GeoLog

General Assembly

GeoTalk: To understand how ice sheets flow, look at the bedrock below

GeoTalk: To understand how ice sheets flow, look at the bedrock below

Geotalk is a regular feature highlighting early career researchers and their work. In this interview we speak to Mathieu Morlighem, an associate professor of Earth System Science at the University of California, Irvine who uses models to better understand ongoing changes in the Cryosphere. At the General Assembly he was the recipient of a 2018 Arne Richter Award for Outstanding Early Career Scientists.  

Could you start by introducing yourself and telling us a little more about your career path so far?

Mathieu Morlighem (Credit: Mathieu Morlighem)

I am an associate professor at the University of California Irvine (UCI), in the department of Earth System Science. My current research focuses on better understanding and explaining ongoing changes in Greenland and Antarctica using numerical modelling.

I actually started glaciology by accident… I was trained as an engineer, at Ecole Centrale Paris in France, and was interested in aeronautics and space research. I contacted someone at the NASA Jet Propulsion Laboratory (JPL) in the US to do a six-month internship at the end of my master’s degree, thinking that I would be designing spacecrafts. This person was actually a famous glaciologist (Eric Rignot), which I did not know. He explained that I was knocking on the wrong door, but that he was looking for students to build a new generation ice sheet model. I decided to accept this offer and worked on developing a new ice sheet model (ISSM) from scratch.

Even though this was not what I was anticipating as a career path, I truly loved this experience. My initial six-month internship became a PhD, and I then moved to UCI as a project scientist, before getting a faculty position two years later. Looking back, I feel incredibly lucky to have seized that opportunity. I came to the right place, at the right time, surrounded by wonderful people.

This year you received an Arne Richter Award for Outstanding Early Career Scientists for your innovative research in ice-sheet modelling. Could you give us a quick summary of your work in this area?

The Earth’s ice sheets are losing mass at an increasing rate, causing sea levels to rise, and we still don’t know how quickly they could change over the coming centuries. It is a big uncertainty in sea level rise projections and the only way to reduce this uncertainty is to improve ice flow models, which would help policy makers in terms of coastal planning or choosing mitigation strategies.

I am interested in understanding the interactions of ice and climate by combining state-of-the-art numerical modelling with data collected by satellite and airplanes (remote sensing) or directly on-site (in situ).  Modelling ice sheet flow at the scale of Greenland and Antarctica remains scientifically and technically challenging. Important processes are still poorly understood or missing in models so we have a lot to do.

I have been developing the UCI/JPL Ice Sheet System Model, a new generation, open source, high-resolution, higher-order physics ice sheet model with two colleagues at the Jet Propulsion Laboratory over the past 10 years. I am still actively developing ISSM and it is the primary tool of my research.

More specifically, I am working on improving our understanding of ice sheet dynamics and the interactions between the ice and the other components of the Earth system, as well as improving current data assimilation capability to correctly initialize ice sheet models and capture current trends. My work also involves improving our knowledge of the topography of Greenland and Antarctica’s bedrock (through the development of new algorithms and datasets). Knowing the shape of the ground beneath the two ice sheets is key for understanding how an ice sheet’s grounding line (the point where floating ice meets bedrock) changes and how quickly chunks of ice will break from the sheet, also known as calving.

Steensby Glacier flows around a sharp bend in a deep canyon. (Credit: NASA/ Michael Studinger)

At the General Assembly, you presented a new, comprehensive map of Greenland’s bedrock topography beneath its ice and the surrounding ocean’s depths. What is the importance of this kind of information for scientists?

I ended up working on developing this new map because we could not make any reliable simulations with the bedrock maps that were available a few years ago: they were missing key features, such as deep fjords that extend 10s of km under the ice sheet, ridges that stabilize the retreat, underwater sills (that act as sea floor barriers) that may block warm ocean waters at depth from interacting with the ice, etc.

Subglacial bed topography is probably the most important input parameter in an ice sheet model and remains challenging to measure. The bed controls the flow of ice and its discharge into the ocean through a set of narrow valleys occupied by outlet glaciers. I am hoping that the new product that I developed, called BedMachine, will help reduce the uncertainty in numerical models, and help explain current trends.

3D view of the bed topography and ocean bathymetry of the Greenland Ice Sheet from BedMachine v3 (Credit: Peter Fretwell, BAS)

How did you and your colleagues create this map, and how does it compare to previous models?

The key ingredient in this map, is that a lot of it is based on physics instead of a simple “blind” interpolation. Bedrock elevation is measured by airborne radars, which send electromagnetic pulses into the Earth’s immediate sub-surface and collect information on how this energy is reflected back. By analyzing the echo of the electromagnetic wave, we can determine the ice thickness along the radar’s flight lines. Unfortunately, we cannot determine the topography away from these lines and the bed needs to be interpolated between these flight lines in order to provide complete maps.

