Chasing Sea Ice While Playing Tag With a Satellite

New sea ice growing in a lead at different stages of formation with the pink skies creating nice lighting on the ice. Credits: NASA/Linette Boisvert

 

by Linette Boisvert / PUNTA ARENAS, CHILE /

This mission, called Mid-Weddell, is probably the most complex of not only the fall 2018 Antarctic campaign but all of IceBridge.

Overnight I got to take part in a truly historic Operation IceBridge (OIB) mission and I couldn’t be more happy or excited to tell you all about it! This mission, called Mid-Weddell, was probably the most complex of not only the fall 2018 Antarctic campaign but all of IceBridge. To add to this, some unforeseen issues made this particular mission difficult. Upon landing after our previous mission, we were informed that there was a local fuel trucker strike. This meant NO FUEL for all of Punta Arenas, Chile. So we had no fuel for our plane, which meant we couldn’t fly the next day and had no clue when this strike would be resolved.

The strike was resolved after a few days, but the Mid-Weddell mission was again delayed when we found out that there were cracks in the NASA DC-8 pilot’s window. A new one had to be sent from Palmdale, California, and installed before we could fly again.

Local Chilean fuel truckers burning tires along the side of the road in protest. Credits: NASA/Jeremy Harbeck

 

NASA’s DC-8 Crew replacing the pilot’s window. Credits: Kyle Krabill

After all of these added stressors, we began to worry that we wouldn’t even be able to pull off this mission because it was an overnight flight and had to be timed perfectly with an ICESat-2 satellite overpass. These two mandatory factors are not so easy to achieve based on: 1) The weather in the Weddell Sea has to be clear, as in no low or high clouds, so that ICESat-2 can see the sea ice that we are flying over; 2) there has to be a crossover of ICESat-2 in the middle of the night and in the middle of the Weddell Sea.

Map of the Mid-Weddell sea ice mission. Credits: NASA/John Sonntag

In order to make things easier on ourselves (please note my sarcasm here), we were also “chasing the sea ice” during this flight. Why do we need to chase the sea ice, one might ask? Because sea ice, frozen floating sea water, is constantly in motion, being forced around by winds and ocean currents. This makes it rather difficult to fly over the same sea ice as ICESat-2  because the satellite can fly over our entire science flight line in about 9 seconds, where as it takes us multiple hours to do so by plane.  Thus, in order to fly over the same sea ice, the sea ice must be chased during flight.

A view of NASA’s DC-8 engines and wing as we were chasing the sea ice below. Credits: NASA/Linette Boisvert

Chasing the sea ice is essentially my OIB baby project, and before this campaign I diligently worked on writing code that would take in our latitudes and longitudes along our flight path, and, depending on the wind speed, wind direction, and our altitude from the plane, determine where the sea ice that ICESat-2 flew over would have drifted by the time our plane got there. This way we could essentially fly over the same sea ice that the satellite flew over. To do this we asked the pilots to take the plane down to 500 feet (yes, 500 FEET!!) above the surface and stay there for roughly a minute in order to take wind measurements. I then plugged these values into my code program and changed our flight path so that we could fly over the same sea ice. We monitored the winds during flight, and if they changed significantly we would do this maneuver again. Now how cool is that? I was in charge of changing our flight path as we flew! Can’t say I’d ever “flown” a plane before.

Lynette Boisvert, Operation IceBridge’s deputy project scientist, is “chasing the sea ice” during the science mission. Credits: NASA/Hara Talasila

 

During our flight and because of our flight path we were able to see multiple sunsets and sunrises as the sun bobbed up and down across the horizon.

Since our flight was a low-light flight it had to be conducted at night, so we took off from Punta Arenas at 7pm for an 11-hour flight, heading south to the Weddell Sea. During our flight and because of our flight path we were able to see multiple sunsets and sunrises as the sun bobbed up and down across the horizon. Because of the low lighting, the sky changed from oranges to pinks to blues, making for quite the show from the DC-8’s windows. Even the land ice lovers enjoyed it.

Sunrise over the Weddell Sea and sea ice below from the window of the DC-8 Credits: NASA/Linette Boisvert

Right before 1:35am local time, John Sonntag began a 10-second countdown, and when zero was reached, ICESat-2 crossed directly above our plane, thus “playing tag with the satellite” and making history, as it was the first time this was done since the satellite’s launch a little over a month ago. We all began chatting on our headsets about how awesome it was to be part of this mission and to be able to witness this moment. This is what OIB had been working toward since its beginning in 2009. The data gap was now successfully bridged between ICESat and ICESat-2.

An ICESat-2 flyover as seen from Punta Arenas, Chile, in the middle of the night. Credits: NASA/Jeremy Harbeck

Later, during the flight, I began to think about how everyone on the team really stepped up and how easily we were all able to work together to make this mission happen. I mean, we literally chased sea ice and played tag with a satellite during this flight! It took the pilots’ maneuvering, the aircraft crew’s hard work, the instrument teams’ and scientists’ steady collecting of data—everyone working together all night long—for this mission to run smoothly. I am truly grateful for everyone’s hard work and dedication and was so happy to be there that night. As we on OIB say, “Team work makes the dream work.”

IceBridge Deputy Project Scientist Linette Boisvert is interviewed, explaining how the crew chases sea ice in flight. Credits: NASA/Hara Talasila)

Chasing Clouds and Smoke Over the Southeast Atlantic

By Michael Diamond / SÃO TOMÉ AND PRÍNCIPE /

Michael is a PhD student at the University of Washington in Seattle.

Image 1: Michael Diamond in front of the P-3 at São Tomé International Airport before the October 10th, 2018, ORACLES flight. Photo credit: Rob Wood
Michael Diamond in front of the P-3 at São Tomé International Airport before the October 10th, 2018, ORACLES flight. Photo credit: Rob Wood

Our October 2018 deployment may be our last of the ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) campaign, but it certainly won’t be our least. (We love each of our three deployments equally, of course.) During ORACLES, scientists from multiple NASA centers, universities, and other partners came together to study the complex interactions between smoke from fires on the African continent and low-lying clouds, called stratocumulus, over the Atlantic Ocean between September 2016 and October 2018.

Image 2: View of smoke produced by fires in southern Africa over low-lying clouds in the southeast Atlantic Ocean from onboard the P-3 during the October 10th, 2018, ORACLES flight. Photo credit: Michael Diamond
View of smoke produced by fires in southern Africa over low-lying clouds in the southeast Atlantic Ocean from onboard the P-3 during the October 10th, 2018, ORACLES flight. Photo credit: Michael Diamond

As my colleague Andrew wrote previously, climate models struggle to accurately capture the physical processes that occur when smoke particles, also known as aerosols, overlie and mix into clouds, in part because these processes occur at such small scales. The effects of aerosol-cloud interactions can include warming from sunlight being absorbed by the smoke and/or cooling from changes in the clouds’ brightness, coverage, and precipitation — it is still uncertain whether the heating or cooling effects cancel each other out or if one effect wins out in the end. We need the best observations we can get to better understand the fundamental physics and chemistry of this smoke-cloud system and use that knowledge to improve the models. Because the clouds and smoke we’re interested in are many miles away from land, the best way to study them is from the air.

