glacier is an enormous sheet of ice, but the etymological root of that word is the same root that underlies glass (which looks like ice in its nearly-clear, fragile, appearance of solidity) and glaze (which means to coat or polish a surface so that it appears to be covered in ice, a metaphor that is extended into frosting and icing on cakes).  And in many European countries, you can order a frozen treat by asking for a glacé.  Also, when a frozen chunk of the leading face of a glacier breaks free of the main body of the glacier, the event is called a calving, as the inventor of that term in that context must have seen the many ways that the event is like the birthing of a smaller baby cow from its much larger mother.

(By the way, calved chunks of glaciers that fall into bodies of liquid water don’t sink, but rather they float to become icebergs.  Most substances become denser when they freeze from liquids into solids, but water is unusual.  The buoyancy of water ice – which you’ve experienced on a small scale every time that you see ice cubes floating in a glass of drinking water – is caused by the greater density of liquid water compared to the lesser density of frozen water, as electrochemical forces lock water molecules into a more spread-out lattice during the freezing process than those same molecules experience as they flow more closely around one another in the liquid state.)

NOAA Ship Rainier at port in Juneau

NOAA Ship Rainier at port in Juneau, Alaska

Rita Larson, August 15, 2009

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

Beautiful Kachemak Bay

Beautiful Kachemak Bay

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)

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.

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.

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 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.

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.)

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.

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

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

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 was our chart at the beginning of the day.

This is our chart after a hard days work!

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.

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!

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.