The IASC and the SURFEIT project joint hybrid workshop titled “Polar Winter Climate and Processes: Towards Filling Knowledge Gaps in the Understanding of the Coupled Climate System” was held at the British Antarctic Survey (BAS) in Cambridge, UK, from 23 to 25 April 2025. The objective of the workshop was to provide an interdisciplinary platform for scientists to present recent research, exchange ideas, and foster collaborations in the study of polar winter climate. The event attracted 110 registered participants from 18 countries, representing over 40 institutions. More than 40 participants attended in person, with the remainder joining virtually.
A total of 42 abstracts were submitted, encompassing a wide array of topics—from in situ field measurements to remote sensing, laboratory studies to numerical modelling, and micro-scale processes to large-scale dynamics. The workshop featured a strong presence of early career researchers (ECRs), including PhD candidates and postdoctoral fellows. Eleven ECRs were awarded travel fellowships, five funded by IASC and six by the UK National Capability project SURFEIT. ECRs actively contributed to the workshop by serving on the organising committee, co-chairing sessions, and providing rapporteur support.
The programme was structured around four core themes: 1. Polar winter storms, sea ice, and climate impacts; 2. Aerosols, clouds, and chemistry in the polar winter; 3. Teleconnections between polar, mid-latitude, and lower-latitude regions; 4. Identifying and addressing critical knowledge gaps. Each session consisted of a keynote lecture, several oral presentations, and breakout group discussions that engaged both in-person and online participants. Additionally, we organised a poster session featuring a 2-minute lightning presentation for each poster presenter.
Session 1 featured a series of presentations addressing the complex interactions between polar storms, sea ice, and the broader climate system. It commenced with a keynote on air–ice–ocean coupling during Arctic cyclone events, emphasising their role in modifying surface fluxes and ice dynamics. The subsequent talk provided a climatological analysis of Arctic cyclones, detailing recent trends in their frequency, intensity, and impact on sea ice and upper-ocean structure. Arctic sea ice projections (e.g. ice-free by 2050) and the internal variability alongside external forcing of the observed sea-ice changes were covered in two presentations. Antarctic perspectives were introduced through two presentations on heatwaves: one focused on the intensification of winter heatwaves using pseudo-global warming frameworks and climate model diagnostics, while the other addressed the occurrence of heatwave events in the Antarctic interior. Additionally, the impact of extreme wind events in Nares Strait and an introduction to the Churchill Marine Observatory were reported during this session.
Session 2 centred on recent advancements in understanding the sources of aerosols, the aerosol–cloud interactions, and some chemical processes in the polar winter atmosphere, encompassing observational data, laboratory work, and modelling. It began with a keynote presentation emphasising the value of remote sensing in enhancing winter observations of aerosol–cloud interactions under low-light conditions. Several presentations addressed measurements of ice-nucleating particles (INPs) in the Arctic, Southern Ocean, and Antarctica. Two modelling studies concentrated on cloud representation in the UK Earth System Model, including cold-air outbreak clouds in the Arctic. The potential role of blowing snow in Arctic black carbon production was reported. Additionally, one study explored the blowing snow fragmentation process through modelling, while another examined the sublimation process in regulating the production of salt particles using an environmental electron microscope. Two presentations focused on polar chemistry; one provided laboratory evidence of the freezing-induced increase in brine acidification, while the other demonstrated field evidence of the significance of nocturnal snow chemistry in regulating reactive nitrogen.
Session 3 focused on the dynamic linkages between polar regions and lower latitudes, emphasising atmospheric teleconnections and their role in driving extreme weather patterns and climate variability. It commenced with a keynote on the role of atmospheric rivers in Antarctica and their teleconnections to lower-latitude weather systems, supported by a presentation on trend analyses of atmospheric river activity across the Arctic and western North America. Two presentations examined the dynamics of high-latitude atmospheric blocking and the seasonal behaviour of the Amundsen Sea Low, identifying their influence on mid-latitude weather regimes and storm tracks. The impact of polar sea-ice variability on subtropical precipitation was explored in two regional studies focusing on the Indian summer monsoon and spring rainfall over South China. The final talk centred on the sensitivity of Antarctic coastal fast ice to remote climatic drivers.
