To study the areas where subglacial lakes fill and drain more frequently with satellite data, Siegfried worked with Fricker, who played a crucial function in creating the method the ICESat-2 mission observes polar ice from area.
Siegfried and Frickers new research study reveals that a group of lakes consisting of the Conway and Mercer lakes under the Mercer and Whillans ice streams in West Antarctica are experiencing a draining duration for the third time considering that the initial ICESat mission began measuring elevation changes on the ice sheets surface area in 2003. The 2 recently discovered lakes likewise being in this region.
In addition to supplying crucial data, the study likewise exposed that the details or limits of the lakes can change slowly as water gets in and leaves the tanks.
” Were actually mapping out any height abnormalities that exist at this point,” Siegfried said. “If there are lakes filling and draining pipes, we will find them with ICESat-2.”
Helping United States Observe Under the Ice Sheet
Exact measurements of basal meltwater are essential if researchers wish to get a better understanding of Antarcticas subglacial pipes system, and how all that freshwater may change the speed of the ice sheet above or the circulation of the ocean into which it ultimately flows.
An enormous dome-shaped layer of ice covering the majority of the continent, the Antarctic ice sheet streams slowly outwards from the central region of the continent like extremely thick honey. As the ice approaches the coast, its speed changes dramatically, turning into river-like ice streams that funnel ice quickly toward the ocean with speeds up to a number of meters per day. How quick or slow the ice moves depends partially en route meltwater oils the ice sheet as it moves on the underlying bedrock.
As the ice sheet moves, it suffers fractures, crevasses, and other flaws. When lakes under the ice gain or lose water, they likewise deform the frozen surface above. Big or little, ICESat-2 maps these elevation changes with a precision down to simply a couple of inches utilizing a laser altimeter system that can determine Earths surface with unmatched detail.
ICESat-2 will offer researchers with height measurements that produce a global portrait of Earths third measurement, collecting information that can precisely track modifications of surface consisting of glaciers, sea ice, forests and more. The single instrument on ICESat-2 is ATLAS, the Advanced Topographic Laser Altimeter System, will measure melting ice sheets and investigate how this impacts sea level rise, examine changes in the mass of ice sheets and glaciers, quote and research study sea ice thickness, and determine the height of plant life in forests and other ecosystems worldwide. Credit: NASA/Ryan Fitzgibbons
Tracking those intricate processes with long-term satellite missions will provide vital insights into the fate of the ice sheet. A fundamental part of what glaciologists have discovered about ice sheets in the last 20 years comes from observations of how polar ice is altering in reaction to warming in the environment and ocean, but surprise procedures such as the method lake systems transportation water under the ice will also be type in future research studies of the Antarctic Ice Sheet, Fricker stated.
” These are procedures that are going on under Antarctica that we wouldnt have a hint about if we didnt have satellite information,” Fricker stated, stressing how her 2007 discovery made it possible for glaciologists to confirm Antarcticas surprise plumbing system carries water much more quickly than previously thought. “Weve been having problem with getting great predictions about the future of Antarctica, and instruments like ICESat-2 are helping us observe at the process scale.”
A Water System That Is Connected to the Whole Earth System
How freshwater from the ice sheet may impact the blood circulation of the Southern Ocean and its marine ecosystems is among Antarcticas finest concealed. Since the continents subglacial hydrology plays a crucial role in moving that water, Siegfried also stressed the ice sheets connection to the rest of the world.
” Its not simply the ice sheet were speaking about,” Siegfried stated. “Were truly speaking about a water system that is connected to the entire Earth system.”
Recently, Fricker and another team of scientists explored this connection in between freshwater and the Southern Ocean– but this time by looking at lakes near the surface area of an ice shelf, a big slab of ice that floats on the ocean as an extension of the ice sheet. Their study reported that a big, ice-covered lake collapsed quickly in 2019 after a crack or fracture opened from the lake floor to the base of Amery Ice Shelf in East Antarctica.
With data from ICESat-2, the team evaluated the rugged change on the landscape of the ice shelf. The occasion left a doline, or sinkhole, a remarkable anxiety of about four square miles (about 10 square kilometers), or more than 3 times the size of New York Citys Central Park. The fracture funneled almost 200 billion gallons of freshwater from the surface area of the ice shelf into the ocean listed below within three days.
Throughout the summertime, thousands of turquoise meltwater lakes adorn the brilliant white surface of Antarcticas ice shelves. However this abrupt occasion took place in the middle of the winter, when researchers anticipate water on the surface of the ice shelf to be completely frozen. Because ICESat-2 orbits Earth with exactly duplicating ground tracks, its laser beams can show the dramatic modification in the terrain before and after the lake drained, even during the darkness of polar winter season.
The height profile above was obtained by NASAs Ice, Cloud, and land Elevation Satellite 2 (ICESat-2) using the Advanced Topographic Laser Altimeter System (ATLAS). The image reveals the elevation information gotten by three various ATLAS laser beams as the satellite passed over an ice-covered lake that collapsed all of a sudden and abruptly on the surface area of Antarcticas Amery Ice Shelf in 2019. Credit: NASAs Earth Observatory
Roland Warner, a glaciologist with the Australian Antarctic Program Partnership at the University of Tasmania, and lead author of the research study, first found the scarred ice rack in images from Landsat 8, a joint objective of NASA and the U.S. Geological Survey. The drainage occasion was probably triggered by a hydrofracturing process in which the mass of the lakes water resulted in a surface area crack being driven right through the ice shelf to the ocean listed below, Warner stated.
” Because of the loss of this weight of water on the surface of the drifting ice rack, the entire thing flexes upwards focused on the lake,” Warner stated. “Thats something that would have been hard to determine just looking at satellite images.”
Meltwater lakes and streams on Antarcticas ice shelves prevail during the warmer months. And since scientists expect these meltwater lakes to be more common as air temperatures warm, the threat of hydrofracturing could likewise increase in coming years. Still, the group concluded its too early to identify whether warming in Antarcticas environment caused the demise of the observed lake on Amery Ice Shelf.
Seeing the development of a doline with altimetry information was a rare opportunity, but it is also the type of occasion glaciologists need to examine in order to study all of the ice dynamics that matter in models of Antarctica.
” We have actually found out so much about ice sheet vibrant processes from satellite altimetry, it is crucial that we plan for the next generation of altimeter satellites to continue this record,” Fricker stated.
Referral: “Illuminating active subglacial lake procedures with ICESat-2 laser altimetry” by M. R. Siegfried and H. A. Fricker, 7 July 2021, Geophysical Research Letters.DOI: 10.1029/ 2020GL091089.

