Just imagine: one fine day, a fish revealed to you …
With proto-limbs, a monstrous face, all tinged with silver-blue!
Huge and strange and other-worldly, long thought to be lost,
In the flesh (starting to smell!) so many epochs crossed.
The coelacanth! Good Old Four Legs, to some, the “Living Fossil,”
The animal itself is big, its history colossal!
Ms. Latimer, she recognized its weirdness and allure;
Decades later, of its story some things were not sure.
But now we have its genome clear and plain for all to see,
Shedding light on autopods, immune systems, and pee!
More closely tied to humans than to tuna or to trout,
Holding secrets of the beasts who from the sea, climbed out.
Living fossil genome unlocked, Nature News
African coelacanth genome provides insights into tetrapod evolution, Amemiya et al., Nature 2013
First posted 4/19/13 at Katherine Allen’s website.
Behold! New treasures from the Burgess Shale,
In black and silent strata long held firm.
From features soft, a bold ancestral tale …
Be proud, descendants of the noble worm!
Oh, glorious the hemichordate line,
Spartobranchus tenuis among them,
On slime and mud they heartily do dine;
History has surely under-sung them.
From which deep root, vertebral creatures grew?
A scarcity of fossils long obscured;
Into this question we can dive anew,
With gorgeous, detailed imprints that endured.
A wondrous time, the Cambrian Explosion …
Move over, Eve; my roots are in the ocean!
- Tubular worms from the Burgess Shale, Nature / News & Views by Henry Gee:
- Tubicolous enteropneusts from the Cambrian period, Caron et al., Nature 2013
First posted on 3/29/13 at Katherine Allen’s website.
I walked out of the house Thursday morning when my nose detected it – a forest fire! Having worked for two years in the piney woods of southwest Georgia, I had become accustomed to and, actually, come to love forest fires. That classic line kept coming into my mind, “the scent of fire in the morning reminds me of healthy forests.” The scent can be better than a campfire. It can be a little sweeter. That morning, it filled the entire town. Firefighters were just beginning to quench the fire. As of Saturday night, it had burned about 40 ha (ca 100 acres), but was still uncontained on its northern end. I might have been one of the few people to be thrilled to be in a smoke-filled town. It reminded me that we lived in a heavily forested area, and an active ecological event was playing out just up the hill.
It was fascinating to see the coverage of this fire. There were many resources thrown at it. It is understandable. Clausland Mountain is beautiful, beautiful enough that it is ringed by expensive houses. Twenty-six fire units, composed of about 150 firefighters, were actively fighting the fire (about one fire unit for every 1.5 hectares (3.8 acres)). Two helicopters were brought in to douse the flames. The breathless words of the reporter are fascinating as well, “remote areas” and “extremely dangerous.”
The large response is what happens in the wildland-urban interface, especially outside of one of the largest cities in the world. The conflict between humans and ecological processes has been on the rise as we move out into natural areas and as we become more aware of important ecological processes that maintain ecosystems and the services they provide for humanity. Fire is one of these processes.
So, Sunday we went on a hike to see the impact of the fire. Bushwhacking, we went into the northern end where the fire was still smoldering (though the fire took care of many bushes). It is steep and the ash makes the slope a bit slippery. Much of the leaf litter was consumed, though not completely. In some places, logs were consumed down to the mineral soil. Death shadows are evident. The potentially severe rainstorms approaching from the west should put out the fire. (Update: they did.)
