Formation and fate of freshwater on an ice floe in the Central Arctic

˜The œcryosphere, Journal Year: 2025, Volume and Issue: 19(2), P. 619 - 644

Published: Feb. 7, 2025

Abstract. The melt of snow and sea ice during the Arctic summer is a significant source relatively fresh meltwater. fate this freshwater, whether in surface ponds or thin layers underneath leads, impacts atmosphere–ice–ocean interactions their subsequent coupled evolution. Here, we combine analyses datasets from Multidisciplinary drifting Observatory for Study Climate (MOSAiC) expedition (June–July 2020) process study on formation freshwater floes Central Arctic. Our budget suggest that high fraction (58 %) derived melt. Additionally, contribution stored precipitation (snowmelt) outweighs by 5 times input situ (rain). magnitude rate local meltwater production are remarkably similar to those observed prior Surface Heat Budget Ocean (SHEBA) campaign, where cumulative totaled around 1 m both. A small (10 remains ponds, which higher more deformed second-year (SYI) compared first-year (FYI) later summer. Most drains laterally vertically, with vertical drainage enabling storage internally freshening brine channels. In upper ocean, can accumulate transient order 0.1 thick leads under ice. presence such substantially system reducing bottom allowing false growth; heat, nutrient, gas exchange; influencing ecosystem productivity. Regardless, majority inferred be ultimately incorporated into ocean (75 (14 %). Terms as annual could used future work diagnostics global climate models. For example, range values CESM2 model roughly encapsulate total production, while underestimated about 50 %, suggesting pond terms key investigation.

Language: Английский

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Surface Energy Balance Responses to Radiative Forcing in the Central Arctic From MOSAiC and Models

Journal of Geophysical Research Atmospheres, Journal Year: 2025, Volume and Issue: 130(6)

Published: March 10, 2025

Abstract The Arctic surface energy budget (SEB) couples the atmosphere with sea ice, making it useful for both studying processes as well evaluating models. Improved understanding of atmosphere‐ice interactions is required to improve models, requiring year‐round observations address seasonally dependent biases. This work uses novel from MOSAiC expedition quantify responses fluxes radiative forcing over ice throughout a complete annual cycle. We identify two primary regimes flux response: an growth regime in winter and melt summer. In regime, changes impact upwelling longwave, sensible heat, subsurface heat fluxes, whereas primarily alter amount transmission because temperature fixed. These observed are used evaluate seven weather forecast models during regime. most do not match observations. Many also have biased downwelling longwave. One model (the Coupled Forecast System; CAFS) adequately captures mean winter. CAFS further evaluated against spanning full year, demonstrating sufficient agreement provide more generalized these SEB process relationships across Arctic.

Language: Английский

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Overview of the MOSAiC expedition: Ecosystem

Elementa Science of the Anthropocene, Journal Year: 2024, Volume and Issue: 12(1)

Published: Jan. 1, 2024

The international and interdisciplinary sea-ice drift expedition “The Multidisciplinary drifting Observatory for the Study of Arctic Climate” (MOSAiC) was conducted from October 2019 to September 2020. aim MOSAiC study interconnected physical, chemical, biological characteristics processes atmosphere deep sea central system. ecosystem team addressed current knowledge gaps explored unknown properties over a complete seasonal cycle focusing on three major research areas: biodiversity, biogeochemical cycles, linkages environment. In addition measurements core along cycle, dedicated projects covered specific habitats, or organisms higher taxonomic temporal resolution in time windows. A wide range sampling instruments approaches, including coring, lead with pumps, rosette-based water sampling, plankton nets, remotely operated vehicles, acoustic buoys, applied address science objectives. Further, broad process-related address, example, productivity patterns, migrations, diversity shifts, were made both situ onboard RV Polarstern. This article provides detailed overview approaches used main It highlights program examples habitat- process-specific sampling. initial results presented include high activities wintertime discovery hotspots underexplored habitats. unique interconnectivity coordinated efforts also revealed insights into cross-disciplinary interactions like impact biota cloud formation. further presents lessons learned conducting such demanding field campaign an outlook spin-off be next years.

Language: Английский

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Final combined version

Published: Jan. 4, 2025

Abstract. Satellite retrievals of Arctic sea ice thickness typically assume fixed values bulk density (IBD), overlooking its seasonal evolution and spatial heterogeneity, which are influenced by factors such as the age, deformation, brine, air inclusions ice. This study investigates variability IBD during freezing season from October to April, across Distributed Network (DN) scale Multidisciplinary drifting Observatory for Study Climate (MOSAiC) expedition. To estimate IBD, we combined snow observations mass balance buoys, pits, repeated transects, cores, together with high-resolution along-track freeboard data obtained airborne laser scanning (ALS) Ice, Cloud, land Elevation Satellite-2 (ICESat-2). Assuming hydrostatic equilibrium, IBDs were determined level components MOSAiC floes, consisted predominantly second-year (SYI). Our results revealed significant two main phases at scales DN (~ 50 km), L-sites 25 Main Coring Site (MCS, ~ m). Throughout season, mean estimated (910 ± 7 kg m⁻³) was close that SYI cores MCS (912 2 m⁻³), highlighting SYI-dominated regional properties. We also identified freeboard, along ratios total or thickness, critical indicators determine tens kilometers. have therefore developed parameterizations expected be applicable throughout region, is type currently dominates central Ocean. The proposed potential optimize basin-scale estimation improve satellite-derived thickness.

