Yesterday we left our first study region with new samples from the seafloor and a healthy respect for the ocean currents that can erode sediment deep in the ocean. The samples will be useful for our research but we had to work for them. The seafloor we surveyed was heavily eroded and we had to look carefully before finding sites that were promising enough to sample. Even then we ran into difficulties getting the sediments back to the ship.
We spent several days surveying the seafloor using instruments on the ship to identify possible sites for sampling. We looked for flat areas where we could see layers of sediment below the seafloor. These layers show up in the echoes from sound pulses in a type of measurement called seismic reflection (see previous blog post). Unfortunately much of the region we surveyed has deep gullies with no sediment layers. Ocean currents have scoured these regions leaving no sediment for us to core. We finally located several small areas that had a hint of sediments and one big pile of sediment we thought would be our best chance for samples.
We use a sediment corer to take samples of the seafloor. The corer is a long tube with heavy weights on top that push the tube down into the seafloor. When the tube is pulled out it removes a long cylinder of sediment that we bring back to the surface. The corer is lowered on a steel cable at about 1.5 miles per hour and takes more than an hour to reach the seafloor. At 150 feet above the seafloor, a mechanical trigger releases the corer from the cable and 5,000 pounds of steel rocket towards the bottom. The weight and speed push the corer up to 30 feet into the sediments. Then we have to pull the corer back out. Sometimes this is easy but if the sediments stick to the corer it can take almost 20,000 pounds of pull to free the tube and slide it out.
The other important step in coring is to keep the sediments inside the tube on their two-mile trip back to the surface. This seems obvious but we ran into troubles with the very first core we took. Usually a ring of metal fingers in the bottom of the core (called a core catcher) keeps the sediment inside the tube. However, the sediment we were coring contained a lot of sand-sized shells that was washing out of the tube leaving us with no sediment by the time the corer reached the surface. To prevent this, we added a sock of fabric around the core catcher to keep the sand from washing out. Bingo! The fabric kept the sand in the corer and we started recovering sediments to study.
When the sediment corer arrives at the ocean surface it is laid horizontally along the ship’s rail where we take a sample of the sediment in the core catcher to determine the age of the bottom of the core. This age is determined by looking for a striking, pink colored shell made by a type of plankton called foraminifera. This pink foraminifera was abundant in the Pacific Ocean until 120,000 years ago, so if we find pink shells we know the sediments are at least 120,000 years old. We will do more detailed analyses later but this age gives us our first peek at how much time it took for the sediments to accumulate.
Next, we cut the core into smaller sections that are easier to handle and the core is split open so we can see how the sediment looks. We study its color, texture and composition before storing it in a refrigerated container aboard the ship. At the end of the cruise we will send the container to the Deep-Sea Core Repository at Lamont-Doherty Earth Observatory where the sediments will be preserved for researchers around the world to study.
We are now steaming south to the equator to start a new survey to find the right locations to drill more sediment cores.
Evidence of the retreat of glaciers since the last glacial maximum (check), flying over sites of ancient Inuit, Norse and present day settlements (check), and a personal recollection of my own past in this location (check) – yes after reviewing the list ‘Southwest Glaciers 01′ was definitely the best flight – well at least until the next one!
In 1997 I got to spend a summer in Southwest Greenland, with the organization British Schools Exploring Society (BSES). They bring students at the end of high school/start of university to remote areas to spend six weeks on a combination of adventure and science – a great way to kick start a young adult into both a career path and self-discovery. I spent my time in Tasermuit fjord, a 70 km long stretch of water reaching inland from Greenland’s southwestern tip to the ice cap, and bounded by steep ridges the tallest standing over 2000 meters high. I learned about archeology and botany and developed a taste for field science that led fairly directly to my studying geology at university. Fifteens years later that study has brought me back around to Tasermuit fjord, this time having swapped my backpack and Zodiac inflatable boat for a rather large gravimeter and the P3 aeroplane. Tasermuit fjord looks exactly the same. I imagine I do too.
