Intensification and shutdown of deep convection in the Labrador Sea were caused by changes in atmospheric and freshwater dynamics

Communications Earth & Environment, Journal Year: 2024, Volume and Issue: 5(1)

Published: March 27, 2024

Abstract Labrador Sea winter convection forms a cold, fresh and dense water mass, Water, that sinks to the intermediate deep layers spreads across ocean. Convective mixing undergoes multi-year cycles of intensification (deepening) relaxation (shoaling), which have been also shown modulate long-term changes in atmospheric gas uptake by sea. Here I analyze Argo float ship-based observations document 2012-2023 convective cycle. find highest cooling for 1994-2023 period was 2015, while deepest 1996-2023 2018. continued deepen after 2015 because 2012-2015 events preconditioned column be susceptible three more years. The progressively intensified 2012-2018 convections generated largest densest class Water since 1995. Convection weakened afterwards, rapidly shoaling 800 m per year winters 2021 2023. Distinct processes were responsible these two shutdowns. In 2021, collapse an eastward shift stratospheric polar vortex, weakening southwestward Icelandic Low resulted extremely low surface depth. 2023, contrast, shutdown caused extensive upper layer freshening originated from extreme Arctic sea-ice melt due Amplification Global Warming.

Language: Английский

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Subsurface warming associated with Pacific Summer Water transport toward the Chukchi Borderland in the Arctic Ocean

Scientific Reports, Journal Year: 2025, Volume and Issue: 15(1)

Published: Jan. 10, 2025

Recent rapid sea ice reduction in the Pacific sector of Arctic Ocean is potentially associated with inflow Pacific-origin water via Bering Strait. For first time, we detected remarkable subsurface warming around Chukchi Borderland over recent two decades (i.e., early 21st century). A statistically significant decadal trend 16.6 ± 10.6 MJ m− 2 year− 1 ocean heat content during 1999–2020 was captured by shipboard hydrographic data, and transport Summer Water from Barrow Canyon northwest Alaskan coast, where similar appeared. Satellite-derived geostrophic velocity indicated that northwestward current flowing to became faster late 2010s, association southeastward shift Beaufort Gyre, circulating clockwise Canada Basin. Therefore, suggest passing shelf intensification along shelf–basin boundary both acted enhance contributed positive downstream content. Our findings fill important gaps understanding distribution/transport, which a key factor for freezing/melting, central Arctic.

Language: Английский

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Monitoring the Multiple Stages of Climate Tipping Systems from Space: Do the GCOS Essential Climate Variables Meet the Needs?

Surveys in Geophysics, Journal Year: 2025, Volume and Issue: unknown

Published: Feb. 18, 2025

Language: Английский

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Circulation Timescales and Pathways of Atlantic Water in the Canada Basin: Insights From Transient Tracers ¹²⁹I and ²³⁶U

Journal of Geophysical Research Oceans, Journal Year: 2024, Volume and Issue: 129(6)

Published: June 1, 2024

Abstract Anthropogenic radionuclides 129 I and 236 U are used to investigate pathways of the Atlantic Water flow in Canada Basin, estimate transport timescales, mixing dynamics within layer overlying Pacific Water. Transit Time Distribution (TTD) model mean ages indicate water takes 25–35 years reach Basin from entrance Arctic, with limited lateral vertical along core Arctic Ocean Boundary Current. Mode obtained yield shorter times 20–32 years. These age estimates agree previous studies using these ventilation tracers this region, indicating a steady‐state for last 15 The distribution isotopes indicates two may take into basin, supported by TTD model. End‐member models that Winter acquires 20%–40% signal radionuclides, upwelled over short periods, most likely shelf Barrow Canyon region.

Language: Английский

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Opportunities for Earth Observation to Inform Risk Management for Ocean Tipping Points

Surveys in Geophysics, Journal Year: 2024, Volume and Issue: unknown

Published: Nov. 6, 2024

Abstract As climate change continues, the likelihood of passing critical thresholds or tipping points increases. Hence, there is a need to advance science for detecting such thresholds. In this paper, we assess needs and opportunities Earth Observation (EO, here understood refer satellite observations) inform society in responding risks associated with ten potential large-scale ocean elements: Atlantic Meridional Overturning Circulation; Subpolar Gyre; Beaufort Arctic halocline; Kuroshio Large Meander; deoxygenation; phytoplankton; zooplankton; higher level ecosystems (including fisheries); marine biodiversity. We review current scientific understanding identify specific EO related modelling each these elements. draw out some generic that apply across several These common include importance maintaining long-term, consistent time series; combine data consistently situ types subsurface), example through assimilation; reduce work mismatches resolution (in both directions) between models datasets. Our analysis shows developing EO, prediction systems together, strengths limitations each, provides many promising paths towards monitoring early warning tipping, development next generation models.

