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Cryospheric Sciences

Antarctica

Mapping the bottom of the world — an Interview with Brad Herried, Antarctic Cartographer

Mapping the bottom of the world — an Interview with Brad Herried, Antarctic Cartographer

Mapping Earth’s most remote continent presents a number of unique challenges. Antarctic cartographers and scientists are using some of the most advanced mapping technologies available to get a clearer picture of the continent. We asked Brad Herried, a Cartographer and Web Developer at the Polar Geospatial Center at the University of Minnesota, a few questions about what it’s like to do this unique job both on and off the ice.


Before we go too much further… what is the Polar Geospatial Center, and what does it do for polar science and scientists?

The Polar Geospatial Center (PGC), founded in 2007 by Director Paul Morin, is a research group of about 20 staff and students at the University of Minnesota with a simple mission: solve geospatial problems at the poles (Antarctica and the Arctic). Because we are funded (primarily) through the U.S. National Science Foundation (NSF) and NASA Cryospheric Sciences, that is the community we support – other U.S.-funded polar researchers. We provide custom maps, high-resolution commercial satellite imagery, and Geographic Information System (GIS) support for researchers who would like to use the data for their research but may not have the expertise to do so.

Our primary service is providing high-resolution satellite imagery (i.e. from the DigitalGlobe, Inc. constellation) to U.S.-funded polar researchers – at no additional cost to their grants – through licensing agreements with the U.S. Government. It has proven beneficial to researchers to have a service so that we do the hard parts of data management, remote sensing, and automation of satellite imagery processing so that they don’t have to. So, a glaciologist or geomorphologist or wildlife ecologist studying at the poles may come to us and say: I would like to use satellite imagery to study phenomenon x or y. Some groups use it just for logistics (these are some of the least mapped places on Earth after all) to get to their site. Some groups’ entire research is done using remote sensing.

What kinds of data and resources do you use?

The PGC’s polar archive of high-resolution commercial imagery is absolutely astounding (like, in the thousands of terabytes). The imagery, although licensed to us by U.S. Government contracts, is collected by the DigitalGlobe, Inc. constellation of satellites (e.g. WorldView-2), much like the imagery where you can see your house/car in Google Earth. The benefit is that we can provide it at no cost to our users (researchers). That resource, along with the expertise of the staff at PGC, can provide solutions to users, whether it’s making a simple map of a remote research site or providing a time-series of satellite imagery for a researcher studying change detection (like, say for a glacier front in Greenland).

This also presents a challenge. How do we manage and effectively deliver that much data? We have relied on skilled staff, ingenuity, cheap storage, high-performance computing, and automation to become successful.

As the saying goes, automate or die.

What’s your role at the PGC? How did you find your way into a job like this?

I started at the PGC as a graduate student in 2008. I knew nothing about Antarctica or the Arctic, but my background and studies in GIS & cartography offered a wide range of jobs. After I graduated, I became a full-time employee as the lead cartographer of the (at the time, very small) group. Currently, I do a lot more GIS web application development and geospatial data management. We have recognized the need for more automated, “self-service” systems for our users to get the data they need in a timely manner, and less of asking a PGC employee for a custom product. As the saying goes, automate or die. But, of course, I still spend a fair bit of my times creating maps to keep my cartographic juices going.

Antarctica and the South Polar Regions. Map from the American explorer Richard Byrd’s second expedition in 1933. [Credit: Byrd Antarctic Expeditions]

What kind of work do PGC employees do in Antarctica?

The PGC staffs an office at the United States’ McMurdo Station annually from October to February, with 3-5 staff rotating throughout the field season. It is really an extension of our responsibilities, with a couple interesting twists, both good and bad. First, a majority of our users (NSF-funded researchers) come through McMurdo Station in preparation for their fieldwork. It’s a beneficial and unique experience to meet with them one-on-one and solve problems, ironically, faster than email exchanges back in the States. Second – and this is true of all of Antarctica – the internet bandwidth is very limited. So, we have to a) prepare more regarding what data/imagery we have on site and b) do more with less. That always proves to be a fun challenge because it is impossible to access our entire archive of imagery from down there.

How could I forget collecting Google Street View in Antarctica.

There have been several years, however, when we do get to go out into the field! In past years, we have conducted various field campaigns in the nearby McMurdo Dry Valleys to collect survey ground control to make our satellite imagery more accurate. And, how could I forget collecting Google Street View (with some custom builds of the typical car-camera system for snowmobiles, heavy-duty trucks, and backpacks). The Google Street View provides a window into the world of Antarctica – history, facilities, science, and of course its beautiful landscapes – to a wide audience who only dream of visiting Antarctica.

Brad on a snowmobile collecting Google Street View imagery [Credit: Brad Herried]

What are some of the interesting projects PGC has worked on? What’s exciting at PGC right now?

The PGC does a lot to contribute to polar mapping. There’s not exactly a ton of geospatial data or maps for the polar regions, especially Antarctica. What data or maps there are, it is not often of very high quality. For example, there are regions of Antarctica (especially in inland East Antarctica) which have not been properly mapped or surveyed since the 1960s. Those maps offer little help if you’re trying to land an aircraft in the area. So, PGC has done a lot to improve that geospatial data including creating more accurate coastlines, improving geographic coordinates of named features (sometimes the location can be off by 10s of kilometers!), organizing historic aerial photography, and digitizing map collections. These are important to have, but it all changes when you can collect data 100 times more accurate with satellites…

There’s not exactly a ton of geospatial data or maps for the polar regions, especially Antarctica.

