Cryospheric Sciences

Image of the Week – Changes in the Greenland Ice Sheet Documented by Satellite

Emma C. Smith February 19, 2016

Changes in mass of the Greenland Ice Sheet over 10 years from GRACE satelite data (Luthcke et al., 2013).

Monitoring the changing ice mass of the Greenland Ice Sheet provides valuable information about how the ice sheet is responding to changing climate, but how do we make these measurements over such a large area of ice? Using NASA’s GRACE satellites (twin-satellites flying in formation) it is possible to make detailed measurements of the Earth’s gravitational field. As ice is gained/lost from ...[Read More]

Image of the Week — slush on top of sea ice

Sophie Berger February 5, 2016

Fieldwork on Greenland sea ice/slush (Credit: Marie Kotovitch)

Many glaciologists look forward to going on fieldtrips and then, once they are back, they make us dream by posting breathtaking photos (like THIS or THIS or THIS). However, the reality of the field can sometimes be very different…. The picture illustrates how difficult it can be to work on sea ice when the snow on top of it starts to melt and forms slush (a mixture of snow and liquid water t ...[Read More]

Image of the Week: Icequakes! Stick-Slip motion under Western Greenland

Emma C. Smith January 29, 2016

Schematic stick-slip source model explaining the observed first-motion pattern of a basal icequake (orange dot). For each station, the stacked waveform of the direct P wave is shown with first up or down motion. These observations are consistent with the beach ball, which represents a low-angle thrust fault in the ice flow direction. Inset: schematic side view of the stick-slip mechanism, where the ice is sliding over the bed. Beachball and radiation pattern are shown.

The Greenland Ice Sheet contains enough fresh water to raise global sea level by around 6 m, therefore it is very important to understand how the ice moves from the interior of the ice sheet towards the oceans. Processes that happen at the base of the ice sheet, where the ice meets the bed, are known to be a key control on how the ice moves. Geophysical techniques, such as recording tiny icequakes ...[Read More]

Image of the Week — Greenland ice sheet and clouds

Sophie Berger January 15, 2016

The effects of clouds on the Surface Mass Balance (SMB) of the Greenland ice sheet during the period September 2007–September 2010. (Credit: Van Tricht et al, 2016)

A new study combining satellite observations and model simulations shows that clouds increase meltwater runoff in Greenland by one-third compared to a cloud-free scenario. Precipitation effects not considered, clouds above the Greenland ice sheet reduce its Surface Mass Balance (SMB) [red in figure] compared to clear-sky conditions [blue in figure]. Because clouds trap the outgoing radiation from ...[Read More]

Image of the Week: Greenland Glacier Seen from a Drone

Nanna B. Karlsson November 5, 2015

UAV on its way back from a mission with Store Glacier, West Greenland, in the background. Credit: Johnny Ryan

The use of drones or Unmanned Aerial Vehicles (UAVs) is one of the most exciting development in glaciology in recent years. The picture was taken during fieldwork conducted in the summer of 2014 by Johnny Ryan and colleague Nick Toberg. The aim was to survey Store Glacier once a day using a fixed-wing UAV, that was equipped with a digital camera, which took photos every two seconds during its dang ...[Read More]

Image of Week: Inside the Greenland Ice Sheet

Nanna B. Karlsson October 23, 2015

Cross-section of the age of the Greenland Ice Sheet from radar data. Credit: NASA's Scientific Visualization Studio and MacGregor et al., 2015.

The image shows a cross section of the Greenland Ice Sheet, where a recent study by MacGregor et al. have mapped the layers imaged by radar. Thanks to ice core measurements the age of the layers have been determined, and in the image the layers from the Holocene period (the past 11.700 years) are shown in green. The ice formed during the last ice age, that spanned 11.700 to 115.000 years ago are c ...[Read More]

Riding the Storm: The Arctic Circle Traverse 2015

Babis Charalampidis October 8, 2015

Stormy day at Dye-2, 20th of May. Credit: Babis Charalampidis.

In the morning on the 19th of May, we – the Arctic Circle Traverse 2015 – found ourselves in a great dilemma; to stay or to go? On our check-in conversation with the KISS crew, we were informed that an east front from Kulusuk was expected to hit our location up on the ice sheet sometime in the afternoon. The relatively low winds that we were experiencing would get stronger, and the visibility woul ...[Read More]

Image of the Week : SAFIRE team getting ready to drill in Greenland

Sophie Berger October 2, 2015

The SAFIRE team sets up the drilling device on the Store Glacier, Western Greenland. Credit : T.J. Young

How do you get a hot water drill onto an ice sheet? The Subglacial Access and Fast Ice Research Experiment (SAFIRE) uses a hot water drill to directly access and observe the physical and geothermal properties where the ice meets rock or sediment at the glacier-bed interface. Here, SAFIRE principal investigator Bryn Hubbard and post-doc Sam Doyle help fly in the drill spool at the start of the Summ ...[Read More]

Image of the Week: GISP II Borehole

Nanna B. Karlsson September 11, 2015

The GISP II (Greenland Ice Sheet Project Two) borehole at Summit Station, Greenland. Credit: N. B. Karlsson

Climate records from ice cores have helped scientists understand the past changes in climate.The GISP II (Greenland Ice Sheet Project Two) ice core was more than 3km long and was drilled during a five year period in the 1990s. After the drilling ended the casing of the borehole was extended above the surface, so that the borehole can still be accessed for remeasurements of, for example, temperatur ...[Read More]

Image of the Week: Greenland Ice Streams

Nanna B. Karlsson September 4, 2015

Credit: Copernicus data (2015)/ESA/Enveo

This image is from the west coast of Greenland and it shows several glaciers flowing towards the sea (upper part of the image), transporting ice into the ocean. The colours show the velocity of the ice. As the ice gets nearer to the coast it speeds up reaching speeds over 15m/day. The velocities were calculated using two Sentinel-1A radar scans from 3 and 15 January 2015. You can download a high r ...[Read More]