The SW Glaciers mission brought me past the site of my 1997 basecamp….and also right past the mouth of the spectacular valley I spent several rainy days walking through. The valley is called Klosterdalen, and the mountain on the right hand is Ketil – a name associated, I am sure, with the Ketilidian orogeny that deformed these rocks in the Paleozoic some 2000–1750 Ma. Norse history would tell us that Ketil was one of Eric the Red’s men, and this was where he chose to settle. While Ketil himself postdated the orogenic event, in one of life’s ironies it appears all those million years later Ketil was responsible for the name given the orogeny and the resulting mountain. Of course the local Greenlandic have their own name for the mountain, Uiluit Qaqa, or “Oyster Mountain”, perhaps for the banks of mussel that become visible at low tide.
These pictures put a human scale on Greenland for me, because I know intimately how it feels to walk through the valleys. It is also a part of Greenland with a very clear human history, with physical evidence of both Inuit and Viking settlements in this region, including the ruins of a Norse settlement at the head of Klosterdalen.
Just around the corner (in our plane anyway – it took about a week to travel by fishing boats when I was here the first time) was the town of Narsarsuaq – an airport town, the site of an old US base and also very close to Erik the Red’s dwelling, the first Norse settlement in Greenland.
So we had some human history, and some personal history, but then we got some glacial history too, showing the retreat of the Greenland glacier from the last glacial maximum. Greenland glaciers offer some classic images of the processes we find described in textbooks.
So all in all it was a great flight. Evidence of the retreat of glaciers since the last glacial maximum, flying over sites of ancient Inuit, Norse and present day settlements, and some personal recollections. I would be grounded for the next week by night shifts, but these too were not without some fine sights.
Finally, we arrive at the Canadian Forces Station (CFS) Alert around noon. Our home for the next few weeks.
We are in the fifth day of our research cruise to the Line Islands and shipboard life is beginning to settle into a routine. Most people have their ‘sea legs’ and our sleep schedules are adjusting to the midnight to noon or noon to midnight work shifts. Meals are a time to catch up with scientist and crew, and the motivated scientists have begun regular exercise schedules in the ship’s gym.
As we steam over the incredibly wide expanse of the Pacific Ocean, the waves seem endless and monotonous, and the wind blows steadily from the same direction for days on end. However, beneath us the seafloor is far from monotonous. Huge mountains rise 10,000 feet above the seafloor and create escarpments, ridges and valleys that would rival the peaks of the Rocky Mountains. It is along these mountains that we hope to find sediment for our research.
Using scientific instruments we peer ‘through the looking glass’ to learn what the seafloor and sediments look like. The analogy to the looking glass is apt: Alice stepped through the mirror to see the world beyond and we peer through the bottom of the ocean to see what is below. However, unlike Alice, we use our ears. Short pulses of sound from the ship are focused on the seafloor and we listen to the echo and reverberations that return to the ship. Depending upon the pitch and intensity of the sound we can look at the top layer of the sediment or much deeper.
The most basic echo we listen to comes from the very top of the sediments. This echo travels down through ocean, bounces off the top of the sediments and returns back to the ship. We measure the time it takes to go down and come back up, and knowing how fast sound travels through seawater (~one mile per second or 3,400 miles per hour!) we can determine the distance to the bottom of the ocean. The times are very short, about two seconds for water a mile deep. We use these distances to construct a detailed map of the bottom of the ocean. This map shows the mountains and valleys on the seafloor where we will take our sediment samples. We also listen to how loud the echo is when it comes back to the ship. Hard surfaces like rock have a loud echo while soft sediment gives a quiet echo. This is an additional way to determine where there are ocean sediments to sample.
If we turn up the sound volume and use a lower pitch we can look beyond the seafloor into the sediments below. Now rather than just one echo from the seafloor, we begin to hear many echos as sound reflects off the different layers in the sediments. These echos allow us peer beneath the seafloor to know how thick the sediment is and whether it is nicely layered or jumbled and distorted.