It will be interesting to see how the forest responds. Fire is an important ecological process. It reduces the disease and pest load in an ecosystem; it is an antiseptic in a way. It favors some plants more than others. Like me, fire favors blueberries! Oak trees in the eastern United States do not seem to be regenerating very well over the last 40-50 years. The re-introduction of fire is today’s response to a lack of oak regeneration. Much money is being spent on prescribed fires and education about fire. The lack of oak regeneration seems complex. It is said that the rise of mesophytic species, the species “taking the place” of oak, is changing the forest in such a way that it ecologically dampens the forest, making it hard for fire to take hold. However, the re-introduction of fire doesn’t seem to be having its hypothesized impact – oaks still do not seem to be regenerating in experiments employing fire, while mesophytic species seem to be handling the fire pretty well. Important for the context of this ecological scenario, many changes have occurred in the forest over the last 50-100 years, all of which could be a factor of a reduction in oak regeneration – increased deer populations, loss of important megafauna, and changing land-use and cultural patterns (Hello Smoky Bear!). And, climate change might be playing a direct role in the “mesophication” of the East.
One physical mechanism has been detected – flammability of and differential drying of forest fuels (leaves). Fire is a very physical process. The variation in forest fuels, especially the finer fuels that carry fire in wetter regions, plays an important role in flammability. Thinner leaves absorb moisture more easily. Large, curling leaves, especially lobed leaves, dry faster. Curling leaves make the duff (or “litter”*), the fuel layer, fluffier, allowing better oxygenation of fire, to literally fuel the fire even more. One hypothesis for why eastern forests burn less is the loss of the great American icon, the American chestnut tree. Research by Morgan Varner supports this hypothesis.
It will be especially interesting to see how the Clausland forest responds to this fire. It is getting much wetter in this part of the world. Deer populations are high because of the high human density and the amount of forest preserve in the county (there is no hunting in the area, and deer have learned home gardens are a smörgåsbord). And, the diversity in this little patch of woods is pretty amazing. On our 0.5-mile hike, if that (our 2-year-old doesn’t hike great yet), I spotted 13 major broadleaf tree species, one conifer, the fading eastern hemlock, and two small tree species (I wasn’t even trying to seek out species; there must be more). Amazingly, yellow birch, a boreal species more common to the Adirondacks, New England and southeastern Canada, is mixed in with pignut hickory and sweet birch, species more common to Virginia.
The understory might respond a little differently, though in the little patch we hiked, the wineberry looked just fine. Guess we’ll have to go back out and hike a little more next spring. Shucks.
A pictorial of the aftermath of the November 2013 Clausland Mountain fire.
We met a colleague and his wife on the trail. They were out to check out the fire. They live near the burn and watched the fire grow and the efforts to stop the fire. She noted that it was like a ring of fire. Absolutely!
* = really? Can we get rid of the term “litter”? Fallen leaves, twigs, branches, bud scales, etc., enrich the soil by returning nutrients back to the Earth and increasing the soil’s ability to retain moisture. If that is “litter,” call me trash.
It was midday. It was dark. It was June! It was pouring. We were sitting in my folk’s cabin in the Adirondacks when my dad groaned, “This is depressing”. Later on that same day, a hometown friend made a similar exclamation. Elizabeth’s update triggered a deluge of similar sentiments. During that discussion, she made reference to The Long Rain. It was the perfect comparison. Judging from the sentiment in our cabin, in the newspapers, and on Facebook, Central New York was on the edge of insanity because of the unrelenting rain.
It was too early in the season to write this post. Predicting future rainfall is like trying to predict Dennis Rodman’s next career move: It will move in a new direction, but no one can pinpoint the trajectory. But now, as Cortland and Macoun apples grace us with their presence, we can now safely say that summer is over (I do not care what the tilt of the Earth says. It is apple season!). In fact, the Northeast Regional Climate Center and NOAA have completed an early overview of this past summer’s climate. Their conclusion regarding precipitation in the Northeastern US? The Pluvial continues.