Enter the NASA P-3 Orion: a four-engine turboprop plane that can directly sample the smoke plume and the clouds, from 20,000 feet in the air all the way down to just above the ocean surface.

Image 3: Michael Diamond (front) operating a Counterflow Virtual Impactor Inlet System (CVI), which lets instruments make aerosol measurements within the clouds, and Steve Broccardo (back) operating the 4STAR (Spectrometers for Sky-Scanning, Sun-Tracking Atmospheric Research) instrument, a sunphotometer that can measure smoke properties at multiple wavelengths of light, aboard the P-3 on the October 10th, 2018, ORACLES flight. Photo credit: Andrew Dzambo
Michael Diamond (front) operating a Counterflow Virtual Impactor Inlet System (CVI), which lets instruments make aerosol measurements within the clouds, and Steve Broccardo (back) operating the 4STAR (Spectrometers for Sky-Scanning, Sun-Tracking Atmospheric Research) instrument, a sunphotometer that can measure smoke properties at multiple wavelengths of light, aboard the P-3 on the October 10th, 2018, ORACLES flight. Photo credit: Andrew Dzambo

Initial results from our September 2016 deployment showed that, because it takes a fairly long time for the smoke from above to mix down into the cloudy layer, it may be best to study the smoke-cloud interactions by following individual cloud systems. This means we can account for how a cloud changes and evolves over time and how long the clouds and smoke have been in contact. For two of our ORACLES-2018 flights, we attempted to do just this, using a forecast model from the National Oceanographic and Atmospheric Administration (NOAA) to predict where clouds sampled on one flight would end up the next day, and then sampling the clouds there. For a fairly typical wind speed of around 10 knots, the clouds can travel approximately 300 miles in one day.

A great opportunity for this type of flight arose on October 2nd. The day before, a “pocket of open cells,” or POC, developed around the area we normally fly. In a POC, the stratocumulus clouds arrange themselves in a quasi-hexagonal pattern, with cloudy areas on the edges and clear skies in between. In “closed cell” clouds, which we sampled more regularly, the opposite pattern holds, with clear slots at the sides and overcast skies in between. During most ORACLES flights, we aimed to sample “polluted” clouds, with lots of aerosols in the air below the cloud. POCs are an interesting case because they tend to be very “clean,” removing aerosols from the air through drizzle. This precipitation is very likely the driving factor determining whether the clouds arrange themselves in open or closed cellular formations. We still have open questions remaining about whether aerosols can suppress precipitation and induce the open cells to transition into closed cells.

Image 4: True color image of the POC on October 1st from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. The dotted black line shows the trajectory of a point (white circle) originally inside the POC for three days as it travels around the southeast Atlantic. The POC can be seen as the anvil-shaped collection of open cell hexagonal clouds between 8 and 12 degrees south and 0 and 8 degrees east. Image credit: Michael Diamond/NASA Worldview/NOAA Air Resources Laboratory (ARL)
True color satellite image of the POC on October 1st from NASA’s Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. The dotted black line shows the trajectory of a point (white circle) originally inside the POC for three days as it travels around the southeast Atlantic. The POC can be seen as the anvil-shaped collection of open cell hexagonal clouds between 8 and 12 degrees south and 0 and 8 degrees east. Image credit: Michael Diamond/NASA Worldview/NOAA Air Resources Laboratory (ARL)

We first sampled the POC on October 2nd, flying above, below, and within the clouds. We were also able to sample another interesting feature: the white diagonal line of cloud that can be seen cutting through the POC near where we flew is called a ship track. Ship tracks are formed where the exhaust from ships emits particles and gases that form new aerosols, which can then interact with the clouds. (There are some other ship tracks visible in the satellite imagery from October 1st and October 2nd as well.) As expected, most clouds we sampled were drizzling and the below-cloud air was very clean. The more overcast linear feature in the ship track will help us better understand how clouds transition between open and closed cells.

Image 5: True color image of the POC on October 2nd from MODIS. The dotted black line shows the trajectory from before. The white circle is now at the location the original air was forecasted to have traveled to one day later. The POC can be seen as the anvil-shaped collection of open hexagonal clouds between 6 and 10 degrees south and 2 and 10 degrees east. Image credit: Michael Diamond/NASA Worldview/NOAA ARL
True color satellite image of the POC on October 2nd from MODIS. The dotted black line shows the trajectory from before. The white circle is now at the location the original air was forecasted to have traveled to one day later. The POC can be seen as the anvil-shaped collection of open hexagonal clouds between 6 and 10 degrees south and 2 and 10 degrees east. Image credit: Michael Diamond/NASA Worldview/NOAA ARL

On October 3rd, we set out on a mission to resample the POC and see how the clouds had changed and whether any smoke had been mixed into the below-cloud layer. We were heartened to see from our satellite imagery that the POC had traveled to roughly the same area we had forecasted. The POC by this time was dissipating: some well-developed open cells are still visible, but the POC boundaries had eroded and more “actinoform,” or lace-like, clouds had formed.

Image 6: True color image of the dissipating POC on October 3rd from MODIS. The dotted black line shows the trajectory from before. The white circle is now at the location the original air was forecasted to have traveled to two days later. The POC can be seen as the collection of open cells and actinoform clouds between 6 and 9 degrees south and 3 and 9 degrees east.)
True color satellite image of the dissipating POC on October 3rd from MODIS. The dotted black line shows the trajectory from before. The white circle is now at the location the original air was forecasted to have traveled to two days later. The POC can be seen as the collection of open cells and actinoform clouds between 6 and 9 degrees south and 3 and 9 degrees east.

More analysis will need to be done after we’ve had a chance to calibrate and quality control the data, but our initial readings suggested the below-cloud layer was still relatively clean, with some mixing of smoke from above evident.

At the end of this October 2018 deployment, data collection for the ORACLES campaign will be complete, but there will be plenty of science left to do. Not only do we have our own data to analyze, but there have been other American, British, French, German, and Namibian and South African teams studying similar questions in the same region that we will collaborate with. Together, the multiple field campaigns and model intercomparison projects just completed and currently in the works will greatly improve our understanding of smoke-cloud interactions over the southeast Atlantic and their implications for the regional and even global climate system.

Inspiring Students 1,500 Feet Above Antarctica

A rainbow appears in the backdrop of NASA’s DC-8 at the Punta Arenas Airport in Chile before takeoff. Credits: NASA/Jeremy Harbeck

by Linette Boisvert / SKIES ABOVE ANTARCTICA /

NASA’s Operation IceBridge (OIB) fall campaign in the Antarctic  has been a much different experience for me compared to past campaigns. This is in part because of my new role and responsibilities as deputy project scientist for OIB, but also because I am currently in the southern hemisphere for the first time and seeing Antarctic sea ice and land ice for the first time in person! If that wasn’t enough new stuff, I am now spending 12 hours a day flying over Antarctica, almost nearing the South Pole. (That is the topic of a future blog…so stay tuned!)

