GeoLog

EGU GA 2018

GeoTalk: the climate communication between Earth’s polar regions

GeoTalk: the climate communication between Earth’s polar regions

Geotalk is a regular feature highlighting early career researchers and their work. In this interview, we caught up with Christo Buizert, an assistant professor at Oregon State University in Corvallis, who works to reconstruct and understand climate change events from the past. Christo’s analysis of ice cores from Greenland and Antarctica helped reveal links between climate change events from the last ice age that occurred on opposite ends of the Earth. At this year’s General Assembly, the Climate: Past, Present & Future Division recognized his innovative contributions to palaeoclimatology by presenting him with the 2018 Division Outstanding Early Career Scientists Award.

Christo, thank you for talking to us today! Could you introduce yourself and tell us about your career path so far?

Thanks for having me on GeoTalk! I’m a palaeoclimate scientist working on polar ice cores (long sticks of ancient ice drilled in Greenland and Antarctica), combining data, modeling and fieldwork. My background is in physics, and I did a MSc thesis project on quantum electronics. As you can see, I ended up in quite a different field. After teaching high school for a year in my home country the Netherlands, I pursued a PhD at the Niels Bohr Institute in Copenhagen, Denmark, working on ice cores. I must say, doing a PhD is a lot easier than teaching high school! I have gained a lot of respect for teachers.

After obtaining my PhD I moved to the US for reasons of both work and love (not necessarily in that order). I got a NOAA Climate & Global Change Postdoctoral Fellowship at Oregon State University (OSU). OSU has a great palaeoclimate research group and Oregon is one of the prettiest places on Earth, so the decision to stick around was an easy one.

What inspired you to pursue palaeoclimatology after getting your MSc degree in quantum electronics?

I wish I had a better answer to this question, but the truth is that I was drawn by the possibility of doing fieldwork in Greenland, mainly.

At the General Assembly, you received a Division Outstanding Early Career Scientist Award for your work on understanding the bi-polar phasing of climate change. For those of us who aren’t familiar, could you elaborate on this particular field of study?

The final drill run of the WAIS Divide ice core, with ice from 3,405 m (11,171 ft) depth that has been buried for 68,000 years. (Credit: Kristina Slawny/University of Bern)

During the last ice age (120,000 to 12,000 years ago), the world experienced some of the most extreme and abrupt climate events that we know of, the so-called Dansgaard-Oeschger (D-O) events. About 25 of these D-O events happened in the ice age, and during each of them Greenland warmed by 8 to 15oC within a few decades. Each of the warm phases (called interstadials) lasted several hundreds to thousands of years. Greenland ice cores provide clear evidence for these events.

The abrupt D-O events are thought to be linked to changes in ocean circulation. Heat is transported to the Atlantic Ocean by the Atlantic Meridional Overturning Circulation (AMOC) from the southern hemisphere to the northern hemisphere. The AMOC keeps the Nordic Seas free of sea ice and effectively warms Greenland, particularly during the winter months. However, the strength of this heat circulation went through abrupt changes during the last ice age. Marine sediment data and model studies show that changes to the AMOC strength caused the extreme temperature swings associated with the D-O events.

During weak phases of the AMOC, less heat and salt are brought to the North Atlantic, leading to expansive (winter) sea ice cover and cold conditions in Greenland. These are the D-O cycle’s cold phases, the so-called stadials. And vice versa, during the AMOC’s strong phases, the ocean transports more heat northwards, reducing sea ice cover and warming Greenland. These are the warm (interstadial) phases of the D-O cycle.

When the AMOC is strong, it warms the northern hemisphere at the expense of the southern hemisphere. This inter-hemispheric heat exchange is sometimes referred to as ‘heat piracy,’ since the North Atlantic is ‘stealing’ heat from the southern hemisphere. So when Greenland is warm, we see Antarctica cool, and when Greenland is cold, Antarctica is warming. These opposite hemispheric temperature patterns are called the bipolar seesaw, after the playground toy. Using a new ice core from the West Antarctica Ice Sheet (the WAIS Divide ice core), we were able to study the relative timing of the bipolar seesaw at a precision of a few decades – which is extremely precise by the standards of palaeoclimate research.