Actually, these overviews typically discuss climate of just the most recent month or season year or versus the “climate normal.” While useful, these summaries do not paint the full picture. Consider this: A climate normal is often based on a recent 30-year period, like 1970-2000. Now consider this: Instrumental records for the Northeastern U.S. (below) and analyses for the Catskills region and southern New York State, here and here, indicate that since the 1960s drought, the region has seen a substantial increase in precipitation; in fact, hydroclimate seems quite unusual since 2000. Now really consider this: A tree-ring reconstruction of moisture availability indicates that the recent wetting comes at the end of a 120-180 year trend (and maybe longer). So, the daily comparisons on TV or other media sources are typically based upon recent climate and ignore the past. Thus, based upon paleo records, the full picture indicates that we are sitting in one of the more unusually wet periods of the last 500 years.
I return to this topic because of: 1) the many implications of this climatic shift and, most importantly, 2) what seems to be a limited amount of public awareness of how wet it has become in recent decades (though this awareness is growing). The substantial change in moisture across the Northeastern U.S. (the draft of the 2013 3rd assessment is here) is more commonly known in the scientific literature, but it seems to be less well-known outside of that community. For example, under the tab “Climate Change” on the Northeast Regional Climate Center’s excellent web resource, one can only find minimum and maximum temperatures when seeking to understand how much the climate has changed. An increasing trend in precipitation just doesn’t seem to grip the attention of most people like an intense heat wave or drought. In fact, an editor remarked to a freelance writer that they’d only do a story on the change in precipitation in the NYC region if “they were painting the lawns green on Staten Island.”
For the people in Vermont, the Catskills, Mohawk Valley, and those wishing to use beaches in the summer along the coast, this seems a bit short-sighted. Excess rain is costly. It costs the people still trying to rebuild in the Catskills from the flooding of 2011 (and it isn’t just the two tropical storms that triggered the flooding – new research indicates that because the soils were saturated, the impact of Irene and Lee were worse than they might have been in other times). It costs people in Vermont wanting to rebuild their cultural heritage. It will cost all of us in NY State if tax breaks are given to expand flood relief measures in five counties and restoration and reconstruction of managed water systems; climatic change disregards political boundaries. It might cost us if we are managing forests for a long-gone climatic era. It further erodes trust between country and city folk as well as citizens and their government. Tragically, it costs lives.
So, as we become aware of the impacts of additional rainfall (and certainly there are additional costly impacts than what is listed above), we need to know that precipitation is likely to increase over the coming century. Model projections indicate it is likely that the Northeast will get wetter and have more extreme rain events. This doesn’t mean we will not experience droughts in the future, nor does it mean each summer will be like 2011 or 2013. And, these model projections could be wrong. But, our state of knowledge indicates that these Long Rain conditions could become more common.
This shouldn’t be viewed as more environmental doom and gloom. Humans have enormous brains and know how to use them! See: Klaus Jacob. We have the ability to prepare for potential adversity. And, if it isn’t clear by now, humans are one of the more adaptable and flexible animals on the planet. Heck, we might even celebrate wetter conditions with some enormous fun. And, from my Broadleaf perspective, the Northeast could become a temperate rainforest with bigger trees and a denser forest.* Folks spend enormous money to experience such things.
* unless future warming overwhelms our rain wealth and stunts the future forest…. apologies. It is hard to avoid all of the potential doom and gloom…
We are experiencing trouble with a home directory server this morning. It is affecting 40-50% of our users. Multiple short outages may continue throughout today and tomorrow as we prepare and execute plans to migrate users to another server. We apologize for this inconvenience and appreciate your patience as we work to resolve the problem.
Ideally, seismic stations are sited in remote, quiet locations away from any possible cultural noise, especially people, who are very noisy (even if they are not New Yorkers). But other considerations besides peace and quiet are important for a good station, particularly security. As a result, we placed most of our stations in towns near schools, hospitals or town halls, where people could keep an eye on them.
We often attract crowds while installing our exotic seismic gear. Field work with an audience has pros and cons. It’s certainly somewhat distracting to labor and sweat under the sun, tinkering with wires and programming equipment with a big crowd in attendance. Some of the sites are in relatively tight spots, so the curious onlookers occupied much of our working space, making for very close quarters. Several days ago, we installed a station next to the village hall in Ndalisi as a small crowd looked on and an animated town meeting took place next door. Loud passionate speeches inside were matched by loud banging outside as we mounted a solar panel for our station on the roof.
