Our two most recent ice2ice Phds; Sunniva and Karita Kajanto, are already busy spreading their knowledge. They have engaged with Norwegian school children to help them understand how the Arctic is currently changing due to sea ice disappearing and the consequences on climate.
More information in the article below (in Norwegian)
Christmas holidays and the turn of the year are soon over us. With snow for those who are eager to explore the seasonal cryosphere, and family gatherings and relaxation in line for most of us. 2017 has been an exciting year for our project, where we have taken decisive steps to start integrating results and we start to see how all of our efforts come together. Papers and PhD theses are being produced in increasing numbers and many of you are now active in cross-team integration efforts which we hope will be central in the upcoming all staff in a month or so.
We are very much looking forward to working closely with all of you on exiting science in the coming year, and with this wishing you all a merry Christmas and a Happy New Year!
Mari F jensen successfully defended her PhD thesis 1st of december -2017 on “Abrupt changes in sea ice and dynamics of Dansgaard-Oeschger events”. Mari is the second ice2ice Phd to finish her studies. Luckily Mari has decided to continue in Science, a great benefit to all of us and the ice2ice objectives. Through her Phd Mari has published 1 peer reviewed article and submitted another two, that all form part of her thesis. You can read and download the thesis here.
The subject of Maris thesis has been to study the dynamics of Dansgaard Oeschger events. Changes in sea ice are proposed as an important component in Dansgaard-Oeschger events; the abrupt climate change events that occurred repeatedly during the last ice age. Paleoclimatic reconstructions suggest an expansion of sea ice in the Nordic Seas during the cold stadial periods of the Dansgaard-Oeschger cycles. However, as the present configuration of the Nordic Seas does not allow for an extensive sea-ice cover in this region, the hydrography must have been different during glacial times. In fact, reconstructions show that the Nordic Seas hydrography during cold stadial periods was similar to the stratification of the Arctic Ocean today. However, the dynamic impacts of changing freshwater input and Atlantic water temperature on the Arctic stratification and sea ice are unclear.
Maris study aimed to assess the potential for Arctic-like stratification in the Nordic Seas during the last glacial period and the dynamics behind Dansgaard-Oeschger events, using models and theory. The results are presented in three papers.
In the first paper, she and co-authors developed a simple conceptual two-layer ocean model including sea ice representing the Nordic Seas during stadial times. Here, they find that the sea-ice cover is sensitive to changes in freshwater input, subsurface temperature, and the representation of vertical mixing. Abrupt changes in sea ice can occur with small changes to surface freshwater supply or Atlantic water temperatures. You can read the full paper here.
In the second paper we apply a three-dimensional eddy resolving numerical model to the same problem and find further support for the conclusions from the first paper; the stability of a sea-ice cover in the Nordic Seas is dependent on the background climate and large changes in stratification and sea ice occur with small changes in forcing. In addition, additional results presented in this dissertation show self-sustained oscillations in sea-ice cover without a change in forcing. From the second paper, it was shown that an extensive sea-ice cover and an Arctic-like stratification with a fresh surface layer and a halocline can exist in the Nordic Seas without an external freshwater supply. Under sufficient cold conditions, a halocline capped by sea ice emerges spontaneously due to redistribution of freshwater through sea-ice formation and melt. Further it was shown that an extensive sea-ice cover slows down the local overturning in the Nordic Seas; decreases the heat import to the basin; warms intermediate waters, and cools deep waters. The paper is under review.
In the third paper, the importance of background climate is further stressed. In this study, rather than studying an Arctic-like stratification, the focus is on sea-surface temperature variability in the region of the Nordic Seas and North Atlantic. Mari and co-authors compile all available planktic foraminifera records from the North Atlantic during Dansgaard-Oeschger events with a sea-surface temperature reconstruction. These are then combined with fully coupled climate model simulations using a proxy surrogate reconstruction method. The resulting spatial sea-surface temperature patterns agree over a number of different general circulation models and simulations. However, freshwater forced runs from glacial times are needed to capture the amplitude of the temperature variability as seen in the proxy records. They suggest that sea-ice changes are important in extending the oceanic temperature signals to land. You can read the submitted paper here.
Combined, the three papers argue for an important role of the Nordic Seas during DansgaardOeschger events, consistent with paleoclimatic reconstructions. Maris results are also relevant for understanding potential future changes in Arctic sea-ice cover, and we argue that changes in Atlantic water temperature are of large importance.
