Tag Archives: Antarctica

Book Review: Terra Incognita by Sara Wheeler

Ms. Wheeler is not the touchy-feely kind when she describes scientists and technicians in Antarctica during the 7-month that she spent with them in science camps. She turns awes and wonders into a refreshing set of stories about people and places. At a fast clip she surprises with delightful encounters describing a different breed of people in a different land. “Terra Incognita” is not all ice, mountains, deserts, and hardship, but it is about the people who live and work there. As a scientist I felt at times described like a caged animal on display in her writing. She pokes fun of subjects and self that the feeble may not always like. Her book made me laugh and smile often. It still does.

terra-incognita-by-sara-wheeler

The people in Ms. Wheeler’s book reminded me of many companions that I lived with in close quarters working on Arctic research vessels and out of remote field camps. She succeeds to show the essence of men and women who live science. With humor and gripping commentary she depicts the human side of science well. This is travel writing at its very best, ever since Bruce Chatwin stopped writing. Along with Ms. Wheeler’s first book “Travels in a Thin country” that is Chile, “Terra Incognita” reflects a healthy thirst for life, people, and wanderlust.

Antarctic Plane Crash Kills 3 Canadians

Polar research requires ships, planes, and helicopters to supply bases and move people, instruments, fuel, and food to places where instruments need to placed, recovered, or serviced. While these activities are fairly routine and safe where most of us live, they are neither routine nor safe in extreme cold, extreme winds, or extremely remote places such as Arctic Canada, Greenland, or Antarctica.

I just learnt from an NSF Press Release that a Kenn Borek Twin Otter crashed into Mount Elizabeth in the Queen Alexandra Range of the Transantarctic Mountains at an elevation of about 3,900 m or 11,000 feet less than 2 weeks ago. All three Canadian crew aboard were killed. The plane was in transit from a research station at the South Pole to the Italian station at Terra Nova Bay to support Italian field work.

A memorial ceremony for the aircrew at NSF's Amundsen-Scott South Pole Station [Photo Credit: Blaise Kuo Tiong, NSF]

A memorial ceremony for the aircrew at NSF’s Amundsen-Scott South Pole Station [Photo Credit: Blaise Kuo Tiong, NSF]

Here are the words of Dr. Kelly Falkner, Director of NSF’s Polar Division (source):

January 28, 2013
On behalf of the U.S. National Science Foundation and all in the U. S. Antarctic Program, I wish to extend our profound sympathies to the families, friends, and colleagues of the three Kenn Borek Twin Otter crew, whose deaths in Antarctica while en route to support the Italian national Antarctic science program have recently been confirmed.

We have been privileged to experience first-hand their professionalism, skill, and dedication to the arduous task of supporting science in an extremely remote and inhospitable environment. In many ways, their contributions make possible hard won but vital advances in scientific knowledge that serve all of mankind. Although everyone associated with the pursuit of science in Antarctica makes personal sacrifices to do so, very infrequently and sadly, some make the ultimate sacrifice.

While it may come as little consolation at this very sorrowful time, the families, friends, and colleagues of the crew members should know that the thoughts of everyone in the U.S. Antarctic Program were with them through the long ordeal of the past few days and remain so now.

To the families and friends of the crew, I commend your loved ones for their commitment and dedication to their profession and offer our condolences. The sense of loss is keenly felt throughout the U.S. program and no doubt throughout the international Antarctic community.

-NSF-

I am also thinking of Marty Bergmann, a Canadian Polar scientist turned administrator. He perished 2 summers ago in a plane crash outside Resolute, Nunavut in the Canadian High Arctic working his Government Canada job to tirelessly help others in their Arctic research. Unlike the photo below, I remember him with a massive ear-to-ear grin on his face and a twinkle in his eye.

The Royal Canadian Geographic Society will recognize Martin Bergmann, the director of the Polar Continental Shelf Program who died in a plane crash in Resolute last year, by creating a medal for excellence in Arctic leadership, science and exploration. [Credit: CBC News]

Martin Bergmann, Director of the Polar Continental Shelf Program who died in a plane crash in Resolute Aug.-20, 2011. [Credit: CBC News]

Pine Island Glacier Ice Island 2012 Shoving Off

NASA published a stunningly crisp image of Pine Island Glacier (PIG), Antarctica yesterday that is already out of date, because the PIG is on the move. Glaciers change rapidly these days and the speed of the PIG is anything but glacial. The image below from Nov.-13, 2011 shows a massive crack that will develop into an ice island about 3-4 times larger than the one formed from Petermann Glacier, Greenland in 2010. While the image indicates that the part seaward of the crack is still attached, I am convinced that it is already moving independently of the glacier.

Nov.-13, 2011 image of Pine Island Glacier, Antarctica from the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument. Area shown cover 27 by 32 miles or 44 by 52 kilometers. Image Credit: NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team.

