Imagine a 12-hour flight that takes off and lands in exactly the same place. Now imagine willingly boarding that flight six days per week. This is the routine that NASA’s Operation IceBridge team in Punta Arenas, Chile, follows for six weeks every fall in order to collect data on Antarctica’s changing ice sheets, glaciers and sea ice. Operation IceBridge’s mission is to collect data on changing polar land and sea ice and maintain continuity of measurements between ICESat missions. The original ICESat mission ended in 2009, and its successor, ICESat-2, is scheduled for launch in 2018.
Our DC-8 flying laboratory can’t land on the icy surface of Antarctica, so instead we base our operations as close as we can get—near the southern tip of Chile. The schedule is grueling but incredibly important for maintaining a yearly record of Antarctica’s changing ice.
What is it like inside the airplane every day for those 12-hour flights?
There are generally about 25 of us aboard, including pilots and crew and a team of scientists and engineers who operate a variety of instruments measuring the thickness and extent of ice sheets.
Much of the roughly 12-hour flight is spent flying to and from Antarctica, with the meat of the science in the middle hours of the flight (between 3-9 hours after takeoff, if our mapping target of the day is near the Antarctic coast, or between 4-8 hours after takeoff if our mapping target is closer to the pole). Most of the instruments do not collect data until we get to Antarctica, so this leaves hours of downtime at the beginning and end of each flight for many of the people aboard (except for the pilots and navigators, of course!). We often fill this time with outreach and educational activities, as our airplane’s satellite data system allows us to live chat with classrooms back in the United States and all over the world. Over the past 4 years, nearly 5,000 students in K-12 classrooms across the US and in Canada, Mexico and Chile have connected directly with our IceBridge teams in-flight.
In order to keep ourselves in shape and build team morale, an informal airborne Antarctic workout club has formed to help pass the time during our long flights. Originally inspired by a Navy tradition of dropping and doing 25 pushups on the hour, every hour, our DC-8 version of this tradition persists on many missions due to the encouragement of DC-8 Navigator Walter Klein, Operations Engineer Matt Berry and by IceBridge Project Manager John Woods.
On recent IceBridge flights, in addition to (or in place of) pushups (depending on the person), the on-the-hour exercise also includes squats, stretching, yoga and ballet.
While not everyone gets up every hour due to their various duties, there are usually a few people nearly every hour doing activities to keep the blood flowing and their minds and bodies engaged during the long daily flights over Antarctica.
“Svalbard was really nice. Thule was really cold. Kangerlussuaq was really small. We’re still trying to figure out what Iceland is really.”
That’s principal investigator Josh Willis’ capsule description of the Oceans Melting Greenland (OMG) campaign so far. Approaching the end of a month-long deployment in the Arctic, the team members are pacing themselves to finish their mission without running out of energy, patience or clean socks. It’s been a marathon campaign, relocating to a new base every few days, each one in a different time zone.
But there are compensations. Even the been-everywhere, seen-everything crew of the NASA G-III has been impressed by the spectacular Arctic scenery.
Few people on Earth have seen as much of the Greenland coast as this team. It’s a dramatic coastline scored with hundreds of fjords. Many contain glaciers—the places where warm subsurface ocean waters may have a chance to melt Greenland’s ice from below. Behind the fjords is a jumble of rock, snow and ice, and in front is ice and water. The OMG crew has now dropped about 180 of its planned 250 probes in open water within fjords, along the coastline and out onto the continental shelf.
The team has been operating out of four bases: Thule, in northwest Greenland; Kangerlussuaq, in southwest Greenland; the island of Svalbard, Norway; and their current location in Keflavik, Iceland. The bases allow them to stay close to whatever part of the coast they’re measuring rather than wasting fuel flying for hours across the huge island from a single base. Each base is in a different time zone, and the farthest jump is five hours’ difference.
What about jetlag?
“With so many time changes, I don’t try to adapt,” said flight engineer Phil Vaughn. “I sleep when I’m sleepy.”
Blizzard season starts in mid-September in cold Thule. This being an air base, storms are ranked using the air controller’s alphabet: Alpha, Bravo, Charlie or Delta. One night, the OMG crew watched conditions deteriorate to Charlie—complete lockdown. “The winds blow snow from the local icecaps so thick that it decreases visibility and it’s dangerous to be outside,” Willis said. “You don’t go outside at all. We used the time to get a little bit of outside work done and answer emails.” The storm lasted about 20 hours.
Having that much time for anything but work was something of a luxury on a field campaign. The crew is required to take a “hard down” day after every six flight days, giving them a chance to catch up on sleep or chores. But in a new location, one day may not be enough to find fresh produce, do laundry or pick up supplies that have run out. Hotels offer most of these services, but the fee can be hefty. One crew member grumbled that he was charged $90 for a small load of laundry at an earlier stop.
When I asked what happens if someone gets sick, the crew just looked at me. Finally, flight engineer Terry Lee said, “You try to stay away from the other people.” That’s not physically possible in a small plane. But staying home isn’t an option either.
OMG’s mission success makes up for a lot of inconveniences, though. After weeks of practice and with the keen eyes of the pilots, Willis and the team have gotten very good at finding alternate drop locations in thick ice or cloud cover. Engineers Lee and Vaughn have become expert marksmen at hitting small patches of water. And though the scenery is undeniably jaw-dropping, Willis’ favorite sight from the entire trip is something quite different. “After we dropped one probe, we did a very steep bank and started to climb. I looked over my shoulder and saw a tiny splash. I think that was our probe hitting the water.”