But there are very big upsides. People from the villages where we deployed stations have provided an enormous amount of help with building our sites. We have also had abundant opportunities to tell people what we hope to learn about the active tectonic environment where they live. Continental rifting here gives rise to geohazards such as earthquakes and volcanoes. Because we have tried to locate many of our sites near schools, we particularly hope to communicate our science to students and teachers. At the Matema Beach High School, students peppered us with questions as we installed our gear. Their school is just a stone’s throw from the Livingstone Mountains, the surface expression of a major rift fault that has caused large earthquakes. But our seismic installations admittedly may not be entirely positive; today at Kifule Secondary School, students took a long math exam inside while we were making a racket outside. But hopefully the pros out weigh the cons… Even at Kifule, students burst out of classroom after the test all smiles, so apparently we were not too disruptive.
Driving around the Rungwe volcanic province in the southern East Africa Rift installing seismometers, we have the chance to observe first hand how geological processes in action create the most dramatic forms at Earth’s surface. Looming volcanoes flanked by cinder cones lie along the rift valley, often very close to rift faults. The Livingstone Mountains, the surface expression of a major fault system that bounds the rift to the east in this area, soar over 1.5 km over the valley below, including Lake Malawi (Nyasa).
The remarkable geological structures evident above ground motivate us to look deeper in the earth. We see volcanoes in particular places at the surface, but where are magmas located at depth below the volcanoes and the rift? Likewise, we see dramatic faults that are helping to thin and break the crust at the surface, but how do they relate to stretching of the entire crust and lithosphere beneath this part of the East Africa rift? And how are the magmas and faults related to one another? These are the core scientific questions motivating our study of the rift around northern Lake Malawi (Nyasa). We hope to use data collected during this program, including the 15 seismic stations that we are deploying now around the Rungwe province, to answer these big questions.
The last time we visited the southern part of the East Africa Rift, we were responding to an unusual series of earthquakes in December 2009 that shook northern Malawi. The faults responsible for these events had not produced any earthquakes historically, and thus caught everyone by surprise. The unexpected occurrence of earthquakes on these faults highlights our poor overall understanding of how the African continent is slowly stretching and breaking apart.
This time, we return to this part of the rift system as a part of a more comprehensive effort to understand the underpinnings of this continental rift using a spectrum of geological and geophysical tools and involving a big international team of scientists from the U.S., Tanzania and Malawi. In the coming three weeks, we plan to deploy ~15 seismometers in southwest Tanzania around the Rungwe volcanic province, the southernmost volcanism in the East Africa Rift system. These stations will record small local earthquakes associated with active shifting of faults and moving of magmas at depth. They will also record distant earthquakes that can be used to create images of structures beneath Earth’s surface and map the faults and magmas.
144 miles separates Kangerlussuaq from Raven Camp. Not far really, just 144 miles – like traveling from the southern tip of New York City up to Albany. Flying at 270 knots we can be there in about half an hour, no time at all, and yet to the casual observer they seem worlds apart.
Kanger sits nestled in the arm of Sondrestrom Fjord, where over the years Russell Glacier has found the soft belly in the rock base, wearing the surface down flat and pushing the rock flour out to sea. Currently the tip of Russell Glacier is a full 20 kms (14 mi) up the fjord. In the summer months, as research teams move through the village, glacial meltwater fills the carved channel that borders the small town.
Meltwater Rushing Behind Kangerlussuaq, Greenland
“Summer meltwater from Russell Glacier rushes around the edge of Kangerlussuaq.”
Although modest in size by our standards, Kangerlussuaq is a transportation hub for Greenland, and has a steady year-round population of ~500 residents.