The same Terra space craft that provides the very crisp and high-resolution ASTER image also has sensors that image a larger area at slightly coarser 250 meter resolution. And monday was again an exceptionally clear day over Pine Island Glacier that revealed this (false color) image of radiation received at a “color” that is out of range of our eyes, the near infrared (865 nanometers):

Pine Island Glacier, Antarctica as seen Jan.-30, 2012 from MODIS sensors on Terra spacecraft. The crack is visible as the white line. For reference I am also showing where the front of the glacier was seven years ago with a thin black line. The thick black line shows where the glacier is grounded to the bedrock more than 1000 meters deep (grounding line).

The glacier has advanced a fair amount, the crack breaking off is a perfectly normal event. This is what tidewater glaciers do, they move out to sea and break off icebergs and ice islands. Subtracting the January-30, 2012 image from a Nov.-3, 2011, I think that the thick red line below shows how far and fast the new ice island has moved the last 3 months. Its speed is at least ten times that of the glacier behind the crack:

Difference of two MODIS images, thick red line on left (seaward edge of glacier) shows the area that the new ice island had moved into on Jan.-30, 2012 that was water on Nov.-3, 2011.

Lets leave the boring crack alone, nothing to worry there. What is important at Pine Island Glacier is the retreat of the grounding line, the location where ice, ocean, and bedrock meet. All ice located seaward of the grounding line is floating and does not add to rising global sea level. [Actually, it does raise sea level a tiny amount on account of subtle nonlinearity on how volume of water and ice are influenced by temperature, salinity, and pressure, but lets neglect this detail for now as everyone else does for a good reason).

It is the ice landward of the grounding line that will raise sea level as it passes the grounding line and becomes floating ice. And the thickness of this part of the glacier is decreasing at a rapid and alarming rate, because the glacier is melting from below by the ocean and much of the bedrock landward is below sea level, thus allowing the PIG to become “unhinged.”

The problem with this process is that we cannot see it as easy from space, as we can see changes at the surface. The ocean melting does not give the stunning images that portray drama, concern, and excitement the same way that new ice islands do. Yet, for most large glaciers like Pine Island, Antarctic and Petermann, Greenland, the oceans are eroding and melting these glaciers from below. It is the physics on how this works that we scientists do not yet know and understand very well. It is one thing to have a theory and perhaps a model, but only hard data from the ice and the ocean will give us the confidence and understanding to make smart decisions that balance our energy use contributing to global warming with the need to economically develop. Smart development allows us to live better lives and cope with calamities, some of which may be caused by global warming and the sea level rise it brings.

Pine Island Glacier Grounding and Unhinging

I can’t get Pine Island Glacier, Antarctica out of my mind. Checking my e-mail over breakfast, I was alerted to the forum post of Dr. King, a geophysicist working at the University of Newcastle in northern England. His post provided a hint and link to data on where all glaciers around Antarctica are grounded. The file at the National Snow and Ice Data Center was too slow to download at home, so I quickly bicycled to work, got the data, wrote a little script , and plotted Pine Island Glacier’s grounding and “coastline”:

Pine Island Glacier, Antarctica as seen Jan.-12, 2012 from MODIS Terra. The blue colors top-left are ocean, red-yellow are ice. Thick black line shows where the glacier is grounded to the bedrock below sea level, that is, all "red" areas to the left (west) of this line are floating on the ocean. The thin black line is the "coastline." Grounding and coastlines are from National Snow and Ice Data Center'. North is to the top.

The image indicates a problem in a rapidly changing world: Both the “coastline” and the “grounding line” change with time, rapidly so. The black lines shown above come from hundreds of cloud-free satellite images from the 2004/05 summer in Antarctica. Dr. Scambos, Lead Scientist for the National Snow and Ice Data Center painstakingly analyzed these data and assembled them into the “Mosaic of Antarctica.” The derived coastline for the Pine Island region suggests, that the glacier advanced over 10 km in 7 years. The crack behind it identifies the next ice island that, I speculate, has already separates from the glacier, as its front is moving 10 times faster than the glacier itself. The grounding line looks different from one that I have seen before, too, e.g.,

Bottom topography under Pine Island Glacier and grounding line. North is to the bottom. (NASA)

Trying to resolve this issue, I google searched “Pine Island Grounding Line” only to find a number of excellent science essays and publications on the impacts that Pine Island Glacier and its streaming ice have on climate change and global sea level rise:

Good science essays hide in strange places: “West-Antarctic Ice: Slip-sliding Away” by Dr. Bruce E. Johansen of the University of Nebraska makes reference to a 2010 publication in the Proceedings of the Royal Society of Dr. Katz, University of Oxford. This theoretical fluid dynamicist modeled “Stability of ice-sheet grounding lines” . It is a very theoretical paper whose results are summarized in The New Scientist. This is where I am now, hoping on my bicycle to visit my BrewHaHa coffee shop to read the paper away from my desk over lunch.

Oh, I also stumbled into a NASA animation of how Pine Island and adjacent ice streams accelerate and become thinner very far inland as a result. The graphics are stunning, the data are free, and the message is scary, yet, the science is exciting and I feel very lucky to be able to study this. Watch it, get hooked on science, and have fun.