From above, the Antarctic Ice Sheet may look like a calm, continuous ice blanket that has covered Antarctica for millions of years. An enormous dome-shaped layer of ice covering many of the continent, the Antarctic ice sheet streams slowly outwards from the main area of the continent like extremely thick honey. As the ice approaches the coast, its speed changes considerably, turning into river-like ice streams that funnel ice quickly toward the ocean with speeds up to numerous meters per day. How fast or slow the ice moves depends partially on the way meltwater lubes the ice sheet as it moves on the underlying bedrock.
The single instrument on ICESat-2 is ATLAS, the Advanced Topographic Laser Altimeter System, will determine melting ice sheets and examine how this effects sea level increase, investigate changes in the mass of ice sheets and glaciers, price quote and study sea ice density, and measure the height of plant life in forests and other ecosystems worldwide.

NASAs Land, ice and cloud Elevation Satellite 2, or ICESat-2, allowed scientists to specifically map the subglacial lakes. The satellite measures the height of the ice surface, which, despite its massive density, increases or falls as lakes fill or empty under the ice sheet.
Numerous meltwater lakes conceal deep underneath the expanse of Antarcticas ice sheet. With a powerful laser altimeter system in space, NASAs Ice Cloud and land Elevation Satellite-2 (ICESat-2) is assisting researchers “see” under the ice. Credit: NASAs Goddard Space Flight
The research study, published on July 7, 2021, in Geophysical Research Letters, incorporates height information from ICESat-2s predecessor, the initial ICESat objective, in addition to the European Space Agencys satellite committed to keeping track of polar ice thickness, CryoSat-2.
Hydrology systems under the Antarctic ice sheet have actually been a secret for decades. That began to alter in 2007, when Helen Amanda Fricker, a glaciologist at Scripps Institution of Oceanography at the University of California San Diego, made a breakthrough that assisted upgrade classical understanding of subglacial lakes in Antarctica.
Using information from the initial ICESat in 2007, Fricker discovered for the very first time that under Antarcticas quick flowing ice streams, an entire network of lakes get in touch with one another, filling and draining pipes actively gradually. Before, these lakes were believed to hold meltwater statically, without filling and draining.
” The discovery of these interconnected systems of lakes at the ice-bed user interface that are moving water around, with all these impacts on glaciology, oceanography, and microbiology– that was a big discovery from the ICESat objective,” said Matthew Siegfried, assistant teacher of geophysics at Colorado School of Mines, Golden, Colo. and lead private investigator in the brand-new research study. “ICESat-2 resembles placing on your glasses after utilizing ICESat, the information are such high precision that we can truly start to map out the lake limits on the surface.”
Researchers have hypothesized subglacial water exchange in Antarctica results from a combination of aspects, consisting of fluctuations in the pressure exerted by the enormous weight of the ice above, the friction in between the bed of the ice sheet and the rocks below, and heat coming up from the Earth listed below that is insulated by the thickness of the ice. Thats a plain contrast from the Greenland ice sheet, where lakes at the bed of the ice fill with meltwater that has actually drained pipes through cracks and holes on the surface.

NASA scientists on the surface area of the Antarctic Ice Sheet as part of the 88-South Traverse in 2019. The 470-mile expedition in one of the most barren landscapes on Earth offers the very best ways of assessment of the accuracy of information collected from area by the Ice Cloud and land Elevation Satellite-2 (ICESat-2). Credit: NASAs Goddard Space Flight Center/Dr. Kelly Brunt
NASAs ICESat-2 Map Antarctic Meltwater Lakes With Astonishing Precision
From above, the Antarctic Ice Sheet may look like a calm, perpetual ice blanket that has actually covered Antarctica for millions of years. The ice sheet can be thousands of meters deep at its thickest, and it conceals hundreds of meltwater lakes where its base meets the continents bedrock. Deep listed below the surface, a few of these lakes fill and drain continuously through a system of waterways that ultimately drain pipes into the ocean.
Now, with the most sophisticated Earth-observing laser instrument NASA has actually ever flown in area, researchers have actually enhanced their maps of these concealed lake systems under the West Antarctic ice sheet– and found two more of these active subglacial lakes.
The brand-new study supplies important insight for spotting brand-new subglacial lakes from space, along with for evaluating how this concealed pipes system influences the speed at which ice slips into the Southern Ocean, adding freshwater that might change its flow and environments.