Convergent control of soil temperature on seasonal carbon flux in Tibetan alpine meadows: An in-situ monitoring study

Ecological Indicators, Journal Year: 2023, Volume and Issue: 156, P. 111116 - 111116

Published: Oct. 20, 2023

The Tibet Plateau, with its extensive carbon pools, plays a pivotal role in the global budget. Nevertheless, driving factors of dioxide budget remain disputed, and impact freeze–thaw process on release is still unclear due to harsh climate lack monitoring data. To clarify primary affecting alpine meadow ecosystems examine release, we employed LI-8150 automated continuous measurement system. This system, conjunction eddy covariance meteorological data, Boosted Regression Tree (BRT) model, multiple stepwise regression analysis, were used analyze seasonal variations flux (e.g., net ecosystem exchange [NEE], gross productivity [GPP], respiration [Reco]). We also investigate sources sinks ecosystem, as well predominant factor flux. Our findings include: (1) shift seasonally monthly daily scales. On scale, functions moderate sink June, July, August, September weak source from October through May. (2) Overall, located northeastern Qinghai Lake basin, serves (-58.53 g C m−2 year−1). (3) Soil temperature most observed NEE, Reco, GPP, contributing 48.05 %, 78.61 65.05 respectively. temperature, soil water dynamics influenced by freeze thaw processes, their interaction plant growth collectively play crucial regulating ecosystems. provide first-hand observational data for offer future guidance studying Plateau.

Language: Английский

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A leaf age‐dependent light use efficiency model for remote sensing the gross primary productivity seasonality over pantropical evergreen broadleaved forests

Global Change Biology, Journal Year: 2024, Volume and Issue: 30(8)

Published: Aug. 1, 2024

Abstract Tropical and subtropical evergreen broadleaved forests (TEFs) contribute more than one‐third of terrestrial gross primary productivity (GPP). However, the continental‐scale leaf phenology‐photosynthesis nexus over TEFs is still poorly understood to date. This knowledge gap hinders most light use efficiency (LUE) models from accurately simulating GPP seasonality in TEFs. Leaf age crucial plant trait link dynamics phenology with seasonality. Thus, here we incorporated seasonal area index different cohorts into a widely used LUE model (i.e., EC‐LUE) proposed novel age‐dependent (denoted as LA‐LUE model). At site level, (average R 2 = .59, average root‐mean‐square error [RMSE] 1.23 gC m −2 day −1 ) performs better EC‐LUE across nine sites .18; RMSE 1.87 ). continental scale, monthly estimates are consistent FLUXCOM data ( .80; 1.74 ), satellite‐based retrieved global Orbiting Carbon Observatory‐2 (OCO‐2) based solar‐induced chlorophyll fluorescence (SIF) product (GOSIF) .64; 1.90 reconstructed TROPOspheric Monitoring Instrument SIF dataset using machine learning algorithms (RTSIF) .78; 1.88 Typically, estimated not only successfully represents unimodal near Tropics Cancer Capricorn, but also captures well bimodal Equator. Overall, this study for first time integrates information provides feasible implementation mapping entire

Language: Английский

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Exploring the environmental drivers of vegetation seasonality changes in the northern extratropical latitudes: a quantitative analysis ^*

Environmental Research Letters, Journal Year: 2023, Volume and Issue: 18(9), P. 094071 - 094071

Published: Sept. 1, 2023

Abstract Vegetation seasonality in the northern extratropical latitudes (NEL) has changed dramatically, but our understanding of how it responds to climate change (e.g. temperature, soil moisture, shortwave radiation) and human activities elevated CO 2 concentration) remains insufficient. In this study, we used two remote-sensing-based leaf area index factorial simulations from TRENDY models attribute changes integrated vegetation ( S ), which captures both concentration magnitude growth throughout year, climate, , land use cover (LULCC). We found that 2003 2020, enhanced average NEL (MODIS: 0.0022 yr −1 p < 0.05; GLOBMAP: 0.0018 S3 [i.e. scenario considering time-varying LULCC]: 0.0011 ± 7.5174 × 10 −4 0.05) was primarily determined by (5.3 3.8 secondly controlled combined (4.6 6.6 > 0.1). Geographically, negative trends were dominated (31.4%), while (47.9%) (31.9%) contributed growth. Furthermore, around 60% study areas showed simulated major climatic drivers variability exhibited same dominant factor as observed either MODIS or GLOBMAP data. Our research emphasizes crucial connection between environmental factors seasonality, providing valuable insights for policymakers managers developing sustainable ecosystem management strategies amidst a changing climate.