Where it gets really interesting is how we can apply our archive of satellite imagery to help researchers solve problems or come up with cutting-edge solutions with the data. One example is the ArcticDEM project. In a private-public collaboration, PGC is using high performance computing (HPC) to develop a pan-Arctic Digital Elevation Model (DEM) at a resolution 10 times better than what exists now. This project requires hundreds of thousands of stereoscopic satellite imagery pairs to be processed using photogrammetry techniques to build a three-dimensional model of the surface for the entire Arctic. There are countless more applications for the imagery and we’ll continue to push the limits of the technology to produce innovative products to help measure the Earth and solve really important research questions.

ArcticDEM hillshade in East Greenland. DEM(s) created by the Polar Geospatial Center from DigitalGlobe, Inc. imagery. [Credit: Brad Herried/ Polar Geospatial Center].

 

What resources can cryosphere researchers and other polar scientists without US funding get from PGC to enhance their research?

Our website provides a wealth of non-licensed data, freely available to download. That includes our polar map catalog (with over 2,000 historic maps of the polar regions), aerial photography, and elevation data. The ArcticDEM project I mentioned before is freely available (see https://www.pgc.umn.edu/data/arcticdem/), as are all DEMs created (derived) from the optical imagery. Moreover, we work with the international community on a regular basis to continue mapping efforts across both poles.

 

What advice do you have for students interested in a career in science or geospatial science?

This might be a little bit of a tangent, but learn to code. I was trained in cartography ten years ago and we hardly touched the command line. Now? You certainly don’t have to be an expert, say, Python programmer, but you’re behind if you don’t know how to automate some of your tasks, data processing, analysis, or other routine workflows. It allows you to focus on the things you’re actually an expert in (and, employers are most certainly looking for these skills).

ArcticDEM hillshade of Columbia Glacier, Alaska. DEM(s) created by the Polar Geospatial Center from DigitalGlobe, Inc. imagery. [Credit: Brad Herried/ Polar Geospatial Center].

Personally, what has been the highlight of your time at PGC so far?

I will never forget the first time I stepped off the plane landing in Antarctica as a graduate student. A surreal, breathtaking (literally), and completely foreign feeling. To be able to experience the most remote places on Earth first-hand naturally leads to a better understanding of them. So, the highlight for me is this: I find myself asking more questions, talking to the preeminent researchers and students about their work, and discovering the purpose of it all. I may be a small piece in the puzzle of understanding our Earth’s poles, but I’m humbled to be a part.

Interview and Editing by George Roth, Additional Editing by Sophie Berger

Image of the Week – See sea ice from 1901!

Image of the Week – See sea ice from 1901!

The EGU Cryosphere blog has reported on several studies of Antarctic sea ice (for example, here and here) made from high-tech satellites, but these records only extend back to the 1970s, when the satellite records began. Is it possible to work out what sea ice conditions were like before this time? The short answer is YES…or this would be a very boring blog post! Read on to find out how heroic explorers of the past are helping to inform the future.


During the Heroic Age of Antarctic Exploration (1897–1917), expeditions to the “South” by explorers such as Scott and Shackleton involved a great deal of time aboard ship. Our image of the week shows one such ship – the ship of the German Erich von Drygalsk – captured from a hot air balloon in 1901.

These ships spent many months navigating paths through sea ice and keeping detailed logs of their observations along the way. Climate scientists at the University of Reading, UK have used these logs to reconstruct sea-ice extent in Antarctica at this time – providing key information to extend satellite observations of sea ice around the continent.

Why do we want to know about sea-ice extent 100 years ago?

In the last three decades, satellite records of Antarctic sea-ice extent have shown an increase, in contrast to a rapid decrease in Arctic sea-ice extent over the same period (see our previous post). It is not clear if this, somewhat confusing, trend is unusual or has been seen before and without a longer record, it is not possible to say. This limits how well the sensitivity of sea ice to climate change can be understood and how well climate models that predict future ice extent can be validated.

To help understand this increase in Antarctic sea-ice extent; records of ice composition and nature from ships log books recorded between 1897–1917 have been collated and compared to present-day ice conditions (1989–2014).

What does the study show?

The comparison between sea ice extent in the Heroic Age and today shows that the area of sea ice around Antarctica has only changed in size by a very small amount in the last ~100 years. Except in the Weddell sea, where ice extent was 1.71o (~80 km) further North in the Heroic Age, conditions comparable to present-day were seen around most of Antarctica. This suggests that Antarctic sea-ice extent is much less sensitive to the effects of climate change than that Arctic sea ice. One of the authors of the study, Jonny Day, summarises these findings in the video below:

References and Further Reading

Planet Press

planet_pressThis is modified version of a “planet press” article written by Bárbara Ferreira and originally published on 26th November 2016 on the EGU website .

It is also available in Dutch, Hungarian, Serbian, French, Spanish, Italian and Portuguese! All translated by volunteers – why not consider volunteering to translate an article and learn something interesting along the way?

 

Edited by Sophie Berger

Image of the Week – A new way to compute ice dynamic changes

Fig. 1: Map of ice velocity from the NASA MEaSUREs Program showing the region of Enderby Land in East Antarctica [Credit: Fig. 1 from Kallenberg et al. (2017) ].

Up to now, ice sheet mass changes due to ice dynamics have been computed from satellite observations that suffer from sparse coverage in time and space. A new method allows us to compute these changes on much wider temporal and spatial scales. But how does this method work? Let us discover the different steps by having a look at Enderby Land in East Antarctica, for which ice velocities are shown in our Image of the Week…


Mass balance of ice sheets

The mass balance of an ice sheet is the difference between the mass gain of ice, primarily through snowfall, and the mass loss of ice, primarily via meltwater runoff and ice dynamic processes (e.g. iceberg calving, melting below ice shelves). When the mass gain is equal to the mass loss, the ice sheet is in balance. However, if one exceeds the other, the ice sheet either gains or loses mass.

