Tag Archives: topography

Credit: British Antarctic Survey.

What Greenland’s landscape looks like without any ice

The most detailed map of Greenland’s topography was released this week by a team of British and American researchers. An accompanying video simulates what the massive island would look like if it were free of ice. Speaking of which, the new findings suggest that Greenland’s ice sheet has the potential to contribute more to global sea level rise than believed.

Credit: British Antarctic Survey.

Credit: British Antarctic Survey.

Greenland’s ice sheet is immense. Covering more than 660,000 square miles, thicker than a mile, and measuring a volume of 684,000 cubic miles, it would drown anything lower than 25 feet (~7.5 meters) above sea level were it to melt.

The new map carted by researchers at the British Antarctic Survey (BAS), the University of Bristol, and the University of California at Irvine (UCI), now offers a glimpse of what the island’s topography looks like under that huge blanket of ice.

We can see streams on top of valleys carved by water that used to flow well before the ice sheet even existed. The valley system creates perfect lubricating conditions for meltwater to run off and discharge into the ocean. What’s more, Greenland’s topography could foster the creation of more channels in the future, further speeding up the run-off.

Already, Greenland lost 269 billion tons of ice each year since 2002. According to an earlier study, meltwater sourced from Greenland’s ice sheet accounted for 25 percent of the global sea level rise in 2014.

This refined view also shows that Greenland’s ice sheet is thicker than previously thought, in some places by up to 100 meters.

“This new compilation of the 3-D landscape beneath the Greenland Ice Sheet provides the first seamless transition between the landmass and its adjoining seabed, and this gives scientists a bird’s eye view of the fringes of Greenland which are experiencing the most changes,” said BAS cartographer Peter Fretwell, who was involved in producing the printed map.

“What’s also surprising is that there is more ice and the bed is deeper in some places than previous maps suggest, so this means the total contribution from the ice sheet to global sea level rise would be 7.42 meters if it were to melt completely, slightly higher than previously calculated,” he added.

To make this detailed map, scientists employed data collected by different instruments operated by over 30 institutions worldwide. This includes data collected by satellites, airborne and ground-based radar, as well as seabed mapping from ships. A printed 1:3,500,000 scale version was presented this week at the American Geophysical Union meeting in New Orleans. A summy of the paper has been published in the journal Geophysical Research Letters.

“This map will improve our understanding of the ice-ocean interactions and how the ice sheet will evolve in a changing climate,” said glaciologist professor Jonathan Bamber at the University of Bristol who had a NERC-funded project to develop the printed map and data set.

Another study published on Wednesday in Science Advances found that in 2003, the ice sheet over Greenland suddenly began melting at a much faster rate. For instance, ice sheet run-off into the Tasersiaq catchment, which spans more than 2,500 square miles, increased by 80 percent compared to the average runoff rate in the decades prior. This suggests that global warming, though increasing gradually, can set off sharp, massive shifts in ice melt.

The topography of comet 67P. Photo: ESA

The most detailed topography of a comet

Ten years ago, the European Space Agency launched the Rosetta probe tasked to orbit a comet for the very first time and study it up close with unprecedented detail. Six billion miles later, the probe reached its target, the four-kilometer wide 67P comet, and has beamed back some of the most breathtaking images of a comet science has witnessed. The most recent shot released by ESA captures the comet so close that we can even see its intricate topography.

Captioned below, the photograph in question was captured while Rosetta was hovering only 65 miles (104 kilometers) away from the 2.5-mile-wide (four-kilometer) comet. We can clearly distinguish the three sections of the comet: the head (top view – filled with cliff-like structures), neck (narrow middle view – a smooth surface) and body (bottom view – riddled with peaks and valleys). Looks familiar? Sure it does. It’s a beautiful mountain (of ice) hurling away in space! How often do you get to see that?

The topography of comet 67P. Photo: ESA

The topography of comet 67P. Photo: ESA

If this is a comet, where’s its tail? Ahh, the magic is about to happen soon enough when 67P’s orbit will enter an area where the sun’s radiation is greater, causing ice displacement and melting. That’s when the comet’s corona and tail will form and Rosetta will be there to image the event in all its splendor. Before this happens, though, Rosetta is tasked with a mission of even greater importance.

Some scientists believe comets play a crucial role in distributing compounds throughout the solar system that are quintessential to forming life. This November, the spacecraft will get close enough to the comet to release the Philae lander, a tiny probe that will drill through the comet’s insides and analyze its chemical makeup.

BONUS! Below is the same image of 67P, only in 3D. You’ll need 3D glasses to view it, so dust off those old theater goggles from the attic.

comet_67p3d

 

Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta’s Philae lander is provided by a consortium led by the German Aerospace Center, Cologne; Max Planck Institute for Solar System Research, Gottingen; French National Space Agency, Paris; and the Italian Space Agency, Rome. JPL, a division of the California Institute of Technology, Pasadena, manages the U.S. participation in the Rosetta mission for NASA’s Science Mission Directorate in Washington.

Astronomers make high-res topographical map of Moon

Astronomers from the Arizona State University have used NASA’s Lunar Reconnaissance Orbiter (LRO) this mind blowing map of the Moon; it is the highest resolution near-global topographical map of our neighbor so far.

As you’ve probably already figured out, the map reveals the Moon’s surface, using colors to depict elevation – from white and red (highest) to purple (lowest). Now I don’t know about you, but if you ask me, this map is absolutely glorious, and it looks delicious too (kind of a pancake, wouldn’t you say?). But the way the map was created is perhaps even more wonderful.

It was created using the orbiting probe’s Wide Angle Camera (WAC), a device so small that you could literally hold it in your hand. But even though its size isn’t impressive, it can capture an astonishing view of the Moon 70 km wide. Due to the fact that the Moon’s lighting changes every 30 days, the WAC can record how different rocks reflect and shade the light and built this topographic wonder.

However, the little camera can’t do it all by itself. The satellite’s poles are almost constantly shrouded by darkness – but have no fear, the LRO’s Lunar Orbiter Laser Altimeter is here, and it excels at scanning the topography of the poles.

“Our new topographic view of the moon provides the dataset that lunar scientists have waited for since the Apollo era,” said Mark Robinson, Principal Investigator of the Lunar Reconnaissance Orbiter Camera (LROC) from Arizona State University, in a press release.

“We can now determine slopes of all major geologic terrains on the moon at 100 meter scale. Determine how the crust has deformed, better understand impact crater mechanics, investigate the nature of volcanic features, and better plan future robotic and human missions to the moon.”

Via WIRED