Less than two weeks after arriving the port of Tromsø with G.O. Sars the ice2ice Team Jansen members started the comprehensive sedimentological analyses of the retrieved sediments form the Western Nordic Seas.
Focus are put on two 20 m long piston cores from the shelf outside Scoresbysund and the first results indicate that the selected cores cover ice2ice target intervals: the Eemian interglacial, Marine Isotope Stage 3 and the Holocene.
Our new team member Ida Synnøve Olsen has started sampling and sieving sediments from the mid Scoresbysund transect. Ida is sampling every 5 cm, then sieving and in a microscope picking out foraminiferas (marine plankton with carbonate shells) in order to get a oxygen isotope record.
These cores are currently scanned at the University of Bergen using the X-ray fluorescence (XRF) method. Like on the cruise the team members are working in shifts at the XRF scanner in order to generate as much data as possible within a short time period. That approach will give indications about the elemental composition of the marine sediments and in combination with the existing data from onboard measurements of magnetic susceptibility we are able to develop initial age models for the cores. In which resolution these intervals are resolved in the equivalent cores is currently established by using oxygen isotope stratigraphy and radiocarbon based age determination.
Over the next few weeks the PhD students Evangeline and Henrik, as well as Ashley (Fulbright student) and the new Ice2ice master student Ida will be working in the sediment lab sampling the two piston cores. Sampling will be done at 5 cm intervals in 1/2 cm slices. These will be weighed, dried and sieved before being picked for various foraminifera to conduct isotope analysis. The analysis will help us construct past temperatures and help us to determine the age of the core when compared with isotope concentrations from ice cores. When the MIS3, and DO events are “located” in the core, we will sample the rest of the core in that time frame to conduct other multi-proxy analysis such as Mg/Ca on benthic foraminifera to capture past bottom water temperatures.
In addition to the lab work Henrik is currently working on a high-resolution sea ice record based on biomarkers in core MD99-2284 from the southern Norwegian Sea, which will cover at least two D-O cycles around DO 8 and 7. After having the first age models for our new cores, he will start to generate similar sea ice records for cores from the northern Denmark Strait and the East Greenland margin.
In-depth studies of tephra are conducted by Sarah and scheduled later this autumn. She is currently exploring how to utilize the Flow-cam at the new Earth Lab hosted by Dept. of Earth Science at UoB in order to establish a tephracronology in the Scoresbysund cores.
Want to know what is behind the numbers and curves?
The lab work is a crucial part of the ice2ice project providing us with the basis for our paleoclimatic reconstructions. All Ice2ice members are welcome to join or visit us at our laboratories for a day, a week or a month! Contact Jørund Strømsøe.
The Past 4 weeks a large part of the ice2ice members at University of Copenhagen have spend their time in a freezer in Bremerhaven. They have cut the, in total 586 m long, Renland ice core into smaller samples to prepare for the investigation of the climate signal kept within. Samples for water isotopes, which inform on the past temperature, were made for each 55 cm (1064 samples) and also for each 2.5 cm (>23000 samples). Pieces were cut out for the analysis of greenhouse gases, for the analysis of chemical impurities and also a section for analysis of physical properties, such as crystal structure was cut.
8 persons involved in the ice2ice project from University of Copenhagen participated in the work, which took place at -20C.
The cutting was finished Friday the 11th of September 2015. Now the sections are on the way to leading laboratories around the world for high class analysis to be started in October.
Bo Vinther (Primary Investigator UCPH) with the deepest part of the Renland ice core, which is more than 110.000 years old.
Ice2ice researchers Hannah Kleppin and Markus Jochum has published together with coworkers from Colorado a paper titled “Stochastic Atmospheric Forcing as a Cause of Greenland Climate Transitions” in Journal of Climate. The abstract is presented below and the full article can be found here.
Abstract
An unforced simulation of the Community Climate System Model 4 (CCSM4) is found to have Greenland warming and cooling events that resemble Dansgaard-Oeschger-cycles in pattern and magnitude (Figure 1a). With the caveat that only 3 transitions were available to be analyzed, we find that the transitions are triggered by stochastic atmospheric forcing. The atmospheric anomalies change the strength of the North Atlantic subpolar gyre, leading to a change in Labrador Sea sea-ice concentration (Figure 1b) and meridional heat transport. The changed climate state is maintained over centuries through the feedback between sea-ice and sea-level pressure in the North Atlantic. We discuss indications that the initial atmospheric pressure anomalies are preceded by precipitation anomalies in the West Pacific warm pool. The full evolution of the anomalous climate state depends crucially on the climatic background state.
