LIMA NARRATION

Isolated and icy, Antarctica is among the most challenging natural laboratories to access. Getting to Antarctica isn’t easy, and landing a plane on McMurdo Station’s Sea Ice Runway can give even the most seasoned researchers an adventurous arrival. Each year researchers from around the globe brave the frigid conditions to obtain critical field measurements on the ice sheet.

Luckily, remote-sensing scientists have dedicated time to developing detailed, accurate imagery of this frozen land from a far more hospitable vantage point. This new image mosaic, seen here, is known as the Landsat Image Mosaic of Antarctica, or LIMA. The spatial resolution of this satellite image you are seeing is 15 meters per pixel, the most detailed satellite mosaic of the rugged continent ever created.

A hearty few have ventured here, but as you can see, this new image mosaic makes it possible for anyone to explore this remarkable region without ice axes, crampons, or risk of frostbite. Throughout history, this mysterious land has captivated researchers, adventurers, and those drawn to the most remote corners of the Earth. Antarctica is a land of extremes: the highest, driest, coldest, windiest, and brightest of the seven continents

As we approach the mainland of Antarctica, you can see how far the ice shelf extends off the coast of the continent. Roughly the size of the United States and Mexico combined, Antarctica is almost completely covered by a thick layer of ice. The virtual journey of Antarctica, provided by LIMA, is due to the compilation of more than a thousand Landsat images acquired between 1999 and 2001. To create the images, data visualizers combine actual field data measurements and LIMA satellite imagery over a digital elevation model to give a three-dimensional effect.

As we move further inland you can begin to see that Antarctica is much more than an endless plain of snow. You might be surprised to learn how diverse the terrain actually is. The ground beneath the Antarctic ice sheet is a mixture of mountains, plains, and ocean basins, and the tallest mountains raise their rocky faces above the vast ice sheet.

Among Antarctica’s most prominent features are its mighty glaciers, like those seen here. As we move over the Ferrar glacier, we notice that LIMA reveals some areas of bare ground, where blistering winds have swept valleys clean of their snow cover.

Glaciers are essentially slow-moving rivers of ice, and they gradually deform over time. These masses of ice form when snow accumulates on a stretch of land over thousands of years. The snow eventually compresses enough to form dense glacial ice. As the thickness of glacial ice increases, it slowly succumbs to gravity and flows downhill or spreads out across flat lands. Moving glaciers, forced by gravity, sculpt the land as they erode the underlying rock. Antarctica is a glacial hub: 90 percent of the world’s 33 million cubic kilometers of glacial ice is found in the Antarctic ice sheet.

The telltale signs of glaciers are their flow stripes, which you can see in the many smaller glaciers feeding into the large Ferrar glacier.

Few people have the chance to experience a glacier firsthand in their lifetime, and even fewer can access a bird’s eye view of these icy giants. LIMA gives us an opportunity to soar above this unique landscape, and experience a mesmerizing view of Antarctica’s extraordinary glaciers.

This region’s relentless and powerful winds are responsible for one of Antarctica’s most fascinating features: blue ice. Ice absorbs a small amount of red light, but snow crystals are too small to show this light-absorption effect. However, blue ice is composed of larger ice crystals, however, which makes the red light absorption more obvious.

Antarctica is a fascinating natural laboratory, but the continent’s frigid temperatures and inaccessibility have historically made it a difficult place to study. Now armed with the Landsat Image Mosaic of Antarctica, researchers hope to get a better view of Antarctica and to increase their understanding of this fascinating part of our planet.