An infographic explaining the opposite hemispheric temperature patterns, also known as the bipolar seesaw (Illustration by David Reinert/Oregon State University).

We found that the temperature response to the northern hemisphere’s abrupt D-O events was delayed by about two centuries at WAIS Divide. This finding shows that the effects of these D-O events start in the north, and then are transmitted to the southern high-latitudes via changes in the ocean circulation. If the atmosphere were responsible, transmission would have been much faster (typically within a year or so). State-of-the-art climate models actually fail to simulate this 200-year delay in the Antarctic response, suggesting they are missing (or overly simplifying) some of the relevant physics of how temperature anomalies are propagated and mixed in the global ocean. The timescale of two centuries is unmistakably the signature of the ocean, in my view, and so it is an interesting target for testing models.

At the meeting you also gave a talk about the climatic connections between the northern and southern hemispheres during the last ice age. Could you tell us a little more about your findings and their implications? 

A volcanic ash layer in an Antarctic ice core. Volcanic markers like these were used in the new study to synchronize ice cores from across Antarctica. (Credit: Heidi Roop/Oregon State University)

I presented some recently published work that elaborates on this 200-year delay mentioned earlier. Together with European colleagues, we synchronized five Antarctic ice cores using volcanic eruptions as time markers. This makes it possible to study the timing of the seesaw across the entire Antarctic continent with the same great precision as at WAIS Divide. It turns out that the 200-year delayed oceanic response to the northern hemisphere’s abrupt climate change is visible all over Antarctica, not just in West Antarctica.

But the exciting thing is that by looking at the spatial picture, we detect a second mode of climatic teleconnection, superimposed on the bipolar seesaw we talked about earlier. This second mode has zero-time lag behind the northern hemisphere, suggesting that this mode is an atmospheric teleconnection pattern. In my talk I used postcards and text messages as an analogy for these two modes. The oceanic mode is like a postcard, that takes a long time to arrive in Antarctica (200 years). The atmospheric mode is like a text message that arrives right away.

The atmospheric circulation change (the “text message”) causes a particular temperature pattern over Antarctica, with cooling in some places and warming in others. Think of this as the “fingerprint” of the atmospheric circulation. We then compared the ice-core fingerprint to the fingerprints of several wind patterns seen in modern observations. We found that the so-called Southern Annular Mode, a natural mode describing the variability of the westerly winds circling Antarctica, is the best modern analog for what we see in the ice cores.

An infographic explaining how Earth’s polar regions communicate with each other (Illustration by Oliver Day/Oregon State University)

Another piece of the puzzle is that atmospheric moisture pathways to Antarctica change simultaneously with the atmospheric mode. All this supports the idea that the southern hemisphere’s westerly winds respond immediately to abrupt climate change in the North Atlantic. When D-O warming happens in Greenland the SH westerlies shift to the north, and vice versa, during D-O cooling they shift to the south.

This had been predicted in models, and some limited evidence was available from the WAIS Divide ice core, but the new results provide the strongest observational evidence for this effect. This movement of the westerlies has important consequences for sea ice, ocean circulation, and perhaps even CO2 levels and ice sheet stability. So it really urges us to look at these D-O cycle in a global perspective.

You’ve enjoyed success as a researcher, not least your 2018 EGU Award. As an early career scientist, do you have any words of advice for graduate students who are hoping to pursue a career as a scientist in the Earth sciences?

I’m sure there are many different routes to becoming a successful researcher. Developing your own ideas and insights is key, and the secret to having good ideas is having many ideas, because most of them end up being wrong! So be creative and go out on a limb. I am lucky to have had supervisors who gave me a lot of freedom to explore my own ideas. I would also encourage everybody to develop skills in programming and numerical data analysis, for example in Matlab or python.

Christo Buizert (right) and Didier Roche, President of the Climate: Past, Present & Future Division, (left) at the EGU 2018 General Assembly (Credit: EGU/Foto Pflugel).

Frustrating and unfair as it may be, luck plays an important role in getting your research career started. My main PhD project did not work out, but I had a very productive postdoc that grew out of a side project. I ended up in the right place at the right time, because the WAIS Divide ice core had just been drilled, and I got the privilege to work with some of the best ice core data ever measured.