Lynette Boisvert (left) doing an OIB pre-mission briefing on the science objectives with the pilots and instrument team members. Credits: NASA/Jeremy Harbeck

These flights are long (I mean really long) and the days are also long. We have to get to the airport two hours before the flight, and it takes about 25 minutes to get to the airport in Punta Arenas, Chile. Once there, John Sonntag, Eugenia DeMarco, and I go over the satellite imagery available to us as well as some weather forecast models of Antarctica so we can decide which missions are the most viable for maximum data collection during flight.

This is nerve-wracking in two ways: 1) We have limited satellite imagery so the model forecasts don’t always get the weather correct. This is because there are relatively few observations for the models to ingest in Antarctica and the Southern Ocean to include in their forecasts. Basically, the more observations available the better the chance that the models will get the weather forecasts correct. 2) If we make the wrong call and pick a mission where the weather turns out to be different from the forecasts and we are unable to collect good data, we are wasting the project’s valuable flight hour time and money. Let’s just say flying a big plane like the DC-8 is not cheap. So that’s a lot of pressure.

Assessing the forecasts and deciding on a science mission first thing in the morning at Punta Arenas airport from right to left: Joe McGregor, Eugenia DeMarco, John Sonntag and Linette Boisvert. Credits: NASA/Jeremy Harbeck

The reason why our flights are much longer in the Antarctic compared to the Arctic is that the time it takes to get to Antarctica from where we are based, Punta Arenas, is two to hours hours long, meaning that’s how long it takes before we can begin our mission and collect data. About half of our flight time is high-altitude transit. One would think there would be a lot of down time; however, for me this is not the case. I am very big on outreach and giving back by sharing with students of all ages what I do in my job, how I got interested in science, and the science that I do. One of the great things about OIB and NASA airborne science in general is that we have the ability to connect and chat with students in classrooms all over the world during our flights.

Linette Boisvert looking out of the DC-8 window at mountains of the North Antarctic Peninsula during an IceBridge science mission. Credits: Eugenia DeMarco

So this is how I choose to spend my down time on science flights. Teachers can connect their classrooms with us and ask all types of questions, from climate change to what OIB does, what we studied in school, and what we eat on the plane. I have been partaking in this for a few campaigns now, and the majority of the teachers come back campaign after campaign, connecting with us multiple times.

Linette Boisvert (foreground) taking part in a classroom chat during a science mission. This image was taken from a clip that was shown on CBS Evening News. Credits: NASA/Linette Boisvert

One of these teachers is Marci Ward, who teaches third grade in Fairbanks, Alaska, and is fascinated with airborne science and is dedicated and enthusiastic about exposing her students to all types of science. Last spring, when we were stationed in Fairbanks for our Beaufort sea ice flights, I had the opportunity to go to her classroom and talk to her students in person about OIB on one of our down days. Shortly thereafter, I was able to connect with her students again on the plane chat the following week. They were so excited to meet me in person and to chat with me on the plane, it really made me feel good about what I was doing and that I was making a difference (aka giving me the warm and fuzzies inside).

Linette Boisvert talking to Marci Ward’s third grade class in Fairbanks, Alaska, about sea ice and IceBridge in March 2018 during the Arctic spring campaign. Credits: NASA/Emily Schaller

It is very humbling to know that you can have such an impact on students and hopefully inspire and motivate them to pursue a career in science, math, or whatever subject they are passionate about. And it is even better when we receive feedback from the students and teachers, such as Janell Miller, a middle school teacher located in a high-poverty area of central California. “Believe me, your outreach matters to students,” she said. “It brings in a whole world they would not have been able to access first hand. The IceBridge project—speaking with scientists and engineers—this has a lasting impact. I’ve had former students who participated in this chat years ago, when I taught elementary school, write that this was one of their best school memories in their senior papers.”

Seventh and eighth graders at Washington Academic Middle School in Sanger, California, connected live to the NASA IceBridge team aboard the DC-8. Credits: NASA/Emily Schaller

After 12 hours in the air today, we arrive back in Punta Arenas and make it back to our hotel anywhere from one to two hours after we land. The days can be exhausting, and we know that we will be doing this all again tomorrow. But I also know that along with collecting all of this extremely valuable data of Antarctic ice, I and other scientists and engineers aboard also make an impact on students all over the world. Personally, I find it even more important for me to be continually proactive in the student chats because I hope to encourage and inspire young female students to be interested and pursue careers in math and science, areas where we are currently underrepresented and crucially needed.

The NASA DC-8 plane arriving back at the Punta Arenas airport after a 12-hour science mission. Credits: NASA/Linette Boisvert

Refining How We See Aerosols, Clouds, and Precipitation in Climate’s Big Picture

By Andrew Dzambo / SÃO TOMÉ AND PRÍNCIPE /

Andrew is a PhD student at the University of Wisconsin-Madison.

Crew and scientists preparing for the October 2, 2018 research flight aboard the NASA P-3 aircraft. Pictured: Amie Dobracki, University of Miami. Photo Credit: Andrew Dzambo
Crew and scientists preparing for the October 2, 2018 research flight aboard the NASA P-3 aircraft. Pictured: Amie Dobracki, University of Miami. Photo Credit: Andrew Dzambo

Climate models are essential tools to predict climate’s evolution in the next few decades and beyond. Given current computational capabilities, most global models cannot resolve every scale and process; therefore, we often parameterize (i.e. simplify) the mathematical representation of the processes to obtain results in a reasonable amount of time.

Cloud processes are among the most difficult to parameterize for a number of reasons: clouds form on many different spatial scales, have highly variable time scales, and require simultaneous knowledge of a large number of factors that affect their evolution. Precipitation processes are even harder to capture in climate models because they occur on more highly variable spatial and time scales.

Additionally, the presence of aerosols, such as smoke or dust, further complicates the problem because aerosols’ effects on cloud and precipitation processes often depends on the type and amount of aerosol present.  Overall, our knowledge of how aerosols interact with clouds and precipitation is highly uncertain, especially over remote areas like the ocean. In order to better understand these processes and their impacts on the global radiation and energy budgets – essentially, how heat moves around our planet – we require highly accurate measurements of these aerosol and cloud interactions.