Pine Island Glacier on the Move

Pine Island Glacier, Antarctica, is the focus of a large observational effort to better understand how glaciers and floating ice shelves interact with the ocean.

Pine Island Glacier (view is to the north, ocean in the top left) with crevasses and large crack extending from the east (right) to the west (left) as seen from aboard NASA's DC-8 research aircraft in October 2011. Credit: Michael Studinger/NASA

Scientists, pilots, technicians, and students working with NASA’s IceBridge and NSF’s Antarctic programmes tried hard for several years now to reach this glacier, set up a base, and drill through the 400-600 m thick ice shelf to reach the ocean. The data from these gargantuan efforts will reveal physics of ice-ocean interactions. This process is poorly represented in the climate models that are used to project past and present climates into the future. Harsh and hostile conditions cut these efforts short today, again, as reported by OurAmazingPlanet.

The expedition leader, NASA’s Dr. Bindschadler wrote today, that

A decision had been made by NSF the day we left McMurdo that if the helos were not able to be flown to PIG by Saturday, January 7, this year’s field work would be cancelled … We worked through our cargo—some had not been seen for two years when we tested our equipment at Windless Bight—preparing for either helos or the Twin Otter to start moving us onto the ice shelf. Neither came. Weather worsened.

Despite this dramatic turn of events, skies were clear over Pine Island Glacier today as they on New Year Jan.1, 2012. Two MODIS images show detailed features at 250-m resolution. I here show the near infra-”red” signals that the satellite receives (865 nm). The dark ocean reflects little of red (low reflectance) as it is all absorbed while the bright snow and ice reflects lots of red (high reflectance). Recall that the color “white” looks white, because it reflects all colors into our eyes including red, while “black” absorbs all colors, so none are left to reach our eyes.

Pine Island Glacier and Bay, Antarctica on Jan.-1, 2012 as seen by MODIS Terra, notice the whitish crack near the center of the image.

I show lots of the near infra-”red” as, well, red, and I color little red as blue. I chose the colors of the “crayons” to do the coloring. The technical term for this is contouring. Formally, I am depicting a function f=f(x,y) where f is the amount of red and x and y are locations east and north, respectively.

Pine Island Glacier and Bay, Antarctica on Jan.-12, 2012 as seen by MODIS Terra, notice the whitish crack near the center of the image.

They almost look the same, don’t they? If they were identical, then the difference would get zero. Except, glaciers move, especially this one. It is also about to spawn a large ice island. A crack was first reported in Oct.-2011 by scientists aboard a DC-8 of a NASA Icebridge flight. This crack is also widening as, I speculate, the front moves faster seaward of the crack than it does landward. My question is if I can see movements in these easily accessible public MODIS images. And my first answer, to be refined later, is 80 meters per day plus or minus 50%:

Difference of reflectance by subtracting Jan.-1 reflectances from those on Jan.-12, 2012. Very dark red colors show large positive numbers, meaning that the ice occupies a place on Jan.-12 that was water on Jan.1.

I am neither a glaciologist nor a remote sensing person, so I may be running a few red lights differencing two images and assign meaning to it. For example, I estimate the speed at which the front of the glacier moves by dividing the width of the very dark thick red line (about 1 km wide) by 12 days to get 80 meters per day or 3.5 meters per hour. The error here is at least 2 pixels (500-m), about half the estimated speed. My assumption here is that the high reflectance on Jan.-12 at a location with a low reflectance on Jan.1 means that the “bright” glacier has moved to a place that was “dark” ocean before. There is more to this, but I have to start somewhere.

Incidentally, Dr. Bindschadler, the leader of the current Pine Island field project who had to leave the base camp near Pine Island Glacier today, is the very person who wrote a wonderful peer-reviewed paper in 2010 with the title “Ice Sheet Change Detection by Satellite Image Differencing.” I will need to study it more closely … along with the vagarities of field work in polar regions.

It is difficult to get data from the field as opposed to data from remote sensing or modeling. This is especially true for remote and hostile locations the ice and the oceans interact. It is frustrating to be sent home early because of inclement weather and the very narrow window of opportunity when the few available helicopters and planes can fly or the ships can sail near Antarctica and Greenland.

EDIT Jan.-13: The National Snow and Ice Center estimated speeds of Pine Island Glacier as determined from two LandSat images from 1986 and 1988:

Contours of glacier speeds in meter per year of Pine Island Glacier from 1986 and 1988 LandSat Imagery, National Snow and Ice Center

These speeds are very different, 2-3 km per year versus 1 km in 12 days. The former estimate is made from 2 carefully geolocated images 2 years apart without a crack across the floating glacier, while my estimate yesterday is more noisy, but it is for a segment of the glacier that is barely connected to it. Perhaps we should consider the segment seaward fo the crack a separate ice island that is moving with the ocean rather than the glacier?