CATCH Newsletter: April 2021
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CATCH is an activity focused on chemistry, biology and physics in cold regions, sponsored by IGAC, IASC, and SOLAS
Seminar Speaker Article - Arctic Microbes and Clouds
Cold-loving critters: Where do Arctic microbes come from and what do they have to do with clouds? 
Jessie Creamean –
(Department of Atmospheric Science - Colorado State University)

As the Arctic warms at more than twice the global rate, radiative feedbacks from clouds will lead to compounding impacts on glaciers, sea ice, and permafrost. However, the formation of Arctic clouds remains highly uncertain in part due to a poor understanding of aerosols called ice nucleating particles (INPs) that facilitate ice formation in clouds. In particular, the sources and abundance of biological INPs like microbes and their byproducts are not well characterized, yet they may be pivotal for cloud ice formation, especially at temperatures in which Arctic clouds persist. We know microbes from a wide array of surface sources exist in clouds but defining exactly where these specific airborne particles come from and how important they are on a large scale remains a significant challenge. This problem is exacerbated in remote regions like the Arctic where observations of INPs and their sources are especially limited.
Figure 1. This photo was taken during a shipborne expedition on the U.S. Coast Guard icebreaker, the Healy, to assess the role of marine biology impacts on the aerosol and specifically airborne INP population in the Chukchi Sea. Our findings from the first mission are published in Geophysical Research Letters (Creamean et al., 2019) and a team of us are working on a publication highlighting our major findings from all these cross-disciplinary missions.
My research is focused on this exact process, through characterizing the sources of INPs from both Arctic landscapes and the Arctic Ocean. Currently, my projects are focused on assessing INP properties from sources like permafrost soils, the open Arctic Ocean, and open leads and melt ponds over the central Arctic sea ice. These foci were inspired by my first Arctic field campaign looking at INPs in an oilfield on the Arctic Alaska coast. Since pollution is typically ineffective at nucleating ice, I expected to see nothing. To my surprise, I saw enhanced INPs from both the open tundra and ocean during the onset of the melt season. This finding led to multiple deployments on ships and land to attempt to understand these marine and terrestrial sources of aerosols that have the potential to impact Arctic cloud formation.
Figure 2. This is a photo from MOSAiC (the Multidisciplinary Observatory for the Study of Arctic Climate), a year-long transpolar drift experiment, when I was sampling seawater from an open lead in the ice near the North Pole. Photo was taken by Esther Horvath and was featured in the 50th anniversary issue of the Smithsonian Magazine.
My hope is that in the future, modelers can use detailed information on INP sources from studies like mine to better constrain Arctic cloud formation in models of all scales by having the necessary source information. This was one topic that came up in the community discussion during my CATCH seminar that I think is crucial. To reduce the uncertainties of quantifying cloud impacts on the surface energy budget, we have to take a step back to the basics and understand how they form and evaluate the role of aerosols in the formation process.

Article written by Jessie Creamean 
Photography credit: Jessie Creamean and Esther Horvath

Creamean, J. M., Cross, J. N., Pickart, R., McRaven, L., Lin, P., Pacini, A., Hanlon, R., Schmale, D. G., Ceniceros, J., Aydell, T., Colombi, N., Bolger, E., and DeMott, P. J.: Ice Nucleating Particles Carried From Below a Phytoplankton Bloom to the Arctic Atmosphere, Geophys Res Lett, 46, 8572-8581,, 2019. 

Creamean, J. M., Hill, T. C. J., DeMott, P. J., Uetake, J., Kreidenweis, S., and Douglas, T. A.: Thawing permafrost: an overlooked source of seeds for Arctic cloud formation, Environmental Research Letters, 15, 084022, 10.1088/1748-9326/ab87d3, 2020.
CATCH Science Seminar This Friday!
A reminder for our upcoming online CATCH Science Seminar, taking place on Friday 16th April 2021 at 09:00 CEST. This months seminar is on:
"Sea ice biogeochemistry - links to atmospheric composition"
by Dr. Bruno Delille (Université de Liège) and Dr. Daiki Nomura (Hokkaido University)
To register, please use the link below. For more information on the seminar series, please visit the CATCH website
Register here!

Virtual Atmosphere-Cryosphere-Ocean Seminar Series 2021
In lieu of an in-person assembly, IAMAS, IACS and IAPSO are delighted to host an international online seminar series on 19-23 July 2021. Registration is free and can be found here. Seminar themes include:
  • Remote sensing of the atmosphere, ocean and cryosphere
  • Field observations of the atmosphere, ocean and cryosphere
  • Modelling atmosphere, ocean and cryosphere interactions
  • Coupled changes and variability in the atmosphere, ocean and cryosphere
For more detailed information, visit the website here.

Postdoctoral Research Fellow in Marine Modelling

The Norwegian Polar Institute seeks a full-time post-doctoral fellow to join the research team focused on Arctic marine physical and biogeochemical processes. It is funded by the EU-project “The future of Arctic coastal ecosystems - Identifying transitions in fjord systems and adjacent coastal areas” (FACE-IT), and by the Norwegian Research Council project “The Nansen Legacy”. The position is for 3 years. The overall goals of the position involve using modelling to understand the consequences of warming on ocean and sea-ice physics and biogeochemistry. 

For more information about the position and application process, please visit the job announcement here
Closing date is 30 April 2021.

Postdoctoral Researcher on Arctic Aerosol

The Extreme Environments Research Laboratory at the École Polytechnique Fédérale de Lausanne (EPFL) seeks a full-time post-doctoral researcher to develop a data-driven model to investigate potential natural drivers of long-term changes in Arctic aerosol species. The project is called “Arctic climate change: Exploring the Natural Aerosol baseline for improved model Predictions” (ArcticNAP) and happens in collaboration with the Swiss Data Science Center, meaning that data-driven modelling is at the heart of the work. The position is for 2 years

For more information about the position and application process, please visit the job announcement here.

Interested parties may contact Dr. Julia Schmale with any questions. 
Start date is 1 July 2021.
The CATCH e-newsletter is edited by Sarah Johnson, contributions and announcements from the community can be sent to
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