Group picture of some of the science crew from the transit between Sal, Cabo Verde to Sao Tome: Andrew Dzambo (front), Amie Dobracki (middle-left), Art Sedlacek (middle-right), David Harper (back-top), Sam LeBlanc (back-middle), and Tony Cook (back-bottom). Photo Credit: Andrew Dzambo
Group picture of some of the science crew aboard NASA’s P-3 research aircraft from the transit between Sal, Cabo Verde to Sao Tome: Andrew Dzambo (front), Amie Dobracki (middle-left), Art Sedlacek (middle-right), David Harper (back-top), Sam LeBlanc (back-middle), and Tony Cook (back-bottom). Photo Credit: Andrew Dzambo

NASA’s Observations of Aerosols above Clouds and their Interactions, or ORACLES, field campaign has set out to do just that. We are collecting a highly thorough, robust dataset aimed at challenging our current theories about cloud/aerosol interactions and how aerosols affect cloud and precipitation processes in stratocumulus clouds. These clouds might not be as visually stunning as ones associated with severe weather, but to atmospheric scientists, they are very important because they cover a large fraction of Earth’s subtropical oceans and have a large impact on earth’s energy budget. The ORACLES campaign, taking place over the Southeast Atlantic Ocean, bridges an observational data gap where ground and airborne observations are presently limited.

On the October 3, 2018 research flight, the biomass-burning (aerosol) layer is seen just above the stratocumulus cloud deck. Photo Credit: Andrew Dzambo
On the October 3, 2018 research flight, the biomass-burning (aerosol) layer is seen just above the stratocumulus cloud deck. Photo Credit: Andrew Dzambo

Weather radars were first developed during World War II, and radar technology has since expanded considerably. In the United States, WSR-88D radars are capable of observing (nearly) the entire country and are capable of notifying meteorologists of impending rain, snow, or destructive storms. But these radars are designed primarily to detect rainfall or ice particles larger than a small drizzle droplet. However, stratocumulus clouds are made up of even tinier cloud droplets, so the weather radar is not the best observing tool for them. Instead we need a radar system specifically designed for cloud detection.

Enter the NASA Jet Propulsion Laboratory’s 3rd generation Airborne Precipitation Radar (APR-3). With development beginning back in 2002, this radar system operates at three frequency bands used to measure thin clouds and light precipitation (W-band), light to moderate precipitation (Ka-band) and moderate to heavy precipitation (Ku-band). This is the first airborne radar system capable of measuring the atmosphere at three frequencies for the same location, which means it can simultaneously detect clouds and precipitation.

During the ORACLES campaigns from 2016 through 2018, the stratocumulus cloud decks we see most often frequently go undetected by the lower frequency Ku and Ka channels. But by including the high frequency W-band radar we can now see the stratocumulus cloud and characterize its structure at a very high resolution.

Simone Tanelli (Jet Propulsion Laboratory) operating the APR-3 radar. Photo Credit: Andrew Dzambo
Simone Tanelli (Jet Propulsion Laboratory) operating the APR-3 radar. Photo Credit: Andrew Dzambo

Occasionally, the APR-3 system in ORACLES measures both the cloud and precipitation. Detecting precipitation in multiple radar frequencies is useful as the high frequency W-band measurements commonly attenuates when precipitation gets too heavy – meaning the signal is somewhat lost because precipitating raindrops are too large. On the other hand, the other radar bands (usually Ka-band for ORACLES) can see this precipitation with little to no fading of the signal. The end result is that the multiple channels gives us the ability to better characterize the precipitation that’s happening. In turn, that gives us an opportunity to possibly provide a more accurate estimate of precipitation magnitude in these stratocumulus regions.

This is an example of both precipitating and non-precipitating stratocumulus as seen by the APR-3 radar. The highly sensitive cloud radar (W band, bottom) sees both the clouds and precipitation, whereas the Ka (middle) sees only precipitation and the Ku band (top) sees only the heaviest precipitation. Yellows, oranges and reds indicate precipitation, and blues/greens indicate clouds. The white bar at 0 kilometer/kilofeet (1000 feet) altitude shows the surface. Image Credit: Andrew Dzambo
This is an example of both precipitating and non-precipitating stratocumulus as seen by the APR-3 radar. The highly sensitive cloud radar (W band, bottom) sees both the clouds and precipitation, whereas the Ka (middle) sees only precipitation and the Ku band (top) sees only the heaviest precipitation. Yellows, oranges and reds indicate precipitation, and blues/greens indicate clouds. The white bar at 0 kilometer/kilofeet (1000 feet) altitude shows the surface. Image Credit: Andrew Dzambo

The ORACLES APR-3 contributes one component of a highly robust dataset designed to study the effects of aerosols on cloud and precipitation processes. Other direct and remote sensing instruments from the ORACLES field campaign collect highly detailed information about aerosol type and amount in the atmosphere – both of which are needed to properly assess cloud/aerosol interactions and their net effect on precipitation. Ultimately, ORACLES will greatly improve how we describe aerosol/cloud/precipitation interactions in future climate models.

Students Traverse Land, Air, and Water in Canada with NASA’s ABoVE

Joanne Speakman helps scientists map wetlands near the city of Yellowknife in the Northwest Territories, Canada. Credits: Paul Siqueira

by Joanne Speakman / NORTHWEST TERRITORIES, CANADA /

My name is Joanne Speakman and I’m from the Northwest Territories (NT) in Canada. I’m indigenous to the Sahtu Region and grew up in Délįne, a beautiful town of about 500 on Great Bear Lake. Now I live in Yellowknife, NT, and study environmental sciences at the University of Alberta. I was a summer student this year with the Sahtu Secretariat Incorporated (SSI), an awesome organization in the NT that acts as a bridge between land corporations in the Sahtu. My supervisor, Cindy Gilday, helped organize a once-in-a-lifetime opportunity for me and a fellow student from Délįne, Mandy Bayha, to fly with NASA. It was a dream come true.

One of NASA’s projects is called the Arctic-Boreal Vulnerability Experiment (ABoVE), which is studying climate change in the northern parts of the world. People from the circumpolar regions have seen firsthand how drastically the environment has changed in such a short period of time, especially those of us who still spend time out on the land. Weather has become more unpredictable and ice has been melting sooner, making it more difficult to fish in the spring. Climate change has also contributed to the decline in caribou, crucial to Dene people in the north, both spiritually and for sustenance.

Studies like ABoVE can help explain why and how these changes are happening. Along with traditional knowledge gained from northern communities, information collected by ABoVE can go a long way in helping to protect the environment for our people and future generations.

Wednesday, August 22, 2018:

Joanne Speakman sits behind the pilots during takeoff. Credits: Mandy Bayha

It was exciting to meet the ABoVE project manager, Peter Griffith, and the flight crew because it’s amazing what they do, and to fly with them was an incredible opportunity to learn from one another. Although we were from different parts of the world, at the end of the day we are all people who care about taking care of the environment. We flew on a Gulfstream III jet to survey the land using remote sensing technology. We flew from Yellowknife to Kakisa, Fort Providence, Fort Simpson and then back to Yellowknife.

During the flight, crew ran the remote sensing system and they explained to us how it works. It got complicated pretty quickly, but from what I understood, a remote sensor is attached to the bottom of the plane and sends radio waves to the ground and bounce back, providing information about the land below and how it is changing from year to year.