The first thing you notice about the Oceans Melting Greenland (OMG) crew is the shared memories. “Where did we get that great pizza—Thule?”
“No, at the little restaurant in Svalbard, remember?”
The next is a story that begins “When we were in . . . ” could continue anywhere: Kazakhstan, Alaska or the Middle East. This is a team that has been working together well for a long time, in more far-flung locations than most world travelers even dream of.
The OMG crew is a textbook example of a high-performance team: a group with diverse and complementary expertise, well-defined jobs, ambitious goals and a strong commitment to the mission and to each other. On their arrival in Iceland, the group consisted of two mechanics/ground crew, two pilots, three flight engineers, the project manager and the principal investigator. A few people have swapped in and out since then, but each team member has distinct responsibilities, and each is essential to keep the mission running. “It’s been a great team effort here,” summarized flight engineer Phil Vaughn. “We’ve got the coordination down to a real good point where everybody knows what each other is doing.”
Johnny Scott and Dave Fuller are the ground crew, responsible for preflight and postflight checks and routine maintenance. Scott has worked on the NASA G-III for eight or nine years. The preflight check, which takes an hour or more for the two crew members, includes a walkaround where they simply apply their trained eyes to the aircraft inside and out. “After you’ve looked at the airplane so long, you’ll catch things fast,” Scott said. “You’ll say, ‘Hey, that’s not right.’ You’ll investigate. Most of the time you don’t find anything [significant], but you might find a leak or a crack, or something out of place.”
Arctic cold hasn’t added a lot of additional maintenance chores, Fuller said, because the planes are in heated hangars at their bases. The main difference Is air pressure. Just as you change your car’s tire pressure in winter in a cold climate, the plane systems also need to change. It’s not just tires: it’s things like the brake accumulator pressure—the reserve air needed for emergency brakes. “If the conditions are set correctly on the ground, then the plane will be fine while flying,” he explained.
Flying is the business of the pilots, and so are all the concerns that go with it—weather, flight plans, fuel management and a multitude of details. Bill Ehrenstrom is the pilot in charge. He and Scott Reagan have flown so many hours over Greenland already that they were concerned they would hit the 30-day limit of 100 hours, so they were joined in Iceland by Chris Condon. “We’ve been lucky to see things that a lot of people don’t ever get to see,” Ehrenstrom said about flying all those hours. “But the weather has been a challenge. We haven’t been able to drop probes in some place because of the weather, and it hasn’t always been the greatest at the sites.”
All three pilots had former careers in the military, and Reagan is planning to undertake a third career soon that some people would find even more intimidating than his first two: teaching high school history or physics.
“Never in my life did I think I’d get to drop things out of the airplane when we were out flying,” said flight engineer Vaughn. A flight engineer is responsible knowing all the plane’s electrical and computer systems and monitoring them during the flights, as well as supporting the pilots. On top of that, it’s safe to say that Vaughn and Terry Lee are the world’s experts on dropping probes out of a G-III—this is the first experiment ever to do such a thing, and the aircraft had to be specifically modified to allow it. “It’s kind of a rush,” Lee said.
“Project manager” sounds like a desk job, but not on a NASA field project. Steve Dinardo doesn’t just track expenses; he tracks probe data at the airborne computer as well as shipboard operations in support of OMG and myriad other details. “To get this to all hang together and work sometimes is a miracle,” he said. Dinardo started at NASA working on space missions. “Aircraft projects are a lot more fun than spacecraft and a lot more challenging. I get to see the whole project from Step 1 to Step 100. That’s something you don’t get with spacecraft.”
The last team member is principal investigator Willis. OMG is his brain child, and he’s responsible for overall execution, as well as helping with science-related decisions in the field such as choosing good alternate sites for probe drops if the original choice is too iced in. Willis has integrated well with the rest of the crew, and he’s thrilled with their work. “I couldn’t have asked for a better team to support this mission,” he said. “It’s been a spectacular ride.”
The Oceans Melting Greenland science team carefully planned each location for the team to drop its ocean probes. Some sites are in narrow fjords; others are hundreds of miles out on the continental shelf. Each site was chosen to add value to the data the team is collecting.
The two biggest enemies of this planning are ice and weather.
Sea ice is at its lowest at this time of year, but there’s plenty of it around Greenland, especially in the north. The probes can’t punch through it to reach the water below. If a drop site is ice covered, the team looks for a location that is “close by and second best,” said principal investigator Josh Willis. They might need to go to the next fjord over or a bit farther out on the shelf. Since no data whatsoever have been collected from much of the northern coastline, these alternatives have value too.
Project manager Steve Dinardo has been working on airborne projects for 38 years. “Weather is always the problem. When you don’t want clouds, you get clouds. When you want clouds, you don’t get them,” he said.
OMG doesn’t want clouds. If the team can’t see the ocean, they can’t risk hitting a ship or whale by blindly dropping a probe. “We’re always looking for places where we can get a lot of work done in a short period of time,” Willis said. “If we fly in a region where the clouds are low and we can’t see the water through them, those can be really frustrating days.”
Turbulence can be a problem as well. To prepare and drop the probes, team members have to move around the cabin, not sit with the seatbelts securely fastened like commercial airline passengers.
On the windy flight of Oct. 1, Dinardo was sitting at the computer to read the probe data. “We were getting pretty hammered in the back,” he said. “Between me vibrating up and down and the keyboard vibrating up and down, I hit a number-lock key on the keyboard. The computer froze and I had to reboot it.” Despite that mishap, it was a successful day, with 14 probes dropped and returning signals.