Raven Camp sits high up on the Greenland Ice Sheet on a frozen bed of ice, almost 2 kms thick (~1 mi) and millions of years in the making. At almost 7,000 feet of elevation, no seasonal change will bring a rushing river or a population to match that of Kangerlussuaq, but summer research does bring an influx of summer scientists, swelling the population beyond the posted total of 2. With a handful of tents and collapsible housing structures, Raven Camp is a “summer town.”
Today we fly to Raven Camp to complete a survey grid over the ice landing strip. A year ago the camp staff detected several cracks (crevasses) in the ice running perpendicular to the airstrip. Crevasses are to be expected around the edges of an ice sheet, where the ice is faster flowing, however, at this elevation and this far inland it is more unusual. Published data for ice movement in this area shows at the base the ice is moving about 2.5 cm a day, while at the surface ice is moving closer to 7 cm a day. It is no surprise that the ice at the base moves more slowly, a result of the increased friction at the bed causing the ice to stick and slow.
Currently measuring only 10 cms across, it certainly doesn’t seem that this could cause much trouble. But if the crevasses are deep and continue to widen, they will threaten the landing strip. A team of scientists has been collecting measurements on the ground to see if these rates are changing (2013 polarfield blog1); our job is to survey the area with our instruments. The Shallow Ice Radar and the infrared camera collect the depth of the cracks and the temperature differences as the cracks move deeper into the ice. Pulling all this data together will help us understand what is happening to the ice in this area.
Our flight grid will be flown low, at 1,000 ft. above the ice surface, one third our normal survey elevation. Two East/West lines are flown perpendicular to the landing strip at 600 meters apart. Then three tie lines are flown parallel to the runway at 100 meters apart.
Once the grid is complete, we land on the airstrip, testing the seal on the pod door and collecting some camp cargo. The landing is smooth.
Temperatures today at Raven are a warm 1°C. The snow has lost some of the crispness we had experienced when we had landed in April to install a GPS on the ice. The pod is inspected. The camp looks all but abandoned, yet a snow vehicle appears with cargo that is stashed and secured for transit. While the cargo is loaded, we snap a quick IcePod team photo.
The new eight-bladed propellers on Skier 92 do their job and the take-off is smooth for our return to Kangerlussuaq, just 144 miles, 30 minutes of transit, and yet seemingly worlds apart.
1 For more on the science being collected on the ground on ice movement: http://www.polarfield.com/blog/tag/greenland-ice-cap/
For more on IcePod: http://www.ldeo.columbia.edu
The Langseth Galicia 3D seismic cruise is winding down. By tomorrow we will be back at the dock in Vigo. Like most seagoing science, we will miss the ship experience, we will miss the new colleagues we have met, we will look forward to getting back on shore, and for many of us the awesome multi-year task of processing, interpreting, and publishing the boatload of data we have acquired.
This is an example of the data we have collected. Right is to the East and left is to the West. This is a cross section of the Earth about 65 km long. The blue is water. The water depth here is about 5 km. The red and gray colors are a cross section of the rocks below the water. The flat layers are sedimentary rocks. The lumpy bumps (that is a technical term!) consist of blocks of continental crust and of the mantle.
We thank the Langseth’s Captain and crew for making this possible! These are men and women who live on the sea, and who share their ocean world with us for a month or two. Every now and then, when you can walk 100 meters in a straight line, ask yourself, “Where is the Langseth now, and who is steering the ship, or keeping the engines running, or keeping the deck ship-shape, or providing good food, or every other important task on the ship?” Under your breath say thank you for the experience you had on Langseth.
We thank Robert and his technical team. They worked tirelessly to assemble the 24 km of hydrophone streamer that hears the reflections from the Earth, the 40 or so airguns that make the booms, and all the rigging it takes to tow them spread out behind the ship over 600 meters wide and 7000 meters long. That was just the start. Then they operated the electronic equipment that received the seismic data and recorded it for the scientists. Without them we could not do the science we love.
