The northern Antarctic Peninsula is a hotspot of climate extremes on the White Continent. It is the region of the Southern Hemisphere that has experienced the greatest warming (Carrasco et al., 2021). The all- time Antarctic temperature record was set there in March 2015 and has been followed by several additional temperature records in subsequent years (Bozkurt et al., 2018). Extreme temperatures have led to events of record-breaking surface melting (i.e., Gorodetskaya et al., 2022) similar to those that 3. Objectives presumably contributed to the collapse of the Larsen A ice shelf in January 1995 and Larsen B in February– March 2002 (Trusel et al., 2015). The record-low sea ice extent observed in recent years in Antarctica has List specific scientific and coordination objectives, following SMART principles. been linked to severe anomalies in the Bellingshausen Sea, along the west side of the Peninsula (Cordero et al., 2023), and climate models suggest that the most vulnerable ice shelves in Antarctica are indeed located on the Peninsula (Feron et al., 2021).
Most of the recent extremes on the Antarctic Peninsula have been associated with meridional warm-air Target species/systems or variables advection events, likely linked to broader changes in atmospheric circulation reflected in variations of the – Sampling methods and technologies Southern Annular Mode (SAM). The SAM measures the mid- to high-latitude atmospheric pressure gradient and indicates the strength and position of the westerly winds encircling Antarctica (Fogt & Marshall, 2020). Stronger summer westerly winds, associated with a positive SAM trend (Fogt & Marshall, 2020), may have increased the frequency of meridional warm-air advection events (Wille et al., 2021), such as those driving recent compound temperature-surface melting extremes (e.g., Gorodetskaya et al., 2022).
King George Island, located in the Southern Ocean near the northern tip of the Peninsula, offers an ideal setting to study meridional warm-air advection events and the transient northwesterly flow that drives climate variability across the region. Since 2016, our team has operated an atmospheric monitoring station attached to the Chilean Antarctic Institute’s (INACH) Escudero Base on King George Island. The fully equipped station has supported Chilean Antarctic research over the last decade and has also been instrumental in detecting recent extremes, including intercontinental aerosol transport from fires in Patagonia and Australia (i.e., Pulimeno et al., 2025) , record surface UV radiation linked to anomalies in stratospheric circulation (Cordero et al., 2022a), and the first-ever winter rain shower recorded on King George Island in July 2023 (Bozkurt et al., 2024). Ensuring the continuity of atmospheric observations on King George Island is essential to better understand climate extremes on the White Continent.
This working group aims to conduct ground-based atmospheric observations on King George Island to generate a unique multi-year dataset for climate and atmospheric research in one of the fastest-warming regions of the Southern Hemisphere. This dataset will enable progress in understanding:
While this multi-year observational effort may not be sufficient to fully resolve the influence of large-scale climate modes (MJO, ENSO, SAM) on the frequency of meridional warm-air advection events, it constitutes a critical step forward.
These objectives comply with the SMART principles:
Specific: we define what will be studied (warm-air advection events, westerly winds, SAM, MJO, ENSO) and where (King George Island and the northern Antarctic Peninsula). We also specify how this will be achieved: through continuous ground-based atmospheric observations.
Measurable: we will generate a multi-year observational dataset of key atmospheric indicators (see details below).
Achievable: Our plan relies on well stablished atmospheric monitoring techniques (see details below). Moreover, our objectives focus on improving understanding, not fully resolving all variability.
Relevant: We address key scientific questions in polar climatology and climate-teleconnection research related to understanding warm-air advection drivers, tropical–polar linkages, and large-scale circulation variability.
Time-bound: Our objectives are explicitly framed around a multi-year observational effort, defining a temporal scope within which progress will be made. Although long-term climate modes require decades of data for full characterization, our multi-year observations will provide a crucial step forward.
Aimed at summer warm-air advection events, our working group plans to conduct continuous observations during the 2026–2030 period, using existing instrumentation available at the Chilean Antarctic Institute’s (INACH) Escudero Base on King George Island (Fig. 1).
These observations include longwave and shortwave broadband radiometers, shortwave spectrometers, multi-channel photometers, an all-sky camera, a micropulse lidar (MPL), and retrievals of aerosol optical depth (AOD), atmospheric inversion products, and precipitable water (PW) derived from multi-channel sun photometers (Table 1).
All measurements follow established quality-assurance standards and include regular calibrations against traceable reference sources. The station already contributes quality-controlled data to several open- access international networks, including:
Moreover, spectral measurements of surface irradiance are conducted following the specifications of the Network for the Detection of Atmospheric Composition Change (NDACC), while longwave and shortwave broadband radiometer measurements are performed at a 1-minute temporal resolution. In line with our commitment to open science, all measurements generated within the framework of this working group will be released under open licenses, allowing free use, sharing, and adaptation.
In addition to support our research agenda, these observations also enable the linkage of cloud properties, atmospheric aerosol concentrations, and moisture content with surface broadband radiation components, and thus they can support the validation of satellite products and model outputs.
| Instrument | Measurements |
|---|---|
| BIOSPHERICAL Multifilter radiometers | Direct, diffuse, and global irradiances at 12 wavelengths |
| BENTHAM Spectroradiometer | Downwelling spectral shortwave irradiance 280- 2500 nm |
| CIMEL Sun sunphotometer | Aerosol Optical depth and water vapor column |
| SIGMASPACE MPL (LIDAR system) | Cloud altitude, optical thickness, and signal depolarization as well as cloud phase. |
| Balloon-borne sounding system | Vertical profiles of T, P, RH, wind speed and direction |
| Automatic Weather Meteo Station | 2-m T, P, RH, wind speed and direction |
| Pyranometer (downward-looking and upward looking) | Downwelling and upwelling shortwave irradiance |
| Pyrgeometers (downward-looking and upward looking) | Downwelling and upwelling longwave irradiance |
| Cloud sky Camera | Cloud fraction |
| PREDE Sun photometer | Aerosol, Optical depth and spectral direct solar irradiances |
| UV Radiometer | Erythemal effective irradiance |
Links with existing initiatives
SCAR: Our working group directly will support SCAR priorities on long-term Antarctic observations of the Antarctic climate system by providing quality-controlled open-access atmospheric datasets.