The pilots, Terry Luallen (left) and Troy Asher, make flying look easy. It was remarkable to see them work and to listen to them over the headset, says Speakman. Credits:
At work in the Gulfstream III jet are flight engineer and navigator Sam Choi from NASA’s Armstrong Flight Research Center and radar operator Tim Miller from NASA’s Jet Propulsion Laboratory. Credits: Joanne Speakman
From left: NASA pilot Terry Luallen, Mandy Bayha, NASA ABoVE Chief Support Scientist Peter Griffith, Joanne Speakman, NASA pilot Troy Asher.

August 24, 2018

NASA’s also working on building a satellite called the NASA-ISRO Synthetic Aperture Radar, or NISAR, which will help study the effects of thawing permafrost. Two of the lead scientists working on NISAR are Paul Siqueira and Bruce Chapman. While they were in Yellowknife, Mandy and I got invited to join them for a day to help collect field data.

Rock climbing isn’t the easiest in rubber boots, but Joanne Speakman and Paul Siqueira make it safe and sound. Credits: Mandy Bayha

We met with Paul and Bruce early in the morning and then drove out on the Ingraham Trail until we reached a small, marshy lake. We got out and walked along the lake’s edge, making measurements of the amount of marshy vegetation from the shore

Joanne Speakman admires a stunning view after the climb. The Northwest Territories has so many hidden gems, she says. Credits: Paul Siqueira

to the open water, an area that I learned is called inundation. We used our own estimations and also a cool device that uses a laser to tell you exactly how far away an object is. Paul and Bruce will use the information we collected that day to figure out the best way to map wetlands, which will help the ABoVE project study permafrost thaw and help with development of the NISAR satellite by comparing our results to satellite images of the area.

Mandy Bayha and Joanne Speakman use their canoeing skills. With them is NASA scientist and engineer Bruce Chapman, who Joanne is excited to learn has spent time studying the surface of Venus. Credits: Joanne Speakman
University of Massachusetts Amherst scientist Paul Siqueira enjoys the last canoe ride of the day with Joanne Speakman and Mandy Bayha. Credits: NASA/Bruce Chapman

In the afternoon, we surveyed a second lake, this time using a canoe. The sun came out and we saw ducks, a juvenile eagle, and many minnows swimming around. Nothing’s perfect, but this day was close to it and we learned a lot along the way.

Meeting and spending time with the NASA team, especially Bruce, Paul, and Peter, was the highlight of the two days. They’re incredibly kind and thoughtful and took the time to share their knowledge with us. ABoVE is a 10-year program and I hope there will be many more opportunities for northern youth to participate in such an exciting, inspiring project. There is so much potential out there. Thanks again for an amazingly fun learning experience!

A New Deputy Gearing up for a New Deployment

Linette Boisvert, deputy project scientist for Operation IceBridge, “hanging out” in the belly of NASA’s DC-8 flying laboratory. Credits: Linette Boisvert

Hi all, you may remember me, Linette Boisvert, from previous blogs such as “Team Sea Ice or Team Land Ice?” and “Sick Sacks for Science,” where I gave a visiting scientist’s perspective on test flights for NASA’s Operation IceBridge Arctic Spring campaign. Well now I am back, but this time as the deputy project scientist for IceBridge. Yes, a lot has changed since my last blog.

The location of Punta Arenas, Chile. Credits: Google Maps

Beginning the second week of October, I will be flying down to Punta Arenas, Chile, (basically the other end of the Earth!) on NASA’s DC-8 flying laboratory to help lead IceBridge’s Antarctic Fall campaign. As I have never been to Chile, seen Antarctic sea ice in person (this is kind of a big deal), or flown on the DC-8 or met the crew, I took a short trip to NASA’s Armstrong Flight Research Center located in the California desert town of Palmdale, where the DC-8 is based.

Once on center, I entered the massive hangar that houses multiple planes. This hangar was originally used to make B-52 bombers before it was acquired by NASA, and it is so massive that scenes from Pirates of the Caribbean were even filmed inside. (They had to bring in a very large pool.) But there it was, dwarfed by the large hangar: the DC-8. It will be my mobile “office” for the month of October, when we’ll do 12-hour flights from Punta Arenas, flying over the Antarctic sea ice and land ice and back again, taking measurements with lasers and radars. We do this every fall to monitor changes in the ice thickness.

The hangar at NASA’s Armstrong Flight Research Center, with the DC-8 in the background. Credits: Linette Boisvert
NASA’s DC-8 flying laboratory. Credits: Linette Boisvert
A mostly empty DC-8 interior. Credits: Linette Boisvert

Now, this plane is a whole different beast than the NASA P-3 that I am accustomed to. It can seat up to 44 people with instruments aboard, compared to the 20 people that the P-3 can carry. The DC-8 has first class seats that recline and also has THREE bathrooms, and they’re like commercial airline bathrooms and not like composting toilets—what luxury! But when I first stepped onto the plane, it was basically empty. Seats were scattered around, there were containers about. I thought: “Are we really going to be able to fly this in a few weeks?” You see, I had arrived at the beginning of what we can “install,” and clearly there was a lot of work to be done. So naturally I was ready to lend a hand in any way that I could.

The desert around Palmdale and some Joshua trees. Credits: Linette Boisvert

My first task was to help Mission Scientist John Sonntag, “The man, the myth, the legend” (as he is often called), with a ground Global Positioning System (GPS) survey. This basically means we would spend hours outside in the desert heat and sun, looking a little silly, pushing a cart around with a GPS antennae attached. We would be doing this at multiple specific locations around the parking lot and the runway. Now you might be wondering why we are torturing ourselves. For science and the mission of course! We need highly accurate GPS locations of easy-to-spot points from digital imagery so that we can geolocate our digital imagery and calibrate our camera during the test flights. Our instruments need to be calibrated so we can know the exact locations of our data when we fly and take measurements.

Our GPS ground survey antennae and cart just after sunrise. Credits: Linette Boisvert

So now that is cleared up you might be wondering, okay, why do you have this antennae jerry rigged to this cart? I learned that GPS antennas are finicky, and the antennae need to be pointed unobstructed to the sky to receive signals from the multiple satellites orbiting overhead. Thus, it cannot be blocked by anything from above, such as your head, lampposts, or trees because if any contact with the satellites is lost during the survey, it would have to be done all over again. The other option would be to carry this around with the antennae above your head the whole time, so having the choice, I think I will take the cart.

GPS ground survey on the runway with John Sonntag. NASA’s SOFIA plane is in the background. Credits: Linette Boisvert
GPS ground survey in the dessert brush. NASA SOFIA plane in the background. Credits: Linette Boisvert
GPS ground survey team John Sonntag and Linette Boisvert. Credits: John Sonntag

Well, it turns out we had to eventually abandon the cart, because some of our survey points were located in the desert brush, and our little cart was not made for off-roading. We tried. As we were trudging through the desert carrying the antennae above our heads, John told me all about rattlesnakes and what I should be on the lookout for. Great, with my luck we would come upon one. But alas, we didn’t run into any of our reptilian friends and were able to complete our surveys, albeit a bit parched, sunburnt, and sweaty.