Thank you to the Science Party. We had a total of 20 scientists, including undergraduate students, graduate students, post-docs, researchers, and professors. On Leg 1 we had 14 scientists and on Leg 2 we had 10 scientists. Four scientists weathered both legs. Six joined us for Leg 2. I am very grateful for all your efforts on behalf of the Galicia 3D science. I hope that you learned a lot, had a good time, and met other scientists for the first time. I suspect that we will meet one another many times in the future.I look forward to that!
This is the Technical team and the Science team for Langseth Leg 2.
I want to thank the Protected Species Observers for sailing with us. They spent countless hours in the observing tower, high above any other part of the ship. They have sighted hundreds of whales, but most did not come close to the ship. It is windy and cold up there, but their role is important for making sure that collecting our scientific data does not interfere with the creatures who call the ocean home.
Thank you for sending your loved ones off on the Langseth. I can certify that they now know how to do their own laundry and to clean up their cabin before they leave the ship. During the weekly emergency drill, they run quickly up to the muster station on deck and put on safety gear. I recommend that you continue to enforce these behaviors ruthlessly! They will forget them if you let them slack-off. On the other hand, they did not have to cook their own food, or wash and dry their dishes. You will still have to work on these behaviors!
As I write this from the Langseth, we should remember that the Galicia 3D experiment goes on. Our colleagues from GEOMAR and University of Southampton will be on the FS Poseidon from 25 August to 10 September. They will be recovering the 78 Ocean Bottom Seismometers that are still on the bottom (on purpose!). They have been recording approximately 150,000 airgun array shots fired by the Langseth. I know what you are thinking. “How many total recordings of shots are recorded in all the OBS’s?” That would be about 11.7 million shot recordings. This will keep the OBS scientists busy for a while!
I particularly want to thank James Gibson for creating this blog. It has reached out to our friends and to strangers. We plan to keep the blog alive. This project will continue for years.
Best regards,Dale SawyerRice University
This week we have been exploring all the parts of the ship we have not yet discovered and were lucky enough to get shown around the engine room and the bridge. It is evident that each area of a ship (bridge, engines, science etc.) has a group of people doing those specific jobs and that the combination of everyone doing their part keeps everything running smoothly; like cogs in a massive machine.
The engine room control panel. With that many buttons no wonder it takes so much training to work in the engine room!The engine room is located in the hull of the ship and is the biggest room on board by far, taking up about 2/3rds of the bottom deck. This is obviously a very important part of the ship because without it we would not be moving anywhere! The Langseth has 2 engines leading to 2 propellers and also 1 bow-thruster. There are so many different bits of machinery down there that it can take 4 years of studying to be qualified to work in the engine room. It is very loud and warm but surprisingly clean and tidy. There are also 2 compressors which are used to pressurise the air for the air guns that we tow.
One of the very noisy compressors. It is hard to portray the size of these in a photo, they are huge!The heat from the engines is used to produce all the hot water for the ship and the engine room also has machines for desalinising our water. Fuel usage is constantly monitored and fuel moved between all the many tanks spread around the ship to ensure even weight distribution. Even though we only travel at about 4 knots whilst acquiring data we burn between 5000-6000 Gallons of fuel a day due to the massive load of the equipment we are towing behind us.
One of the two enginesThe bridge sits at the front of the ship on top of the main living quarters. From here it seems as if practically everything can be controlled. They drive the ship when we are not driving from the main science lab during acquisition, control the speed, can manage the safety aspects including all alarms and watertight doors and keep a look out for anything floating past that might get caught up in our seismic gear (so far buoys and pallets have been sighted). One very important job of the bridge is to communicate with other nearby vessels. Nobody would expect us to be towing 6km of streamers so we have to make sure we let other ships know with enough time to arrange safe passing, therefore avoiding collisions.