Figure 1: (a) Greenland annual minimum surface temperature [◦C] averaged from 55 ◦ to 15 ◦W and 65◦ to 80◦N. (b) Annual maximum of sea ice concentration in the LS (53 ◦ to 65 ◦N to 60◦ to 45 ◦W). The different phases of interest are indicated on top, NA_w1 is the period from year 50 to year 250 and NA_c1 from year 350 to 550. The transition between different warm and cold phases, based on Greenland temperature changes, are marked by red horizontal lines. (c) Surface temperature difference between years 350 and 550 (NA_c1) and 50 and 250 (NA_w1). Regions are only shaded if correlation with Greenland surface temperature (averaged over the same region as in (a)) for the period between year 270 and 470 is significant on a 95 %-level.
The climate modelling part of ice2ice had a very productive meeting in Copenhagen in September with an opportunity to both hear about progress in the simulations and discuss problems, potential pitfalls and the potential results. The science part of the programme commenced with a good overview of the representation of sea ice in CMIP5 models and how this is likely to change presented by Shuting Yang. These results showed that even in a 2°C world, Arctic sea ice is likely to be gone in September. We also considered the EC-Earth – PISM results for the extended RCP8.5 scenario. Shuting showed a linear relationship between sea ice and surface mass balance in this run and there was much discussion on the implications of Arctic ocean stratification and salinity in the models and how this anaylsis can be both used for ice2ice and extended with other models, output and datasets.
Mats Bentsen gave an interesting overview of the NorESM model, the updates since CMIP5 that will be used in CMIP6 and the configuration for the palaeo-simulations. The run-time is impressive and there has been a significant improvement in model performance in the North Atlantic.
Rasmus Pedersen presented a detailed overview of his PhD work using the CESM model to identify the atmospheric response to regional sea ice change, where sensitivity experiments in different sectors of the Arctic Ocean were carried out, with some rigorous questioning afterwards, which he acquitted well.
Peter Langen presented some statistical work on the CMIP5 model outputs and ways to better define uncertainties in projections which is relevant for the way we will analyse the ice2ice datasets.
We also managed to set up some remote participation with Norwegian colleagues not able to join us; Lu Li updated us from Bergen on the challenges and progress in setting up WRF to model the Greenland domain. A couple of issues were identified and the future strategy for both regional models (WRF and HIRHAM5) was firmed up.
Finally there was a wide-ranging discussion session that dealt with coordination of the modelling programme, the planned palaeo-runs and sensitivity experiments and how to synthesise the data and analysis together.
30 eager European and US-based PhD students and PostDocs joined some 10 lecturers in Laugarvatn, Iceland, to spend two weeks together delving into this year’s topic ”Climate and Volcanism”.
Student-led summary of key aspects of this year’s topic Climate and Volcanism. Photo by Daniel McCoy
The diverse background of the lecturers and students reflected the interdisciplinary nature of the topic, bringing together atmospheric science, aerosol chemistry and physics, geology, glaciology, oceanography and paleoclimate.
The most challenging but exciting aspect of the theme proved to be linking the wide range of time scales involved, from Earth’s mantle processes, via the glacial cycles and mid-ocean ridge volcanism to the rapid sequence of events following a single volcanic eruption.
When not listening and discussing the latest scientific buzz about how volcanoes affect climate and vice versa (!), students were working hard on group projects on tephra, lake sediments, mid-ocean ridges and sea level, causality and volcanic aerosols.
Eager inspection of a section of volcanic ash deposits. Photo: Henning Åkesson
The two weeks were blessed by unbelievably good weather. This provided great conditions for several field excursions around central and southern Iceland, including vast lava fields, natural hot springs and glaciers.
Snow scooter excursion to learn how to measure surface energy balance, mass balance and glacier motion at the ice cap Myrdalsjökull. Photo: Henning Åkesson
We are happy to announce that yet another PhD position is available within the ice2ice project.