When we find the right sediments—not too deep, smooth, with nice layers—we will take cores of the sediment to study the climate history preserved in the layers.
Despite reading about these temperate rainforests, this is not the Turkey I imagined. This might not be the Turkey most people imagine. I’m really not sure what you envision when you think about Turkey. A dry, open landscape? That is what I thought until I stepped into Artvin Province. Because what I saw there was green, steep, lush, heavily forested. Really? Yes!
In prepping for our pilot research in the temperate rainforests of Turkey, I pulled out the travel guide to get more background. I love going to the history section and learning the long-term trajectory of the people and region. Man, talk about long term and a wide mix of culture. There cannot be too many other places that have that mix of people and culture. At the end of the trip, I was seeing the ecology of Turkey in the same way.
After a day getting settled in Istanbul, my colleague and host, Dr. Nesibe Kose, flew with me to the far northeast corner of Turkey to catch up with another colleague on this project, Dr. Dario Martin Benito (post-doc at the TRL), and Nesibe’s former MS student, Tuncay Guner, who agreed to help with our planned field work. They flew out two days earlier because our original “domestic” flight was canceled just two weeks before our trip. So, they headed out early so we didn’t lose too much time, given our very tight schedule.
How far east did we have to fly to reach Artvin Province and our ultimate home away from home on this trip (Borçka)? Georgia! Not the Georgia next to South Carolina, the Georgia bordering Azerbaijan and Armenia. It is so mountainous in northeastern Turkey that the best place to land is apparently in Turkey’s neighboring nation. An agreement has been worked out so that we can then board a bus and pass through the border as though we are still on a domestic flight. Except that in Hoopa, on the Black Sea, we actually had to transfer buses and go through a border check. Traveling from Istanbul to beautiful downtown Borçka takes about as much time as it took to go from NYC to Istanbul. And, we were not going that deep into northeast Turkey.
This winter has been weird in many parts of the Northern Hemisphere. Northeast Turkey is no exception. It was still snowing in early April and it was said most of the roads where we wanted to go were blocked. I swear I heard the phrase ‘7 meters of snow’ when discussing this last winter in the region; Istanbul was covered in snow in late-January. So, on top of the canceled flight, we had to work around the unusual winter of 2011-2012. Our plan was to sample in Camili Biosphere Reserve. Snow covered roads forced us to work around Artvin. This is often a reality in fieldwork: unexpected conditions overrule the best-laid plans sometimes.
It is a shame we were not able to make it to Camili. It sounds like a kind of heaven. A survey indicated 990 taxa and 432 genera. Importantly to our project, there are 946 angiosperm taxa (BROADLEAF!). As we learned on this trip, bees and bears are an important part of the culture here. UNESCO states, “The basin is the only area where the Caucasus bee race has remained without its purity being damaged. It is one of the three most important bee races in the world.” We saw this in action over breakfast one morning. They asked us how many kilos of honey did we want to take home to the US. Dario and I both answered, “Kilos?” I offered that ½ a kilo would be fine with me. Our local hosts looked extremely disappointed. From the discussion of honey that followed, some bear genes might have migrated into the human genome in northeast Turkey.
As you will see as an extreme example in a future post and as a mirror of the people and culture of Turkey, the ecology of the flora in this part of Turkey is incredibly mixed. The floral survey indicates that the sources of the flora in Camili come from three regions: Euro-Siberian, Irano-Turanian, and Mediterranean, with about half being multi-regional. So, our team, being composed of a Mediterranean European (Dario) and a Turk, was set for all the vegetation that would be thrown at us.
We finally decided to head up a remote valley east of Borçka. What I learned on this portion of the trip is how amazing and adaptable the human race is. We traveled up a narrow valley with steep mountains for several miles before we saw anything that looked old. Much of the forest, unfortunately, had been heavily cut. The trees we found were quite large, but as you know, that doesn’t make them old.