During my PhD, I developed a new method to infer the bed topography beneath the ice sheets at high resolution based on the conservation of mass and optimization algorithms. Instead of relying solely on bedrock measurements, I combine them with data on ice flow speed that we get from satellite observations, how much snow falls onto the ice sheet and how much melts, as well as how quickly the ice is thinning or thickening. I then use the principle of conservation of mass to map the bed between flight lines. This method is not free of error, of course! But it does capture features that could not be detected with other existing mapping techniques.

3D view of the ocean bathymetry and ice sheet speed (yellow/red) of Greenland’s Northwest coast (Credit: Mathieu Morlighem, UCI)

What are some of the largest discoveries that have been made with this model? 

Looking at the bed topography alone, we found that many fjords beneath the ice, all around Greenland, extend for 10s and 100s of kilometers in some cases and remain below sea level. Scientists had previously thought some years ago that the glaciers would not have to retreat much to reach higher ground, subsequently avoiding additional ice melt from exposure to warmer ocean currents. However, with this new description of the bed under the ice sheet, we see that this is not true. Many glaciers will not detach from the ocean any time soon, and so the ice sheet is more vulnerable to ice melt than we thought.

More recently, a team of geologists in Denmark discovered a meteorite impact crater hidden underneath the ice sheet! I initially thought that it was an artifact of the map, but it is actually a very real feature.

More importantly maybe, this map has been developed by an ice sheet modeller, for ice sheet modellers, in order to improve the reliability of numerical simulations. There are still many places where it has to be improved, but the models are now really starting to look promising: we not only understand the variability in changes in ice dynamics and retreat all around the ice sheet thanks to this map, we are now able to model it! We still have a long way to go, but it is an exciting time to be in this field.

Interview by Olivia Trani, EGU Communications Officer

Imaggeo on Mondays: Getting involved with EGU!

Imaggeo on Mondays: Getting involved with EGU!

Today’s featured photo comes from the 2017 General Assembly. Did you enjoy this year’s 666 unique scientific sessions, 68 short courses and 294 side events? Did you know that EGU members and conference attendees can play an active role in shaping the scientific programme of the conference? It’s super easy!

You can suggest a session (with conveners and description), and/or modifications to the existing skeleton programme sessions. So, if you’ve got a session in mind for the 2019 conference, be it oral, poster or PICO, be sure to submit it before 6 September. Have a great idea for a Union Symposium or Great Debate? Make sure to submit your proposal by this Wednesday, 15 August!

But helping us prepare the next General Assembly is not the only way you can have a say in EGU activities over the coming weeks. The EGU’s Autumn Elections are coming up too and we need your help to identify suitable candidates for EGU’s next Treasurer. Until 15 September you can nominate candidates for the position. Think you’ve got it takes to have a go at the role? Then you are also welcome to nominate yourself!

Do you need funding to organise a training school in the Earth, planetary or space sciences? EGU training schools offer early career scientists specialist training opportunities they do not normally have access to in their home institutions. But hurry and submit your application before the deadline this week, 15 August.

In addition, we welcome proposals for conferences on solar system and planetary processes, as well as on biochemical processes in the Earth system, in line with two new EGU conference series we are launching that are named in honour of two female scientists. The Angioletta Corradini and Mary Anning conferences are to be held every two years with their first editions in 2019 or 2020. The deadline to submit proposals is also 15 August.

For other EGU related news, why not visit our news pages, or catch up on the latest via our monthly newsletter?

Imaggeo is the EGU’s online open access geosciences image repository. All geoscientists (and others) can submit their photographs and videos to this repository and, since it is open access, these images can be used for free by scientists for their presentations or publications, by educators and the general public, and some images can even be used freely for commercial purposes. Photographers also retain full rights of use, as Imaggeo images are licensed and distributed by the EGU under a Creative Commons licence. Submit your photos at http://imaggeo.egu.eu/upload/.

 

Help shape the conference programme: Inter- and Transdisciplinary Sessions at the 2019 General Assembly

Help shape the conference programme: Inter- and Transdisciplinary Sessions at the 2019 General Assembly

Do you enjoy the EGU’s annual General Assembly but wish you could play a more active role in shaping the scientific programme? Now is your chance! But hurry, the session submission deadline is fast approaching. You’ve got until September 6th to propose changes.

As well as the standard scientific sessions, subdivided by Programme Groups, EGU coordinates Inter- and Transdisciplinary Sessions (ITS) at the conference.

Now, you may be asking yourself: what exactly are ITS?

  • Interdisciplinarity looks for links between disciplines in a coordinated and coherent effort, with the aim of creating new approaches that would not be possible if handled separately.
  • Transdisciplinarity transcends traditional boundaries of disciplines by reaching out to, for example, social, economic, and political sciences.

The Earth, oceans, space and society are interconnected in many different ways; rarely can one system be perturbed without others being affected too.

The aim of ITS is to foster and facilitate exchange of knowledge both across scientific divisions. These sessions should either link disciplines within the geosciences in a novel way to address specific (and often new) problems (interdisciplinary sessions) or link the geosciences to other disciplines, in particular from the humanities, to address societal challenges (transdisciplinary sessions).