Over the weeks of the mission, the team has gained skill at hitting small targets, Willis said. “We got really lucky one day when we were operating out of Svalbard, Norway. On a day when we were particularly frustrated by ice, we found a gigantic iceberg pushing through a huge area of sea ice, leaving a small wake behind it. The team amazingly bullseye’d the wake, dropping an ocean probe right through the water on the backside of the iceberg. It was a shining moment when the team showed we could hit a very small target from an aircraft traveling 200 knots.”
Today, however, weather is keeping the team on the ground. For several days, Dinardo and senior pilot Bill Ehrenstrom have been watching a forecast storm approach from the south. Today, it finally arrived. The crew was grounded by clouds and gusty winds over Greenland. Tomorrow doesn’t look any better, with the forecast calling for gusts up to 55 miles per hour.
“I think we have at least one more day before we have any chance of flying,” Ehrenstrom said, though he won’t make the final call till tomorrow morning.
Over the last three weeks, the Oceans Melting Greenland team has spent many hours flying over spectacular Arctic scenery. Fjords, glaciers, icebergs, the northern lights — they’ve seen enough sights to fill a guidebook. But the most compelling view, the view they came all the way north to see, is on a computer screen inside the plane.
OMG is in the field this fall to do one thing 250 times: drop ocean probes from an airplane around the entire coast of Greenland and read its measurements of ocean temperature and salinity. Relayed to the airborne computer, the data from the probes shows where warm, highly salty, subsurface Atlantic water is able to reach the bottoms of glaciers along the coast.
This water is warm only in comparison with the polar runoff that forms the surface layer, but its extra 6-8 degrees Fahrenheit (3-4 degrees C) makes it plenty warm enough to melt glacial ice. The polar water can be as cold as 4 degrees below freezing Fahrenheit (-2 degrees C). At those temperatures it doesn’t melt ice at all.
On 13 research flights since Sept. 13, the team has dropped 163 of the probes around all of Greenland except the southeast coast. They’ll pepper that coastline with the remaining probes from their new location in Keflavik, Iceland.
In the last year or two, various research teams have done seafloor surveys of a few Greenland glaciers and found deep gashes on the edge of the continental shelf where subsurface warm water can creep up on the shelf and melt the glaciers more quickly than the colder shallower water. But these few locations to the whole coastline would be risky business. Willis says that when they began the survey in mid-September, “I didn’t know what to expect. We knew that Atlantic water was getting into a few of these fjords, but the shelf has not been measured extensively before, and satellite data won’t tell you if warm, salty Atlantic water is there because it’s so far below the surface. You have to go drop a temperature sensor in the water.”
The probes relay their measurements in real time to the airborne computer, so the OMG team got views of subsurface conditions starting with the very first drop. As the measurements kept rolling in, the view from the computer screen became more and more disturbing.
“Very soon, it became clear that there was a good deal of warm water on the shelf — not just in the fjords but spread out. As we mapped farther and farther north, we could see more warm water on the shelf. Now we’ve sampled [most of] the continental shelf, and everywhere that it’s deep enough, there seems to be Atlantic water present,” Willis said.
It’s unlikely that the southeast section will contain surprises, he added, because scientists already know that glaciers in this sector are melting very quickly and ocean warming is evident on the surface.
Willis emphasizes this is only a first impression from watching the data on screen. However, he pointed out, “Every time we make a discovery about ice melt in Greenland, we find the picture is worse than we thought it was before. I don’t think this will be any exception.”
AN ARCTIC PORFOLIO
Crew members of NASA’s Oceans Melting Greenland mission have seen extraordinary sights during their latest deployment, both from the plane and at their four bases. Here are a few highlights.
NASA’s Ocean Melting Greenland, or OMG, campaign is back in the Arctic, and this month it’s dropping scientific probes out of a NASA aircraft into the water just off Greenland’s coastline. The probes are the fourth and final part of OMG’s observations this year documenting how seawater is melting the underside of the world’s second largest ice sheet.
Three things about Greenland: it’s huge, it’s remote, and it’s melting so fast that scientists use words like “falling apart” and “vanishing” to describe what they’re seeing. But the hugeness and remoteness mean that many parts of the island have gone completely unmeasured. There aren’t enough data for scientists to be confident that they understand how processes are interacting now, much less how the melting will progress in coming years.
“It’s hard to predict what’s going to happen to Greenland because we’ve never watched it melt before,” said Josh Willis, OMG’s principal investigator with NASA’s Jet Propulsion Laboratory, Pasadena, California. The measurements OMG is making this month, and over the next four Septembers, should reduce some of the uncertainty.
To collect data around Greenland’s entire coastline, the OMG team is using four bases. Slice two imaginary lines across the island, one north-south and the other east-west, and there’s a different OMG base for each quarter, more or less. The bases for measuring the west side of the island are on Greenland itself; for the east side, the bases are in Iceland and on the Norwegian island of Svalbard.
OMG isn’t moving methodically around the island. It’s spending a few days in one location and then another, sometimes doubling back to the first location, as logistics and weather dictate. An Earth Expeditions reporting team will catch up with the team in a few days from Iceland. For now, here are some images from the field, captured by the team members themselves.
Willis and the other OMG scientists timed this campaign to coincide with the Arctic sea ice minimum (conditionally announced on Sept. 10) so they would have the best chance of finding open water to drop probes into. But even at minimum, there’s still plenty of ice around Greenland. In loosely packed ice like this, dropping probes has been no problem. But in other locations, the water is almost completely covered with big plates of ice separated by narrow cracks, testing the team’s ability to hit their open-water targets. Some areas are completely ice-covered, with no possibility for dropping probes.