Research is fundamentally a collaborative enterprise, and so developing a good network of collaborators is maybe the most important thing you can do for yourself. Be generous and helpful to your colleagues, and it will be rewarded.

A career in science sometimes feels like a game of musical chairs, with fewer and fewer positions available as you go along. But if you can hang in there it’s definitely worth it; we have the privilege of thinking about interesting problems, traveling to beautiful places, all while interacting with a global network of fantastic colleagues. Could it get much better?

Interview by Olivia Trani, EGU Communications Officer

EGU announces 2019 awards and medals

EGU announces 2019 awards and medals

From 14th to the 20th October a number of countries across the globe celebrate Earth Science Week, so it is a fitting time to celebrate the exceptional work of Earth, planetary and space scientist around the world.

This week, the EGU announced the 45 recipients of next year’s Union Medals and Awards, Division Medals, and Division Outstanding Early Career Scientists Awards. The aim of the awards is to recognise the efforts of the awardees in furthering our understanding of the Earth, planetary and space sciences. The prizes will be handed out during the EGU 2019 General Assembly in Vienna on 7-12 April. Head over to the EGU website for the full list of awardees.

Sixteen out of the total 45 awards went to early career scientists who are recognised for the excellence of their work at the beginning of their academic career. Twelve of the awards were given at division level but four early career scientists were recognised at Union level, highlighting the quality of the research being carried out by the early stage researcher community within the EGU.

Sixteen out of the 45 awards conferred this year recognised the work of female scientists. Of those, six were given to researchers in the early stages of their academic career.

As a student (be it at undergraduate, masters, or PhD level), at the EGU 2018 General Assembly, you might have entered the Outstanding Student Poster and PICO (OSPP) Awards. A total of 64 poster contributions by early career researchers were bestowed with a OSPP award this year recognising the valuable and important work carried out by budding geoscientists. Judges took into account not only the quality of the research presented in the posters, but also how the findings were communicated both on paper and by the presenters. Follow this link for a full list of awardees.

Further information regarding how to nominate a candidate for a medal and details on the selection of candidates can be found on the EGU webpages. For details of how to enter the OSPP Award see the procedure for application, all of which takes place during the General Assembly, so it really couldn’t be easier to put yourself forward!

The EGU General Assembly is taking place in Vienna, Austria from 7  to 12 April. The call-for-abstracts will open in mid-October. Submit yours via the General Assembly website.

GeoTalk: Nilay Dogulu, Early Career Scientist Representative

GeoTalk: Nilay Dogulu, Early Career Scientist Representative

In addition to the usual GeoTalk interviews, where we highlight the work and achievements of early career researchers, this month we’ll also introduce one of the Division early career scientist representatives (ECS). They are responsible for ensuring that the voice of EGU ECS membership is heard. From organising short courses during the General Assembly, through to running and attending regular ECS representative meetings, their tasks in this role are varied. Their role is entirely voluntary and they are all active members of their research community, so we’ll also be touching on their scientific work during the interview.

Today we are talking to Nilay Dogulu, ECS representative for the Hydrological Sciences (HS) Division and past chair of the Young Hydrologic Society.

Before we get stuck in, could you introduce yourself and tell us a little more about yourself, your involvement with EGU and how you became interested in hydrology?

I am a PhD candidate at the Middle East Technical University (METU) in Ankara, Turkey, researching clustering methods for data-driven hydrology at the Water Resources Laboratory. This year I attended the General Assembly (GA) in Vienna for the fifth time in a row. Since 2014, the Assembly has been the one and only conference that I have persistently and willingly participated in. The Hydrological Sciences (HS) division’s scientific programme at the GA had a special role in shaping my career as a researcher, so I would like to share my journey in the hydrological sciences lightened up by the EGU GA and its HS community.

First, little about me. I am a civil engineer by training. I was a third year (BSc) student at METU (ODTU) when I took the course “Engineering Hydrology.” It was the first time I learned about the terms catchment, basin and hydrograph. In that very semester I had the opportunity to participate in the 5th World Water Forum in Istanbul. That was it. I was determined to specialize in water for my future career.