We cored several species that day, but focused mostly on the Oriental beech. There were some outstanding individuals on the landscape, but none more outstanding than this one.
We soon realized that there has been heavy cutting in the high elevation, steep portion of the older looking forest. Most of the trees were young’ish (maybe only 150 years old). Most of the older looking trees we spied turned out to be ‘bee trees’. These were trees left behind to ‘house’ bees.
One of their specialties is to take logs and use them as bee hives. It apparently makes a better honey. Most of the larger beech turned out to be host trees for these log homes.
And, the value of these special bee hives is clear in how they were protected from the brown bear inhabiting these woods.
The fun part for me working in these was the chance to be around natural chestnut trees. The American chestnut is essentially gone, though we still live with its lore. The sweet chestnut in the rainforests of Turkey likely rival what was growing in the southern US. A roadside chestnut blew us away, but it was the old stump we found late in the day that was the clue to how big the sweet chestnut trees could grow.
Seeing sweet chestnut in temperate, old-growth rainforests of northeastern Turkey will have to wait for another trip.
All in all, it was a very fun and eye-opening day. Besides the massive trees, perhaps the most interesting thing was the avalanche we witnessed. We were hydrating after swimming through Rhododendron throughout the warm day when all of a sudden I hear a low rumble. I realize we had not heard a plane all day (this region is only a bird corridor, not travel corridor). I looked up and saw nothing. The low rumble kept getting louder and was sustained. I finally spotted it. Across the valley we saw snow pouring downhill. We didn’t see any trees come down, but the force of the snow looked tremendous.
I’ll sign off with some scenes from our early days in Borçka.
A true bonus of tracking old trees in various parts of the world is that it takes you to some real outposts of the human race. Artvin was no different. First, it was really interesting to live among people who you could pluck out of Poland, Bulgaria, or perhaps anywhere in central and eastern Europe. Making it more interesting, the population is predominantly Muslim. It certainly would blow commonly held stereotypes held in the US. It was really interesting, too, to be in a heavily forested region that looked like a combination of the Adirondacks and Rocky Mountains and hear a call to prayer throughout the day.
Second, we reserved a table in a local club to see local folk music. It is hard for me to describe – it sounded like gypsy-infused eastern European music. The crowd was just as interesting. In near opposition to most of the restaurants we visited, ~65% of the audience was female. Curiously, the restaurants were almost always 90% men.
The night we were there, it seemed a famed emeritus musician was in the crowd. They honored him partway through the set.
Enjoy clips of the music we heard that night.
and, does anyone remember dancing?
Arctic summer sea ice is declining rapidly: a trend with enormous implications for global weather and climate. Now in its eighth year, the multi-year Arctic Switchyard project is tracking the Arctic seascape to distinguish the effects of natural climate variability from human-induced climate change. The University of Washington is leading the project.
- A) The Canadian Forces Station, Alert
We will fly from the Canadian military base at Alert, Ellesmere Island, land on the ice by ski plane to drill holes, deploy instruments and retrieve water samples. We will measure water temperature, salt content and levels of dissolved oxygen, and a wide variety of natural and man-made substances. Our goal is to understand how much fresh water is entering the system, where it is coming from (sea ice melt, river run-off and so on) and where it exits the arctic, altering currents in the North Atlantic Ocean.
During the next few weeks we will blog from the field; Follow our work on the Arctic Switchyard project page.
It is the middle of the night and I am wide awake thinking about the ocean, specifically the bottom of the ocean. Is it rocky? Jumbled? Smooth? I am wondering this because I want to take samples of the seafloor to study. Rocky is bad. Jumbled is bad. Smooth is good.