A recent study co-authored by Joel B. Pedro, a postdoc with ice2ice at the Niels Bohr Institute has received quite some media attention.
The study was published in Quaternary Science Research (QSR), together with lead author Jan M. Strugnell and co-author Nerida G. Wilson and is titled “Dating Antarctic ice sheet collapse: Proposing a molecular genetic approach”
The study proposes a genetic technique to resolve when the West Antarctic Ice Sheet last collapsed. Last time WAIS collapsed, a west Antarctic seaway, facilitating genetic exchange was opened. Thus by looking into the population genomic data on both sides of the basin, one can estimate when the exchange last took place. The approach is novel and serve as an independent test of ice sheet models.
Read the full article in the journal QSR, or the shorter popular version in the Guardian.
PhD Nicholas Rathmann is the lead author of a new article on “Highly temporally resolved response to seasonal surface melt of the Zachariae and 79N outlet glaciers in Northeast Greenland” published in Geophysical Research Letters. Below a short description of the main findings. You can find the full paper here.
The northeast Greenland ice-stream (NEGIS) drains 16% of the Greenland ice sheet, holding approximately 1m of sea level rise equivalent, but its response to a warming climate is poorly understood, partly due to its remote location.
Now, a team of researchers headed by ice2ice PhD Nicholas Rathmann part of the European ice2ice project have published a study in Geophysical Research Letters where they identify which processes control the present-day mass loss from this less understood region. By using surface images taken every 12 days over NEGIS from one of the newest generation European Space Agency (ESA) satellites, Sentinel 1-A, the researchers derived state-of-the-art surface velocity maps in collaboration with ESA’s climate change initiative project to study the seasonal behavior of the NEGIS terminus region.
Combined with computer models of the ice flow and the present-day atmospheric state, the researchers found that future contribution to sea level rise from this region might be significantly effected by a warming atmosphere, but also raises further questions about the moderating effect sea ice mélanges might have – i.e. the composite “soup” of sea ice and calved ice bergs.
Moreover, the researchers also point to the importance of considering large calving events, such as what recently happened at the Larsen C ice shelf at Antarctica, on an individual basis since the plug-like effect of ice shelfs might depend on the details of the local balance of forces. Specifically, at Nioghalvfjerdsfjorden, one of the marine terminating glaciers of NEGIS, the researchers found up to 80% of the 76km long shelf could be lost without influencing the glacier’s mass loss (contribution to sea level rise).
These conclusions were drawn by the researchers by investigating the influences exerted by four important processes known to control the mass loss from these kind of glaciers:
(1) Melting of snow and ice at the surface, which is subsequently transported to the below bedrock through cracks in the ice where the water may lubricate the bedrock. There, water may lead to enhanced sliding of the above ice and thereby an increased mass loss.
(2) The large amount of sea ice and calved ice bergs (ice mélange) blocking the further escape of ice into the ocean at the Zacharia marine-terminating glacier of NEGIS.
(3) The large ice shelf at Nioghalvfjerdsfjorden, a second marine-terminating glacier of NEGIS, possibly acting as a plug holding back the flow of ice into the ocean.
(4) Sub-glacial “sticky spots” which may moderate the enhanced sliding caused by water lubricating the bedrock.
By combining the surface velocity maps with computer models of the ice flow, the researchers found a large influence is exerted by (1) and (2), but not (3) and (4). This, the researchers say, points to the importance of considering the local processes and dynamics of marine-terminating glaciers when estimating their possible future mass losses, and thus their contribution to sea level rise.
For the duration of 6 days between the 25th and 30th of September 2017, 28 young scientists meet up at the Niels Bohr institute in Copenhagen. A collection of master-, phd students and post docs all with varies backgrounds and outlooks came together for the common goal of mastering the analysis of ice-cores. ICAT 2018 had begun.
by Andreas Plach and Jesper Baltzer Liisberg, students at ICAT 2018
The course ICAT (ice core analysis and techniques) first presented us to the history of our climate and the drilling of ice-cores. This was followed with a round of presenting ourselves. Each person had prepared a 3-minute video of who they were, what they did, and why they were interested in ice-cores. This proved an engaging and fun new take on what is often done as forgettable powerpoint presentations, and you got to remember the different people much better.
The first two days offered a similar program at the Rockefeller building, with student videos and visits to the different laboratories located there. Here we were presented with the different aspects of ice-core analysis. Isotope, gas and impurity measurements each telling their own side of the combined story that is our climate history.