If inter- and transdisciplinarity is important to you and your work, know that you too can co-organise your session as an Inter- and Transdisciplinary Session. Read on to discover how!

The skeleton programme for the 2019 General Assembly currently features three ITS themes and a general open call for ITS sessions:

  • ITS1: History of Earth, Planetary and Space Sciences
  • ITS2: Resources and the energy transition
  • ITS3: Contributions of Earth, Planetary and Space Sciences to changes in society
  • ITS4: Open call for ITS sessions

Sessions within each of these ITS themes will be scheduled closely together, to foster cross-division links and collaborations.

To propose a session in one of the planned inter- and transdisciplinary themes, follow these simple steps:

  • Visit the ITS pages on the EGU 2019 website
  • Suggest a new session (within one of the four ITS options)
  • Choose a Programme Group that will be the scientific leader. For example, if you choose BG, your session will be listed in the programme as ITS/BG
  • Suggest more Programme Groups for co-organisation in the comment box

Wondering whether your session would fit as an ITS? Just ask ITS Programme Group Chairs, Peter van der Beek (its@egu.eu) or Susanne Buiter (programme.committee@egu.eu).

Peter and Susanne, are looking forward to a strong inter- and transdisciplinary programme at the 2019 General Assembly. But they need your help to achieve this!

You can also find more information about the call for sessions (and the organisation of the scientific programme in general) on the EGU 2019 website.

The EGU’s 2018 General Assembly, takes place in Vienna from 7 to 12 April, 2019. For more news about the upcoming General Assembly, you can also follow the official hashtag, #EGU19, on our social media channels.

Organise a short course at EGU 2019: follow this simple guide!

Organise a short course at EGU 2019: follow this simple guide!

When it comes to supercharging your scientific skills, broadening your base science communication, or picking up tips on how to boost your career, short courses can be one of the highlights of the General Assembly programme.

But, did you know that any EGU member (you!) can propose a short course? You’ve got until 6 September 2018 to complete the application. This quick guide, will give you some pointers for submitting and organising your own short course at the EGU 2019 General Assembly!

Before you even put pen to paper and plan your workshop, remember that the courses should provide a forum to teach your General Assembly peers something of interest. Ideally, short courses should be designed to be open to all conference participants, though they can also be affiliated with one or more of the meeting’s programme groups.

Planning your short course

As the organiser, you are free to choose the content and set-up of the course. But the content should be of interest to (a subset of) the community that the EGU represents! The decision as to whether your course will be included in the final conference programme is made by the programme committee chair, Susanne Buiter, and the short course programme group chairs: the ECS Union representative Stephanie Zihms and Sam Illingworth.

To submit your course, you’ll need:

  • a title and a short description
  • the details of the course organiser

You also have the option to co-organise your course with a scientific division(s) (meaning it’ll appear in the both the Short Course Programme Group and that of your favored division(s)). You might consider doing this if your workshop is aimed at a specific community, as well as being of broad appeal.

Choosing a time-slot

If your short course submission is approved, you can specify preferences for certain time blocks, days or back-to-back scheduling online in the session tagging tool between 12-20 January 2019. Note that assignments depend on availability. No short courses will be scheduled during the poster sessions from 17:30 to 19:00 each day or on the Sunday before the conference officially opens.

The logistics

All short course rooms come complete with a microphone, a data projector, a notebook, wired internet connection, and a VGA switch to use up to three individual notebooks in addition to the permanently installed one of that room. Technical assistance will also be provided in each short course room.

If you require participants to register in advance of the course, it is your responsibility as the organiser to coordinate this. Be sure to include a registration email address or a Doodle link in the description of the short course, so potential participants know how to sign-up.

Food and drink can liven up any meeting! Should you wish to provide catering throughout your workshop (at your own expense), please get in touch with the General Assembly caterer (Motto Catering) by completing their online order form before 31 March 2019. This online form will be made available by the end of the year.

Dos & Don’ts

  • Do make skills/abilities related to science and research the focus of your workshop
  • Do aim to provide training in skills needed by people working in science
  • Do promote your short course
  • Do make your course interactive or include hands-on activities (if possible)
  • Do let participants know (via the description) if they’ll need to bring along materials (e.g. laptop, tablet, specific software) to participate in the course
  • Do allow time for questions

 

  • Don’t invite too many speakers
  • Don’t engage in commercial activities during the course (e.g. sales)
  • Don’t charge admission fees or course fees – these are strictly prohibited

For a full list of guidelines head over to the EGU 2019 website. If you have questions about submitting a short course request please contact the Programme Group Chairs or the EGU Communications Officer, Olivia Trani.

The EGU General Assembly 2019 takes place in Vienna from 7 to 12 April. For more news about the upcoming General Assembly, you can also follow the official hashtag, #EGU19 on our social media channels.