In one of my favorite New Yorker cartoons a woman says, “I don’t know why I don’t care about the bottom of the ocean, but I don’t.” Well, for the next four weeks our research group will care a lot about the bottom of the ocean. We are sailing to the middle of the Pacific Ocean where we hope to collect sediment to study how climate has changed in the past. Our destination is a group of atolls and seamounts collectively known as the Line Islands. They include Kingman Reef (U.S.A.), Palmyra Atoll (U.S.A.) and part of the island nation of Kiribati.
The ocean around the Line Islands is over two and a half miles deep (4 km)—too deep to preserve the climate changes we want to study. So, we are going to take sediment cores on the flanks of the islands where the sediments are better preserved. The flanks are also where a lot can happen to the sediments. Slumps can break off huge chunks of sediment, ocean currents can erode the sediment and slumps from higher up the flank can deposit thick layers of sediment. All of these happenings alter or erase the regular ordering of the sediment (the stratigraphy in geologists terms) and make them unusable for our research. So, I am thinking about the bottom of the ocean.
Our group is sailing on the research vessel (R/V) Marcus G. Langseth, an oceanographic research vessel operated by Lamont-Doherty Earth Observatory (where I work). The ship is a floating scientific laboratory, with the ability to study and take samples of the ocean water and sediments wherever we go. The scientists on board include seventeen researchers from nine institutions. In addition, there are 34 technicians and sailors who make sure the ship and scientific instruments are functioning properly so we can collect the data we need. The moment we leave the dock in Hawaii will be the culmination of almost a year of planning, a lot of hard work by the crew of the Langseth, and financial support from the U.S. National Science Foundation.
Our goal for this cruise is to collect cores of deep ocean sediment that we can use to study the past behavior of El Niño as well as the climate of the tropical Pacific Ocean. Although our studies focus on the Pacific Ocean, the results could tell us about many different areas of the globe. El Niño weather affects regions as far apart as Indonesia and New York State. In fact, El Niño events are responsible for the largest year-to-year changes in global weather. Our goal is to learn how El Niño has varied in the past so that we can develop better forecasts for the future of El Niño into the 21st century and beyond.
Over the next four weeks I will be writing a series of articles about our cruise. Topics will include El Niño, life aboard the ship and how we actually collect water and sediment samples from the ocean. Stay tuned!
In the meantime you can track where we are online.
The charge is simple – Operation Ice Bridge will fly all 200 Greenland outlet glaciers with an end dimension of over 2 km. The reason? These outlet glaciers (fast moving ice bounded by mountains) are the major mechanism carrying ice off this mega-island and into the surrounding ocean. Greenland is surrounded by a ring of high mountains that work like fingers encircling the ice to hold it in place. Between these mountain ‘fingers’ ice slips through in streaming rivers transporting its frozen cargo to the sea. Ice sliding from the land into the surrounding waters results in a major human impact – Sea Level Rise.
Measuring the ice thickness (ATM, RaDAR), the shape and opening size of the land beneath the ice (RaDAR, gravity), and the type of geology (magnetics) will help with determining how much ice is on this northern land and to calculate how quickly it might move from land into the ocean. These 200 outlet glaciers are key to this calculation. Each flight mission covers a different group of glaciers, some repeating flights from earlier years to measure any change in ice elevation, and some new flights over glaciers never before measured in order to collect baseline data. In addition to flying the outlet glaciers each mission involves transit lines. Careful planning goes into laying out these lines in order to build a comprehensive ‘blueprint’ of Greenland’s land mass. Hidden under several kilometers of ice the land is slowly being pieced together with each line of data collected.
Each instrument on the plane collects valuable information for the project, but with four types of RaDAR being collected this season most of the flights include at least one of these as a ‘priority instrument’. RaDAR, an acronym for radio detection and ranging, has been a part of our vocabulary and has enhanced our understanding of the world since the Second World War. Sending out radio waves and capturing their return has provided us information on ships, aircraft, missiles, weather formations, speeding motor vehicles and – the focus of this project – the terrain. Each of the RaDAR used in Ice Bridge has been designed by CReSIS (Center for Remote Sensing of Ice Sheets) with a unique frequency and penetration for a specific use, yet all have overlap or redundancy.
