Tag Archives: Mapping

How big is Greenland?

Maps of Greenland were sketched with broken bones, frozen limbs, and starved bodies of men and dogs alike. On April 10, 1912 four men and 53 sled dogs crossed North Greenland from a small Inuit settlement on the West Coast where today the US Air Force maintains Thule Air Base. In 1912 Knud Rassmussen, Peter Freuchen, Uvidloriaq, and Inukitsoq searched for two explorers lost somewhere on Greenland’s East Coast 1200 km (760 miles) away. They returned 5 months later with 8 dogs without finding Einar Mikkelsen or Iver Iversen. These two arrived in North-East Greenland to find diaries, maps, and photos of three earlier explorers who had starved to death in the fall of 1908. Mikkelsen and Iverson found the records, but struggled to survive the winters of 1910/11 and 1911/12 alone stranded before a passing ship found them. I ordered their 1913 Expedition Report yesterday.

Dog sled teams drive across Greenland’s Inland ice in April 1912 from Clemens Markham’s Glacier in the west to Denmark Fjord in the east. All 4 explorers returned, but only 8 dogs did.
Map of Greenland as included in the Report of the First Thule Expedition 1912 by Knud Rasmussen.

I worked along these coasts in 2014, 2015, 2016, 2017, and 2018 on German research vessels, Swedish icebreakers, Greenland Air helicopters, and American snowmobiles. We explored the oceans below ice and glaciers with digital sensors but without hunger, cold, or lack of comfort. I feel that I know these coasts well, read what others have written and suffered. I make my own maps, too, to reveal patterns of oceans, ice, and glaciers that change in space and time. And yet, I am often lost by distances and areas. I do not know how big Greenland is.

Clockwise from top left: Ocean observatory on sea ice off Thule Air Base (Apr.-2017); refuelling helicopter in transit to ocean observatory on Petermann Gletscher (Aug.-2016); Swedish icebreaker in Baffin Bay (Aug.-2015); and deployment of University of Delaware ocean moorings from Germany’s R/V Polarstern off North-East Greenland at 77 N latitude (Jun.-2014).

At home I know distances that I walk, bicycle, or drive as part of my daily routine. I know areas where I live from weather and google maps, weekend strolls, and where family and friends live. Once we travel in unfamiliar lands, however, we are lost. Americans rarely know how small most European countries are while Europeans rarely know how far the Americas stretch from Pacific to Atlantic Oceans. Nobody knows the size of Greenland or Africa. On World Atlases Greenland appears as large as Africa, but this is false. Just look at this map:

The size of Africa on the same scale as the USA (green), Greenland (orange), and Germany (blue). Germany is about the same size as Botswana while Greenland is a tad larger than Kongo and the USA is about as big as the Sahara.

Thus North Greenland’s explorers walked distances similar to walking across Texas, Mississippi, and Florida (and back) or distances similar to walking Germany from its North Sea to the Alps (and back) or distances similar to walking across Kenya (and back). Making these maps, I found the tool at https://thetruesize.com These playful maps compare Greenland’s size by placing its shape onto North-America, Europe, and Asia:

Three explorers starved and froze to death November 1907 because they underestimated their walking area. Their shoes wore thin and they walked barefoot. Daylight disappeared and was replaced by polar night. Food vanished with no game to hunt. Jorgen Bronland, Niels Hoeg Hagen, and Ludvig Mylius-Erichsen were 29, 30, and 35 years young when they died mapping Greenland. I sailed the ice-covered coastal ocean. I was helped by maps they made walking.

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.