CR
Cryospheric Sciences

Remote sensing

Image of the Week – How geometry limits thinning in the interior of the Greenland Ice Sheet

May 26, 2017
Image of the Week – How geometry limits thinning in the interior of the Greenland Ice Sheet
Figure 1: (a) Mass change of the Greenland ice sheet measured by NASA’s GRACE mission in cm/yr water equivalent from January 2003 to December 2013 [Credit: modified from Velicogna et al., 2014]. (b) Dynamic surface elevation change and mass loss along the margin of West Greenland as measured by DEM differencing. The map shows surface elevation change from 1985 to present for 16 outlet glaciers. Circles represent mass change (estimated using 917 kg m-3 as ice density) with circle areas proportional to magnitude of mass change. [Credit: Denis Felikson]

The Greenland ice sheet flows from the interior out to the margins, forming fast flowing, channelized rivers of ice that end in fjords along the coast. Glaciologists call these “outlet glaciers” and a large portion of the mass loss from the Greenland ice sheet is occurring because of changes to these glaciers. The end of the glacier that sits in the fjord is exposed to warm ocean water that can me ...[Read More]

Image of the Week – Antarctica’s Flowing Ice, Year by Year

May 12, 2017

Today’s Image of the Week shows annual ice flow velocity mosaics at 1km resolution from 2005 to 2016 for the Antarctic ice sheet. These mosaics, along with similar data for Greenland (see Fig.2), were published by Mouginot et al, (2017) last month as part of NASA’s MEaSUREs (Making Earth System Data Records for Use in Research Environments) program. How were these images constructed? The mosaics s ...[Read More]

Image of the Week — The ice blue eye of the Arctic

February 24, 2017
Image of the Week — The ice blue eye of the Arctic
Ice floe with a melt pond (light blue patch), observed in Nares Strait , in August 2015 from I/B Oden [Credit: C. Heuzé]

“Positive feedback” is a term that regularly pops up when talking about climate change. It does not mean good news, but rather that climate change causes a phenomenon which it turns exacerbates climate change. The image of this week shows a beautiful melt pond in the Arctic sea ice, which is an example of such positive feedback. What is a melt pond? The Arctic sea ice is typically non-smooth, and ...[Read More]

Image of the Week – Icelandic glaciers monitored from space!

February 17, 2017
Image of the Week – Icelandic glaciers monitored from space!
Figure 1: Exceptionally cloud free view of Iceland taken from ESA Envisat on 21, July 2010. Rates of surface elevation change between 2010-2015 derived from ESA CryoSat-2 swath-processed elevations are overlaid over the six largest ice caps. The time series shows thinning below 1200 m elevation over Vatnajökull, the largest ice cap in Iceland and Europe (by volume) -see Foresta et al. (2016) [Credit: L. Foresta and Dr. N. Gourmelen, University of Edinburgh, School of GeoSciences]

Located in the North Atlantic Ocean, just south of the polar circle, Iceland is a highly fascinating land. Covered by some of the largest glaciers in Europe and hosting active volcanoes, geothermal sites and subglacial lakes, it is extremely dynamic in nature and ever changing. With this Image of the Week we will tell you a bit about the changing ice caps of Iceland and how we can monitor them fro ...[Read More]

Image of the Week – Sea Ice Floes!

December 2, 2016
Image of the Week – Sea Ice Floes!
Left: Floes in the Southern Ocean surrounding the Nathaniel Palmer, taken by a multi-rotor drone. The length of the Nathaniel Palmer, about 100 m, is shown for comparison [Credit: EOS]. Right: Floes in the Bering Strait in May, 2000 from the MODIS satellite. Arrow shows the width of the Bering Strait, 85 km, for comparison [Credit: NASA Earth Observatory].

The polar regions are covered by a thin sheet of sea ice – frozen water that forms out of the same ocean water it floats on. Often, portrayals of Earth’s sea ice cover show it as a great, white, sheet. Looking more closely, however reveals the sea ice cover to be a varied and jumbled collection of floating pieces of ice, known as floes. The distribution and size of these floes is vitally imp ...[Read More]

Image of the Week – What an ice hole!

November 25, 2016
Image of the Week – What an ice hole!
A schematic representation of what causes polynyas to open [Credit: Céline Heuzé]

Over the summer, I got excited… the Weddell Polynya was seemingly re-opening! ”The what?” asked my new colleagues. So today, after brief mentions in past posts, it is time to explain what a polynya is. Put it simply, a polynya, from the Russian word for “ice hole”, is a hole in the sea-ice cover. That means that in the middle of winter, the sea ice locally and naturally opens and reveals the ocean ...[Read More]

Image of the Week – Satellite Measurements of Arctic Sea Ice

September 16, 2016
Image of the Week – Satellite Measurements of Arctic Sea Ice
The map above shows the region around Fram Strait that separates Greenland and Svalbard (Spreen et al., 2009) . The colours show the amount (volume flux) of sea ice that was moving from the Artic Basin and south in October/November 2006 as measured by satellites. The arrows show the direction of sea ice.

Sea ice is an important part of the Earth’s climate system. When sea ice forms, it releases heat and salt. When sea ice melts, it takes up heat and adds freshwater to the salty ocean water. It is also important for the exchange of energy between the atmosphere and the ocean surface, and for the ocean currents that transport warm and cold water from the equator to the poles and back. The main route ...[Read More]

Image of the Week – How ocean tides affect ice flow

July 8, 2016
Image of the Week – How ocean tides affect ice flow
(a) Shaded relief map of Rutford Ice Stream (West Antarctica) and surrounding area. Red box indicates the region shown in b. (b) Horizontal velocity where colors indicate speed, arrows show flow direction, and grayscale background is horizontal speed from Rignot et al. (2011). (c) Detrended along-flow displacements measured with GPS stations beginning December 2003. Locations of stations are indicated in (b). ( Credit : Brent Minchew )

Ice streams discharge approximately 90% of the Antarctic ice onto ice shelves , and ultimately into the sea into the sea (Bamber et al., 2000; Rignot et al., 2011). Whilst flow-speed changes on annual timescales are frequently discussed, we consider here what happens on much shorter timescales! Previous studies have shown that ice streams can respond to ocean tides at distances up to 100km inland ...[Read More]

European Space Agency Living Planet Symposium 2016

May 26, 2016
European Space Agency Living Planet Symposium 2016
Background: Prague Castle as viewed from the Charles Bridge (Credit: Stephen Chuter)

Living Planet Symposium Between the 9th and 13th May, Prague played host to the European Space Agency’s (ESA) fourth Living Planet Symposium. The event, the largest in its history with over 3300 attendees, brought together the earth observation community across multiple disciplines to discuss significant scientific results and the future developments of earth observation missions. Earth Observatio ...[Read More]

Careers at the European Space Agency – How and Why?

May 3, 2016
Careers at the European Space Agency – How and Why?
Flow speed of Jakobshavn Isbræ outlet glacier (South West Greenland) in winter 2014. Credit: ESA

As the pace of modern life speeds up and job competition becomes even more fierce, it is good to have a focused plan of where you would like to be in the future. The European Space Agency (ESA) offers traineeships and research positions to young scientists on a regular basis. They may be a springboard into your chosen career path, but how do you go about bagging one of these valuable opportunities ...[Read More]