For detecting the very freshest snow the Ku band is important. Ku uses the highest frequency, 12-18 GHz, providing high-resolution information on the top 15 meters of snow cover, and has been used this season to separate the snow layer thickness on top of the sea ice when trying to determine overall ice thickness. The Snow RaDAR operates at 2-8 GHz and focuses on the top 30 meters of snow cover, often an area of unconsolidated ice (the firn layer), and an interim stage between snow and glacially compressed ice. Accumulation RaDAR operates at a lower resolution of 600-900 Mhz penetrating down a full km into the ice providing data on the internal layers of ice as they collect and move over the landforms. Lastly, the MCoRDS RaDAR is the priority for information on the bed shape beneath the ice sheet. MCoRDS uses a low frequency or 180-210 Mhz to penetrate down to 4 km beneath the ice surface giving us the depth and shape of land below, and any constrictions to ice flow.
The RaDAR can provide information on the shape of the land surface but not on the geology, and if there is water it can’t image through to see what lies below. This is where Lamont’s gravity and magnetics teams work to fill in the missing information. Matching the bed shape to the gravity/magnetics information on the ‘bed’ material is important in developing our understanding of how the glacier may move in the future.
Measuring Greenland’s ice sheet and the land that holds it in check is a first step in a long walk that will take us to predicting the future of that ice sheet and its impacts on sea level rise. Every line of Ice Bridge data collected fills a blank that moves us closer.
Special thanks to Aqsa Patel & Kevin Player for their willingness to answer all my questions on the CReSIS radar systems, and Beth Burton and Kirsty Tinto on the magnetics and gravity systems.
For more blogs on this project: http://blogs.ei.columbia.edu/tag/greenland-ice-sheet/
For more on this project at LDEO: http://www.ldeo.columbia.edu/icebridge
For more about NASA Ice Bridge: http://www.nasa.gov/icebridge/
Columbia University IT group is investigating intermittent problems with the myUNI services for password changes and resets. Some users are experiencing long wait times and a <
To Norse mythology Midgard is a place that is impassable, surrounded by a world of ocean. Thor, the hammer-wielding warrior god often traveled across to Midgard, and one imagines evidence of his fiery power remains in the highly charged rocks that are left behind. Magnetized rocks containing Thor’s energy and the fiery touch of his lightning bolts.
We are soaring today 1500 ft. over the surface of the twisting branches of the Midgard glaciers. Patches of low lying clouds drape around the tops of the mountains, like smoke from Thor’s lightning singes, but as the sky opens we see row upon row of majestic peaks. It is hard to balance the icy cold of the Greenland exterior with the molten heat of Thor’s lightning. Midgard, is cold and impassable, yet it is evident why Thor was attracted to this land.
Greenland’s geology is diverse. Some of the oldest rocks on Earth are found in southwestern Greenland in the Isua Greenstone Belt, an Archean belt between 3.7 and 3.8 billion years of age. Today, however, we are flying over the opposite side of the country.
The Midgard glaciers hug the southeast of Greenland where the main rock is Archean gneiss, later reworked and cut through with a mafic, or iron rich, intrusion. Perhaps this occurred when Thor was traveling these peaks. We see the changes as spikes in our magnetic data, and visual features that appear as well.
Magnetic measurements are some of the many measurements being collected by Operation Ice Bridge. Rocks have different magnetic properties, so collecting magnetic data can tell us something about the type of rocks that are under the ice, assisting in refining our understanding of how the overlying ice will interact with what is below.
Measuring the magnetic field can be challenging from a metal plane, however the P3 is designed for magnetic surveys so the data requires only a minimal ~10nT (nanoTeslas) adjustment to remove the interference. Originally used by the Navy for locating submarines the P3 has a tail stinger or boom designed to hold the instrument while minimizing magnetic interference from the plane. The Ice Bridge P3 holds two magnetometers. One measures the total magnetic field, the other is a flux gate, with three orthogonal sensors to record plane directional maneuvers, information that is needed for later data corrections.