The candidate will work within the fields of global climate modeling. The focus will be on Arctic interactions between atmosphere, sea ice, and ocean and their possible control on the Greenland Ice Sheet. Both present-day, palaeoclimatic and future climate states will be central to the work. The work will contribute to further development of the EC-Earth state-of-the-art Earth System Model. In particular, the aim is to study the role of changes in sea-ice conditions as a controlling mechanism for the state of the Greenland Ice Sheet.
The successful applicant will be enrolled at the University of Copenhagen and take part in scientific activities both at the Centre for Ice and Climate and DMI. In addition to working on the research project, publications, and PhD thesis, the candidate must take PhD courses, participate in congresses, and participate in teaching and dissemination activities. The position involves a stay at an external research institution for a few months, preferably abroad.
The ideal candidate has experience with climate dynamics and modelling (preferably global climate modelling or modelling sea-ice–ocean–atmosphere interactions). Experience with programming in FORTRAN/UNIX and knowledge about HPC computing is also a large advantage.
More information on the position and how to apply is available here.
The Norwegian research vessel G.O. Sars after arriving in Tromsø with more than 200 m of sediment cores to document past abrupt climate change. Photo credit: Iben Koldtoft
Going on a cruise for a month sounds tempting for most people and that is exactly how I spent one month of my summer. Instead of sunshine and 25 degrees, the temperature was closer to the freezing point on the thermometer and normal summer weather was replaced by milder weather conditions. The destination of the cruise was the western Nordic Sea and the east Greenland Margin. The ice2ice cruise was not a regular cruise, but a scientific cruise, starting in Reykjavik then heading towards the east coast of Greenland and ending in Tromsø, Northern Norway. Without the option to go ashore and far away from civilization, I spent four weeks aboard the Norwegian RV G.O. Sars. When I came home from the middle of the ocean, I realized that I had been part of a unique project
The ice2ice cruise logo, where the red dots indicate the more than 30 sites of coring marine sediments under the ice2ice cruise. Photo credit: Amandine Tisserand
Why are climate scientists going on a cruise?
The purpose of the cruise was to collect marine sediment cores in the western Nordic Seas and along the east Greenland Margin. The retrieved sediments can be used to document abrupt changes in sea ice cover and ocean circulation along the East Greenland continental margin, during glacial times and for the more recent past. For this purpose three different sediment coring systems were used. The multicore, which samples sediments, including the sediment/water interface at the sea floor, the gravity core that is used to get information about the deeper marine sediments (up to 5 meter), and the calypso core that could retrieve up to 20 m long sediment cores, containing muddy sediments from the ocean floor to the ship’s deck.
One of the main questions of the ice2ice project is why there are abrupt climate changes. The sediment cores should be ideal for correlation to the RECAP (http://recap.nbi.ku.dk/) ice core from Renland Ice Cap in Eastern Greenland, drilled earlier this year. Together it is a unique material, which hopefully can bring information of the sea ice cover and its extent back in time.
Sediments: a split calypso core showing a clear pattern of a tephra layer from a volcanic eruption (left), and the multicore on the way up with four successful sediment cores (right). Photo credit: Iben Koldtoft and Ida Synnøve Olsen.
When everything is new – also the type of cruise
This was my first cruise ever, and before I boarded the ship in Reykjavik in mid-July, my knowledge of marine sediments and the ocean was very limited. Most of the people on board the ship were geologists who knew a lot about sediments from the ocean and had been on cruises before. Now a month later, my knowledge about sediments and the life aboard a research ship has become much larger. I think I had the steepest possible learning curve about sediments, because there were no stupid questions to ask, and everyone was very nice about answering questions, even if it was outside their area. Usually I work with ice cores and modelling of glacier ice and for me everything was new. This meant that I could contribute with knowledge about the RECAP ice core instead. Now I can take part in a conversation about sediments together with other geologist.
Normally when going on a cruise, there are only a few scientists on board on the ship. This means that there is only time to core the sediments and cut them into sections, while all the scientific work takes places later, when the sediments are in the lab. On this cruise, as something new, we were several scientists, so when the sediments were on deck, we immediately did a splendid job of handling the cores, describing and analysing the material. Thus, the detailed lab analyses can start right away after the material gets back to Bergen.
