Impacts of benchmarking choices on inferred model skill of the Arctic–Boreal terrestrial carbon cycle

Environmental Research Ecology, Journal Year: 2025, Volume and Issue: 4(1), P. 015007 - 015007

Published: Feb. 3, 2025

Abstract Land surface models require continuous validation against observations to improve and reduce simulation uncertainty. However, inferred model performance can be heavily influenced by subjective choices made in the selection application of observational data products. A key area often misrepresented is Arctic–Boreal region, which a potential tipping point region Earth’s climate system due large permafrost carbon stocks that are vulnerable release with warming. We use International Model Benchmarking (ILAMB) framework evaluate how skill TRENDY-v9 varies based on choice observational-based benchmark benchmarks applied evaluation. This analysis uses global datasets integrated into ILAMB new, regionally-specific products from Vulnerability Experiment. Our results cover overall time period 1979–2019 show scores vary substantially depending product applied, higher indicating better observations. The lowest occur when benchmarked regional, compared global, datasets. also observed modeled functional relationships between ecosystem respiration air temperature gross primary production precipitation. Here, we find magnitude shape responses strongly impacted dataset approach used construct relationship benchmark. These suggest evaluation studies could conclude false sense if only using single or not applying regional performing analysis. Collectively, our findings highlight influence benchmarking need for guidelines assessing skill.

Language: Английский

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Permafrost carbon cycle and its dynamics on the Tibetan Plateau

Science China Life Sciences, Journal Year: 2024, Volume and Issue: 67(9), P. 1833 - 1848

Published: June 26, 2024

Language: Английский

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Inland water greenhouse gas emissions offset the terrestrial carbon sink in the northern cryosphere

Science Advances, Journal Year: 2024, Volume and Issue: 10(39)

Published: Sept. 27, 2024

Climate-sensitive northern cryosphere inland waters emit greenhouse gases (GHGs) into the atmosphere, yet their total emissions remain poorly constrained. We present a data-driven synthesis of GHG from considering water body types, zones, and seasonality. find that annual are dominated by carbon dioxide ( 1149.2 1004.8 1307.5 teragrams CO 2 ; median Q 1 3 ) methane 14.2 10.1 18.5 CH 4 ), while nitrous oxide emission 5.4 − 1.4 12.2 gigagrams N O) is minor. The –equivalent (CO e) 1.5 1.3 1.8 or 2.3 2.8 petagrams e using 100- 20-year global warming potentials, respectively. Rivers 64% more GHGs than lakes, despite having only one-fifth surface area. continuous permafrost zone contributed half emissions. Annual exceed region’s terrestrial net ecosystem exchange, highlighting important role in cryospheric land-aquatic continuum under climate.

Language: Английский

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Permafrost Region Greenhouse Gas Budgets Suggest a Weak CO₂ Sink and CH₄ and N₂O Sources, But Magnitudes Differ Between Top‐Down and Bottom‐Up Methods

Global Biogeochemical Cycles, Journal Year: 2024, Volume and Issue: 38(10)

Published: Oct. 1, 2024

Abstract Large stocks of soil carbon (C) and nitrogen (N) in northern permafrost soils are vulnerable to remobilization under climate change. However, there large uncertainties present‐day greenhouse gas (GHG) budgets. We compare bottom‐up (data‐driven upscaling process‐based models) top‐down (atmospheric inversion budgets dioxide (CO 2 ), methane (CH 4 ) nitrous oxide (N O) as well lateral fluxes C N across the region over 2000–2020. Bottom‐up approaches estimate higher land‐to‐atmosphere for all GHGs. Both show a sink CO natural ecosystems (bottom‐up: −29 (−709, 455), top‐down: −587 (−862, −312) Tg ‐C yr −1 sources CH 38 (22, 53), 15 (11, 18) O 0.7 (0.1, 1.3), 0.09 (−0.19, 0.37) O‐N ). The combined global warming potential three gases (GWP‐100) cannot be distinguished from neutral. Over shorter timescales (GWP‐20), is net GHG source because dominates total forcing. Boreal forests wetlands largely offset by fires inland water emissions waters, with smaller contribution emissions. Priorities future research include representation waters models compilation process‐model ensembles O. Discrepancies between methods call analyses how prior flux impact budgets, more well‐distributed situ measurements improved resolution techniques.

Language: Английский

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Strong legacies of emerging trends in winter precipitation on the carbon-climate feedback from Arctic tundra

The Science of The Total Environment, Journal Year: 2025, Volume and Issue: 962, P. 178246 - 178246

Published: Jan. 1, 2025

Changes in winter precipitation accompanying emerging climate trends lead to a major carbon-climate feedback from Arctic tundra. However, the mechanisms driving direction, magnitude, and form (CO2 CH4) of C fluxes derived forcing (i.e. GWP, global warming potential) tundra under future scenarios remain unresolved. Here, we investigated impacts 18 years shallow (SS, -15-30 %) deeper (IS, +20-45 %; DS, +70-100 snow depth on ecosystem GWP moist acidic over growing season. The response accumulation was markedly non-linear. Both shallow- deeper- decreased CO2 emissions relative ambient (AS), ultimately reducing losses Gross primary productivity (GPP) increased with moderate increases further closely following transitions shrub abundance. Photosynthetic uptake, however, tightly regulated by canopy structure plant respiration (Raut) GPP ratio highly conserved despite substantial transformations community across treatments revealing prominent role heterotrophic (Rhet) net exchange. Consistently, gains responded constraints Rhet temperature limitation within colder soils at SS, snow- thaw-induced soil-water content (SWC) that promoted anaerobic decomposition dampened sensitivity IS DS. Greater CH4 wetter soils, potential (GWP) DS decreases losses. Overall, our findings indicate tussock reduce season but also significantly contribute precipitation.