Measuring mass balance changes of ice sheets is crucial due to their potential contribution to sea level rise (see previous post). You can have a look at this nice review for further details about the recent changes in the mass balance of the two biggest ice sheets on Earth, i.e. Antarctica and Greenland.

Ice mass changes from snowfall and meltwater runoff (what we call ‘surface mass balance’ changes) are reasonably well simulated by regional climate models, which give good agreement with observations (see this study for Antarctica and this one for Greenland). Mass changes from ice dynamics are more complex to obtain. They are commonly estimated by combining ice velocity and ice thickness. Ice velocity is measured via satellite radar interferometry, while ice thickness is obtained thanks to airborne radar. Unfortunately, these measurements have sparse temporal and spatial coverage, especially in Antarctica, which makes the computation of mass changes from ice dynamics challenging.

A new method to estimate ice dynamic changes

Kallenberg et al. (2017) conducted a study focussing on Enderby Land in East Antarctica (see our Image of the Week) in which they use a novel approach to estimate ice dynamic changes. This region of Antarctica has experienced a slightly positive mass balance in past years, meaning that the ice sheet has slightly thickened in this region.

Kallenberg et al. (2017) first used satellite observations to compute the total changes in ice sheet mass. They took advantage of two high-technology datasets. The first one, “Gravity Recovery And Climate Experiment” (GRACE), measures changes in the Earth’s gravity field, from which ice mass changes can be derived. A summary explaining how GRACE works can be found in this previous post. The second satellite dataset, “Ice, Cloud, and land Elevation Satellite” (ICESat), measures changes in ice surface elevation, from which changes in ice mass can be computed by using ice density.

However, Kallenberg et al. (2017) were not interested in the total ice mass changes, as obtained from GRACE and ICESat satellites, but rather in ice dynamic changes. They subtracted two quantities from the total mass changes in order to obtain the remaining dynamic changes:

  1. Surface mass balance changes: changes from processes happening at the surface of the ice sheet (e.g. snow accumulation, meltwater runoff). These changes were obtained from model simulations using the Regional Atmospheric Climate Model (RACMO2), for which details can be found in this previous post.
  2. Glacial Isostatic Adjustment: changes in land topography due to ice loading and unloading. These changes were computed from Glacial Isostatic Adjustment models.

What does this study tell us?

The results of this study show that it is possible to compute changes in ice mass resulting from ice dynamics with higher spatial and temporal coverage than before, using a combination of satellite observations and models.

Also, the use of two different satellite datasets (GRACE and ICESat) shows that they agree quite well with each other in the region of Enderby Land (see Fig. 2). This means that using one or the other dataset does not make a big difference.

Finally, this new method also shows that differences between GRACE and ICESat reduce when using the newer version of RACMO2 for computing surface mass balance changes. This tells us that comparing results of ice dynamics from both satellites with different models is a good way to identify which models correctly simulate surface processes and which models do not.

Fig. 2: Ice dynamic changes (dH/dt, where H is ice thickness and t is time) computed from (a) GRACE and (b) ICESat and expressed in meters per year [Credit: Fig. 5 from Kallenberg et al. (2017) ].

Further reading

Edited by Clara Burgard and Emma Smith


David Docquier is a post-doctoral researcher at the Earth and Life Institute of Université catholique de Louvain (UCL) in Belgium. He works on the development of processed-based sea-ice metrics in order to improve the evaluation of global climate models (GCMs). His study is embedded within the EU Horizon 2020 PRIMAVERA project, which aims at developing a new generation of high-resolution GCMs to better represent the climate.

Image of the Week — High altitudes slow down Antarctica’s warming

Elevations in Antarctica. The average altitude is about 2,500m. [Credit: subset of Fig 5 from Helm et al (2014)]

When it comes to climate change, the Arctic and the Antarctic are poles apart. At the north of the planet, temperatures are increasing twice as fast as in the rest of the globe, while warming in Antarctica has been milder. A recent study published in Earth System Dynamics shows that the high elevation of Antarctica might help explain why the two poles are warming at different speeds.


The Arctic vs the Antarctic

At and around the North Pole, in the Arctic, the ice is mostly frozen ocean water, also known as sea ice, which is only a few meters thick. In the Antarctic, however, the situation is very different: the ice forms not just over sea, but over a continental land mass with rugged terrain and high mountains. The average height in Antarctica is about 2,500 metres, with some mountains rising as high as 4,900 metres.

A flat Antarctica would warm faster

Mount Jackson in the Antarctic Peninsula reaches an altitude of 3,184 m  [Credit: euphro via Flickr]

Marc Salzmann, a scientist working at the University of Leipzig in Germany, decided to use a computer model to find out what would happen if the elevation in Antarctica was more like in the Arctic. He discovered that, if Antarctica were flat, there would be more warm air flowing from the equator to the poles, which would make the Antarctic warm faster.

As Antarctica warms and ice melts, it is actually getting flatter as time goes by, even if very slowly. As such, over the next few centuries or thousands of years, we could expect warming in the region to speed up.

Reference/further reading

planet_pressThis is modified version of a “planet press” article written by Bárbara Ferreira and originally published on 18 May 2017 on the EGU website
(a Serbian version is also available, why not considering adding a new language to the list? 🙂 )

Image of the Week – The birth of a sea-ice dragon!

Image of the Week – The birth of a sea-ice dragon!

