The GFDL Earth System Model Version 4.1 (GFDL‐ESM 4.1): Overall Coupled Model Description and Simulation Characteristics

Journal of Advances in Modeling Earth Systems, Journal Year: 2020, Volume and Issue: 12(11)

Published: Aug. 13, 2020

Abstract We describe the baseline coupled model configuration and simulation characteristics of GFDL's Earth System Model Version 4.1 (ESM4.1), which builds on component developments at GFDL over 2013–2018 for carbon‐chemistry‐climate contributing to sixth phase Coupled Intercomparison Project. In contrast with CM4.0 development effort that focuses ocean resolution physical climate, ESM4.1 comprehensiveness system interactions. features doubled horizontal both atmosphere (2° 1°) (1° 0.5°) relative previous‐generation ESM2‐carbon CM3‐chemistry models. brings together key representational advances in dynamics physics along those aerosols their precursor emissions, land ecosystem vegetation canopy competition, multiday fire; ecological biogeochemical interactions, comprehensive land‐atmosphere‐ocean cycling CO 2 , dust iron, interactive ocean‐atmosphere nitrogen are described detail across this volume JAMES presented here terms overall coupling resulting fidelity. provides much improved fidelity chemistry ESM2 CM3, captures most CM4.0's simulations characteristics, notably improves (1) Southern Ocean mode intermediate water ventilation, (2) aerosols, (3) reduced spurious heat uptake. has transient equilibrium climate sensitivity compared CM4.0. Fidelity concerns include moderate degradation sea surface temperature biases, some regions, strong centennial scale modulation by convection.

Language: Английский

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Twenty-first century ocean warming, acidification, deoxygenation, and upper-ocean nutrient and primary production decline from CMIP6 model projections

Biogeosciences, Journal Year: 2020, Volume and Issue: 17(13), P. 3439 - 3470

Published: July 6, 2020

Abstract. Anthropogenic climate change is projected to lead ocean warming, acidification, deoxygenation, reductions in near-surface nutrients, and changes primary production, all of which are expected affect marine ecosystems. Here we assess projections these drivers environmental over the twenty-first century from Earth system models (ESMs) participating Coupled Model Intercomparison Project Phase 6 (CMIP6) that were forced under CMIP6 Shared Socioeconomic Pathways (SSPs). Projections compared those previous generation (CMIP5) Representative Concentration (RCPs). A total 10 CMIP5 13 used two multi-model ensembles. Under high-emission scenario SSP5-8.5, global mean (2080–2099 values relative 1870–1899) ± inter-model SD sea surface temperature, pH, subsurface (100–600 m) oxygen concentration, euphotic (0–100 nitrate depth-integrated production +3.47±0.78 ∘C, -0.44±0.005, -13.27±5.28, -1.06±0.45 mmol m−3 -2.99±9.11 %, respectively. low-emission, high-mitigation SSP1-2.6, corresponding +1.42±0.32 -0.16±0.002, -6.36±2.92, -0.52±0.23 m−3, -0.56±4.12 %. Projected exposure ecosystem depends largely on extent future emissions, consistent with studies. The ESMs generally project greater but lesser declines than comparable radiative forcing. increased warming results a general increase sensitivity CMIP5. This enhanced increases upper-ocean stratification projections, contributes ventilation. acidification primarily consequence SSPs having higher associated atmospheric CO2 concentrations their RCP analogues for same We find no reduction uncertainties, even an net uncertainties CMIP6, as

Language: Английский

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How Well Do We Understand the Land‐Ocean‐Atmosphere Carbon Cycle?