Now while we were surveying in the desert, the Airborne Topographic Mapper (ATM) team, the “Dream Team,” as I call them, were hard at work in the hangar installing their GPS ground station ATM T-6 and T-7 lasers

The ATM T-7 laser. Credits: Linette Boisvert

onto the belly of the DC-8, as well as their racks, which hold all of their computers and servers on the interior. They worked diligently for four long days, and at the end of the fourth day, they were finally ready to install ATM T-7. This baby weighs about 200 lbs and to me looked to be too big to fit into the door in the belly of the plane, so I knew I had to witness this!

 

The laser was wheeled out to the plane, where it was then put onto a forklift, lifted up, and gingerly slid into the belly of the plane. It was a tight fit, and I was nervous to say the least, but it all worked out in the end. Phew! Next week the radar instrument teams will begin their install.

The ATM T-7 installation into the belly of the DC-8. Credits: Linette Boisvert

Before I left on my last day, I took a few quiet moments in the DC-8. Compared to when I arrived, the plane looked almost put together. I was in shock with how quickly and seamlessly the crew and the ATM team worked together. The seats were nearly all set up, and the ATM and navigation racks were installed. I felt a sigh of relief knowing that I would be working with a group of scientists and engineers who worked hard, and that no matter what unexpected issues or problems arose on this upcoming campaign, we would all be able to work together to fix the problem and continue to collect valuable science data of the Antarctic ice. Lets just say I couldn’t be more proud and honored to be a part of this IceBridge team.

A nearly completely installed DC-8 plane. Credits: Linette Boisvert

I also want to note that I am also very content to not be partaking in the DC-8 test flights next week over the desert, where they can be very turbulent, because I am not looking forward to having to test out any more “sick sacks.”

Oh, The Places We’ll Go: Tales From a Traveling Scientist

Golden hour looks good on the CTD, too! Credits: Alex Niebergall

Alex Niebergall is a PhD student in Earth and Ocean Sciences at Duke University and worked aboard the R/V Sally Ride in the North Pacific in August and September.

Before I joined the science crew aboard the R/V Sally Ride and set sail for the middle of the Pacific Ocean for my first ever research cruise, I can honestly say I did not know what to expect. Would it be an adventure? I hoped so. Would it be long hours in the lab? Undoubtedly. Would it be like stepping into National Talk-Like-A-Pirate-Day for an entire month? Maybe not. What I did know is that the research cruise meant 34 days on the open ocean doing what I love, and that was the only enticement I needed to sign up!

Scientists and crew aboard the Sally Ride watches the sunset as the ship leaves port in Seattle. Credits: Alex Niebergall

For me, it has always been about the ocean. Don’t get me wrong, I love science. I know this because my time as a researcher has taken me to far more windowless labs in the basements of old science buildings than remote, dream-like field locations, and I have enjoyed every second of this work too! But even this windowless basement science ties back to Earth, the environment, and most importantly (in my eyes) the ocean. Throughout elementary and high school, I was drawn to science and math because they gave me new ways to look at the world around me. Suddenly, every baseball game was a math problem—the velocity of the pitch, the angle of impact, the parabolic motion of the ball as it headed into the outfield (why no… I’ve never been very good at sports, how did you guess?).

As an avid outdoorswoman, science unlocked even more secrets. Physics and geology courses taught me about wave motion and erosion. Biology, ecology, genetics, and evolution classes allowed me to go to tide pooling and appreciate the radial symmetry of an ochre sea star while understanding its predatory role in the intertidal ecosystem. A firm grasp of chemistry allowed me to look at the ocean on a much smaller scale—a system of salinity gradients, dissolved nutrients, and pH balance. (Not to mention that chemistry makes cooking more interesting!) These subjects were interesting because I saw them every day around me, connected and continuously in flux, influencing each other in every way and giving me a new appreciation for all the activities and places I already loved.

Oh the places we’ll go…

In truth, science has taken me to some of the coolest places I could possibly imagine. As an undergrad, I went to field sites in the depths of the Northern California wilderness that look so wild and untouched they could be the set for the next Jurassic Park movie. I’ve been to redwood forests studying ecosystem dynamics. Science training took me to the underwater kelp jungles of Monterey Bay, California, and offshore Oregon where I learned, among other things, that measuring baby sea stars (sometimes the size of my thumb nail) becomes infinitely more challenging in a surge that forces you 8 feet in either direction. I also learned that sea creatures (specifically sea otters and trigger fish) have the ability and the instinct to irreparably damage science equipment, but THAT is a story for another time! Research took me to the underwater paradise that is the coral reefs of Indonesia, where night diving with bioluminescent dinoflagellates meant that the water around me perfectly mirrored the stars that sparkled out of the darkness overhead.

Alex Niebergall helps with Winkler titrations by mixing reagents with water samples to fix the dissolved oxygen. Credits: Collin Roesler
Alex Niebergall samples water from the morning optics cast. Credits: Abigale Wyatt

Now as a brand new graduate student in Earth and ocean science, I found myself living on a floating laboratory in the middle of the Pacific Ocean, with a view of the waves as far as the eye can see in a blue hue that is unlike anything I ever saw in my life. My group’s project aboard the ship was focused on quantifying how the plankton communities in the ocean influence carbon export by estimating the net community production at the ocean’s surface. We did this by measuring biological oxygen concentrations in the surface water and pairing these data with genetic analyses of the microbial community. These measurements allowed us to infer how much carbon was being taken up by biological processes and thus, taken out of the atmosphere.

With this project, those same subjects I learned to love in the tenth grade—chemistry, ecology, genetics, math—tied together (with the help and expertise of many, many other dedicated scientists) to give us a comprehensive view of what is happening in the ocean and how it affects our planet’s climate.

Yuanheng Xiong watches the sunrise from the back deck of the R/V Sally Ride. Credits: Alex Niebergall

To some, the idea of being a floating speck in the middle of the ocean may seem isolating (or at the very least, nausea-inducing). To me, it is the coolest place I’ve ever been. The view reminds me that I am a small part of something big, not just as a junior scientist in the immense scientific undertaking that is the EXPORTS project, but also as one small human in the middle of an enormous planet that we have the privilege to explore, admire, question, and hopefully understand. Today, I am a happy, and very lucky, scientist because I was on this wild adventure, working alongside some of the most inspirational and dedicated scientists I have ever met.

But tomorrow? Tomorrow I am eagerly waiting to see where science will take me next.