If you want to drop probes along the coast, you need to be able to see the coast. The weather doesn’t always cooperate. On this day, no data were successfully collected.
The probes are similar to those dropped by hurricane hunters to monitor the ocean during storms. There’s a parachute to waft the package safely to the ocean surface. When it hits the water, a float inflates to hold up a radio transmitter. A sensor, tethered to the transmitter by wire, sinks some 3,000 feet (if the water is that deep), measuring water temperature and salinity on the way down. The transmitter relays these data back to the aircraft. OMG will drop about 250 of these probes by the end of its deployment in early October. Combined with maps of the seafloor shape around the coast that OMG is also producing, the probe measurements will give a picture of where warm, deeper water can creep onto the continental shelf and eat away at the glaciers fringing the ice sheet.
by Alan Buis / OFF HERON ISLAND, QUEENSLAND, AUSTRALIA /
Bob Carpenter surveys the seafloor surrounding the research vessel Anthias as it glides over Blue Lagoon, the largest part of the reef that envelops Heron Island. He and his team, which is conducting the in-water validation of reef metabolism for NASA’s Coral Reef Airborne Laboratory (CORAL) mission, are searching for a good spot among the numerous small patch reefs in the lagoon to erect what he calls an “underwater construction project.”
The boat stops to look at an area more closely.
“It’s looking pretty algalicious here,” says Carpenter with a laugh, knowing he just made up a word. He asks skipper Sam Ginther, a research technician at California State University, Northridge, where Carpenter is a professor of biology, to continue to another location.
Carpenter has brought his three-person team to the Great Barrier Reef to make in-water measurements of the productivity and calcification of the community of living organisms found on the seafloor here at Heron Island and also at Lizard Island, on the northern Great Barrier Reef. Their data will help the CORAL team validate CORAL’s advanced Level 4 science products.
It’s mid-September and day two out in the field for the team at Heron. They’ll be here for another week, installing instruments at up to 10 sites around Heron Reef. Yesterday they deployed a float called a drogue to track the paths of currents below the water surface to help guide their placement of instruments. On today’s trip they’ll be deploying two types of instruments: samplers that collect water for later analysis in the lab, and gradient flux instruments that measure oxygen and water flow.
At this location they are deploying the “gradient flux” instruments. The instruments will measure two of the three key aspects of reef metabolism his team is studying: primary productivity and respiration (the third is calcification). Metabolism refers to the processes by which reef communities acquire energy for growth and build their limestone skeletons.
The team must work quickly, because the high and low tides here at this time of the month are extreme.
“I think the difference at this time of day is 7.2 feet, so we need to get out to the lagoon when it’s high tide so we’ll have deep enough water to navigate in when we’re entering the lagoon and going over the reef crest,” says Chiara Pisapia, a postdoctoral researcher from Italy who came to Australia six years ago and recently completed her postdoc at James Cook University. She’s now joining Bob’s group at CSUN. “If we’re still in the lagoon when the tide goes down, we’ll be stuck here until the next high tide.” The team will have a little more than two hours in the lagoon, which averages about 11 feet in depth, to accomplish today’s tasks. The instruments have to be placed where they won’t go dry when the tide goes out.
The gradient flux system—oxygen sensors and acoustic Doppler velocimeters—will be mounted at two heights above the seafloor. The bottom instruments are placed 4 inches above the flora and fauna on the seafloor, with the top instruments placed 43 inches above the seafloor. The method they’re using relies on the flow of water to carry water and oxygen (either produced by photosynthesis or taken up by respiration) past the instruments.
“The water here doesn’t always flow in the same direction, so we’re looking for a coral patch that’s fairly uniform where the water will carry data signals on the surrounding habitat past these sensors,” Carpenter says. “We’ll then place the sensors right in the center of that patch so they will integrate the metabolism from that point to a larger scale: anywhere from 108 square feet to perhaps 538 square feet , depending on the speed of the water flow. Since the pixel size for PRISM’s spectrometer on the Gulfstream IV aircraft is 86 square feet, we’re able to match its scale really well.”
The team locates a suitable spot in the lagoon and gets to work, donning scuba gear and taking the equipment they will need down to the seafloor below. The equipment includes a tall cylindrical stand with adjustable brackets and clamps that hold the four gradient flux instruments in place at fixed heights to eliminate any bias in the measurements.
The sensors will continuously measure oxygen and water flow across the layer of water directly above the organism-covered seafloor, providing measurements of the area’s net productivity during the day and its respiration at night. Upon completing the installation, the divers release a special yellowish-green, reef-safe dye, which allows them to verify that water is flowing across the instruments. A member of the team notes the location of the installation using a portable GPS receiver. The team will repeat the process tomorrow, moving the instruments to a new location on the reef every 24 hours.
Earlier in the day, the team used GPS coordinates to locate instruments they installed in the lagoon yesterday that are used to measure reef metabolism, and placed two CSUN-built integrated water samplers at the same locations. The water samplers were placed about 1,312 feet apart, one downstream from the other, moored to the seafloor. They remain in place for five consecutive days.
“The water samplers take tiny little sips of water—only about 3 or 4 milliliters a minute—and they do that for six hours, so you get this long-term water sample, and we do that at both ends of the transect, and then we can come out tomorrow and collect the samples from the sample bags,” Carpenter says.
The team swaps the sample bags out and takes them back to the lab to analyze for total alkalinity. Changes in total alkalinity can be used to estimate reef calcification, a key element of reef metabolism.