Shipboard analyses indicated that the material we have brought back to the laboratories in Bergen covers a time span from the present and probably a few hundred thousand years back in time. Not all the data have been analysed yet but we are looking forward to start and we are eager to see the results.
Midnight sun over the Greenland Sea. Photo credit: Dag Inge Blindheim.
The science
During the one month long cruise, we had collected numerous samples of shells from the ocean floor from 32 stations west of Iceland. We did CTD (Conductivity, Temperature and Depth) measurements, to get information about how the temperature, salinity, density and oxygen content of the water vary in the ocean, and we collected water samples at different depths to analyse oxygen and carbon isotopes. We also collected sediments from 31 stations and every core has passed the DNA sampling, color and MS measurements stations. The cores were then cut into sections, split down through the middle, logged and described so that we could get an initial feel for the quality and utility of the samples we retrieved, before they are brought to shore for much more detailed analysis.
Ashley, Margit and Ida cut a gravity core into sections (left), while Alby brings a multicore from the deck down to the lab (right). Photo credit: Dag Inge Blindheim and Kerstin Perner
Working 24-hour shifts on the ship meant that we achieved a lot and we brought home more than 200 m of muddy sediment cores from the sea floor from the western Nordic Seas and the east Greenland Margin and more than 190 water samples.
Henrik is taking DNA samples of a gravity core (left) and water samples from the CTD (middle). Photo credit: Iben Koldtoft. I am happy after having packed one of the last sediment sections, which is now ready to be sent to Bergen and further analyzed (right). Photo credit: Kerstin Perner
Although it was 12 hours of hard work most of the days, it was a pleasure to be part of the cruise. It has certainly not been my last cruise, if it is up to me, and I will look forward to a new cruise if I am lucky enough to get the chance. Weather was nice most of the time, but of course, we had some days of rough seas. The professionalism of the crew of G.O. Sars created an excellent atmosphere for work and time off, it was more like being on a real 4 star cruise if we ignore the time we worked.
On the ice2ice cruise the scientists were Eystein, Carin, Jørund, Dag Inge, Bjørg, Christian, Margit, and Amandine from Uni Research (Uni Research Climate, Norway), Stig, Sarah, Evangeline, Henrik, Ashley, and Ida from UiB (University of Bergen, Norway), Flor from GEUS (Geological Survey of Denmark and Greenland, Denmark), Mads from CIC (Centre for Ice and Climate, Denmark), Kerstin from IOW (Leibniz Institute for Baltic Sea Research Warnemünde, Germany), Albertine from Bris. (University of Bristol, UK), and myself Iben from DMI & CIC (Danish Meteorological Institute & Centre for Ice and Climate, Denmark). We were 19 participants, 8 men and 11 women, representing 8 different nationalities, and supported by a ship crew of 15. We were in good spirits all the time and a successful cruise!
The scientific crew of the ice2ice cruise. Photo credit: Iben Koldtoft
The cruise would not be possible without support from the European Research Council Synergy project ice2ice (Danish-Norwegian), Bjerknes Centre for Climate Research (Norway) and Institute of Marine Research (Norway), who provided research vessel and crew onboard.
You can read more about the ice2ice project on this homepage.
A 20 meter long calypso core on the way from the sea floor to the ship’s deck. Photo credit: Iben Koldtoft
Iben Koldtoftis PhD student within the ice2ice project at Danish Meteorological Institute and Centre for Ice and Climate, University of Copenhagen, Denmark and supervised by Jens H. Christensen and Christine S. Hvidberg. She is interested in modelling the dynamics of the Greenland Ice Sheet and the smaller glacier, Renland Ice Cap, in the Scoresbysund Fjord, Eastern Greenland. Currently she is coupling the ice sheet model PISM to the ocean by implementation of calving to the model. Surface mass balance simulations of the Greenland Ice Sheet will later be used to assess the quality of the interaction between the ice sheet model and a climate model in comparison to observations.
Hard working, but happy, ice2ice members in the cold freezer.