Diagnosing Diatoms: Do Anemic Diatoms Alter North Pacific Food Webs?

by Kris Gomes and Travis Mellett / NORTHEASTERN PACIFIC OCEAN /

The focus of our team is on a group of phytoplankton called diatoms, which are the floating, single-celled plants of the ocean. These organisms, through photosynthesis, use the energy from sunlight and the carbon dioxide we exhale and other sources to create food. Thus, they act as the base of a food web that sustains other animals in the ocean. Iron also plays an important role in the nutrition of these organisms.  When iron is too low, diatom growth can be reduced and their photosynthesis less efficient, resulting in low diatom abundance and decreased energy transfer further up the marine food web. In the part of the Pacific Ocean sampled by the Export Processes in the Ocean from Remote Sensing, or EXPORTS, program, iron is at some of the lowest levels in the global ocean and not at levels that can support high diatom growth. That being said, diatoms persist in this nutritionally challenged system, which drives the main goal of our EXPORTS experiments: to understand the impact that nutrients, such as iron, have on the role of diatoms in ocean carbon export.

To help us better understand this nutrient/carbon export relationship, we are performing large incubation experiments and following rates of nutrient use using natural diatom communities that we fertilize with precise amounts of nutrients to simulate natural changes that can occur in the environment. These experiments will improve our understanding of how these changes in nutrient availability affect diatom growth, diatom photosynthetic efficiency, and carbon production, as well as whether diatom species composition shifts or their gene expression alters in response to nutrient amendments.

In addition, we are also using radioactive isotopes of carbon and silica to track changes in diatom nutrient uptake rates and their metabolic activity.  Working with the rest of the EXPORTS science team, we will evaluate how shifts in diatom nutrient physiology drive diatoms through different food web pathways that lead to the export of diatom carbon to the deep sea.

In order to understand the growth rates and functions of diatoms in their natural environment, it is also important to study them in their natural conditions, which can be challenging when you are roaming the ocean in a large metal ship.  To ensure that our experiments are free from contamination, we take special measures to guarantee that we are collecting iron-clean samples, which is where our trace metal experts come into play.

On this cruise, there are three main techniques (a trace metal trifecta) we use to collect iron-clean water and the diatoms in this water:

One: Trace metal clean rosette system.

This is the bread and butter of collecting clean water samples from depth. We send the bottles down open, and close them at specific depths to bring that water back to the surface for measurements. These are standard sampling devices on all research ships, but ours is special in that we have swapped the nasty metal parts out for clean plastic parts, and the metal wire replaced with a stronger and metal-free Kevlar wire.

Bottles loaded on the trace metal clean rosette system. The shower caps protect the openings from any contaminating particles that may be floating around the deck. Credits: Travis Mellett

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A short montage of the rosette system deployment and recovery from the stern of the ship. Credits: Travis Mellett and Salvatore Caprara

Two: Clean sampling spaces

One of the biggest problems we have with keeping samples clean is dust, which is absolutely riddled with iron and is everywhere aboard the ship. To avoid this, we create spaces where we pump only the finest of filtered air in to fill our delicate lungs and keep dust out of our samples.  On the ship we have two places dedicated to clean sampling. The first is out in the trace metal van at the back of the ship where our rosette bottles live and are sampled from hot off of a rosette cast.

The trace metal van is very close to the rosette, facing its back to the deck, where bottles are loaded and unloaded just before a cast is made. Credits: Travis Mellett

The second place we trace metal chemists feel comfortable enough to let loose and open our sample bottles is in our bubble in the main lab. The space is our clean, plastic fort we have constructed (and decorated) and pumped with clean filtered air (to puff the bubble) so we can still work in the main lab while avoiding the mess of our dusty and rusty neighbors.

Travis Mellett stands in front of the trace metal clean filter rigs collecting samples to analyze dissolved iron concentrations, which are placed under a hanging double filter air unit. Pete Morton stares longingly through the vinyl window that allows for visual communication with the outer bubble world. Credits: Bethany Jenkins
We use colored sharpies to allow others (and ourselves) to decorate the outside of the bubble and bring a little flair to the white space in the main lab. Credits: Kris Gomes

Three: Trace metal surface tow-fish

The fish allows us to collect clean surface seawater by swimming out away from the dirty wake of the ship and sipping up that delicious iron-clean seawater through a plastic tube that we have hooked to a Teflon pump, bringing it right into our bubble.

The trace metal team unleashing the tow fish for a morning of grazing on iron-clean seawater. Credits: Bethany Jenkins

Diatom Incubations at Sea

After collecting the diatom communities, we conduct a variety of experiments.  After fertilizing them with nutrients, we need to allow them time to grow and adapt to their new conditions, while maintaining otherwise natural conditions. To accomplish this, we use large deck board incubators, which are continually filled with flowing sea water collected from the surface to keep them at natural temperatures. The incubators are also wrapped in dark screening to help simulate light levels found within the water column where we collected each sample.

Twenty-liter bottles appear weightless in the incubator on the back deck at sunset. Credits: Alyson Santoro

We monitor the response of the diatoms by measuring how fast they take up the nutrients under natural and fertilized conditions.  In some experiments we use radioisotopes of silicon and carbon to do this, and we collect the samples in a special van dedicated to radioisotope use. In other experiments we look at how diatom physiology responds to fertilization by measuring what genes diatoms are turning on and off as they encounter different conditions. For these experiments, bottles that have been growing in the incubators are brought inside to the bubble to be harvested and ultimately filtered in the ship’s main lab. Water from the bottles is passed through a series of filters using peristaltic pumps to collect the larger diatoms as well as any other smaller organisms that are in the water. These filters are flash-frozen in liquid nitrogen, acting as a cellular snapshot, freezing the metabolic status of each cell in place for future analysis.

Work in the van is done under red light, which is nearly invisible to diatom photosynthetic systems, to prevent the diatoms from changing while we collect them by filtration. Credits: Mark Brzezinski
The filter rigs are used to sample genetic information from the experiments. Credits: Bethany Jenkins
The incubation bottle fertilized with iron is visibly different from other bottles, indicating it is filled with lots of happy diatoms. Credits: Salvatore Caprara

This combination of field and laboratory work, bridging chemistry and biology, will provide data that will improve our understanding of why diatoms follow specific pathways through the food web of the upper ocean, providing a predictive understanding of the processes that lead to carbon export by diatoms, which are one piece of the biological puzzle pumping carbon to the deep ocean twilight zone.

The team, from left to right: Travis Mellett (USF), Mark Brzezinski (UCSB), Pete Morton (UF), Salvatore Caparara (USF), Bethany Jenkins (URI), and Kris Gomes (URI). Credits: NASA

Getting Particles in the Northeastern Pacific: An Unexpected Honeymoon

On your mark: Muntsa Roca Martí ready to start the deployment of six pumps in the Northeast Pacific Ocean. Credits: Abigale Wyatt

by Montserrat Roca Martí / NORTHEAST PACIFIC OCEAN /

I am Montserrat Roca Martí, but I like to be called Muntsa, which is a Catalan name. I come from Barcelona, Catalonia, where I finished my PhD one year ago.