Calcification is the secretion of calcium carbonate—what we think of as limestone. Coral skeletons and other calcifying organisms such as calcified algae build the reef framework, allowing reef systems to grow vertically over time to create the largest biogenic structures on Earth. The process of calcification is fundamental to the growth of corals and reefs in general. As climate changes and sea surface temperature and ocean acidification increase, calcification is predicted to decrease. In fact, experiments are showing that calcification decreases with simulated increases in ocean acidification and temperature.
Carpenter says the team wants to sample as many different habitats as they can so that CORAL’s benthic cover in-water validation team will know exactly what the metabolism is for these different habitat patches. “We install the instruments in a location, leave them for about 24 hours, and mark them with a float,” he says. “Then the benthic cover team comes the next day and creates their photo mosaic of the area. So we end up knowing exactly what’s there and exactly what the rates of metabolism were in those same patches. We can then match those different habitats with PRISM data to hopefully extrapolate what the reef is doing on a larger scale.”
Their work for the day complete, Pisapia takes the helm and carefully navigates the boat through the shallow corals out of the lagoon and back to the harbor. Tomorrow they’ll go out again and move another set of instruments. Their work here on Heron Island will be followed by several months of data processing and analysis.
As they head for shore, a large humpback whale and her calf breach out of the water a short distance away. They stop for a minute to watch in awe. Life is good.
by Alan Buis / OFF HERON ISLAND, QUEENSLAND, AUSTRALIA /
It’s a warm and sunny morning in mid-September as Stacy Peltier and her colleagues on NASA’s Coral Reef Airborne Laboratory (CORAL) mission survey team prepare for their first day in the water at Heron Island, a 42-acre coral cay about 45 miles off the coast of Queensland, Australia. As she places a Nikon D5500 camera into an underwater housing, several sharks swim nearby in the aquamarine waters of the island’s small harbor dredged out of the reef.
“I’ve never jumped in the water with tons of sharks before,” she quips with nervous laughter. Fortunately for her and her team, the sharks found around Heron Island aren’t particularly dangerous to humans.
The research technician from the Bermuda Institute of Ocean Sciences (BIOS) and her three teammates have come to Heron Island as one of three independent, but coordinated, in-water validation teams that are collecting data on reef condition at Australia’s Heron and Lizard Islands during CORAL’s two-month Great Barrier Reef study. This “ground truth” data will be compared with data collected from the air by NASA’s Portable Remote Imaging Spectrometer (PRISM) instrument to validate the accuracy of the PRISM data and map products. Three fundamental types of data are being gathered: water optics, reef benthic cover and reef metabolism.
Benthic cover is what grows on the seafloor. Reef benthic communities typically consist of a combination of coral, algae and sand. Over the next week, the benthic cover team is collecting a series of high-resolution photomosaics that will depict the composition of the various seafloor communities at multiple spots around the Heron Island reef.
Surveys of reef benthic cover are needed to validate some of CORAL’s more advanced data products. The CORAL mission is collecting benthic cover data for 160 to 250 separate sites across each reef validation location in the global mission. The team will analyze the mosaics to make a highly accurate determination of the percentages of various types of benthic cover in each photo.
By 9 a.m., the boat is loaded with the team’s research equipment and scuba gear. Peltier, co-skipper on today’s trip, slowly guides the Heron Island Research Station research vessel Chromis out of the harbor. As they head out, the ghostly, rusted wreck of the HMCS, Australia’s first official naval vessel, sits on its side on the reef crest at the entrance to the harbor.
On board with Peltier are teammates Yvonne Sawall, a postdoctoral scientist at BIOS; research technician Andrea Millan and team leader Steven Dollar, both of the University of Hawaii; and NASA CORAL project scientist Michelle Gierach, who’s come along to observe and assist from the boat.
Peltier radios the research station to report that there are seven passengers on board and that we are expected back to harbor at 4 p.m.
“Research, Research, Research, this is Chromis,” she says.
The station confirms, and informs us that the Gulfstream IV aircraft carrying NASA’s PRISM instrument is on its way to fly over the Heron Island region and is expected soon.
Our first dive point is an area called Blue Pools. The team attaches the boat to a mooring buoy. The water depth is about 20 feet.
The team quickly gets to work, donning scuba gear and plopping backward into the 72-degree Fahrenheit water. The skipper does not get in the water; she must remain with the boat at all times for safety purposes. The divers are handed one of the three cameras on board and they submerge.
It’s painstaking work. One team member first lays 1.6-foot-long poles across the seafloor to delineate 33-by-33 foot square plots, a size that correlates to the spatial resolution of CORAL’s PRISM instrument from 28,000 feet above sea level.
The other team members use their cameras to photograph the entire plot, with one diver scanning east to west and the other scanning north to south, swimming about 6 feet above the seafloor. A snorkeler at the water’s surface carries a handheld GPS unit to precisely mark the location of the plots to correlate with the plane data.
The team takes up to 1,000 pictures per plot, a process that takes 15-20 minutes. On a typical day the team will do two to three locations, collecting measurements from three to four sites at each location. They start in the deepest water, then move up the slope of the reef toward shore. If the water becomes too shallow they snorkel instead of scuba.
Later, back on land, a special software tool called Agisoft PhotoScan will stitch all the photographs together into a mosaic, which scientists can then use to characterize what the community structure of the coral reef is at the given spot.