Session 4 addressed outstanding scientific uncertainties in polar climate research, highlighting emerging areas that require targeted investigation and enhanced observational efforts. The keynote speech synthesised recent advances in understanding Antarctic weather and climate extremes, including the representation of synoptic processes and extreme events in climate models. The following presentation reported findings on how complex terrain and synoptic forcing jointly influence near-surface wind variability in East Antarctica. One introduced the AWACA project, detailing radar-based snowfall case studies and instrumentation deployment strategies in challenging polar environments. While most presentations focused on physical processes, one showcased novel observations of microbial biodiversity in Antarctic precipitation, emphasising the need for a deeper understanding of biogeochemical cycling and the potential for winter microbial transport. Another highlighted the ecological ramifications of storm-driven rain-on-snow events during the polar winter, which impact snowpack structure, soil freezing dynamics, and terrestrial biodiversity. Extending the theme of cryospheric vulnerability, one reported on the role of dust deposition from South Asian dust storms in accelerating the melting of Himalayan glaciers.
The poster sessions covered various topics, including tropical rain belts, moisture fluxes towards Antarctica by synoptic eddies, observed and projected Arctic sea ice, Antarctic temperature, marine heatwaves, and laboratory work on sea salt aerosol formation. The discussions identified several urgent scientific changes and emphasised the importance of interdisciplinary collaboration to address these challenges. Initiatives such as Antarctica InSync (https://www.antarctica-insync.org) and ACTRIS (https://www.actris.eu) were highlighted as key platforms for fostering synergistic efforts across observational, modelling, and theoretical communities. Enhancing these collaborations will lead to a more integrated understanding of polar processes and their global climatic significance.
Feedback from participants indicated that the workshop was both scientifically productive and collegially rewarding.
Next steps: The organisers are currently preparing a meeting report for submission to the Bulletin of the American Meteorological Society (BAMS). The outcomes of the workshop will inform ongoing efforts under ICARP IV and IPY-5 planning.
Acknowledgements: We gratefully acknowledge financial support from IASC (https://iasc.info) and the SURFEIT project (https://www.bas.ac.uk/project/surfeit/), as well as sponsorship from CliC (https://www.wcrp-climate.org/clic), CATCH (https://igacproject.org/activities/CATCH), ICPM (http://www.icpm-iamas.aq), and the British Antarctic Survey (https://www.bas.ac.uk) for providing resources to host the workshop.
Highlights:
- Observational Gaps in Polar Winter Conditions. A significant obstacle in both Arctic and Antarctic research is the limited availability of observational data for key parameters, such as winter sea ice thickness, snow salinity, and turbulent surface fluxes. The absence of wintertime measurements impedes the understanding of ice dynamics and atmosphere–ice–ocean interactions. The workshop recommended expanding autonomous observational networks, including drone and buoy deployments, to improve data coverage in remote and logistically challenging regions.
- Aerosol–Cloud Interactions and Associated Uncertainties. Uncertainties in aerosol–cloud coupling, particularly during the polar night, represent a significant knowledge gap. These uncertainties are especially pronounced in Antarctica, where data are sparse. To address this, the workshop emphasised the need for continuous, year-round aerosol monitoring using remote sensing and autonomous platforms. In addition, enhancing model parameterisations for sea salt aerosol production over sea ice, cloud condensation nuclei, and ice-nucleating particle activity is essential for improving polar climate model performance and reducing uncertainty in cloud microphysical processes.
- Complexities in Teleconnections and Model Representation. Understanding the mechanisms underlying polar–tropical teleconnections remains a critical challenge. Current climate models often fail to adequately capture these cross-scale interactions, resulting in discrepancies in simulated climate variability. Workshop participants recommended coordinated multi-model experiments to evaluate teleconnection robustness across modelling frameworks. They also advocated for targeted observational campaigns focused on atmospheric rivers and blocking events that influence polar systems
Photo courtesy of the Workshop Organisers: Participants on Day Two.
Date and Location
23-25 April 2025 I British Antarctic Survey in Cambridge, UK
IASC Working Group funding the Project:
AWG
Project Leaders:
Xin Yang British Antarctic Survey, NERC, Cambridge, UK and Xiangdong Zhang North Carolina State University, US
Year funded by IASC:
2024