Role of Micrometeorological Memory in Modulating Sub‐Daily Scale Variability of Net Ecosystem Exchange

Journal of Geophysical Research Biogeosciences, Год журнала: 2025, Номер 130(1)

Опубликована: Янв. 1, 2025

Abstract Net Ecosystem Exchange (NEE) is crucial for understanding the carbon balance in ecosystems, indicating whether they act as sinks or sources. While impact of hydrometeorological factors on NEE at daily and monthly scales has been well‐researched, significance sub‐daily variability influence memory micrometeorological variables remain understudied. This study addresses this gap by analyzing temporal dynamics using half‐hourly data from 29 FLUXNET sites over least 6 years. We found that contributes 10%–55% 13‐day variability, depending seasonal cycles biome characteristics. Using an information theory based transfer entropy (TE) approach, we identified causal drivers within a 6‐hr memory. Our results show significantly impacts NEE, surpassing their instantaneous effects. Temperature (TA), vapor pressure deficit (VPD), soil water content (SWC Mean ) consistently affect memory, whereas sensible heat (H) incoming shortwave radiation (SW IN diminishes higher lags. magnitude average TE to exhibits notable variations, structure how transferred does not differ across seasons, reflected shape values various time SWC , VPD, TA jointly, while H SW have overlapping Additionally, precipitation influences indirectly through . findings highlight importance accounting high‐frequency its underlying when investigating ecohydrological interactions, shedding light role carbon‐water interactions.

Язык: Английский

---

The Response of Carbon Uptake to Soil Moisture Stress: Adaptation to Climatic Aridity

Global Change Biology, Год журнала: 2025, Номер 31(3)

Опубликована: Март 1, 2025

The coupling between carbon uptake and water loss through stomata implies that gross primary production (GPP) can be limited by soil availability reduced leaf area and/or stomatal conductance. Ecosystem land-surface models commonly assume GPP is highest under well-watered conditions apply a stress function to reduce as moisture declines. Optimality considerations, however, suggest the should depend on climatic aridity: ecosystems adapted more arid climates use conservatively when high, but maintain unchanged down lower critical soil-moisture threshold. We eddy-covariance flux data test this hypothesis. investigate how light-use efficiency (LUE) of depends across representing wide range aridity. 'Well-watered' estimated using sub-daily P model, first-principles LUE model driven atmospheric remotely sensed vegetation cover. Breakpoint regression used relate daily β(θ) (the ratio data-derived modelled GPP) via generic balance model. resulting piecewise describing varies with aridity, hypothesised. Unstressed LUE, even declines increasing aridity index (AI). So does Moreover, for any AI value, there exists level at which maximised. This increases. behaviour captured universal non-linear functions relating both unstressed threshold AI. Applying these aridity-based predict site-level response substantially improves simulation water-stressed conditions, suggesting route towards robust, representation effects low leaf-level photosynthesis.

Язык: Английский

---

Atmospheric Vapor Pressure Deficit Outweighs Soil Moisture Deficit in Controlling Global Ecosystem Water Use Efficiency

Journal of Geophysical Research Biogeosciences, Год журнала: 2025, Номер 130(3)

Опубликована: Март 1, 2025

Abstract High vapor pressure deficit (VPD) and low soil moisture (SM) lead to atmospheric droughts, which can stress carbon‐water coupling in terrestrial ecosystems. However, the strong collinearity between VPD SM, particularly under certain climatic conditions, makes it challenging disentangle their independent contributions carbon water dynamics land‐atmosphere interactions. This study aimed clarify long‐term response of global vegetation coupling, based on ecosystem water‐use efficiency (WUE E ) plant canopy Et ), decoupled SM from 1982 2100. WUE is defined as ratio gross primary productivity evapotranspiration, while transpiration. The results indicate that 2018, both before after decoupling over 64% zones experienced stronger than drought consistently impacting . influence gradually declined, presented a tendency increase. small difference responses attributed effects varied across cover gradients, biomes, zones. As intensifies coming decades, are those all four socio‐economic shared pathway (SSP) scenarios. In high SSP scenarios (SSP5‐8.5 for SSP3‐7.0 dominant expected expand.

Язык: Английский

---

Understanding the dynamics of 2024 extreme heat event in India: Spatial variability, hydrometeorological impacts, and model evaluation

Atmospheric Research, Год журнала: 2025, Номер unknown, С. 108154 - 108154

Опубликована: Апрель 1, 2025

Язык: Английский

---

Micrometeorological drivers affecting the variability of CO2 uptake in the Himalayan Oak and Pine dominated ecosystems: An assessment of causal relationships

Journal of Hydrology, Год журнала: 2024, Номер 647, С. 132333 - 132333

Опубликована: Ноя. 17, 2024

Язык: Английский

---