To broaden my understanding of hydrological processes and gain a critical view of the latest hydrology topics, I gathered the courage—as only a BSc student at the time—to attend the 6th National Hydrology Congress and the 2nd National Flood Symposium. Then a three-month internship at the State Hydraulic Works of Turkey introduced me to the wider community of hydrological sciences in the world.

My class notes from the Engineering Hydrology course back in March 2009 (Credit: Nilay Dogulu)

In Fall 2011, I joined the FLOODRisk Master to study floods, from modelling them to understanding their socio-economic effects. This two-years programme enriched my academic background on flood risk management and provided me with different insights into water-related problems.

Could you tell me about your first experience with the EGU General Assembly?

With EGU HS Division president Elena Toth (right) and president-elect Maria-Helena Ramos (left) at EGU 2018

The EGU GA brings together researchers from all around the world. The EGU Hydrological Sciences Division is EGU’s largest division with a diverse and comprehensive scientific programme at the GA, large enough to fill in the whole second (red) floor of the conference venue.

The EGU HS division is a great platform aimed at addressing current research challenges in hydrology. During the GA, one can follow up with the latest research on various topics within these areas and network with members (of all stages) of this great community. At the 2018 EGU GA, hydrological sciences programme had 2350 abstracts submitted to 91 HS-lead sessions (66 oral and poster sessions, 6 poster only sessions, 19 PICO sessions)—equivalent to 13.5% of total EGU GA submissions.

Given this, I was very motivated to experience the General Assembly for the first time! I submitted an abstract summarizing part of my MSc research—on predictive uncertainty estimation for flood forecasting using data-driven modelling techniques; and once it was accepted, I started to get ready for EGU and Vienna! Flight and accommodation booked, poster printed, weekly conference schedule prepared. This was the first poster presentation of my career and I was quite excited. Luckily, all went really well.

EGU Hydrological Sciences Division

I remember having a busy week at EGU 2014: from presenting my first poster, working on a manuscript with my co-authors, as well as attending project meetings, sessions on flood forecasting and flood risk management, and short courses organized by the Young Hydrologic Society (YHS).

There were many interested people visiting my poster and asking questions. There were many posters I visited too—I have to admit, sometimes I asked so many questions that the presenters thought  I was an OSPP Award judge.

Throughout the week I listened presentations, many of which were given by researchers I cited in my master’s thesis. Matching the papers with authors’ faces was amazingly so much fun! Moreover, I arranged a small meeting with my co-authors to discuss the manuscript draft (which has been later published in HESS) that we had only been working on remotely before then.

At the time, I was also working for the EU-FP7 project ASTARTE (Assessment, STrategy And Risk Reduction for Tsunamis in Europe). The EGU GA is an excellent time for research project teams, editorial boards of journals, etc. to schedule meetings.  ASTARTE team (26 partners from 16 countries) also took this opportunity to meet up to discuss the progress following the project’s first 6-months period. During this meeting, I presented one of the very important deliverables of the project which focused on tsunami resilience from a social sciences perspective.

On the Saturday after the conference there was the Vienna Catchment Science Symposium organized by the Vienna University of Technology Centre for Water Resources Systems. It proved to be a very enlightening symposium for a young hydrologist.

Sounds like a great first experience! How has your time at the GA changed over the years?

After enjoying the academic fun of EGU 2014, I wanted to come back to Vienna for EGU 2015. Another reason was that I was very curious why people were heading to the conference venue on the very last hours of the last day (Friday): I left around 5 pm and many people were coming out of metro!

METU Water Resources Lab researchers at EGU 2016

In 2015 I had one PICO presentation and two short course convenerships, How to write (and publish) a scientific paper in hydrology and Hydroinformatics for Hydrology. Both were co-organized with the Young Hydrologic Society and proved to be very successful!

Without any hesitation, I decided to attend EGU 2016 and EGU 2017 in the next years. Although I didn’t have any presentations in 2016, listening to presentations covering my research interests helped me stay updated and synthesise various perspectives on overarching problems in hydrology. The sessions kept me thinking about some questions that had been tingling my mind—which later became the research questions in my PhD thesis proposal.

At EGU 2017, my poster presentation was a literature review on application of clustering methods in hydrology, and actually it attracted more people than I expected. EGU poster sessions provide an excellent way to bring together early career researchers while they stand in front of their posters, paving the way for interesting discussions.