Antarctic Treaty System (ATS) & ATCM: Our working group will provide environmental indicators relevant to the Environmental Protocol of the Antarctic Treaty, particularly in relation to air quality, and impacts of aerosols deposition.
WMO Global Atmosphere Watch (GAW): Our observations will adhere to WMO-recommended standards, and will contribute to global climate monitoring efforts.
CCAMLR (Commission for the Conservation of Antarctic Marine Living Resources): By characterizing atmospheric drivers of surface radiation, aerosol deposition, and extreme warming events, our working group will provide physical context for CCAMLR’s ecosystem-based management in the Southern Ocean.
Datasets
We will produce the following datasets:
These datasets may not only be useful for advancing our research agenda, but also for validating satellite products and providing constraints for climate models.
Capacity-Building Activities
Up to four students or early-career researchers (ECRs) will participate each summer in conducting observation (i.e., instrument operation) on King George Island. These students and ECRs will receive training in instrument operation and quality control of the measurements. We expect that their participation in fieldwork will contribute to training the next generation of polar researchers.
Publications
Based on existing instruments, we anticipate the following publications during the first year of the project:
At the end of this multi-year observational effort, we expect to be able to generate two high-impact publications directly related to the objectives of this working group:
Additional publications in subsequent years will be developed through cross–working group collaboration.
Inputs to Policy Bodies
We expect that our measurements of aerosol deposition (including black carbon) will be instrumental in informing the development of the regulatory framework for the rapidly expanding Antarctic tourism industry, adopted during the 2024 Antarctic Treaty Consultative Meetings (ATCM). The northern Antarctic Peninsula hosts a high concentration of research stations and experiences the most intense marine tourism activity in Antarctica. Thus, our aerosol measurements, including black carbon, will provide critical insights into the impacts of energy-intensive local activities on the Antarctic environment.
| Timeframe | Task |
|---|---|
| Austral Summer 2026–2027 | Focus: Observational continuity, and early analyses. Milestones
|
| Austral Summer 2027–2028 | Focus: Cross-scale analysis Milestones
|
| Austral Summer 2028–2029 | Focus: Multi-year synthesis Milestones
|
| Austral Summer 2029–2030 | Focus: Long-term impact, policy relevance, capacity building Milestones
|
| Cross-cutting activities (all summers) |
|
Since our datasets will be open access, it will be available to the entire InSync community. We foresee considerable interest, as our measurements can be useful for researchers in several working groups.
WG1 (Southern Ocean): The Southern Ocean is the region on Earth where climate models exhibit the largest biases, largely due to the poor characterization of clouds. This underscores the importance of our observations, which will improve the characterization of clouds over the Southern Ocean and may help improve the parameterization of climate models in this region.
WG2 (Sea ice): Despite the well-established influence of the circumpolar westerly winds on year-to-year changes in sea-ice cover (Cordero et al., 2023), the influence of atmospheric dynamics on variability in Antarctic sea-ice cover remains understudied. Our observations will improve understanding of Southern Ocean climate dynamics and the mechanisms driving interannual variability in sea-ice extent.
WG3 (Melting ice sheets and ice shelves): The trend toward more positive SAM values, driven by the poleward migration and intensification of the westerlies, has brought Circumpolar Deep Water (CDW) closer to the continent, promoting basal melting in some regions (e.g., Verfaillie et al., 2022). We expect that our observations will improve our understanding of SAM dynamics and thus may also help clarify some of the mechanisms driving basal melt.
WG4 (protection of unique Antarctic life): Among the threats to Antarctic ecosystems are episodic extreme UV events associated with instabilities in polar vortex dynamics, which can transport ozone- depleted air masses toward the Antarctic Peninsula in late summer, when biologically effective UV radiation is most consequential (Cordero et al., 2022a). Our UV observations will improve understanding of polar vortex dynamics and the resulting persistent UV extremes affecting the Antarctic biosphere.
WG5 (Anthropogenic signatures in Antarctica): Although its overall impact remains small compared to other surface mass balance (SMB) drivers, aerosol deposition (including black carbon) can influence SMB in Antarctica by reducing snow albedo and enhancing surface melt, particularly in regions near research stations or tourist hotspots (Cordero et al., 2022b; 2025). This underscores the importance of our aerosol observations, which will improve understanding of the direct effects of aerosol deposition on snow albedo and surface melt, reveal intercontinental transport processes, and provide constraints for environmental management under the Antarctic Treaty.
WG6 (Aerosol–cloud interactions): Clouds remain substantially understudied in Antarctica and the Southern Ocean, despite their crucial influence on the surface energy balance. On the Antarctic Peninsula, they exert a dual effect by warming the surface through longwave radiation trapping while cooling it by reflecting incoming shortwave radiation. These competing effects are a major source of bias in climate models. This further underscores the importance of our cloud observations, which will improve understanding of Southern Ocean climate dynamics and may help improve climate model parameterization in this region.
Moreover, it is worth noting that our working group includes researchers from four national polar research programs: Chile, the Netherlands, the United States, and Belgium.