The Earth’s magnetic field is not constant so collecting data at a magnetic ground station is important in order to gather daily background levels. The magnetic anomaly that we report is the change from this background or anticipated levels. This means that a series of corrections must be applied to all the data collected including removing the Earth’s total magnetic field, daily diurnal fluctuations, and small spikes from the plane radio. What remains is the anomaly, any representation of a magnetic signal from the geology in the area.
Magnetic surveys normally begin with an assessment or compensation flight in a magnetically quiet area, at a high elevation to minimize the effects of high magnetic gradients caused by the geology. This provides the reference points needed for final corrections and processing of the data. This season Ice Bridge has had the opportunity to fly almost continuous missions so the compensation flight has been put on temporary hold. Once that flight is completed, the data will receive a final adjustment.
Today our screens are busy with magnetic shifts tracking on the screen. Seeing the data jump onto the screen is always exciting. The instruments take a reading approximately every meter as we fly above at a rate of close to120 meters a second. The data appears as a wrapping stream of plotted points. When a line travels from one side of the left hand column to the other it shows that the magnetic field has changed by 100 nT. The second column shows greater detail in the measured field with one line showing a change of 10 nT. Peak values of magnetic anomalies appear as a mid-column direction change on the wrapping plot. When the magnetic gradients are high, indicating a distinct geologic boundary, it can appear as a dark block.
What we see on the screen tells us about what happened in the geologic formation of this country millions of years ago. Understanding how the changing rock types affect the flow of ice can help us to predict what might happen in the future.
For more on this project at LDEO: http://www.ldeo.columbia.edu/icebridge
For more about NASA Ice Bridge: http://www.nasa.gov/icebridge/
Even in idyllic Greenland some days start to feel like the movie “Groundhog Day”, however the turn of events today broke that thread. Over our two weeks in Kangerlussuaq we have ended our evenings with a science and weather report, and the hope of flying the program over both coasts. Each morning we wake up, head to the plane and look to see what the weather has dealt us. So far with incredible consistency clouds have dictated a series of flights on the east coast of Greenland. Today started exactly the same with clouds on the west coast driving a plan to fly the centerlines of several large southeast glaciers – Helheim, Kangerdlugssuaq, and Midgard.
But today would not be like every other. We lifted into the air and immediately loud rattling emerged from under the plane. The belly of the P3 has been outfitted for science equipment and directly in the line of the rattle lie a series of elevation survey instruments – two Airborne Topographic Mapper (ATM) lasers, that send and receive a steady series of laser pulses, and two Digital Mapping System (DMS) cameras, that take high resolution surface images every 1.2 seconds. Both of these instruments are used to develop elevation maps of the area surveyed.
Three floor plates were quickly removed and a member of the aircrew is tethered for safety and dropped below. Looking down I could see straight through to the land and a surface dotted with small melt ponds. It seems you could put your hand straight through the bottom of the plane, but there is a surface – clear glass in two portholes and clear acrylic in the third. Each morning I have watched the ATM and DMS teams carefully clean these lenses to the outside world.
After a quick review of the situation the decision is to return to the airstrip and attempt a repair, but first we must lighten the plane. Physics tells us that a fully fueled plane ready for a day of science work is not safe to land. Working with the air tower a place is selected to drop some fuel, we rise in elevation to minimize the impact of the drop, and then we are ready to cycle back to the base for a quick check.
The windows below the ATM and DMS are checked. They must be perfectly clear and there is spatter to be wiped away. A safety inspection and refueling puts us back on the runway taxiing in just over an hour. A warning light appears as we taxi and we aborted again. This time it is a quick fix and we are off and flying within thirty minutes – all in all a 2.5 hour delay which requires an amended mission. Helheim-Kangerdlugssuaq-The Sequel!