“This is a new way of assessing reef structure and function using this mosaic, and we’ll follow it with analysis of these pictures to be able to see things you can’t see any other way but by jumping in the water and putting your eyes on it,” says Dollar, a coral reef biologist and environmental consultant. “This is the equivalent of going from a Model T to a Tesla compared to the way previous reef studies have been done. And the biggest thing that allowed this to happen is digital photography. Here, each time we come out of the water, we’ve taken up to a thousand pictures. This was not possible before the advent of digital photography.”
“We want to get as many different benthic community types as possible, and then match up the mosaics with the pictures we get from the airplane,” says Sawall, a postdoc with CORAL Principal Investigator Eric Hochberg at BIOS, where she specializes in coral metabolism.
A native of the south of Germany, Sawall was first inspired to study coral reefs when she dived the Great Barrier Reef at age 19. “It was my first experience in the ocean; I loved it so much,” she says. “The interplay between the organisms fascinated me. Yet at the same time I could see the impacts that humans were having on reefs, and that drove me to want to protect them.”
Sawall views the team’s work as a vital stepping-stone in our understanding of the health and status of coral reef ecosystems worldwide. “The goal of CORAL is to eventually assess reefs around the world and their status and health and monitor that over time,” she says. “What we are doing here is a little puzzle piece toward achieving that goal.”
The team finishes its work at the first dive location, which is primarily rubble (rocks, sand and dead coral), then they move closer to the reef, which consists of a variety of living corals occurring in a multitude of growth forms. The highest coral cover is typically found on the outside and slope of a reef, while inside the reef lagoon, algae and sand dominate the bottom.
Their first dive location completed, the team stops briefly to munch on some Tim Tams, Australian chocolate-covered biscuits; these have a distinct coconut taste. As they break, schools of little black fish swim next to and below the boat, attracted by our presence. One of the team spots a green sea turtle swimming nearby. The seas are calm.
I ask Peltier to describe what she’s seeing below the surface.
“The reefs at Heron Island are beautiful,” she says. “We were recently at Lizard Island on the northern Great Barrier Reef and you could see a lot of damage from both cyclones and the big bleaching event that happened this summer. But Heron Island farther south has been relatively untouched. We visited a few rubble sites, which are natural. The parts that were covered in coral were just incredible — we saw corals growing on top of corals, which I haven’t seen before. This is my first time diving in an area that has gigantic plate corals.”
Next it’s off to our second survey location, a place called Tenements 2. The team repeats the process of photographing plots of seafloor. As they work, the tide continues to go out, exposing coral heads, which rise like a modern-day Atlantis from the seafloor. Waves begin cresting as they hit the top of the reef. Flocks of birds circle above, looking for lunch.
Their second site completed, the team is ready for lunch themselves. I ask Millan, a native of Troy, Michigan, with the University of Hawaii about her impressions of the second dive site.
“I was surprised by the large diversity of coral, including fire coral,” she says. “There was a big school of unicorn fish. I wanted to go take a look at some things, but I had to keep telling myself, ‘Just keep swimming, stay on the square,’” she says with a laugh.
After lunch, it’s off to the final site: Libby’s Lair. Millan first does a quick snorkel trip to survey the location. It looks suitable, so the team suits up and goes back in the water. They report lots of varieties of coral and big fish.
As the day wraps up, the team is joined by another boat carrying two CORAL Australian collaborators from the University of Queensland: Stuart Phinn and Chris Roelfsema. They are doing separate in-water validation work in conjunction with the other CORAL validation teams. Chris joins us in the water, taking photos and video.
It’s now a little after 3 p.m., and our team has completed its surveys for the day. It’s time to head back to the harbor, unload the boat and clean the equipment.
Today the team photographed seven sites, while PRISM aboard the Gulfstream IV collected 17 lines of data on a nearly 6-hour flight. Today’s activities, combined with the CORAL team’s previous flights up and down the Great Barrier Reef and in-water validation activities at Lizard Island, mean that CORAL is well on its way to achieving its Level 1 science objectives in Australia. All in all, a good day by air and sea.
Heron Island: Like Nowhere Else on Earth
Heron Island is a 42-acre coral cay located within the World Heritage-listed Great Barrier Reef Marine Park, 45 miles (72 kilometers) off the coast of Queensland, Australia. It is surrounded by a 5-mile-long (8-kilometer-long) platform reef that drains at low tide to form a large lagoon around the island.
First discovered in 1843, Heron Island housed a turtle canning factory in the 1920s, but today it is best known as a popular destination for tourists and researchers alike. It was declared a national park in 1943. The island includes a resort and the Heron Island Research Station, Australia’s largest university marine research facility, which is operated by the University of Queensland. The station is involved in research and education on marine sciences and the marine environment.
Heron Island and its surrounding reef teem with life, including sea turtles, whales, sharks, rays, sea cucumbers, sea stars, Christmas tree worms, sea hares, algae, many other varieties of fish, crabs, shrimp, and of course many different species of coral. Named after the reef herons seen feeding on the reef flats, the island is a bird haven: In the summer its bird population is estimated at around 200,000. Flora include grasses, herbs and trees.
My heart races as I sit snugly buckled in the leather seat of our modified Tempus Applied Solutions Gulfstream IV aircraft on the runway at Australia’s Cairns Airport. For NASA’s COral Reef Airborne Laboratory (CORAL) team, the anticipation is palpable – after days of weather delays, would this be the day we get airborne again? Soon I hear the engines roar to life, and we bolt down the runway, faster than any plane I’ve ever flown in before. We go airborne and climb sharply through mostly cloudy skies, then bank left and head south over the Coral Sea. It’s 8:54 a.m. Australian Eastern Standard Time on Sept. 15.