Language: Английский

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Atlantic-origin water extension into the Pacific Arctic induced an anomalous biogeochemical event

Nature Communications, Journal Year: 2023, Volume and Issue: 14(1)

Published: Nov. 2, 2023

The Arctic Ocean is facing dramatic environmental and ecosystem changes. In this context, an international multiship survey project was undertaken in 2020 to obtain current baseline data. During the survey, unusually low dissolved oxygen acidified water were found a high-seas fishable area of western (Pacific-side) Ocean. Herein, we show that Beaufort Gyre shrinks east ocean ridge forms front between within gyre from eastern (Atlantic-side) Arctic. That phenomenon triggers frontal northward flow along ridge. This likely transports toward area; similar biogeochemical properties had previously been observed only on shelf-slope north East Siberian Sea.

Language: Английский

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Dominant inflation of the Arctic Ocean’s Beaufort Gyre in a warming climate

Communications Earth & Environment, Journal Year: 2025, Volume and Issue: 6(1)

Published: Jan. 20, 2025

Language: Английский

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Circulation of Baffin Bay and Hudson Bay waters on the Labrador shelf and into the subpolar North Atlantic

Ocean science, Journal Year: 2025, Volume and Issue: 21(1), P. 241 - 260

Published: Jan. 28, 2025

Abstract. In the coming decades increasing amounts of freshwater are predicted to enter subpolar North Atlantic from Greenland and Arctic. If this additional reaches regions where deep convection occurs, it could potentially dampen ventilation formation waters. study, we use a surface drifter dataset spanning period 1990–2023 investigate pathways followed by waters originating Davis Strait Hudson on Labrador shelf into interior Atlantic. Recent deployments in region allow for an improved understanding circulation shelf, particular its northern part, prior data were sparse. We show that remain as they flow downstream until reach Newfoundland shelf. This confirms very little exchange takes place between Sea. Decomposing five regions, further describe typical these extensive exchanges take coastal shelf-break branches Current. Our results suggest if amount would not directly affect Sea region; instead, lead salinity anomaly off Grand Banks, which then circulate around

Language: Английский

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Key drivers of large scale changes in North Atlantic atmospheric and oceanic circulations and their predictability

Climate Dynamics, Journal Year: 2025, Volume and Issue: 63(2)

Published: Feb. 1, 2025

Significant changes have occurred during the last few decades across North Atlantic climate system, including in atmosphere, ocean, and cryosphere. These large-scale play a vital role shaping regional extreme weather events UK Western Europe. This review synthesizes characteristics of observed atmospheric oceanic circulations past decades, identifies drivers physical processes responsible for these changes, outlines projected due to anthropogenic warming, discusses predictability circulations. On multi-decadal time scales, internal variability, forcings (especially greenhouse gases), natural (such as solar variability volcanic eruptions) are identified key contributors However, there remain many uncertainties regarding detailed various influences, some cases their relative importance. We therefore conclude that better understanding drivers, more accurate quantification roles, crucial reliable decadal predictions projections The online version contains supplementary material available at 10.1007/s00382-025-07591-1.

Language: Английский

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Can the Marked Arctic Ocean Freshwater Content Increases of the Last Two Decades Be Explained Within Observational Uncertainty?

Journal of Geophysical Research Oceans, Journal Year: 2025, Volume and Issue: 130(2)

Published: Feb. 1, 2025

Abstract The freshwater content of the Arctic Ocean has increased dramatically in last two decades, particularly Beaufort Gyre. However, quantifying sources this change is an observational challenge and historically been limited by methodological differences across studies. Here we derive observation‐based budgets from volume mass for Gyre 2003 to 2020. Our include all sinks (river runoff, precipitation minus evaporation, land ice melt, sea export, ocean fluxes) as well storage terms measured satellite. We find that changes are dominated Gyre, reconcile with previous studies argue compensation between rest Arctic. use inverse methods close within uncertainty link observed sinks. budget analysis demonstrates small fluxes (smaller than can measure) account Arctic, highlighting need more careful accounting detailed observations rapidly changing environment.

Language: Английский

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