What are the consequences of the dramatic loss of summer sea-ice for Arctic climate? Will the ice continue to disappear at an ever-increasing rate as the exposed ocean surface absorbs increasing amounts of solar radiation? Or might conditions become progressively more favorable for biological activity and associated cloud-formation, decreasing the amount of solar-radiation received at the surface? How might the Arctic climate change on inter-annual and inter-decadal time scales and quite how sensitive is it to anthropogenic climate change? These are key questions that our project will strive to answer.

To do so, we have conducted unique measurements during a research cruise to the high Arctic in summer 2018 aboard the Swedish icebreaker (I/B) Oden as part of the Arctic Ocean 2018 expedition. During the cruise, which took place throughout the most active period biologically and into the autumn freeze-up (mid July to September), I/B Oden drifted passively whilst moored to an ice floe.

⇒ Click here (or scroll down) to read about recent updates (outreach, presentations and papers).

An overview of the sites installed on the ice during the expedition (photos: Paul Zieger).

Projects at ACES

Within ACES, we are responsible for the following projects during the expedition:

  • Quantifying the source of aerosols from open leads in the High Arctic (PI: Matthew Salter)
  • Aerosol-cloud interactions in the High Arctic (PI: Paul Zieger)
  • Cloud-water and aerosol sampling using a tethered balloon (PI: Paul Zieger and Matthew Salter)

The team from PSI and ACES on top of the triplet container and the Swiss container just before departure (31st of July 2018) in Longyearbyen, Svalbard. Patrick Duplessis is missing on the photo (photo: Matthias Gottschalk).

The ACES-Team on board Oden will be Linn Karlsson, Julika Zinke, Matt Salter and Paul Zieger. Start will be July, 31st, 2018 (Longyearbyen, Svalbard) and end on September 25th, 2018 (Tromsö, Norway).

The team from ACES: Paul Zieger, Julika Zinke, Linn Karlsson, and Matt Salter (“The A-Team”) shortly before departure (6.7.2018). More than 1.8 tonnes of equipment have to be shipped to I/B Oden.

Project 1: Aerosol-cloud interactions in the High Arctic

Aerosol and cloud sampling were performed on the 4th deck using a newly designed whole-air inlet and a special cloud inlet (called the counterflow virtual impactor inlet / CVI), which just samples cloud droplets. Ambient particles and cloud droplets are then dried and characterized using various in-situ instruments. We used instrumentation to determine the size and chemical composition of the particles. A schematic overview is depicted in the figure below.

Julia Schmale and Andrea Baccarini (Paul Scherrer Institute, PSI, Switzerland) contributed by characterizing the role of new particle formation in the high Arctic and by performing high-resolution chemical analysis of cloud condensation nuclei. Their instrumentation were located in the red Swiss container next to the triplet container on the 4th deck. More details and their blog can be found here.

View of the inlet systems and cloud probes installed on top of the triplet container.

View of the inlet system (above) inside the triplet container (below), where ACES installed a large number various instruments to characterize the physical and chemical properties of aerosols and cloud residuals (photo: Paul Zieger).

Here is a short time lapse showing our inlets while Oden is breaking the ice:

Project 2: Sampling of cloud-water and aerosols using a tethered balloon

We developed a new instrument to sample the cloud droplets and ice crystals of elevated clouds in the high Arctic. The samples (or the cloud water) were analyzed in the laboratory with respect to the chemical composition and the ability to form ice nuclei. The mini-CWS (miniaturized cloud water sampler) has been successfully deployed on a tethered balloon during the expedition.

The tethered balloons (from TROPOS, Germany, and the University of Leeds, UK) were used to sample aerosols particles and cloud water (photo: Paul Zieger).

Our new cloud water sampler shortly before departure (photo: Paul Zieger).

Project 3: Sampling at the open leads

Left: Schematic of the project “Quantifying the source of aerosols from open leads in the High Arctic“. A floating chamber will be used to sample particles which are produced by bubble bursting in the open leads. Right: The first test on Brunsviken (June, 2018) was successful.

One highlight was the sampling of particles originating from bubble bursting in the open leads. For this purpose, we designed a floating chamber which is based on the sea spray chamber in our lab at ACES. Particles were characterized concerning their, concentration, size and chemical composition (filter sampling).

The floating aerosol chamber was installed at an open lead at the end of the ice floe (photo: Paul Zieger).

Oden moored to an ice floe close to the North Pole. The photo was taken from our tethered balloon (photo: Paul Zieger).