We will fly over water and glacial ice today giving both ATMs a work out. The primary system has a wider swath (700-800 ft.) working best over glacial ice. The secondary system has a narrower swath width with a smaller angle of incidence, the preferred system for sea ice. Sea ice has a mix of open water leads and thin sheets of ice making it difficult for the primary system to collect wide-angle measurements over both the ice and open water leads.
As we begin the flight the secondary ATM needs adjustment. The laser pulse is sent out through a series of mirrors and collected back through a telescope that needs to be able to ‘see’ the laser return to measure the surface elevation. Once again the floor panel comes up, but the adjustment is a quick fix. The cold weather can be one cause of this drifting.
As we reach the coastline it becomes apparent there is sea fog and wispy clouds laying low over the glacier and waterfront. The trouble with clouds or fog is they will block out both lasers unless we can get under them. In some places we can fly beneath the clouds, but in other areas it is not possible so we will lose some of the ATM data. It can’t be helped. Sea fog is extremely difficult to pick up on the synoptic charts used to assess the weather each day. We are lucky, however, and at the end of the day the ATM team reports 40 gigabytes of data collected. Little was lost to the clouds and fog.
Tomorrow we will need to wait and see if the cycle is broken, sending us to the west coast.
I had been warned of Geikie. “If they fly to Geikie get on that flight” I had been told, but nothing more. At the science briefing last night I knew it was a possibility, but daily science missions are not decided in the confines of a meeting room. Missions are decided by weather, and its weather that drives the transit today forcing us up over the clouds. A snowy air mass has descended upon Kangarlussuaq extending back over the icecap, leaving an opened window over the Geikie Peninsula.
The transit will be high putting many of the instruments out of their range. The Laser altimeter, visual camera and gravity all become a casualty at higher elevation, yet the magnetics and radar continue to collect data during the commute. But the story today is not in the transit, it is in the small jut of rugged cut coastline in Southeast Greenland called the Geikie Peninsula. An elongated ice plateau at more than 6500 ft. of elevation, Geikie is the northern end of a section of steep flood basalts that flowed out like the upward sweep of a hook.
Geikie is both a challenging target, and a bit of an enigma to the science team. Geikie is a hard area to study because of its location. It is the furthest target from any air bases in Greenland and in Iceland, and it is located just at the lip of the weather systems moving in from the Icelandic Low. A notorious herald of foul weather, the Icelandic Low dominates this section of the Southeast Greenland coastline. Pulling warm water from the oceans into the atmosphere between the two ice blocks of Iceland and Greenland, the Icelandic Low contributes to nearly constant bad flight weather in this part of Greenland. Along with being a difficult target the small glaciers we will fly today are surging or dynamic glaciers. Surging glaciers are difficult to fully understand and account for in models. We hope to collect data that will help define the bed beneath the ice in these dynamic glaciers. In order to do this we will fly right down the trunks of eight of Geikie’s glaciers.
When the peaks of Geikie appeared from the snow I was captivated. Line after line, row after row pyramid like peaks rose with a certain regal proudness through the ice sheet. Chiseled points with finely leveled layers stood 1500 ft. and higher through the ice, surrounding the plane, while below us the radar showed the ice thickness to be 1.5 miles. These are towering features. Buried millions of years ago by the ice sheet this truly must be Greenland’s hidden treasure. Sheared edges formed perfect pyramids where competing ice flows had crossed, working in opposition to carve away the rock. Regal gateways of perfectly opposing pedestals of rock showed the promise of rock formation after rock formation through the opening. Large crouching shapes appeared trailing down to rounded blocks of rock emerging like the toes of an Egyptian sphinx standing guard over this magnificent treasure for all these years.
We collect measurement after measurement, image after image as we soared by the guardians of Greenland. While we collected almost two terabytes of data we did not disturb their slumber. We left Geikie as we found it, frozen, vast and arresting. If they fly to Geikie, get on that flight!