Memories from EGU 2017

My fifth year at the EGU GA last April was great too: including two posters, sessions to co-/convene, YHS events (from short courses to PICO sessions), the EGU ECS Representatives Workshop, YHS Hydrodrinks, the HS division meeting, medal lectures and many other activities. Being an experienced EGU GA participant, I also served as a mentor as part of the EGU mentoring programme designed to help novice conference attendees navigate their first EGU experience.

Almost forgot! On Friday evening, the conveners’ reception (and party, with a different theme every year) takes place at the ACV.

In addition to being an EGU ECS representative, you also are involved with the Young Hydrologic Society (YHS). Could you tell me more about this organisation and your role in YHS?

YHS is a bottom-up initiative that aims to help early career hydrologists interact and actively participate within the hydrological sciences community and beyond. We are a group of motivated PhDs and postdocs who enjoy serving our very own community, considering the needs and interests of young hydrologists.

The YHS is most actively involved with the EGU GA, where we organizing short courses, scientific sessions and social events. The full list of all events that YHS has organized for the EGU GA since 2013 can be found on the YHS webpage. The open call for session proposals for EGU GA 2019 has just closed (deadline 6 September) – there have been quite a number short course submissions (in cooperation with YHS) that will play a significant role in shaping the HS programme for ECSs. YHS Hydrodrinks event held annually at the EGU GA is now a 5-year-old tradition where we meet our new team members. If you are planning to come to EGU 2019, don’t miss the chance to meet fellow hydrologists at the Hydrodrinks (however, please note that this is not a sponsored event). Contributing to the academic and social development of early career hydrologists by organising activities at the EGU GA is a unique and rewarding experience, so get involved!

YHS Hydrodrinks at EGU 2014 (Credit: The waiter)

I joined YHS after meeting the team at EGU 2014. Since then I couldn’t help myself but contribute to the aims of the society in many ways—like organizing short courses at conferences (e.g. Hydroinformatics for Hydrology at the EGU GA), managing and contributing to the YHS Blog (Streams of Thought and Hallway Conversations), and acting as a Board member (secretary 2015-16, chair 2016-17).

Right: EGU 2018 Poster 1—Clustering approaches for analysing similarity in ungauged catchments: input variable selection for hydrological predictions Left: EGU 2018 Poster 2—Input variable selection for hydrological predictions in ungauged catchments: with or without clustering? Bottom Centre: YHS team at EGU 2018 (with only a few missing! It is not east to arrange a common time for everyone, even for a group photo)

I also took over the role of EGU ECS Rep for HS division from Shaun Harrigan at EGU 2017. Being elected as the EGU ECS Rep, I became more enthusiastic about advancing the hydrologic science community equally (and globally) in support of, primarily, the ECS. The ECS Rep is expected to contribute to sustainable and inclusive growth of the EGU HS division by fostering the active participation and integration of ECS and the hydrologic science community globally under the umbrella of EGU, keeping in mind the necessity of creating equal opportunities for ECS to enhance their research and communication skills.

EGU ECS Reps at the EGU GA 2018

The ECS Rep for HS division works in close collaboration with YHS to initiate and support inspirational and intelligent ideas in line with the emerging needs of ECS. You also meet with ECS Reps of other EGU divisions and help the EGU community thrive together with its early career members. My term ends in April 2019. So keep your eye on EGU and YHS websites (and twitter) in early 2019—and apply to become the next EGU ECS Representative (April 2019-April 2021) for the HS division!

Do you have any parting words about your time involved with EGU?

It has been a very long post but now here are the last words. The EGU GA means seeing old friends and past professors, meeting fellow hydrologists and listening to presentations from enthusiastic researchers… plus the annual Hydrodrinks event among many other scientific sessions and short courses organized by YHS! I am glad to serve as the EGU ECS Rep for the Hydrological Sciences division – for the wonderful and inspiring people of the red floor:)

Acknowledgements: I would like to express my sincere thanks to Young Hydrologic Society, especially to Wouter Berghuijs, Shaun Harrigan, Hannes Müller and Tim van Emmerik, for their enthusiasm and support over the last five years.

Interview by Olivia Trani, EGU Communications Officer