Reviews of Geophysics, Journal Year: 2022, Volume and Issue: 60(2)

Published: April 8, 2022

Abstract Fossil fuel combustion, land use change and other human activities have increased the atmospheric carbon dioxide (CO 2 ) abundance by about 50% since beginning of industrial age. The CO growth rates would been much larger if natural sinks in biosphere ocean had not removed over half this anthropogenic . As these emissions grew, uptake response to increases partial pressure (pCO ). On land, gross primary production also increased, but dynamics key aspects cycle varied regionally. Over past three decades, intact tropical humid forests declined, changes are offset across mid‐ high‐latitudes. While there substantial improvements our ability study cycle, measurement modeling gaps still limit understanding processes driving its evolution. Continued ship‐based observations combined with expanded deployments autonomous platforms needed quantify ocean‐atmosphere fluxes interior storage on policy‐relevant spatial temporal scales. There is an urgent need for more comprehensive measurements stocks, Arctic boreal regions, which experiencing rapid change. Here, we review atmosphere, ocean, cycles their interactions, identify emerging capabilities a sustainable, operational framework ensure scientific basis management.

Language: Английский

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Magnitude, Trends, and Variability of the Global Ocean Carbon Sink From 1985 to 2018

Global Biogeochemical Cycles, Journal Year: 2023, Volume and Issue: 37(10)

Published: Sept. 11, 2023

Abstract This contribution to the RECCAP2 (REgional Carbon Cycle Assessment and Processes) assessment analyzes processes that determine global ocean carbon sink, its trends variability over period 1985–2018, using a combination of models observation‐based products. The mean sea‐air CO 2 flux from 1985 2018 is −1.6 ± 0.2 PgC yr −1 based on an ensemble reconstructions history sea surface pCO (pCO products). Models indicate dominant component this net oceanic uptake anthropogenic , which estimated at −2.1 0.3 by biogeochemical models, −2.4 0.1 two circulation inverse models. also degasses about 0.65 terrestrially derived but process not fully resolved any used here. From 2001 2018, products reconstruct trend in sink −0.61 0.12 decade while diagnose ‐driven −0.34 0.06 −0.41 0.03 respectively. implies climate‐forced acceleration recent decades, there are still large uncertainties magnitude cause trend. interannual decadal mainly driven climate variability, with climate‐driven exceeding ‐forced 2–3 times. These results suggest dominates potentially highly uncertain consistently captured across different methods.

Language: Английский

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Global Surface Ocean Acidification Indicators From 1750 to 2100

Journal of Advances in Modeling Earth Systems, Journal Year: 2023, Volume and Issue: 15(3)

Published: March 1, 2023

Abstract Accurately predicting future ocean acidification (OA) conditions is crucial for advancing OA research at regional and global scales, guiding society's mitigation adaptation efforts. This study presents a new model‐data fusion product covering 10 surface indicators based on 14 Earth System Models (ESMs) from the Coupled Model Intercomparison Project Phase 6 (CMIP6), along with three recent observational carbon data products. The include fugacity of dioxide, pH total scale, hydrogen ion content, free carbonate aragonite saturation state, calcite Revelle Factor, dissolved inorganic alkalinity content. evolution these presented 1° × grid as decadal averages every years preindustrial (1750), through historical (1850–2010), to five Shared Socioeconomic Pathways (2020–2100): SSP1‐1.9, SSP1‐2.6, SSP2‐4.5, SSP3‐7.0, SSP5‐8.5. These trajectories represent an improvement over previous products respect quantity, spatial temporal coverage, diversity underlying model simulations, provided SSPs. generated offers state‐of‐the‐art management tool 21st century under combined stressors climate change acidification. gridded available in NetCDF National Oceanic Atmospheric Administration (NOAA) Centers Environmental Information: https://www.ncei.noaa.gov/data/oceans/ncei/ocads/metadata/0259391.html , maps are jpeg at: https://www.ncei.noaa.gov/access/ocean-carbon-acidification-data-system/synthesis/surface-oa-indicators.html .

Language: Английский

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Zooplankton grazing is the largest source of uncertainty for marine carbon cycling in CMIP6 models

Communications Earth & Environment, Journal Year: 2023, Volume and Issue: 4(1)

Published: June 14, 2023

Abstract The current generation of Earth system models used by the United Nations to project future climate scenarios (CMIP6) relies heavily on marine biogeochemical track fate carbon absorbed into oceans. Here we compare 11 CMIP6 and find largest source inter-model uncertainty in their representation cycle is phytoplankton-specific loss rates zooplankton grazing. This over three times larger than that net primary production driven large differences prescribed grazing dynamics. We run a controlled sensitivity experiment global model small changes dynamics (roughly 5% what across models) can increase secondary export 5 2 PgC yr −1 , respectively, even when tuned identical production, likely biasing predictions states food security.

