Sang-Jong Park

Intense warming events (IWE) and intense precipitation events (IPE) and their impacts on ice bodies remain overlooked. Using in situ observations, a high-resolution regional circulation model and catalogue of atmospheric river (AR) occurrences, we investigate concurrent IWE over the Patagonian Icefields and IPE over the Antarctic Peninsula Ice Sheet associated with landfalling ARs. Our study focuses on summers (November–March) from 1980 to 2022. We identified 127 compound events linked to a dipole circulation pattern characterized by a ridge over southern South America and a low-pressure system over the Bellingshausen Sea. Both regions experience pronounced surface warming and enhanced melt leading to a negative Surface Mass Balance over the Patagonian Icefields, while positive anomalies still prevailed over the Antarctic Peninsula Ice Sheet were related with increased snowfall associated with AR activity. Surface Energy Balance anomalies were mainly driven by enhanced incoming shortwave radiation over Patagonia but increased longwave radiation over the Antarctic Peninsula, whereas sensible heat flux positively contributed in both regions. These findings highlight the interconnected influence of intense events and AR-driven dipole circulation patterns on the Southern Hemisphere cryosphere, even though individual events exhibit substantial thermodynamic variability and distinct life-cycle characteristics.

Ice-nucleating particles (INPs) influence mixed-phase cloud microphysics and the Earth’s radiative budget, yet observational records over the remote Arctic Ocean and contrasting continental-outflow environments remain sparse. This study presents INP concentrations measured by the Portable Ice Nucleation Experiment (PINE) over the Arctic Ocean during two RV(Research Vessel) Araon campaigns (ARA15A in 2024 and ARA16A in 2025) and at the Korea-Cloud Physics Experiment Chamber (K-CPEC) on Jeju Island, Korea (February–May 2024), totalling 41,524 expansion runs of which 35,370 passed rigorous quality control. INP temperature spectra differed markedly among the three datasets. At a representative warm temperature (−20 °C), median concentrations were 3.68 L⁻¹ (ARA15A), 3.64 L⁻¹ (ARA16A), and 0.89 L⁻¹ at Jeju (Clean-day subset), with Arctic values exceeding Jeju; at a representative cold temperature (−28 °C), the pattern reversed — the Jeju Clean-day median rose to 8.22 L⁻¹ while Arctic medians remained comparatively flat (ARA15A: 7.02 L⁻¹; ARA16A: 6.39 L⁻¹). Campaign-wide medians were comparable between the two Arctic years (6.83 and 6.57 L⁻¹) but differed approximately two-fold in the 75–80° N latitude band (ARA15A: 1.56 and ARA16A: 3.19 L⁻¹). These spectral contrasts are consistent with a marine biogenic-influenced regime at the Arctic warm-temperature end and an Asian-dust-influenced regime at the Jeju cold-temperature end, although direct compositional confirmation (heat treatment, chemical speciation) was not available in this dataset; all source attributions should therefore be interpreted as spectrally-consistent hypotheses rather than established source identifications. A dedicated ship-exhaust quality control scheme applied to both campaigns provides a replicable contamination-removal framework for future shipborne INP studies, and the combined dataset delivers new observational benchmarks for Arctic INP variability across the sampled 2024–2025 cruise periods.