Dragon-skin ice may sound like the name of an episode of the Game of Thrones fantasy franchise. However, this fantasy name hides a rare and bizarre type of ice formation that you can see in our Image of the Week. It has been recently observed by the “Polynyas, ice production and seasonal evolution in the Ross Sea” (PIPERS) research team in Antarctica. This bizarre phenomenon caused by strong wind conditions has not been observed in Antarctica since 2007.


PIPERS expedition observed dragon-skin ice

In early April, the Nathan B Palmer icebreaker (see Fig. 2) began its 65-day voyage to Antarctica to study sea ice in the Ross Sea during the autumn period. This expedition, named PIPERS, was carried out by a team of 26 scientists from 9 countries. Its goal was to investigate polynyas, ice production, and seasonal evolution with a particular focus on the Terra Nova Bay and Ross Sea Polynyas (see Fig. 3).

Fig.2 : The Nathan B Palmer icebreaker caught in sea ice [Credit: IMAS ].

A polynya is an area of open water or thin sea ice surrounded by thicker sea ice and is generally located in coastal areas [Stringer and Groves, 1991]. Ice formation in polynyas is strongly influenced by wind conditions whose action can lead to astonishing spatial patterns in sea ice appearance. Special wind conditions probably also lead to what the members of the PIPERS expedition had the opportunity to observe: ice patterns that resemble dragon scales, therefore called dragon-skin ice. Such a sighting is quite remarkable as the last one dates back from a decade. However, the sparsity of observations of dragon-skin ice phenomena is probably a consequence of the relatively small number of expeditions in Antarctica during the autumn and winter seasons…

Fig. 3: The Terra Nova Bay Polynya and Ross Sea Polynya explored by the PIPERS expedition. [Credit: PIPERS ].

Chaotic ice formation caused by strong winds

Dragon-skin ice is a chaotic result of the complex interplay between the ocean and the atmosphere. Coastal polynyas in Antarctica are kept open by the action of strong and cold offshore winds (see Fig. 4) known as katabatic winds, which blow downwards as fast as 100 km/h for several hours [McKnight and Hess, 2000]. Sea ice forming at the cold sea surface gets blown away by these strong winds, preventing a closed sea-ice cover in this area. As the ice is blown away, an area of open water gets in direct contact with the atmosphere, leading to strong cooling and new formation of ice, that gets blown away again, and so on… Therefore, in general, sea ice in polynyas consists of thin pancake ice (see Fig. 5) i.e. round pieces of ice from 0.3 to 3 meters in diameter, which results from the aggregation of ice crystals caused by the wave action. Due to the wind action, the pieces of ice are pushed out by the wind action to the edges of the polynya.  As these pieces push strongly against each other, dragon-like scales appear on sea ice giving birth to the so-called dragon-skin ice.

Fig.4: Formation of coastal polynyas due to the action of katabatic winds [Credit: Wikimedia Commons ].

Figure 5: Sea ice in polynyas takes the form of pancake ice due to the action of water waves [Credit: PIPERS ].

The importance of polynyas for ocean-atmosphere interactions

Besides providing us with dazzling pictures of the cryosphere, investigating sea-ice production and evolution in polynyas is essential to better understand the complex interactions between the ocean and the atmosphere.
As sea water freezes into sea ice, salt is expelled into the ocean, raising its local salinity. The incessant production of sea ice in polynyas leads to water masses with very high salinity inside the polynyas. As sea water cools down, it releases energy in the atmosphere, leading to a warming of the atmosphere in polar regions. Moreover, due to their high density, these masses of cold and salty water sink and mix with lower ocean layers.
First results from the PIPERS mission show that when sea ice is forming, polynyas release greenhouse gases to atmosphere, instead of capturing it, as it was previously assumed! But fully understanding what’s happening there will necessitate more time and analyses….

Further reading

 

Edited by Scott Watson and Clara Burgard
Modified by Sophie Berger on 3 July 2017 to account for remarks of Célia Sapart (Member of the PIPER expedition)


Kevin Bulthuis is a F.R.S.-FNRS Research Fellow at the Université de Liège and the Université Libre de Bruxelles. He investigates the influence of uncertainties and instabilities in ice-sheet models as a limitation for accurate predictions of future sea-level rise. Contact Email:kevin.bulthuis@ulg.ac.be.

Image of the Week – Ice Ice Bergy

Image of the Week – Ice Ice Bergy

They come in all shapes, sizes and textures. They can be white, deep blue or brownish. Sometimes they even have penguins on them. It is time to (briefly) introduce this element of the cryosphere that has not been given much attention in this blog yet: icebergs!


What is an iceberg?

Let’s start with the basics. An iceberg, which literally translates as “ice mountain”, is a bit of fresh ice that broke off a glacier, an ice shelf, or a larger iceberg, and that is now freely drifting in the ocean. As an approximation, you can consider that since an iceberg is already in the water (about 90% under water even), its melting does not contribute to sea-level rise. However, if you remember our Sea Level “For Dummies” post, you know that the melting of fresh ice reduces the ocean’s density and makes it expand. Icebergs are found at both poles, although they tend to be larger in the Southern Ocean. The largest iceberg ever spotted there was 335 by 97 km, which represents an area larger than Belgium !

Modelled trajectories of icebergs around Antarctica. The different colours represent different size classes, ranging from 0-1 km² (class 1) to 100-1000 km² (class 5). [Credit: subset of Fig 2 from Rackow et al (2017)]

Icebergs can drift over thousands of kilometres (Rackow et al., 2017), during several years. A more thorough account of the life of an iceberg will be given in a future post, but be aware that among other things, as it drifts:

  • The iceberg is eroded by the waves and melted by the relatively warm ocean;
  • It can split in several pieces because of this melting and mechanical stress;
  • Sea ice can freeze around it, trapping it in the pack ice.