These last several weeks have been hectic and at the same time very exciting, as they included a wedding (my own, to be precise) and a big move from Barcelona to Falmouth, Massachusetts, where I am now a Postdoctoral Investigator at the Woods Hole Oceanographic Institution (WHOI). However, I didn’t spend much time in my new office. Instead, I spent most of my time getting equipment ready and packing over one hundred items of all shapes and sizes before leaving for Seattle in August.

Some Café Thorium team members, from right to left: Blaire Umhau, Abigale Wyatt, Sam Clevenger and Muntsa Roca Martí in their working van. Credits: Monserrat Roca Martí

All this activity is devoted to the Export Processes in the Ocean from Remote Sensing (EXPORTS) expedition in the Northeast Pacific. The primary goal of this project is to understand how carbon is converted from inorganic matter (carbon dioxide) to organic matter by phytoplankton. This forest of tiny photosynthetic organisms, mostly algae, represent the primary way the ocean is able to sequester carbon from the atmosphere, regulating Earth’s climate.

So here I am at 50ºN 145ºW aboard the R/V Sally Ride. I never would have imagined that I’d be spending my honeymoon in open ocean waters with 40 people, none of whom are my husband!

I belong to Café Thorium, a team comprised of amazing people who love espresso and also studying thorium in the ocean. We are interested in thorium—a radioactive, metallic chemical element—because it provides very valuable information about the transport of other elements, such as carbon, from the ocean surface to depth as particles sink. My main role in this expedition is to collect particles from different depths down to 500 meters in order to determine their composition and concentration in water. To do that, we use in-situ pumps, which are like underwater vacuum cleaners equipped with filter heads that we lower into the ocean to specific depths and turn them on. These heads contain filters of different pore sizes through which thousands of liters of seawater pass during four to five hours of intense pumping.

Steve Pike (Spike) and Claudia Benitez-Nelson preparing the pumps to be deployed. Credits: Montserrat Roca Martí

This operation requires strong and skillful people to lift nine heavy pumps and attach them to the wire that will transport them to the desired depths. Fortunately, two of our team, Spike and Claudia, are very experienced and have done this complex endeavor hundreds of times.

Large filtration pumps equipped with filter heads that will collect marine particles from 1000s of liters of seawater. Credits: Monserrat Roca Martí
Examples of our precious samples from down to 500 meters depth. Credits: Monserrat Roca Martí

When pumps are back on deck, we have to remove the filters as quickly as possible before the organic particles degrade. This is Rock & Roll time for Blaire and me. We sub-sample as many as 50 filters so we and others can measure a variety of parameters, including microbial activity, pigments and carbon. Only then can we safely store our precious samples until further analyses back at WHOI and a few other institutions. So far, we have collected over 500 samples from more than 77 cubic meters of water (more than 20,000 gallons) and counting! This is how I am spending my honeymoon!

On Finding Things in the Ocean

Crew members aboard the R/V Revelle retrieve a neutrally buoyant sediment trap from the ocean. Credits: Alyson Santoro

by Meg Estapa / NORTHEAST PACIFIC OCEAN /

Meg Estapa is an assistant professor at Skidmore College and leads the EXPORTS sediment trap team.  Her current work focuses on the optical properties of sinking particles and how these can serve as proxy measurements to help us better characterize the spatial and temporal scales of the biological pump. She is currently working aboard the R/V Roger Revelle.

One of the unusual things about the EXPORTS field campaign is the number of independently drifting instruments that we are using. These instruments include profiling floats, gliders, self-ballasted and moored sediment traps, and wave-powered profilers. Untethered from the ships, they multiply the observations we can make directly from the R/Vs Revelle and Ride. My team on the Revelle is responsible for all of the sediment traps and the wave-powered profiler (also known as the WireWalker). Right now we have seven different sampling devices to keep track of that are drifting out there in the ocean! Needless to say, in addition to our science, much of our mental energy at sea is taken up by one very important operational task: finding our equipment in the ocean.

Our sediment traps consist of cylindrical, rain gauge-like devices that capture sinking particles as they drift slowly downward over periods of days. They are attached either to a profiling float that carries them down to drift at depth (a neutrally buoyant sediment trap or NBST) or to an array of trap frames that dangle like a string of beads from a floating buoy at the surface (a surface-tethered trap or STT). None of the traps are connected physically to the R/V Revelle—we release them to drift on their own and then come back to retrieve them three to five days later. The ocean flows at speeds of a few kilometers per day, so the sediment traps won’t stay where we left them.

The buoy for the Surface Tethered Trap array carries a number of aids to finding the array and bringing it back on board.  Credits: Alyson Santoro. Annotations:  Meg Estapa

Recovering sediment traps requires us to engage in a carefully choreographed dance that begins with the deceptively simple-sounding task of locating the positions of our equipment in the ocean. All together there are usually 14 robots and sediment traps in the water out here at Ocean Station Papa, each with its own pattern of dives and resurfacings. These assets are spread out over a box that is roughly 30 nautical miles on a side (that is, 56 kilometers on a side, giving an area of over 3,000 square kilometers!). Visually spotting one of those tiny objects floating on the ocean’s surface is like finding a needle in a haystack.

To improve the odds of recovering our sediment traps, we rely on a collection of old and new technologies. The most important of these are GPS receivers that acquire precise location information, which is then transmitted via satellite back to computers on land. A second satellite connection allows us to access that location data over the Internet from the Revelle.  Some of our traps—the ones that have buoys at the surface—also send their GPS positions to the ship directly using radio transmitting beacons.  All of our traps have bright, flashing strobe lights that are highly visible at night, and some even have two! Finally, the buoy marking our drifting trap array carries an oldie but goodie: a metal radar reflector that bounces radio waves back to the antenna on the Revelle to be seen as a bright “blip” on the bridge’s radar screen.

When the time arrives to pick up a sediment trap, following the trail of GPS fix “breadcrumbs” is usually sufficient to bring the Revelle to within a mile or two of the recovery target. But a device drifting at the surface moves fast, and it takes a few minutes for GPS fixes to be relayed to us on the ship, so we’ll never find our target exactly at its last GPS fix. Especially for our smallest devices, the neutrally-buoyant sediment traps (NBST), the last and sometimes trickiest link is putting our eyes on the trap in the water.  Only the top of the NBST pokes out of the water when it’s awaiting a pickup—about the size of a yellow-and-gray soccer ball, with 25 feet of floating yellow rope streaming out beside it.

On a clear day it is just possible to spot an NBST from a mile away, and at night their flashing strobe lights are visible from a distance of perhaps two miles.  But the cloudy, misty weather out here is less than ideal.  On a typical trap recovery night, a visitor to the bridge of the Revelle would find a line of scientists and crew arrayed along the forward windows in near pitch darkness, hoping to be the first to catch a glimpse of the blinking strobe out on the water. The first exclamation of “I see it!” always produces a bit of an adrenaline rush for me! Following some expert ship handling to bring the Revelle right alongside the NBST, its precious cargo of samples and data is about to come back aboard.