Ice-nucleating particles (INPs) influence mixed-phase cloud microphysics and the Earth’s radiative budget, yet observational records over the remote Arctic Ocean and contrasting continental-outflow environments remain sparse. This study presents INP concentrations measured by the Portable Ice Nucleation Experiment (PINE) over the Arctic Ocean during two RV(Research Vessel) Araon campaigns (ARA15A in 2024 and ARA16A in 2025) and at the Korea-Cloud Physics Experiment Chamber (K-CPEC) on Jeju Island, Korea (February–May 2024), totalling 41,524 expansion runs of which 35,370 passed rigorous quality control. INP temperature spectra differed markedly among the three datasets. At a representative warm temperature (−20 °C), median concentrations were 3.68 L⁻¹ (ARA15A), 3.64 L⁻¹ (ARA16A), and 0.89 L⁻¹ at Jeju (Clean-day subset), with Arctic values exceeding Jeju; at a representative cold temperature (−28 °C), the pattern reversed — the Jeju Clean-day median rose to 8.22 L⁻¹ while Arctic medians remained comparatively flat (ARA15A: 7.02 L⁻¹; ARA16A: 6.39 L⁻¹). Campaign-wide medians were comparable between the two Arctic years (6.83 and 6.57 L⁻¹) but differed approximately two-fold in the 75–80° N latitude band (ARA15A: 1.56 and ARA16A: 3.19 L⁻¹). These spectral contrasts are consistent with a marine biogenic-influenced regime at the Arctic warm-temperature end and an Asian-dust-influenced regime at the Jeju cold-temperature end, although direct compositional confirmation (heat treatment, chemical speciation) was not available in this dataset; all source attributions should therefore be interpreted as spectrally-consistent hypotheses rather than established source identifications. A dedicated ship-exhaust quality control scheme applied to both campaigns provides a replicable contamination-removal framework for future shipborne INP studies, and the combined dataset delivers new observational benchmarks for Arctic INP variability across the sampled 2024–2025 cruise periods.

Ice-nucleating particles (INPs) influence mixed-phase cloud microphysics and the Earth’s radiative budget, yet observational records over the remote Arctic Ocean and contrasting continental-outflow environments remain sparse. This study presents INP concentrations measured by the Portable Ice Nucleation Experiment (PINE) over the Arctic Ocean during two RV(Research Vessel) Araon campaigns (ARA15A in 2024 and ARA16A in 2025) and at the Korea-Cloud Physics Experiment Chamber (K-CPEC) on Jeju Island, Korea (February–May 2024), totalling 41,524 expansion runs of which 35,370 passed rigorous quality control. INP temperature spectra differed markedly among the three datasets. At a representative warm temperature (−20 °C), median concentrations were 3.68 L⁻¹ (ARA15A), 3.64 L⁻¹ (ARA16A), and 0.89 L⁻¹ at Jeju (Clean-day subset), with Arctic values exceeding Jeju; at a representative cold temperature (−28 °C), the pattern reversed — the Jeju Clean-day median rose to 8.22 L⁻¹ while Arctic medians remained comparatively flat (ARA15A: 7.02 L⁻¹; ARA16A: 6.39 L⁻¹). Campaign-wide medians were comparable between the two Arctic years (6.83 and 6.57 L⁻¹) but differed approximately two-fold in the 75–80° N latitude band (ARA15A: 1.56 and ARA16A: 3.19 L⁻¹). These spectral contrasts are consistent with a marine biogenic-influenced regime at the Arctic warm-temperature end and an Asian-dust-influenced regime at the Jeju cold-temperature end, although direct compositional confirmation (heat treatment, chemical speciation) was not available in this dataset; all source attributions should therefore be interpreted as spectrally-consistent hypotheses rather than established source identifications. A dedicated ship-exhaust quality control scheme applied to both campaigns provides a replicable contamination-removal framework for future shipborne INP studies, and the combined dataset delivers new observational benchmarks for Arctic INP variability across the sampled 2024–2025 cruise periods.

Intense warming events (IWE) and intense precipitation events (IPE) and their impacts on ice bodies remain overlooked. Using in situ observations, a high-resolution regional circulation model and catalogue of atmospheric river (AR) occurrences, we investigate concurrent IWE over the Patagonian Icefields and IPE over the Antarctic Peninsula Ice Sheet associated with landfalling ARs. Our study focuses on summers (November–March) from 1980 to 2022. We identified 127 compound events linked to a dipole circulation pattern characterized by a ridge over southern South America and a low-pressure system over the Bellingshausen Sea. Both regions experience pronounced surface warming and enhanced melt leading to a negative Surface Mass Balance over the Patagonian Icefields, while positive anomalies still prevailed over the Antarctic Peninsula Ice Sheet were related with increased snowfall associated with AR activity. Surface Energy Balance anomalies were mainly driven by enhanced incoming shortwave radiation over Patagonia but increased longwave radiation over the Antarctic Peninsula, whereas sensible heat flux positively contributed in both regions. These findings highlight the interconnected influence of intense events and AR-driven dipole circulation patterns on the Southern Hemisphere cryosphere, even though individual events exhibit substantial thermodynamic variability and distinct life-cycle characteristics.