This means that the iceberg changes shape a lot, and can be tricky to monitor (Mazur et al, 2017).

Why do we want to monitor icebergs?

You may have heard of the Titanic, and hence are aware that icebergs pose a risk for navigation not only in the polar regions but even in the North Atlantic. Icebergs also are large reservoirs of freshwater, and depending on how and where they melt, this inflow of melted freshwater can really affect the ocean; it even dominates the freshwater budget in some Greenland fjords (Enderlin et al., 2016).

Icebergs have traditionally been rather understudied, so we are only now discovering how important they are and how they interact with the rest of the climate system: increasing sea ice production (A. Mazur, PhD thesis, 2017), biological activity (Vernet et al., 2012), and even carbon storage (Smith et al., 2011). And sometimes, they have penguins on them!

All eyes in the CryoTeam are now turned to the Antarctic Peninsula, where a giant iceberg may detach from the Larsen C ice shelf soon. To learn how we know that, check this video made by ESA. And of course, continue reading us – we’ll be reporting about the birth of this monster berg!

An iceberg by Antarctica [Credit: C. Heuzé]

Edited by Sophie Berger

Further reading

  • Enderlin et al. (2012), Iceberg meltwater fluxes dominate the freshwater budget in Greenland’s iceberg-congested glacial fjords, Geophysical Research Letters, doi:10.1002/2016GL070718

  • Mazur et al. (2017), An object-based SAR image iceberg detection algorithm applied to the Amundsen Sea, Remote Sensing of Environment, doi:10.1016/j.rse.2016.11.013

  • Rackow et al. (2017), A simulation of small to giant Antarctic iceberg evolution: Differential impact on climatology estimates, Journal of Geophysical Research: Oceans, doi: 10.1002/2016JC012513
  • Smith et al. (2011), Carbon export associated with free-drifting icebergs in the Southern Ocean, Deep Sea Research, doi: 10.1016/j.dsr2.2010.11.027
  • Vernet et al. (2012), Islands of Ice: Influence of Free-Drifting Antarctic Icebergs on Pelagic Marine Ecosystems, Oceanography, doi:10.5670/oceanog.2012.72

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

Fig 1: Map series of annual ice sheet speed from Mouginot et al. (2017). Speeds range from 0 (purple) to 1000+ (dark brown) m/yr. [Credit: George Roth]

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 shown today (Fig 1 and 2) were built by combining optical imagery from the Landsat-8 satellite with radar (SAR) data from the Sentinel-1a/b, RADARSAT-2, ALOS PALSAR, ENVISAT ASAR, RADARSAT-1, TerraSAR-X, and TanDEM-X sensors.

Although the authors used the well-known techniques of feature and speckle tracking to produce their velocities from optical and radar images, respectively, the major novelty of their study lies in the automation and integration of the different datasets.

Fig.2: Mosaics of yearly velocity maps of the Greenland and Antarctic ice sheet for the period 2015-2016.Composite of satellite-derived yearly ice sheet speeds from 2005-2016 for both Greenland and Antarctica. [Credit: cover figure from Mouginot et al. (2017)]

How is this new dataset useful?

Previously, ice sheet modellers have used mosaics composed of satellite data from multiple years to cover the entire ice sheet. However, this new dataset is one of the first to provide an ice-sheet-wide geographic scale, a yearly temporal resolution, and a moderately high spatial resolution (1km). This means that modellers can now better examine how large parts of the Greenland and Antarctic ice sheets evolve over time. By linking the evolution of the ice sheets to the changes in weather and climate over those ice sheets during specific years, modellers can calibrate the response of those ice sheets’ outlet glaciers to different climate conditions. The changes in the speeds of these outlet glaciers have important consequences for the amount of sea level rise expected for a given amount of warming.

How can I start using this data?

The yearly MEaSUREs data is hosted at the NSIDC in NetCDF format. The maps shown in the animated image were made using Quantarctica/QGIS (for more information on Quantarctica, check out our previous post E). QGIS natively supports NetCDF files like these mosaics with no additional import steps. Users can quickly calculate new grids showing speed, changes in velocities between years, and more by using the QGIS Raster Calculator or gdal_calc.

References/ Further Reading

Mouginot, J., Rignot, E., Scheuchl, B., & Millan, R. (2017). Comprehensive Annual Ice Sheet Velocity Mapping Using Landsat-8, Sentinel-1, and RADARSAT-2 Data. Remote Sensing, 9(4), 364. http://dx.doi.org/10.3390/rs9040364

Image of the Week – Quantarctica: Mapping Antarctica has never been so easy!

Image of the Week – A high-resolution picture of Greenland’s surface mass balance

Written with help from Jelte van Oostsveen
Edited by Clara Burgard and Sophie Berger


George Roth is the Quantarctica Project Coordinator in the Glaciology group (@NPIglaciology) at the Norwegian Polar Institute. He has spent the last several years helping researchers with GIS, cartography, and remote sensing in both the Arctic and Antarctic.

A year at the South Pole – an interview with Tim Ager, Research Scientist

A year at the South Pole – an interview with Tim Ager, Research Scientist

What is it like to live at the South Pole for a year?  A mechanical engineer by trade, Tim Ager, jumped at the opportunity to work for a year as a research scientist at Amundsen-Scott South Pole Station.  When not traveling on various adventures he lives in Austin, Texas, and recently took the time to answer a few questions about his time at Pole.


What goes on at Amundsen-Scott South Pole Station?