Following the final lectures Monday we went to see a bit of Copenhagen by going to get an ice-breaker beer (if you will allow us such a pun).
Wednesday we started the day at a different building with lectures on determining snow/ice densification and a detailed description about the development of the ice-core drills.
Following the morning lectures we grabbed a sandwich and went on an excursion to see the scars of the last glacial at the Geopark Sjællands Odde.
Thursday morning was focused on gases and dating of ice cores and followed by an afternoon of discussing ice core variability and a lecture on Dansgaard-Oeschger events. On Friday we learned about dust and impurities and how glacier models are used to estimate annual layer thicknesses and reconstruct accumulation rates. This was followed by some ice core statistics including examples on the misuse of statistics. “With a lot of free parameters you can fit everything!” The day was concluded with a nice ICAT dinner.
Saturday started out with a lecture on atmospheric and ocean dynamics focusing on the bipolar seesaw. This was followed by a great lecture about the search for the oldest ice on Earth within the Beyond EPICA project. After the wrap up of the summer school around noon, there was an extra treat for people interested in Antarctica. A guest lecturer from Tromsø gave an introduction on Quantarctica, a free GIS package for Antarctica.
This ended a great and informative course on ice core related science. For those of you who did not get the chance to attend this course, be sure to sign up for ICAT 2018!
by ice2ice postdoc Anne-Katrine Faber
During the period 10-22. September 25 students and 10 lecturers travelled to Rondvassbu in Norway to join join this years Advanced Climate Dynamics Courses (ACDC). From the ice2ice project. Kerim Nisancioglu joined as a lecturer and organizer and Mads Poulsen and Anne-Katrine Faber joined as students.
The purpose of the summer school was to explore the role of the seasonal cycle in the climate system. Lectures explained the role of the seasonal cycle in the ocean, atmosphere, land and ice and gave insights into cutting edge research questions exploring how the seasonal cycle can be used as a tool to understand climate change.
In between lectures, students worked on group projects. These projects gave the students hands on experience in the analysis of models, observations and proxy records with a focus on better understanding the seasonal cycle across time scales.
A two-day field excursion gave everyone an excellent opportunity to explore the beautiful nature of Rondane National Park. Hikes to interesting geological sites included engaging discussions on the processes that shaped the local landscape over the past thousand to several hundred thousand years.
Outreach activities were also a part of the school. The students got a chance to share their newly achieved knowledge with the local community. Two high school classes came to visit and they learned more about life as a scientist and how tree rings can be used to reconstruct past climate variability.
Overall the ACDC has been a fantastic experience with exiting lectures and plenty of opportunities for networking, discussion and development of new research ideas. Not only did we learn the power of the seasonal cycle, the largest climate change of our time, we also experienced it first hand as we were surprised by a snow storm in the second week of the “summer” school.
by Kerim Nisancioglu & Silje Smith-Johnsen
Sparking off this year governmental election campaign in Norway, Arendalsuka, a political festival in southern Norway, was crowded with top-level politicians and organisations. During the week of the festival, ice2ice scientists organised a joint ice talk and ice concert in the main square of Arendal showcasing ice2ice research on ice and climate. In addition we guided local kindergarten children and high school pupils on a geological and climate tour on Merdø, a tiny island in the new Norwegian marine national park just outside of Arendal, introducing the kids to the geology and history of the deglaciation in the area, as well as putting the past into the context of future changes expected on Greenland.
Ice core research is one of the key research areas of the Ice2ice project. A great number of scientists from the ice2ice project are this summer participating in the drilling of a new ice core. This ice core, the EastGRIP core is expected to contribute to the understanding of ice streams and their role in future sea level rise.
By: Anne-Katrine Faber, Kerim Nisanciouglu and Helle Astrid Kjær
Surrounded by nothing but snow and ice, the ice core drilling camp EastGRIP is located in the northeastern interior of the Greenland ice sheet. Here up to 35 people work towards the same goal, to drill and analyze the EastGRIP ice core.
The ice cores are drilled and analyzed in trenches, “the ice caves”, and approx. 7 meters below the snow surface. Here, far away from the sunlight, the ice caves function as a natural freezer and creates perfect conditions for drilling, logging, cutting and analyzing ice cores.