Updates: Presentations, outreach, papers & other proceedings

  • November 2018: Talks at English School in Nacka and for English school IES in Täby (at SU), Aerosol and cloud research in the Arctic: Report from the US-Swedish icebreaker expedition to the North Pole by Paul
  • March 2019: First data workshop at Stockholm University regarding all online measurements (21-26 March 2019) and official workshop in Stockholm, Sweden (27-29 March 2019) where Andrea, Julia and Paul present first results to the participants of the Arctic Ocean 2019 expedition.
  • April 2019: Presentations by Julia and Paul on first results of the MOCCHA campaign (QuIESCENT Arctic workshop, 4-5  April 2019, British Antarctic Survey, Cambridge, UK)
  • March 2019: Talk at the Bolin Centre Science Seminar, Aerosol-cloud interactions in the Arctic -Recent results from our observations on Svalbard and the high Arctic by Paul (March 2019)
  • March 2019: Talk at the 3rd Arctic Ocean workshop in Stockholm, Aerosols and clouds in the high Arctic -Recent results from the Arctic Ocean 2018 expedition by Paul (March 2019)
  • May 2019: Talk during Earth Week at Stockholm University, Arctic research at ACES – Recent results from our aerosol-cloud observations on Svalbard and the high Arctic by Paul (May 2019)
  • May 2019: Invited talk at MetNo and University of Oslo (Norway), Aerosol-cloud interactions in the Arctic -Recent results from our observations on Svalbard and the high Arctic by Paul (May 2019)
  • August 2019: Presenting new results at the European Aerosol Conference, 25-30 August 2019, in Gothenburg, Sweden
    • Poster presentation by Julia et al., “Aerosol activation in clouds: Marginal ice zone versus North Pole observations
    • Oral presentation by Andrea et al., “New Particle Formation in the Central Arctic Ocean
    • Oral presentation Paul et al., “Aerosol-cloud interactions in the high Arctic
    • Poster presentation by Julika et al., “A miniaturised balloon-borne cloud water sampler: Development, deployment and chemical analysis of samples obtained in the high Arctic”
  • September 2019: Invited talk at the 3rd PACES Open Science Meeting, Oslo, 18-20 September 2019 by Paul, “Aerosol-cloud interactions in the Arctic: Recent results from our observations on Svalbard and the high Arctic
  • November 2019: Second data workshop at Stockholm University (7-15 November 2019)
  • January 2020: Our first publication on “A miniaturised balloon-borne cloud water sampler and its deployment in the high Arctic” has been submitted for publication to Tellus B. A preversion of the manuscript can be found here.
  • April 2020: Poster presentation, “Chemical composition of summertime High Arctic aerosols using chemical ionization mass spectrometry” at EGU 2020 by Karolina (abstract can be found here).
  • May 2020: Presentation at the Nordic Society for Aerosol Research (NOSA) online symposia, “Observing aerosol-cloud interactions in the Arctic” by Paul
  • Fall and spring 2020-2021: We are starting an online seminar series to present and jointly discuss recent findings. Start is 17th of September (every 2nd Thursday).
  • October 2020: First paper on iodine and new particle formation by Andrea et al. published in Nature Communications

Media coverage

More information can be found on social media using the hashtag #ArcticOcean2018 (e.g. on Twitter or Instagram). The cruise reports (also from the other teams) and more impressions can be found here.


Our campaign logo (made by Tinja Olenius, ACES).


The cruise track of the Arctic Ocean 2018 expedition to the North Pole. The sea ice coverage has been taken from OSISAF by EUMETSAT.

Previous media material

More information can be found on social media using the hashtag #ArcticOcean2018 (e.g. on Twitter or Instagram) and on the the expedition website on Polarforskningsportalen. Matt will tweet live here. Paul will post on Instagram and for SU (end of September). The press release from Stockholm University can be found here. Helen Czerski is blogging here, while Julia and Andrea will share updates on this site.

A short video about the upcoming Arctic Ocean 2018 expedition prepared by Stockholm University:

Video from our test flights at Cardington (U.K.) of the mini-CWS together with Ian and Grace from Leeds University:


Contact information

Visiting addresses:

Geovetenskapens Hus,
Svante Arrhenius väg 8, Stockholm

Arrheniuslaboratoriet, Svante Arrhenius väg 16, Stockholm (Unit for Toxicological Chemistry)

Mailing address:
Department of Environmental Science
Stockholm University
106 91 Stockholm

Press enquiries should be directed to:

Stella Papadopoulou
Science Communicator
Phone +46 (0)8 674 70 11

Project Info

Project start: 2017

Funded by

The Swedish Polar Research Secretariat, the US National Science Foundation (NSF) and Vetenskapsrådet (VR). We are also grateful to further funding from the Bolin Centre for Climate Research (RA2) and support within the ACAS project funded by the Knut-and-Alice Wallenberg Foundation.