This is the main control panel in the bridge. There are screens for navigation and
radar as well as all the speed controls. There are two smaller control panels
on the port and starboard sides of the bridge for work that
involves careful maneuvering e.g. picking up OBS's. The last seismic line is just being finished right now and then we can get ready to begin equipment recovery. It is about 40 hours until we are back on dry land again!
Tessa GregoryUniversity of Southampton
A screen capture from the multi-beam sonar Seafloor Information System (SIS).
The image on the left shows swath coverage. The image on the right shows an active ping through the water column.Multi-beam sonar (swath seafloor mapping) data are collected, gridded (binned) to the predefined cell size, and output in two flavors. Bathymetric grids, which are essentially 3D topographic maps, and Backscatter grids, which display the reflectivity of the seafloor. The reflectivity varies due to both incidence angle of the respective beams and the density of the surface (e.g. hard rock, sediment etc). As the ship moves along at a given velocity, the multi-beam sonar sends a "ping" from the transducers (transmitters) to the seafloor and then waits until the receipt of the last return to ping again. The ping rate (Hz or 1/seconds) is a function of the depth of the ocean as well as the sound speed through water (XBT's are useful!). The swath width also scales as a function of depth. Our average depth is ~4800m (2.98 miles), which allows for an achievable swath width of ~20km (12.43 miles!).
Swath coverage display of the backscatter (reflectivity of the seafloor) collected across a swath.In order to gain insight on the density of the multi-channel seismic (MCS) data that we are collecting we use the Spectra software package. Spectra tracks the position of the ship, streamers, and air guns in real time using GPS and an acoustic network, and then bins the data accordingly within the predefined grid. The goal is to get an equal amount of seismic traces (reflected seismic waves) in each bin. The traces can then be stacked (combined), which increases the signal to noise ratio. Stacked traces within a bin are called "fold" and ideally represent traces from all offsets along the streamer in respect to the source.
A screen capture of the Spectra display. The image on the left shows active binning of the MCS data.
The image on the right shows the bins being infilled (filling holes).We are getting to the end of the "No Mores," which means we are finished on Friday!! Stay tuned for a word from our Chief Scientist along with a look at the MCS data (and our cruise pic).
When the New York Air National Guard travels to Kangerlussuaq, they toss in a few fishing poles with the baggage for whatever few hours of free time might be available. A favored pastime for this location’s summer assignments means the local lakes are well known by the crew, so when we sat down to map out the flight plan, a request for locating lakes met with an easy nod. No problem at all. It took only seconds to register that our definition of lakes might differ from theirs.
We are interested in lakes atop the ice sheet surface, places where the ice sheet melt is puddled into lakes of various sizes. It is in locations like these lakes where water, with its darker color, absorbs more heat from the sun than the surrounding white ice surface. This process can contribute to more melt, and in some instances the water finds a weak “joint” in the ice and drains right down to the bottom. Both the extent of the ponding and this process are of interest to the science community in better understanding the ice sheet.
The guard is quick to assure us, no problem, these too can be located!
It was an “optics day,” where our focus is on the cameras in IcePod. Using both our Bobcat (visible wavelength) and our (IR) infrared cameras, we will image surface lakes and the meandering meltwater channels on the ice sheet surface, and then fly over a few of the southwest fjords to image meltwater as it plumes at the calving edge of the ice sheet. This is a day that Chris Zappa, our resident oceanographer and optics expert, has been waiting patiently for. The weather is perfect, the sky crystal clear, and the instruments are humming. We are ready to go.
The surface of the ice sheet barely resembles our April visit. Large lakes, some a mile across, are printed along the ice sheet surface, as if a skipping stone has skimmed along the surface leaving pockets of water in its wake.