Language: Английский

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A Synthesis of Global Coastal Ocean Greenhouse Gas Fluxes

Global Biogeochemical Cycles, Journal Year: 2024, Volume and Issue: 38(1)

Published: Jan. 1, 2024

Abstract The coastal ocean contributes to regulating atmospheric greenhouse gas concentrations by taking up carbon dioxide (CO 2 ) and releasing nitrous oxide (N O) methane (CH 4 ). In this second phase of the Regional Carbon Cycle Assessment Processes (RECCAP2), we quantify global fluxes CO , N O CH using an ensemble gap‐filled observation‐based products biogeochemical models. is a net sink in both observational models, but magnitude median uptake ∼60% larger models (−0.72 vs. −0.44 PgC year −1 1998–2018, extending 300 km offshore or 1,000 m isobath with area 77 million We attribute most model‐product difference seasonality sea surface partial pressure at mid‐ high‐latitudes, where simulate stronger winter uptake. has increased past decades available time‐resolving show large discrepancies increase. major source (+0.70 PgCO ‐e product +0.54 model median) (+0.21 product), which offsets substantial proportion radiative balance (30%–60% ‐equivalents), highlighting importance considering three gases when examining influence on climate.

Language: Английский

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Observation-constrained estimates of the global ocean carbon sink from Earth system models

Biogeosciences, Journal Year: 2022, Volume and Issue: 19(18), P. 4431 - 4457

Published: Sept. 15, 2022

Abstract. The ocean slows global warming by currently taking up around one-quarter of all human-made CO2 emissions. However, estimates the anthropogenic carbon uptake vary across various observation-based and model-based approaches. Here, we show that sink simulated Earth system models can be constrained two physical parameters, present-day sea surface salinity in subtropical–polar frontal zone Southern Ocean strength Atlantic Meridional Overturning Circulation, one biogeochemical parameter, Revelle factor ocean. quantifies chemical capacity seawater to take for a given increase atmospheric CO2. By exploiting this three-dimensional emergent constraint with observations, provide new model- estimate past, present, future is 9 %–11 % larger than previously estimated. Furthermore, reduces uncertainties past present 42 %–59 32 %–62 depending on scenario, allowing better understanding cycle better-targeted climate policies. Our results are good agreement air–sea flux over last three decades based observations partial pressure at Global Carbon Budget 2021, they suggest existing hindcast ocean-only model simulations underestimate sink. key parameters identified here should quantified when presenting as used adjust these if necessary. enhanced acidification 21st century, which further threatens marine ecosystems reducing water volume projected undersaturated towards aragonite 3.7×106–7.4×106 km3 more originally projected.

Language: Английский

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Aragonite dissolution protects calcite at the seafloor

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: March 1, 2022

Abstract In the open ocean, calcium carbonates are mainly found in two mineral forms. Calcite, least soluble, is widespread at seafloor, while aragonite, more rarely preserved marine sediments. Despite its greater solubility, research has shown that whose contribution to global pelagic calcification could be par with of calcite, able reach deep-ocean. If large quantities aragonite settle and dissolve this represents a source alkalinity buffers deep ocean favours preservation less soluble acting as deep-sea, carbonate version galvanization. Here, we investigate role dissolution on early diagenesis calcite-rich sediments using novel 3D, micrometric-scale reactive-transport model combined X-ray tomography structures natural calcite shells. Results highlight important diffusive transport benthic dissolution, agreement recent work. We show that, locally, fluxes seafloor sufficient suppress top layer seabed, possibly causing recrystallization. As producers particularly vulnerable acidification, proposed galvanizing effect weakened future, sediment-water interface will have cover share CO 2 neutralization.

Language: Английский

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Global ecological and biogeochemical impacts of pelagic tunicates

Progress In Oceanography, Journal Year: 2022, Volume and Issue: 205, P. 102822 - 102822

Published: May 19, 2022

Language: Английский

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