Language: Английский

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Dynamic ice–ocean pathways along the Transpolar Drift amplify the dispersal of Siberian matter

Nature Communications, Journal Year: 2025, Volume and Issue: 16(1)

Published: April 14, 2025

Abstract The Transpolar Drift (TPD) plays a crucial role in regulating Arctic climate and ecosystems by transporting fresh water key substances, such as terrestrial nutrients pollutants, from the Siberian Shelf across Ocean to North Atlantic. However, year-round observations of TPD remain scarce, creating significant knowledge gaps regarding influence sea ice drift ocean surface circulation on transport pathways associated matter. Using geochemical provenance tracer data collected over complete seasonal cycle, our study reveals substantial spatiotemporal variability dispersal matter along TPD. This reflects dynamic shifts contributions individual rivers they integrate into large-scale current system, followed their rapid extensive redistribution through combination ice–ocean exchanges divergent drift. These findings emphasize complexity highlight challenges forecasting dynamics light anticipated changes extent, river discharge, patterns.

Language: Английский

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Overview of the studies on the interactions between atmosphere, sea ice, and ocean in the Arctic Ocean and its climatic effects: contributions from Chinese scientists

Acta Oceanologica Sinica, Journal Year: 2025, Volume and Issue: unknown

Published: May 24, 2025

Language: Английский

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Under-ice environment observations from a remotely operated vehicle during the MOSAiC expedition

Scientific Data, Journal Year: 2025, Volume and Issue: 12(1)

Published: June 5, 2025

Language: Английский

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Dynamical reconstruction of the upper-ocean state in the central Arctic during the winter period of the MOSAiC expedition

Ocean science, Journal Year: 2024, Volume and Issue: 20(3), P. 759 - 777

Published: June 11, 2024

Abstract. This paper presents a methodological tool for dynamic reconstruction of the state ocean, based, as an example, on observations from Multidisciplinary drifting Observatory Study Arctic Climate (MOSAiC) experiment. The data used in this study were collected Amundsen Basin between October 2019 and January 2020. Analysing observational to assess tracer field upper-ocean dynamics is highly challenging when measurement platforms drift with ice pack due continuous speed direction changes. We have equipped new version coastal branch global Finite-volumE sea ice–Ocean Model (FESOM-C) nudging method. was carried out assuming quasi-steady state. Overall, model can reproduce lateral vertical structure temperature, salinity, density fields, which allows projecting dynamically consistent features these fields onto regular grid. identify two separate depth ranges enhanced eddy kinetic energy located around maxima buoyancy frequency: upper halocline warm (modified) Atlantic Water. Simulations reveal notable decrease surface layer salinity towards north but no significant gradient east west. However, we find mixed-layer deepening west, 0.084 m km−1 at 0.6 standard deviation, compared weak south north. resolves several stationary eddies Water provides insights into associated dynamics. output be further analyse thermohaline related mesoscale submesoscale processes central Arctic, such estimates heat fluxes or mass transport. developed method utilized incorporate diverse set instruments analysis MOSAiC expedition.

Language: Английский

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In-ice light measurements during the MOSAiC expedition

Scientific Data, Journal Year: 2024, Volume and Issue: 11(1)

Published: June 27, 2024

Abstracts We present light measurements in Arctic sea ice obtained during the year-long MOSAiC drift through central Ocean 2019–2020. Such are important as plays a fundamental role climate and ecosystem. The partitioning of solar irradiance determines availability radiation energy for thermodynamic processes primary productivity. However, observations along vertical path rare. data we were collected by two measurement systems, lightharp lightchain, both measuring autonomously multi-spectral intensity different depths within ice. dataset, retrieval methods derived optical properties, conversion into final, freely available product, following standardized conventions. particularly focus on specifications newly developed system. Combined with interdisciplinary multi-instrument setup MOSAiC, expect great potential dataset to foster our understanding transmission reflection sea-ice cover interactions physical properties polar

Language: Английский

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Air‐Ice‐Ocean Coupling During a Strong Mid‐Winter Cyclone: Observing Coupled Dynamic Interactions Across Scales

Journal of Geophysical Research Atmospheres, Journal Year: 2024, Volume and Issue: 129(17)

Published: Sept. 2, 2024

Abstract Arctic cyclones are key drivers of sea ice and ocean variability. During the 2019–2020 Multidisciplinary drifting Observatory for Study Climate (MOSAiC) expedition, joint observations coupled air‐ice‐ocean system were collected at multiple spatial scales. Here, we present a strong mid‐winter cyclone that impacted MOSAiC site as it drifted in central pack ice. The dynamical response showed structure scale evolving translating cyclonic wind field. Internal stress play significant roles, resulting timing offsets between atmospheric forcing post‐cyclone inertial ringing ocean. Ice motion to field then forces upper currents through frictional drag. strongest impacts from passing occur result surface low‐level jet (LLJ) behind trailing cold front changing directions warm‐sector LLJ post cold‐frontal LLJ. Impacts prolonged ice‐ocean response. Local approximately 120 km wide over 12 hr period or less scales kilometer few tens kilometers, meaning these combined smaller faster time than most satellite Earth models can resolve.

Language: Английский

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