These ice surface lakes are viewed more cautiously than our lakes back home, as they pose a threat of suddenly emptying through a “moulin” or drainage tube. Moulins transfer water from the surface to the bottom of the ice sheet in short order, circumventing a process that could otherwise take many thousands of years. Cutting across the surface in various patterns, meandering channels carry the melting surface water into these catchment pools. On the ice sheet these channels are the equivalent of streams from our home communities. Back home they collect runoff and drain into freshwater lakes. Here they serve the same function but are more striking, as there are no plants to screen them.
The cameras work furiously. The Bobcat, is a 29-megapixel camera. The IR samples at 100 frames per second. Both cameras collect a staggering 60 gigabytes a second. Images play across the screen showing the temperature contrasts as we move over the surface features.
We move from the ice sheet to the coastline, where rugged mountains circle Greenland’s perimeter like a crown. Fjords cut through in many areas, allowing deeply stacked ice in the interior to move off the land. Today we are flying down small “arms” of Godthaab Fjord with a focus on their leading edges, where the ice meets the Atlantic water. We are interested in how the IR camera can be used to track thermal plumes at the interface of the cold glacier meltwater and the warmer ocean water. Combining both the Bobcat and the IR cameras allows sediment plumes to be tracked moving through the fjord. Sediment should warm faster than the surrounding water, and may be transferring more heat into the system. Both will tell us about circulation, mixing and transit of the glacial meltwater systems.
Flying back down the fjord we pass over a small fishing town perched on the edge of the water. There is no apparent movement below. Perhaps they have gone fishing?
For more about the IcePod project: http://www.ldeo.columbia.edu/icepod
Even the most skilled of English language lipreaders are only able to tease apart about 30 percent of the information being shared. I learned this reading a recent article (Kolb, 20131). The author, herself deaf, went on to note that in some transmissions the information capture is higher while in others there is nothing collected. An average of 30 percent information transfer…most of us seek more information, we are curious beings. I don’t know anyone who is happy to sit comfortably saying “yes we know 30 percent, that is good enough.”
I am surrounded by question posers, information seekers, hypothesis formers – scientists are an inquisitive bunch for sure – and that is how we find ourselves back in Greenland in July seeking to learn more about the information operating underneath and deep inside this changing ice sheet, and testing just what our IcePod instruments are capable of telling us. Thirty percent is well in excess of what we currently know about ice sheets and their processes, but every line flown and piece of data collected and analyzed builds upon our current understanding.
Prior to arriving at the base for the morning, flight plans were laid well in advance. Discussions threaded through the series of meetings leading up to our return to Kangerlssuaq, piecing together the right combination of flights that would focus on testing instruments and addressing the science. Instrument range, elevation, seasonal snow conditions, old radar lines all are factored in. Once in Greenland we must weave weather and instrument issues into our planning. Weather is cloudy and reports suggest an improvement during the week, so we will shelve our camera testing for the minute and focus on instruments designed to penetrate through the clouds. Today our flight will focus on tuning our Deep Ice Radar System (DICE).
Located at the crest of the ice sheet the elevation is just over 10,500 ft. and seems just the place to test our deep ice radar. Once aloft, we head for deep ice up over Summit. The weather reports are validated – the whole area is socked in with cloud cover and the pilots switch to Instrument Flight Rules (IFR). Our survey flight at Summit is 3,000 ft. above ground level (agl), but the aircraft instruments tell us we are 13,000 ft. above sea level (asl). The ice is deep and DICE is the focus of the next few hours as we survey and resurvey in the same area with dialogue, testing, refining and learning with each pass.
A question was raised — would we want to move to a second area to look at different conditions? Checking other areas of the ice sheet is tempting, but the science team vetoes this…”We learn more by doing this now,” holding our focus on one location. So we refocused our efforts, collecting more data, making more small adjustments, and consider that with each data point we are improving our lipreading of the ice sheet.
For more about IcePod: http://www.ldeo.columbia.edu/icepod.
1Kolb, Rachel, Seeing at the speed of sound, in Standford Magazine, March/April 2013 http://alumni.stanford.edu/get/page/magazine/article/?article_id=59977