Language: Английский

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Uncertainty in Amazon vegetation productivity in CMIP6 projections driven by surface energy fluxes

Published: March 25, 2024

Abstract. The Amazon basin rainforest is a critical component of the climate system, currently representing 25 % terrestrial carbon gains and storing 150 to 200 billion tonnes carbon. If by which extent will remain net sink an open scientific question, motivated unexplained diversity across Earth System Model (ESM) results. Specifically, divergent responses are observed in vegetation productivity projections, especially under sustained global warming scenarios. We explore this inter-model projected CMIP6 historical ssp585 scenario simulations with thirteen ESM explicitly accounting for relative contributions changes El Niño-Southern Oscillation (ENSO) local mean-state changes. Our results demonstrate dominant role climatic shaping response cycle 7 out 13 ESM, only minor ENSO its teleconnection despite strong ENSO. While temperature water availability influence displays high agreement, most processes determining uncertainty divergence within surface energy balance components, particular shortwave incoming radiation latent heat fluxes. identify main sources model specificities land scheme parameterizations, incorporation Phosphorous limitation, leads stronger reduction therefore advocate increased focus from modelling groups towards more accurate consistent representation radiative turbulent fluxes region. Additionally, we hypothesize that uniform limitation all may contribute minimize uncertainties. This dual approach can lead robust estimates different change

Language: Английский

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Comment on egusphere-2024-823

Published: May 6, 2024

Abstract. The Amazon basin rainforest is a critical component of the climate system, currently representing 25 % terrestrial carbon gains and storing 150 to 200 billion tonnes carbon. If by which extent will remain net sink an open scientific question, motivated unexplained diversity across Earth System Model (ESM) results. Specifically, divergent responses are observed in vegetation productivity projections, especially under sustained global warming scenarios. We explore this inter-model projected CMIP6 historical ssp585 scenario simulations with thirteen ESM explicitly accounting for relative contributions changes El Niño-Southern Oscillation (ENSO) local mean-state changes. Our results demonstrate dominant role climatic shaping response cycle 7 out 13 ESM, only minor ENSO its teleconnection despite strong ENSO. While temperature water availability influence displays high agreement, most processes determining uncertainty divergence within surface energy balance components, particular shortwave incoming radiation latent heat fluxes. identify main sources model specificities land scheme parameterizations, incorporation Phosphorous limitation, leads stronger reduction therefore advocate increased focus from modelling groups towards more accurate consistent representation radiative turbulent fluxes region. Additionally, we hypothesize that uniform limitation all may contribute minimize uncertainties. This dual approach can lead robust estimates different change

Language: Английский

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Terrestrial Ecosystem Model in R (TEMIR) version 1.0: simulating ecophysiological responses of vegetation to atmospheric chemical and meteorological changes

Geoscientific model development, Journal Year: 2024, Volume and Issue: 17(9), P. 3733 - 3764

Published: May 8, 2024

Abstract. The newly developed offline land ecosystem model Terrestrial Ecosystem Model in R (TEMIR) version 1.0 is described here. This of the simulates plant ecophysiological (e.g., photosynthetic and stomatal) responses to varying meteorological conditions concentrations CO2 ground-level ozone (O3) based on prescribed atmospheric chemical inputs from various sources. Driven by same data used GEOS-Chem transport model, this allows asynchronously coupled experiments with simulations unique coherency for investigating biosphere–atmosphere interactions. TEMIR agrees well FLUXNET site-level gross primary productivity (GPP) terms both diurnal monthly cycles (correlation coefficients R2>0.85 R2>0.8, respectively) most functional types (PFTs). Grass shrub PFTs have larger biases due generic representations. performs best when driven local meteorology rather than reanalyzed gridded meteorology. Simulation using annual GPP seasonality spatial distribution a global average 134 Pg C yr−1. Application Monin–Obukhov similarity theory infer canopy does not improve performance, predicting an increase +7 % GPP. Present-day O3 simulated damage scheme at high sensitivity show 2 reduction prominent reductions up 15 eastern China USA. Regional correlations are generally unchanged present reduced, especially regions damage. An concentration 20 ppmv level 2000 2010 modestly decreases reduced stomatal uptake, consistent understanding. Our work showcases utility evaluating biogeophysical vegetation changes composition conditions.