Within minutes the Great Barrier Reef comes into view, in all its stunningly beautiful majesty. A shimmering, luminescent spectacle in shades of aquamarine, turquoise, cyan, white and more, the sight of the massive reef is enough to move one to tears. First a long crescent appeared, fringed by whitecaps, then a wispy auradescent amoeba. As we head farther from the coast, more reef structures appear in an array of sizes and shapes, their sight obscured at times by pockets of clouds. Above us, the sky shines blue and bright; below, clouds dot the seascape. We’re on our way.
It’s hard to imagine that less than three hours ago, as the team assembled for a 6 a.m. weather briefing, the odds of flying seemed uncertain at best due to clouds looming off the coast. Clouds are the enemy of CORAL’s Portable Remote Imaging Spectrometer (PRISM), developed by NASA’s Jet Propulsion Laboratory in Pasadena, California. CORAL will investigate the condition of the Great Barrier Reef and representative reef systems worldwide from its airborne perch 28,000 feet (8,500 meters) above sea level. For the past several days, clouds had grounded the CORAL team.
Hovering above a laptop computer in an office at the plane’s hangar, CORAL project system engineer and mission campaign manager Ernesto Diaz and NASA CORAL project scientist Michelle Gierach, both of JPL, reviewed an animated sequence of satellite cloud imagery. Other members of the team watched or listened in by phone. To the south, the images revealed pockets of clearing over some of CORAL’s target areas. But would the clearing hold for the several-hour duration of a flight?
On the phone Stuart Phinn, professor of geography at the University of Queensland, recommended flying, as the forecast for the next few days was only going to get worse. After further discussion, Diaz recommended the team reconvene at 8 a.m. to make a final go/no-go decision and instructed pilots Josh Meyer and Curt Olds to tow the plane to the tarmac. He also asked the PRISM team to begin preparing for flight. The five-member JPL team aboard the flight – Diaz, optical engineer Holly Bender, lead technician Scott Nolte, JPL videographer Jim Round and I – boarded the aircraft.
As the clock ticked, conditions remained marginal. Finally, it was 8 a.m., and the team convened again by phone. The clear patches to the south had remained. After a few more minutes of discussion, Diaz said, “We are a go.” The target area for today was a region of the Great Barrier Reef near Mackay.
Returning to present time, we head south along the Queensland coastline. It will take about an hour to reach Mackay, located on the south central portion of the reef. The team has targeted up to 20 flight lines to survey with PRISM today out of the CORAL campaign’s planned 151 flight lines over the reef. Our total flight time is expected to be up to five hours (two hours if the weather doesn’t hold when en route).
Diaz and Bender spend the early part of the flight ensuring that PRISM’s flight tracker is set up and jotting down flight lines, while Nolte monitor’s PRISM’s performance. The crew all wear headsets to facilitate communication between themselves and the pilots. PRISM’s focal plane temperature slowly begins to stabilize and eventually reaches its nominal 0 degrees Celsius (32 degrees Fahrenheit). Nolte also monitors the temperature inside the PRISM telescope and the pressure between the vacuum vessel. Thus far, everything looks normal.
We continue heading south, paralleling the Queensland coast, toward our destination about 375 miles (604 kilometers) south of Cairns, a bit more than the distance between Los Angeles and San Francisco.
I ask Diaz and Bender what’s going through their minds at this point in the flight.
“I’m hoping we have no clouds,” says Diaz. “I’m anxious to see how our forecast go/no go decision pans out.”
“I’m really excited,” says Bender, a 10-year JPL employee whose previous NASA airborne flights were in an unpressurized Twin Otter plane. “This is the fourth JPL imaging spectrometer I’ve flown with, but my first day operating PRISM for CORAL. Back at JPL, I work on the optical design and alignment for many of our imaging spectrometers, but to follow an instrument start to finish—from concept to seeing it out in the field—is an incredible feeling. I’m excited to see the data we’re going to get.”
This is essentially a training flight for Bender—the job of collecting PRISM CORAL data is normally a two-person job. The CORAL team members work in two-week stints.
Heading farther down the coast, the city of Townsville appears below along an irregular coastline. To the west, Australia’s vast interior is largely hidden beneath cloud cover. To the left, a large, mostly cloud-free area opens up, with scattered islands piercing the sea surface.
As the team reaches the first target region, they find a mix of cloud cover but it is within acceptable limits. They decide to begin collecting data along their first flight line. A beeping sound from the flight planning tool that sounds something like a percolating coffee pot begins signaling that PRISM is collecting data, in a ground swath measuring 3 miles (4.75 kilometers). They complete the data collection, then maneuver the plane to its next target line, then a third. As they assess the three lines collected, portions of the lines appear cloud-free, while others have 100 percent cloud cover. The team makes a real-time decision about whether to proceed to the next nearest flight line or skip it in favor of one with less cloud cover.
The aerial survey “mows the lawn,” so to speak, as the plane flies back and forth across target regions that have about a 15 percent overlap. Adjacent target flight lines may be in a completely different direction—CORAL scientists target representative reefs across a transsect of the reef from the coastline to the outer reef.
In the meantime, Nolte continues to monitor PRISM. His computer screen shows various data, including the plane’s pitch and roll and its heading, along with a visual of what PRISM sees and a more human-friendly view of the ocean below.
As they continue collecting data, the decision to change the flight plan pans out as flight lines appear to be mostly cloud-free. The team decides to not collect data over some of the flight lines, either due to unfavorable cloud conditions or the sun’s angle above, which becomes increasingly unfavorable as the morning flight continues. “We have about three hours in the morning and three in the afternoon where there are ideal lighting conditions,” Bender says.