Ice-nucleating particles (INPs) influence mixed-phase cloud microphysics and the Earth’s radiative budget, yet observational records over the remote Arctic Ocean and contrasting continental-outflow environments remain sparse. This study presents INP concentrations measured by the Portable Ice Nucleation Experiment (PINE) over the Arctic Ocean during two RV(Research Vessel) Araon campaigns (ARA15A in 2024 and ARA16A in 2025) and at the Korea-Cloud Physics Experiment Chamber (K-CPEC) on Jeju Island, Korea (February–May 2024), totalling 41,524 expansion runs of which 35,370 passed rigorous quality control. INP temperature spectra differed markedly among the three datasets. At a representative warm temperature (−20 °C), median concentrations were 3.68 L⁻¹ (ARA15A), 3.64 L⁻¹ (ARA16A), and 0.89 L⁻¹ at Jeju (Clean-day subset), with Arctic values exceeding Jeju; at a representative cold temperature (−28 °C), the pattern reversed — the Jeju Clean-day median rose to 8.22 L⁻¹ while Arctic medians remained comparatively flat (ARA15A: 7.02 L⁻¹; ARA16A: 6.39 L⁻¹). Campaign-wide medians were comparable between the two Arctic years (6.83 and 6.57 L⁻¹) but differed approximately two-fold in the 75–80° N latitude band (ARA15A: 1.56 and ARA16A: 3.19 L⁻¹). These spectral contrasts are consistent with a marine biogenic-influenced regime at the Arctic warm-temperature end and an Asian-dust-influenced regime at the Jeju cold-temperature end, although direct compositional confirmation (heat treatment, chemical speciation) was not available in this dataset; all source attributions should therefore be interpreted as spectrally-consistent hypotheses rather than established source identifications. A dedicated ship-exhaust quality control scheme applied to both campaigns provides a replicable contamination-removal framework for future shipborne INP studies, and the combined dataset delivers new observational benchmarks for Arctic INP variability across the sampled 2024–2025 cruise periods.

Measurements of surface-atmosphere carbon dioxide (CO ₂ ) and methane (CH ₄ ) fluxes have been relatively sparse across the Arctic tundra and boreal biomes, causing significant uncertainties in carbon budget estimates from the region. While the availability of Arctic-boreal carbon flux data has increased substantially over the past decade, the data have remained spread across different repositories, scientific articles, and unpublished sources, making it difficult to leverage. Here we present a new dataset of monthly Arctic-boreal carbon fluxes (ABCFlux v2) across terrestrial (wetlands and uplands) and freshwater (lakes and rivers) ecosystems compiled from previous syntheses including the Arctic-boreal CO ₂ flux database (ABCFlux v1), the Boreal-Arctic Wetland and Lake Methane Dataset (BAWLD-CH4), and the Global River Methane Database (GRiMeDB). In addition, we consider data from general-purpose (e.g., Zenodo) and flux network repositories, literature, and site principal investigators. The dataset includes surface-atmosphere CO ₂ fluxes of gross primary production (GPP), ecosystem respiration (Reco), and net ecosystem exchange (NEE), alongside CH ₄ fluxes. For aquatic ecosystems, we split CH ₄ fluxes into diffusive and ebullitive flux pathways, and included potential emissions from transient storage in the water column (“storage fluxes”), alongside CO ₂ and CH ₄ concentrations dissolved in the surface water. Fluxes are measured through a variety of methods including chamber and eddy covariance techniques alongside bubble traps, ice-surveys, and concentration-based turbulence-driven modelling in aquatic ecosystems. The monthly flux data are reported together with supporting methodological and environmental metadata. The resulting ABCFlux v2 has 23 847 flux site-months, 8182 concentration site-months, and 199 seasonal observations from 1024 sites, and includes 56 139 reported fluxes (i.e. sum of GPP, Reco, NEE, and CH ₄ fluxes) from the years 1984 to 2024. The majority of monthly observations occurred after 1999. Wetlands had the highest number of site-month observations (8758), followed by boreal forest (6981), lotic ecosystems (6275), lentic ecosystems (3799) and upland tundra (3308). Measurements of CO ₂ dominated the dataset across most ecosystem types (25 222) except for lentic ecosystems, where CH ₄ flux site-months (3098) were more frequent than CO ₂ flux site-months (2915). Overall, ABCFlux v2 includes 160 % more site-months for terrestrial CO ₂ flux data compared to ABCFlux v1. Integrating and updating BAWLD-CH4 flux data from growing season averages to monthly fluxes resulted in 5671 site-months of chamber CH ₄ data compared to 762 site-years. This collaborative initiative, involving contributions from over 260 researchers, provides a comprehensive overview of the current state of the Arctic-boreal carbon flux network and its data, and serves as an important step in reducing uncertainties in Arctic-boreal carbon budgets and in enhancing our understanding of climate feedbacks. The data can be accessed at ORNL DAAC at https://doi.org/10.3334/ORNLDAAC/2448 (Virkkala et al., 2026).