Science!  And lots of it.  Of course there are many people working at Pole just to maintain operations and “keep the lights on,” but it is all in support of science.  There are several large-scale science projects.  A couple highlights that science grantees taught us during science lectures were:

  • The South Pole Ice Core (SPICE Core) project looks back in time into the history of earth through ice cores.  Every year, snow accumulates on the surface, and year after year these layers compress the snow below them into ice.  By drilling down and extracting ice cores, these layers can be studied much like the tree rings.  The ice itself is analyzed, but so are the chemicals, dust, and gas bubbles trapped in it. This analysis gives us a peek into the climate history of our planet (see this post for more details).  Last summer’s project goal of drilling down 1,500 meters (to ice approximately 40,000 years old) was easily surpassed, with the final ice core brought up from a depth of 1,751.5 meters.
  • There are three Cosmic Microwave Background telescopes at Pole that look back in time at the oldest light in the universe, which was created shortly after the big bang.  The South Pole’s near 0% humidity is the ideal place to do this, since the telescopes look for slight ripples of temperature variations in the light and any water vapor gets in the way.
  • IceCube, which is a 1 km³ telescope that sites on the South Pole and collect neutrinos, which are tiny electrically neutral particles that can provide insight into the processes that occur within the sun.  The telescope collects neutrinos that pass through the Earth, which acts like a big filter, and collects only 3 per day.
  • Other projects include studying the weather, the magnetosphere, and ozone depletion.

Inside the collector of the 10 m South Pole Telescope  [Credit: Tim Ager]

Can you tell us a bit about the projects you were working on and what a typical day was like at the station?

I was a caretaker for several projects.  I maintained two GPS projects that tracked the movement of the ice sheet the South Pole Station sits on.  This huge chunk of ice moves about 10 meters per year toward the Weddell Sea.  For the six months that the sun was down I maintained seven aurora cameras.  I was also responsible for SPRESSO (the South Pole Remote Earth Science and Seismological Observatory).  SPRESSO is a seismic listening station for the long-term study of seismicity at the South Pole. It is a part of a 120+ station Global Seismographic Network (GSN) and is located five miles from the South Pole Station to reduce station related “cultural” noise. SPRESSO is located within our “quiet sector” and is the quietest seismic listening post on the planet.  Some additional duties included maintaining the greenhouse, acting as the station cryotech (making and dispensing liquid nitrogen), and testing fuel.

During the summer season there wasn’t a typical day, and I was kept busy helping many science related activities run efficiently.  The typical grantee is only at Pole for one to two weeks, so their time there is very valuable.  Before a grantee arrived, I tracked down any cargo they had sent ahead and made sure any crates that weren’t supposed to freeze were not left outside.  Once the grantee arrived, I helped out with whatever they needed to ensure their visit was a success – from finding and digging out a drifted-over crate left outside several years earlier, to tracking down tools, to delivering liquid nitrogen.  It was never boring and gave me the opportunity to learn about numerous projects.

Amundsen-Scott Station at sunset with markers to help traveling to off-station sites [Credit: Tim Ager]

What did you do when you weren’t working?

There was so much to do that I often had to choose between more than one activity.  There is a weight room, a gymnasium, a sauna, a quiet reading room (filled with lots of books), a game room (with a pool table, foosball table, and even more books), a music room (filled with instruments), an art room (filled with cloth, yarn, paints, markers, colored pencils, paper, sewing machines, and who knows what else), a greenhouse, and two media rooms (filled with DVDs of movies and TV shows, video games, VHS tapes, and even Beta Max tapes – yes, Pole has a working Beta Max player).  People taught classes on a variety of subjects including music, Yoga, particle physics, astronomy, welding, and foreign languages, to name a few.  I learned to play the guitar and became fairly proficient at knitting.

How were the 6 months of darkness and the frigid temperatures?

And the cold wasn’t as uncomfortable as you would think – when you get used to dressing appropriately, -100°F [-75°C] is okay.

The six months of darkness were amazing.  It is hard to explain the magnificence of the night sky.  Given the extremely low humidity at Pole, we could view the stars with unusual clarity, and the aurora activity was nearly constant.  In fact, the auroras frequently obscured the view of the stars, which wasn’t a bad trade-off.  And the cold wasn’t as uncomfortable as you would think – when you get used to dressing appropriately, -100°F [-75°C] is okay.

One of many auroras from the South Pole [Credit: Max Peters]

Was there a big shift in the culture of the station between the summer and the winter?

Yes, the summer and winter seasons are completely different.  During the summer season (usually early November thru mid-February) there is a flurry of activity.  Planes are coming and going, people are coming and going, and the station is full with 150 – 170 people.  Because the summer season is relatively short, everyone is focused on getting as much done as possible.  But once the last plane leaves everything slows down.  The remaining station members put the finishing touches on winterizing the station and settle into a routine that won’t change much, day in and day out, for 8.5 months.

The last plane out doing its customary goodbye flyover – “no one in and no one out” for 8.5 months [Credit: Tim Ager]

Could you share with us any moments that you’ll never forget?  What moments stick out as the highlights of your trip?

The day the last plane of the summer season left was unforgettable.  No matter how well you think you’ve prepared, it is a moment that is extremely unique.  That is when the reality of the situation and the isolation really sinks in.  The remaining 48 of us looked around at each other and pretty much all had the same thought: “Well, this is it.  This is my family for the next 8.5 months.  No one in and no one out.”  Of course we didn’t know that we would have a medevac [i.e., a medical evacuation] in the middle of winter – only the third winter medevac ever, and the first time in total darkness.  It went smoothly and left 46 of us for the rest of the winter.

Although there were many amazing experiences, the highlight was the night sky.  The stars were incredible, and the nearly ever-present auroras were awe inspiring.