After the team completes its 13th line, they decide to return to base. A future flight may collect the other lines. CORAL’s level one science requirement is to image at least half of the mission’s targeted sites. The plane touches down back in Cairns at 1:16 p.m., a little more than 4 hours after takeoff.
“We started off with clouds in the first few lines, but we ended up getting some good weather,” Diaz says. “We collected a good cross section of data from the inner reef to the outer reef. Our decision to fly today was a good one, and PRISM performed like a champ.”
Following the flight, the team shut down the PRISM instrument, removed the nearly 500 gigabytes of data collected and transferred the data to a field server where data processing begins. Initial quick-look data providing a snapshot of what was mapped are typically available within a day—these can sometimes be used to plan the next day’s flight activities. Level one data products take an additional day. More advanced data products are processed off-site.
With the completion of the successful flight, the CORAL team has now collected about a fifth of the data planned for the Great Barrier Reef deployment. The team will remain in Australia through the end of October.
by Alan Buis / Cairns, North Queensland, Australia /
On a non-flight day this week, I had a chance to chat with some of the crew from NASA’s Jet Propulsion Laboratory who are here in Australia to support the Coral Reef Airborne Laboratory’s (CORAL) Great Barrier Reef deployment about their roles in the mission.
Ernesto Diaz is CORAL’s project system engineer and mission campaign manager. He joined JPL in 2010 and is currently in JPL’s imaging spectroscopy group, working on PRISM and other spectrometer instrument programs that are pathfinders to develop technology for a planned NASA satellite called the Hyperspectral Infrared Imager.
Among Diaz’s responsibilities is to assess the weather each day to determine if a flight will be attempted. The team’s routine includes daily 6 a.m. weather assessment briefings. Diaz bases his assessments and recommendations on data from the Australian Bureau of Meteorology.
“I’m not a meteorologist,” he said. “But I’ve come to understand weather patterns well. A key is assessing how weather patterns are going to evolve over the course of a typical CORAL flight over the Great Barrier Reef, which can run from three to six hours.”
Because PRISM is a passive imaging system, meaning that it records the amount of light energy reflected back to it from Earth’s surface, it requires a cloud-free view to the ground below. CORAL’s science requirements state that cloud cover over a target area must be less than 20 percent, including clouds both below and above the plane. Winds must also be light, because strong winds create chop on the sea surface that interferes with PRISM’s performance.
Diaz said PRISM has two flight opportunities each day: one in the morning and one in the afternoon. On days when the initial 6 a.m. forecast looks favorable, the team is given a go to turn the PRISM instrument on. A second weather go/no-go call is then made at 8 a.m. prior to a takeoff at 8:30 a.m. Morning opportunities are typically better for winds.
The CORAL Great Barrier Reef deployment requires collecting data from 10 regions over the reef, and the PRISM aircraft is limited to a total of 48 flight hours. Because weather and technical delays are unpredictable, the CORAL mission has allotted a full two months to collect the necessary data. “There’s no reason to rush and get bad data,” he said. “We want to get the best possible data on flight days. When we don’t fly, it’s an opportunity to do routine maintenance.”
Diaz says CORAL is his favorite project since he’s been involved with it since its inception and he designed all the flight lines for the campaign. Imaging spectrometers have taken him not only to the Pacific, but to Chile and India as well. On the team’s day off this week, he and his wife went to Kuranda Koala Gardens, about 45 minutes north of Cairns, and got to hold and pet a koala. “It’s a perk of the job,” he said.
Technician Scott Nolte built hardware for PRISM’s high-powered UNIX-based electronics subsystem, which has the highest signal-to-noise ratio performance of all of JPL’s imaging spectrometers.
Nolte has worked at JPL for 33 years, 15 of them in the lab’s imaging spectroscopy group. He said he’s seen a lot of growth.
“For the first seven or eight years I was in the group, we only had the Airborne Visible/Infrared Imaging Spectrometer (AVIRIS) Classic instrument. Now we have multiple hyperspectral imager programs.”
For Nolte, a typical day in the field with PRISM consists of cooling the instrument’s camera down and stabilizing its temperature two hours before takeoff, as well as any required troubleshooting as necessary.
Nolte’s work has taken him to places like Hawaii; Norway; Punta Arenas, Chile; St. Croix; and Marathon in the Florida Keys. This is his first visit to Australia. “PRISM gets some pretty sweet deployments,” he said.
Justin Haag is PRISM’s optical engineer. His job is to make sure the PRISM instrument is working and ready. The Illinois native and graduate of Northern Illinois University and UC San Diego joined JPL two years ago.
When I caught up with Haag, he, Diaz and Nolte were making hardware adjustments to part of PRISM’s field health assessment kit. Unlike calibration tests, which are performed on PRISM both before and after its mission campaigns, the field health assessment kit is used to periodically assess PRISM’s performance between flights. It consists of a sphere attached to PRISM’s external camera port on the exterior of the Gulfstream IV aircraft. Two different types of lamps are shined into the sphere, which bounces the light around the sphere’s white, coated interior to create a uniform light input for PRISM to measure.
A previous health assessment test last week had detected some light leaking into the sphere through exterior gaps in the kit fixture’s hardware. The team’s solution? They covered the gaps with black tape. Think of it as an adult version of the arts and crafts we all did in elementary school.
Not every problem requires a high-tech solution. Just a little old-fashioned ingenuity.