Language: Английский

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Scaling Arctic landscape and permafrost features improves active layer depth modeling

Environmental Research Ecology, Journal Year: 2025, Volume and Issue: 4(1), P. 015001 - 015001

Published: Jan. 20, 2025

Abstract Tundra ecosystems in the Arctic store up to 40% of global below-ground organic carbon but are exposed fastest climate warming on Earth. However, accurately monitoring landscape changes is challenging due complex interactions among permafrost, micro-topography, climate, vegetation, and disturbance. This complexity results high spatiotemporal variability permafrost distribution active layer depth (ALD). Moreover, these key tundra processes interact at different scales, an observational mismatch can limit our understanding intrinsic connections dynamics between above processes. Consequently, this could ability model anticipate how ALD will respond change disturbances across ecosystems. In paper, we studied fine-scale heterogeneity its with land surface characteristics spatial spectral scales using a combination ground, unoccupied aerial system, airborne, satellite observations. We showed that airborne sensors such as AVIRIS-NG medium-resolution Earth observation systems like Sentinel-2 capture average scale. found best scale for modeling heavily influenced by vegetation landform patterns occurring landscape. Landscapes characterized small-scale features polygon tussock require high-resolution observations disturbance patterns. Conversely, landscapes dominated water tracks shrubs, manifest larger indicate performance medium resolution (5 m), outperforming both higher (0.4 m) lower (10 models. transcends study show response may vary dominant ecosystem types, driven above- which happening. thus recommend tailoring based landforms distribution, thereby mitigating influences spatial-scale mismatches improving region.

Language: Английский

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Fungi in treeline ecotones – Halting or causing abrupt ecosystem change?

Fungal ecology, Journal Year: 2025, Volume and Issue: 74, P. 101409 - 101409

Published: Feb. 3, 2025

Language: Английский

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The land–ocean Arctic carbon cycle

Nature Reviews Earth & Environment, Journal Year: 2025, Volume and Issue: 6(2), P. 86 - 105

Published: Feb. 1, 2025

Language: Английский

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InSAR-derived seasonal subsidence reflects spatial soil moisture patterns in Arctic lowland permafrost regions

˜The œcryosphere, Journal Year: 2025, Volume and Issue: 19(3), P. 1103 - 1133

Published: March 11, 2025

Abstract. The identification of spatial soil moisture patterns is high importance for various applications in high-latitude permafrost regions but challenging with common remote sensing approaches due to landscape heterogeneity. Seasonal thawing and freezing near-surface lead subsidence–heave cycles the presence ground ice, which exhibit magnitudes typically less than 10 cm. Our investigations document higher Sentinel-1 InSAR (interferometric synthetic aperture radar) seasonal subsidence rates (calculated per degree days – a measure heating) locations compared drier ones. Based on this, we demonstrate that relationship signals can be interpreted assess variations moisture. A range challenges, however, need addressed. We discuss implications using different sources temperature data deriving results. Atmospheric effects must considered, as simple filtering suppress large-scale permafrost-related underestimation displacement values, making Generic Correction Online Service (GACOS)-corrected results preferable tested sites. rate retrieval considers these aspects provides valuable tool distinguishing between wet dry features, relevant degradation monitoring Arctic lowland regions. Spatial resolution constraints, remain smaller typical features drive versus conditions such high- low-centred polygons.

Language: Английский

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What Are the Limits to the Growth of Boreal Fires?

Global Change Biology, Journal Year: 2025, Volume and Issue: 31(3)

Published: March 1, 2025

ABSTRACT Boreal forest regions, including East Siberia, have experienced elevated fire activity in recent years, leading to record‐breaking greenhouse gas emissions and severe air pollution. However, our understanding of the factors that eventually halt spread thus limit growth remains incomplete, hindering ability model their dynamics predict impacts. We investigated locations timing 2.2 million stops—defined as 300 m unburned pixels along perimeters—across vast Siberian taiga. Fire stops were retrieved from remote sensing data covering over 27,000 individual fires collectively burned 80 Mha between 2012 2022. Several geospatial datasets, hourly weather landscape variables, used identify contributing stops. Our analysis attributed 87% all a statistically significant ( p < 0.01) change one or more these drivers, with fire‐weather drivers limiting time constraining it across space. found clear regional temporal variations importance drivers. For instance, drivers—such less flammable land cover presence roads—were key constraints on southeastern where is populated fragmented. In contrast, was primary constraint northern Additionally, central Yakutia, major hotspot fuel limitations previous increasingly restricted spread. The methodology we present adaptable other biomes can be applied globally, providing framework for future attribution studies global limitations. northeast increasing droughts heatwaves, could potentially grow even larger future, implications carbon cycle climate.

Language: Английский

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