I would also like to say that we had an incredible winter-over crew.  People were responsible, hard workers, and always willing to lend a hand.  Although we were all ready to leave once winter was over, I miss the camaraderie of my South Pole family.

The 2016 winterover crew [Credit: Tim Ager]

To conclude is there anything you would like to say to any future winter-overs?

If you have the time and inclination, definitely consider a winter at Pole.  At times it can be physically and/or psychologically challenging, but if you embrace it and live in the moment every day, the time will fly by.  We were all amazed at how quickly it was over.  I am thankful for the opportunity, and often find myself daydreaming about living back at Pole.

Interview led by David Rounce  and edited by Sophie Berger

Image of the Week — Hidden lakes in East Antarctica !

Image of the Week — Hidden lakes in East Antarctica !

Who would have guessed that such a beautiful picture could get you interviewed for the national news?! Certainly not me! And yet, the photo of this englacial lake (a lake trapped within the ice in Antarctica), or rather science behind it, managed to capture the media attention and brought me, one of the happy co-author of this study,  on the Belgian  television… But what do we see on the picture and why is that interesting?


Where was the picture taken?

The Image of this Week shows a 4m-deep meltwater lake trapped 4 m under the surface of the Roi Baudouin Ice Shelf (a coastal area in East Antarctica). To capture this shot, a team of scientists led by Stef Lhermitte (TU Delft) and Jan Lenaerts (Utrecht University) went to the Roi Baudouin ice shelf, drilled a hole and lowered a camera down (see video 1).

Video 1 : Camera lowered into borehole to show an englacial lake 4m below the surface. [Credit: S. Lhermitte]

How was the lake formed?

In this region of East Antarctica, the katabatic winds are very persistent and come down from the centre of the ice sheet towards the coast, that is the floating ice shelf (see animation below). The effect of the winds are two-fold:

  1. They warm the surface because the temperature of the air mass increases during its descent and the katabatic winds mix the very cold layer of air right above the surface with warmer layers that lie above.
  2. They sweep the very bright snow away, revealing darker snow/ice, which absorb more solar radiation

The combination leads to more melting of the ice/snow in the grounding zone — the boundary between the ice sheet and ice shelf — , which further darkens the surface and therefore increases the amount of solar radiation absorbed, leading to more melting, etc. (This vicious circle is very similar to the ice-albedo feedback presented in this previous post).

Animation showing the processes causing the warm micro-climate on the ice shelf. [Credit: S. Lhermitte]

All the melted ice flows downstream and collects in depressions to form (sub)surface lakes. Those lakes are moving towards the ocean with the surrounding ice and are progressively buried by snowfalls to become englacial lakes. Alternatively, the meltwater can also form surface streams that drain in moulins (see video 2).

Video 2 : Meltwater streams and moulins that drain the water on the Roi Baudouin ice shelf. [Credit: S. Lhermitte]

Why does it matter ?

So far we’ve seen pretty images but you might wonder what could possibly justify an appearance in the national news… Unlike in Greenland, ice loss by surface melting has  often been considered negligible in Antarctica. Meltwater can however threaten the structural integrity of ice shelves, which act as a plug of the grounded ice from upstream. Surface melting and ponding was indeed one of the triggers of the dramatic ice shelves collapses in the past decades, in the Antarctic Peninsula . For instance, the many surfaces lakes on the surface of the Larsen Ice shelf in January 2002, fractured and weakened the ice shelf until it finally broke up (see video 3), releasing more grounded ice to the ocean than it used to do.

Of course surface ponding is not the only precondition for an ice shelf to collapse : ice shelves in the Peninsula had progressively thinned and weakened for decades, prior their disintegration. Our study suggests however that surface processes in East Antarctica are more important than previously thought, which means that this part of the continent is probably more vulnerable to climate change than previously assumed. In the future, warmer climates will intensify melt, increasing the risk to destabilise the East Antarctic ice sheet.

Video 3 : MODIS images show Larsen-B collapse between January 31 and April 13, 2002. [Credit:NASA/Goddard Space Flight Center ]

Reference/Further reading

Edited by Nanna Karlsson

Quantarctica: Mapping Antarctica has never been so easy!

Quantarctica: Mapping Antarctica has never been so easy!

One of the most time-consuming and stressful parts of any Antarctic research project is simply making a map. Whether it’s plotting your own data points, lines, or images; making the perfect “Figure 1” for your next paper, or replying to a collaborator who says “Just show me a map!,” it seems that quick and effective map-making is a skill that we take for granted. However, finding good map data and tools for Earth’s most sparsely-populated and poorly-mapped continent can be exhausting. The Quantarctica project aims to provide a package of pre-prepared scientific and geographic datasets, combined with easy-to-use mapping software for the entire Antarctic community. This post will introduce you to Quantarctica, but please note that the project is organizing a Quantarctica User Workshop at the 2017 EGU General Assembly (see below for more details).


[Credit: Quantarctica Project]

What is Quantarctica?

Quantarctica is a collection of Antarctic geographic datasets which works with the free, open-source mapping software QGIS. Thanks to this Geographic Information System package, it’s now easier than ever for anyone to create their own Antarctic maps – for any topic and at any spatial scale. Users can add and plot their own scientific data, browse satellite imagery, make professional-quality maps and figures, and much, much more. Read on to learn how researchers are using Quantarctica, and find out how to use it to start making your own (Qu-)Antarctic maps!