Language: Английский

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Development of a plant carbon–nitrogen interface coupling framework in a coupled biophysical-ecosystem–biogeochemical model (SSiB5/TRIFFID/DayCent-SOM v1.0)

Geoscientific model development, Journal Year: 2024, Volume and Issue: 17(16), P. 6437 - 6464

Published: Aug. 30, 2024

Abstract. Plant and microbial nitrogen (N) dynamics N availability regulate the photosynthetic capacity capture, allocation, turnover of carbon (C) in terrestrial ecosystems. Studies have shown that a wide divergence representations land surface models leads to large uncertainties biogeochemical cycle ecosystems then climate simulations as well projections future trajectories. In this study, plant C–N interface coupling framework is developed implemented coupled biophysical-ecosystem–biogeochemical model (SSiB5/TRIFFID/DayCent-SOM v1.0). The main concept structure its strategy are presented study. This takes more N-related processes into account. dynamic C/N ratio (CNR) for each functional type (PFT) introduced consider resistance adaptation better evaluate response limitation. Furthermore, when available less than demand, growth restricted by lower maximum carboxylation RuBisCO (Vc,max), reducing gross primary productivity (GPP). addition, module respiration rates adjusting with different components at same concentration. Since insufficient can potentially give rise lags phenology, phenological scheme also adjusted availability. All these considerations ensure comprehensive incorporation regulations C cycling. new approach has been tested systematically assess effects limitation on cycle. Long-term measurements from flux tower sites PFTs global satellite-derived products employed references effects. results show general improvement framework, consistent emergent properties, such GPP leaf area index (LAI), compared observations. improvements occur tropical Africa boreal regions, accompanied decrease bias LAI 16.3 % 27.1 %, respectively.

Language: Английский

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Stability of gross primary productivity and its sensitivity to climate variability in China

Frontiers in Plant Science, Journal Year: 2024, Volume and Issue: 15

Published: Sept. 6, 2024

Identifying the stability and sensitivity of land ecosystems to climate change is vital for exploring nature-based solutions. However, underlying mechanisms governing ecosystem sensitivity, especially in regions with overlapping ecological projects, remain unclear. based on Mann-Kendall, analysis method, multiple regression this study quantified gross primary productivity (GPP) variables [temperature, vapor pressure deficit (VPD), soil moisture, radiation] China from 1982 2019. Our findings revealed following: (1) GPP demonstrated an increased trend lower Eastern regions, whereas a decreasing higher was observed Western Southwest China. Notably, highest (74.58%) areas five projects: Grain Green, Natural Forest Resource Protection Project, Three-River Ecological Conservation Restoration Return Grazing Grassland Three-North Shelter Forestation Project. (2) In minimal or no temperature radiation jointly dominated variations. contrast, water-related factors (VPD moisture) significantly affected projects. (3) southwestern northeastern exhibited change, whereas, eastern coastal Tibet, showed low change. Loess Plateau, where projects overlap extensively, carbon sinks primarily demonstrate monotonic increasing trend, high stability, This aimed assess delineate their changes, thereby laying groundwork understanding resilience.

Language: Английский

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A better simulation of water and carbon fluxes in a typical desert grassland ecosystem through the Common Land Model

Journal of Hydrology, Journal Year: 2024, Volume and Issue: unknown, P. 132111 - 132111

Published: Sept. 1, 2024

Language: Английский

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Simulating the land carbon sink: Progresses and challenges of terrestrial ecosystem models

Agricultural and Forest Meteorology, Journal Year: 2024, Volume and Issue: 358, P. 110264 - 110264

Published: Oct. 17, 2024

Language: Английский

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