The entrance to the ice core trenches (Picture: Kerim Nisanciouglu)
EastGRIP is located on top of more than 2,5 km of ice. The ice core is not drilled as one single long core from surface to bottom, but consist of a large number of 2-meter core sections. In order to keep track of the depth of all of these ice core pieces, logging of the ice cores are crucial. Helle Astrid Kjær is one of the ice core loggers from the ice2ice project this year.
Each time the ice core drillers have drilled a new ice core section, the ice core loggers take over and make sure that the ice core sections are well matched and logged. Helle Astrid Kjær explains:
“Each 2 meter ice core section has to be matched well with the previous ice core. This way we know the total depth as well as orientation of each ice core section. The length of the new piece is to be very accurately recorded. Further we mark 55 cm sections, each 55 cm section is called an ice core bag and gets a number, before storing the core in the core buffer. The core is cut prior to storage into 3 bags length (1.65 m) and rest until the science trench takes over the processing”’
Ice2ice Helle Kjær and Korean colleague Khangyuan pointing towards bag 1000, which was logged, the in the end of June: (Photo: Helle Astrid Kjær)
When the ice core is logged, the next task is to cut and process the core. This is done in the “Science trench”. Kerim Nisanciouglu & Sarah Berben spent most of their time underground in the Science trench of EastGRIP with a great team of colleagues from Denmark, Italy and China processing the ice cores. This included, cutting, describing, cleaning, measuring and packing the 400 meters of ice extracted this season as well as the firn core extracted from the surface in 2016.
Kerim Nisanciouglus main task was measuring Electrical Conductivity (ECM) on a clean surface of the archive piece before packing. “During the weeks we found multiple volcanic events including notable ones such as Laki, Tambora and Krakatoa. We also tried to follow historical events and music (!) from the period we processed. The latter proved to be hard once we passed 1200AD, but it was a great journey through time with lots of fun discussions throughout the climate record.”
Kerim in the Science Trench showing ECM measurements (Picture: Kerim Nisanciouglu)
Sarah Berben took care of another important study of volcanic events, the processing of the core for Tephra measurements. These measurements allow is to study ash particles from volcanic events located in the ice core. Later, comparison of ice cores and ocean sediments cores creates possibilities for synchronization of the two different types of climate archives.
The team of Kerim and Sarah processed a record 70 bags during one day (!) and managed to finish processing down to about 400 m several days before time. Below this point the ice started to become more fragile as we approached the brittle zone and it was decided to sore and let the remaining ice rest before processing next year.
The processing team of Kerim and Sarah celebrating their achievements in the Science Trench (Picture: Kerim Nisanciouglu)
Far away from the cold temperatures in the science trench, Anne-Katrine Faber were sampling snow from the surface. As part of the surface science project, she contributed to the ongoing work of understanding how the water isotopes in the snow and air are interacting. This including daily measurements of snow at different depth, snow height measurements in the “bamboo forest” and monitoring of the isotopic composition of the water vapor in the atmosphere at different heights above the snow surface.
Anne-Katrine digging holes for snow pack measurements and transporting the samples back using skis and a sled. (Photo: Anne-Katrine Faber)
Whether you normally work with ocean, atmosphere or ice is not relevant when you are at EastGRIP. Everybody works towards the same common goal, to drill and analyze an ice core. During this work, scientific discussions and collaborations happens spontaneous, probably as a result of the mix of modelers and experimentalist and their different research interests.
A view of inside of the Dome during dinner time (Picture: Anne-Katrine Faber)
Overall the Ice2Ice scientists that got the privilege to join EastGRIP this summer got a fieldwork experience that included scientific achievements, beneficial discussions and last but not least a great del of fun.
A view of the EastGRIP camp and the flag line showing the many different nations present in camp at the given time. (Picture: Kerim Nisanciouglu)
Links for more information:
EastGRIP website: http://s.eastgrip.org/
Watch this video: https://vimeo.com/173730939
Facebook: https://www.facebook.com/EastGRIP/
Instagram: https://www.instagram.com/egripcamp/ or #EastGRIP and #EGRIP
Both positions are placed in Bergen, Norway at the Bjerknes centre for climate research.
One is focusing on developing a detailed chronology and synchronizing climatic time series between marine and ice core records through tephra studies, the other on climate dynamics and the interactions between the marine terminating ice caps, ocean circulation and Arctic sea ice.
Deadline for the application(s) is June 10th.
About the project/work tasks:
Position 1
Position 2