Project Origins

When you make a sandwich, you start with bread, not flour. So why would you start with ‘flour’ to do your science?” — Kenny Matsuoka, Norwegian Polar Institute

Deception Island isn’t so deceptive anymore, thanks to Quantarctica’s included basemap layers, customized layer styles, and easy-to-use cartography tools. [Credit: Quantarctica Project]

Necessity is the mother of invention, and people who work in Antarctica are nothing if not inventive. When Kenny Matsuoka found himself spending too much time and effort just locating other Antarctic datasets and struggling with an expired license key for his commercial Geographic Information System (GIS) software in the field, he decided that there had to be a better way – and that many of his Antarctic colleagues were probably facing the same problems. In 2010, he approached Anders Skoglund, a topographer at the Norwegian Polar Institute, and they decided to collaborate and combine some of the critical scientific and basemap data for Antarctica with the open-source, cross-platform (Windows, Mac, and Linux) mapping software QGIS. Quantarctica was born, and was quickly made public for the entire Antarctic community.

Since then, maps and figures made with Quantarctica have appeared in at least 25 peer-reviewed journal articles (that we can find!). We’ve identified hundreds of Quantarctica users, spread among every country participating in Antarctic research, with especially high usage in countries with smaller Antarctic programs. We’ve been actively incorporating even more datasets into the project, teaching user workshops at popular Antarctic conferences – such as EGU 2017 – and building educational materials on Antarctic mapping for anyone to use.

A great example of a Quantarctica-made figure published in a paper. Elevation, imagery , ice flow speeds, latitude/longitude graticules, custom text and drawing annotations… it’s all there and ready for you to use! [Credit: Figs 1 and 2 from Winter et al (2015)].

What data can I find in Quantarctica?

  • Continent-wide satellite imagery (Landsat, MODIS, RADARSAT)
  • Digital elevation models and/or contour lines of bed and ice-surface topography and seafloor bathymetry
  • Locations of all Antarctic research stations and every named location in Antarctica (the SCAR Composite Gazetteer of Antarctica)
  • Antarctic and sub-Antarctic coastlines and outlines for exposed rock, ice shelf, and subglacial lakes
  • Magnetic and gravity anomalies
  • Ice flow velocities, catchment areas, mass balance, and firn thickness grids
  • Ancient UFO crash sites

…just to name a few!

Four examples of included datasets. From left to right: Ice flow speed, drainage basins, and subglacial lakes; bed topography; geoid height; modeled snow accumulation and surface blue ice areas [Credit: Quantarctica Project]

All of these datasets have been converted, imported, projected to a standard Antarctic coordinate system, and hand-styled for maximum visibility and compatibility with other layers. All you have to do is select which layers you want to show! The entire data package is presented in a single QGIS project file that you can quickly open, modify, save, and redistribute as your own. We also include QGIS installers for Windows and Mac, so everything you need to get started is all in one place. And finally, all of the data and software operates entirely offline, with no need to connect to a license server, so whether you’re in a tent in Antarctica or in a coffee shop with bad wi-fi, you can still work on your maps!

Quantarctica was used in traverse planning for the MADICE Project, a collaboration between India’s National Centre for Antarctic and Ocean Research (NCAOR) and the Norwegian Polar Institute (NPI), investigating mass balance, ice dynamics, and climate in central Dronning Maud Land. Check out pictures from their recently-completed field campaign on Facebook and Twitter! Base image: RADARSAT Mosaic; Ice Rises: Moholdt and Matsuoka (2015); Mapping satellite features on ice: Ian Lee, University of Washington; Traverse track: NCAOR/NPI. [Credit: Quantarctica Project]

Every dataset in Quantarctica is free for non-commercial use, modification, and redistribution – we get explicit permission from the data authors before their datasets are included in Quantarctica, always include any README or extra license/disclaimer files, and never include a dataset if it has any stricter terms than that. We always provide all metadata and citation information, and require that any Quantarctica-made maps or figures printed online or in any publication include citations for the original datasets.

How do I start using Quantarctica?

Quantarctica is available for download at http://quantarctica.npolar.no/. It’s a 6 GB package, so if your internet connection is struggling with the download, just contact us and we can send it to you on physical media. You can use the bundled QGIS installers for your operating system, or download the latest version of QGIS at http://qgis.org/ and simply open the Quantarctica project file, Quantarctica.qgs, after installation.

We’re actively developing Version 3 of Quantarctica, for release in Late 2017. Do you know of a pan-Antarctic dataset that you think should be included in the new version? Just email the Quantarctica project team at quantarctica@npolar.no.

Quantarctica makes it easy to start using QGIS, but if you’ve never used mapping software before or need to brush up on a few topics, we recommend QGIS Tutorials and Tips and the official QGIS Training Manual. There are also a lot of great YouTube tutorial videos out there!

 

Nobody said you could only use Quantarctica for work – you can use it to make cool desktop backgrounds, too! Foggy day in the Ross Island / McMurdo Dry Valleys area? Though it often is, the fog effects image was created using only the LIMA 15m Landsat Imagery Mosaic and RAMP2 DEM in Quantarctica, with the help of this tutorial. [Credit: Quantarctica Project]

Quantarctica Short Course at EGU 2017

Are you attending EGU 2017 and want to learn how to analyze your Antarctic data and create maps using Quantarctica? The Quantarctica team will be teaching a short course (SC32/CR6.15) on Monday, 24 April at 13:30-15:00 in room -2.31. Some basic GIS/QGIS experience is encouraged, but not required. If you’re interested, fill out the registration survey here: https://goo.gl/forms/mLaJg686tZq8bm2N2 and feel free to send any questions or comments to quantarctica@npolar.no. We’ll see you in Vienna!

Edited by Kenny Matsuoka and Sophie Berger

Reference/Further Reading

Data sources

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