Ice2ice members Bo Vinther, Paul Vallelonga and Thomas Blunier started a trip to collaborators at Alfred Wegener Institute (AWI), Bremerhaven, Germany from Copenhagen, Denmark on sunday with a car full of labelled plastic bags.
The plastic bags are used for the multiple pieces of the 584.11 m of Renland ice core. The ice core was already cut into 55 cm pieces while still in Greenland, but are now further being split into sections for different measurements. The cutting takes place at AWI and not in Copenhagen as they at AWI has a freezer set up for exactly such work.
Further Di-electrical profiling (DEP) of the ice can be done there. DEP inform on the electrical properties of the ice. Also preliminary scrapings of the ice core sections are being taken to inform on the temperatures of the past climate as determined by water isotopes and thus help to make a quick constrain on the ages of the Renland ice core.
The cutting of the Renland ice core will continue the next 3 weeks and more ice2ice participants will join the processing.
While most of the ice is in good condition, some sections have been influenced by the long transport from Greenland to Germany.
Ship-board core measurements for creating an initial time scale for the cores (Photo Jørund Strømsøe)
For four weeks, a scientific crew of scientists and students, supported by a ship crew of 15 have been working on 24 hour shifts. The cruise came to an end as the Research Vessel G.O. Sars anchored in Tromsø, Norway on August 14, after spending weeks in icy waters with icebergs and whales nearby on many occations.
Cores packed and ready for shorebased analyses (Photo: Kerstin Perner)
“It has been an eventful and successful cruise” reports cruise leader Eystein Jansen from Tromsø. “We bring with us 200m of sediment cores from the western Nordic Seas and the east Greenland Margin”. Shipboard analyses indicate that the material the scientists bring home to their laboratories cover a time span from the present and probably a few hundred thousand years back in time.
New light on rapid changes
The cruise had the ambition to retrieve sediments that can document abrupt changes in sea ice and ocean circulation along the East Greenland continental margin, both in glacial times and in the more recent past. For this purpose a suite of different sediment coring systems were used, bringing up to 20 m long sediment cores containing muddy sediments from the ocean floor to the ship´s deck. On board, all sediment sequences were logged and described so that the science party can get an initial feel for the quality and utility of the samples they retrieve, before they are brought to shore for much more detailed analyses.
Ship-board core measurements for creating an initial time scale for the cores (Photo Dag Inge Blindheim)
“We have a unique material which we hope will cast new light on rapid changes in sea ice cover and ocean circulation during past times. The cores should be ideal for correlation to the ice cores drilled this summer at Renland in Eastern Greenland by our ice core colleagues from Copenhagen”, says an optimistic cruise leader.”The material is also a unique resource for calibration of our methods to study past sea ice and oceanic changes to modern conditions, and should give us opportunities to compare the changes of the recent past with those occuring today at high time resolution”.
Extensive sea ice cover causes problems
The cruise experienced problems with the quite extensive sea ice cover this summer, but during the cruise the sea ice retreated enough for many sites that were inaccessible at the start of the cruise became sea ice free towards the end.
Midnight sun over the Greenland Sea (Photo: Dag Inge Blindheim)
“Nevertheless we were not able to come into the fjord areas, and those objectives will remain to another option. The project also plans a cruise late next summer, where those possibilities may open up. We also had some problems with the winch system for the long piston coring, but despite of these problems we bring back a nice long core material for the post-cruise studies”, says Jansen.
“The science crew of ice2ice scientists and students did a splendid job of handling the cores, describing and analyzing the material so that the detailed lab analyses can start right away after the material gets back to Bergen in a week from now. We are eager to start and eager to see the results”, says Jansen, who also praise the crew of G.O. Sars for their professionalism, and for creating an excellent atmosphere for the work.
“Being onboard is more like a 4 star hotel despite the harsh conditions. Weather was nice most of the time, but we had some days of rough seas as expected in these areas”.
During the first leg of the Ice2Ice 2015 cruise the team was joined by the German tv production company Along Mekong Productions who have kindly shared this beautiful video with us. It provides the viewer with a bird’s eye view of the cruise.
During the first leg of the Ice2Ice 2015 cruise the team was joined by the German tv production company Along Mekong Productions who have kindly sent us this beautiful video. It provides the viewer with a bird’s eye perspective of the cruise. You can read more about the cruise here and here.