Intense warming events (IWE) and intense precipitation events (IPE) and their impacts on ice bodies remain overlooked. Using in situ observations, a high-resolution regional circulation model and catalogue of atmospheric river (AR) occurrences, we investigate concurrent IWE over the Patagonian Icefields and IPE over the Antarctic Peninsula Ice Sheet associated with landfalling ARs. Our study focuses on summers (November–March) from 1980 to 2022. We identified 127 compound events linked to a dipole circulation pattern characterized by a ridge over southern South America and a low-pressure system over the Bellingshausen Sea. Both regions experience pronounced surface warming and enhanced melt leading to a negative Surface Mass Balance over the Patagonian Icefields, while positive anomalies still prevailed over the Antarctic Peninsula Ice Sheet were related with increased snowfall associated with AR activity. Surface Energy Balance anomalies were mainly driven by enhanced incoming shortwave radiation over Patagonia but increased longwave radiation over the Antarctic Peninsula, whereas sensible heat flux positively contributed in both regions. These findings highlight the interconnected influence of intense events and AR-driven dipole circulation patterns on the Southern Hemisphere cryosphere, even though individual events exhibit substantial thermodynamic variability and distinct life-cycle characteristics.

Ice-nucleating particles (INPs) influence mixed-phase cloud microphysics and the Earth’s radiative budget, yet observational records over the remote Arctic Ocean and contrasting continental-outflow environments remain sparse. This study presents INP concentrations measured by the Portable Ice Nucleation Experiment (PINE) over the Arctic Ocean during two RV(Research Vessel) Araon campaigns (ARA15A in 2024 and ARA16A in 2025) and at the Korea-Cloud Physics Experiment Chamber (K-CPEC) on Jeju Island, Korea (February–May 2024), totalling 41,524 expansion runs of which 35,370 passed rigorous quality control. INP temperature spectra differed markedly among the three datasets. At a representative warm temperature (−20 °C), median concentrations were 3.68 L⁻¹ (ARA15A), 3.64 L⁻¹ (ARA16A), and 0.89 L⁻¹ at Jeju (Clean-day subset), with Arctic values exceeding Jeju; at a representative cold temperature (−28 °C), the pattern reversed — the Jeju Clean-day median rose to 8.22 L⁻¹ while Arctic medians remained comparatively flat (ARA15A: 7.02 L⁻¹; ARA16A: 6.39 L⁻¹). Campaign-wide medians were comparable between the two Arctic years (6.83 and 6.57 L⁻¹) but differed approximately two-fold in the 75–80° N latitude band (ARA15A: 1.56 and ARA16A: 3.19 L⁻¹). These spectral contrasts are consistent with a marine biogenic-influenced regime at the Arctic warm-temperature end and an Asian-dust-influenced regime at the Jeju cold-temperature end, although direct compositional confirmation (heat treatment, chemical speciation) was not available in this dataset; all source attributions should therefore be interpreted as spectrally-consistent hypotheses rather than established source identifications. A dedicated ship-exhaust quality control scheme applied to both campaigns provides a replicable contamination-removal framework for future shipborne INP studies, and the combined dataset delivers new observational benchmarks for Arctic INP variability across the sampled 2024–2025 cruise periods.