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Seasonal divergence in the sensitivity of carbon and water fluxes to climate variability in terrestrial ecosystems

Ting, Wang ; Fu, Zheng ; Makowski, David ; Liang, Guopeng ; Jin, Hongxiao LU and Zhang, Fangyue (2025) In Agricultural and Forest Meteorology 376.
Abstract
Understanding vegetation sensitivity to hydroclimate factors, especially how carbon and water cycles respond to climate change, is crucial for assessing ecosystem vulnerability. However, the seasonal sensitivity of carbon and water fluxes to temperature, radiation, soil water content, and vapor pressure deficit across diverse biomes and climates remains unclear. Here, we use 196 eddy covariance observations from sensor networks distributed globally, along with daily estimates from Earth System Models (ESMs), to quantify the seasonal sensitivity of daily gross primary productivity (GPP), ecosystem respiration (RE), net ecosystem productivity (NEP), and evapotranspiration (ET) to various hydroclimate factors. Our ridge regression analysis... (More)
Understanding vegetation sensitivity to hydroclimate factors, especially how carbon and water cycles respond to climate change, is crucial for assessing ecosystem vulnerability. However, the seasonal sensitivity of carbon and water fluxes to temperature, radiation, soil water content, and vapor pressure deficit across diverse biomes and climates remains unclear. Here, we use 196 eddy covariance observations from sensor networks distributed globally, along with daily estimates from Earth System Models (ESMs), to quantify the seasonal sensitivity of daily gross primary productivity (GPP), ecosystem respiration (RE), net ecosystem productivity (NEP), and evapotranspiration (ET) to various hydroclimate factors. Our ridge regression analysis reveals seasonal variations in the sensitivity of carbon and water fluxes to hydroclimate factors across globally distributed flux sites. GPP and NEP are most sensitive to air temperature (TA) in spring, but to radiation (RAD) in summer, autumn and winter. RE consistently exhibits positive sensitivity to TA across all seasons, while ET shows the highest sensitivity to RAD throughout the year. Although energy-related factors like TA and RAD dominate the influence on carbon and water fluxes at sub-seasonal scales, soil water content (SWC) and vapor pressure deficit (VPD) become increasingly important during summer, particularly in drylands. At sites with long-term measurements, we identified a significant upward trend in the sensitivity of summer GPP to SWC with 0.005 ± 0.002 per year, suggesting that terrestrial ecosystems are becoming more constrained by water stress during summer. Compared to observations, ESMs generally overestimate the sensitivity of GPP to SWC and VPD, while underestimate the sensitivity to RAD and TA during summer. Our findings enhanced the understanding of the seasonal response of ecosystem carbon and water cycles to hydroclimate factors, offering insights into ecosystem function under future climate change. (Less)
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organization
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type
Contribution to journal
publication status
published
subject
keywords
Carbon and water fluxesEddy covarianceHydroclimate factorsSeasonal variationsSensitivity
in
Agricultural and Forest Meteorology
volume
376
article number
110916
publisher
Elsevier
ISSN
1873-2240
DOI
10.1016/j.agrformet.2025.110916
language
English
LU publication?
yes
id
96bb76f5-c097-4e23-b980-a9e1dad28c3e
date added to LUP
2025-11-01 07:57:49
date last changed
2025-11-03 09:28:29
@article{96bb76f5-c097-4e23-b980-a9e1dad28c3e,
  abstract     = {{Understanding vegetation sensitivity to hydroclimate factors, especially how carbon and water cycles respond to climate change, is crucial for assessing ecosystem vulnerability. However, the seasonal sensitivity of carbon and water fluxes to temperature, radiation, soil water content, and vapor pressure deficit across diverse biomes and climates remains unclear. Here, we use 196 eddy covariance observations from sensor networks distributed globally, along with daily estimates from Earth System Models (ESMs), to quantify the seasonal sensitivity of daily gross primary productivity (GPP), ecosystem respiration (RE), net ecosystem productivity (NEP), and evapotranspiration (ET) to various hydroclimate factors. Our ridge regression analysis reveals seasonal variations in the sensitivity of carbon and water fluxes to hydroclimate factors across globally distributed flux sites. GPP and NEP are most sensitive to air temperature (TA) in spring, but to radiation (RAD) in summer, autumn and winter. RE consistently exhibits positive sensitivity to TA across all seasons, while ET shows the highest sensitivity to RAD throughout the year. Although energy-related factors like TA and RAD dominate the influence on carbon and water fluxes at sub-seasonal scales, soil water content (SWC) and vapor pressure deficit (VPD) become increasingly important during summer, particularly in drylands. At sites with long-term measurements, we identified a significant upward trend in the sensitivity of summer GPP to SWC with 0.005 ± 0.002 per year, suggesting that terrestrial ecosystems are becoming more constrained by water stress during summer. Compared to observations, ESMs generally overestimate the sensitivity of GPP to SWC and VPD, while underestimate the sensitivity to RAD and TA during summer. Our findings enhanced the understanding of the seasonal response of ecosystem carbon and water cycles to hydroclimate factors, offering insights into ecosystem function under future climate change.}},
  author       = {{Ting, Wang and Fu, Zheng and Makowski, David and Liang, Guopeng and Jin, Hongxiao and Zhang, Fangyue}},
  issn         = {{1873-2240}},
  keywords     = {{Carbon and water fluxesEddy covarianceHydroclimate factorsSeasonal variationsSensitivity}},
  language     = {{eng}},
  month        = {{11}},
  publisher    = {{Elsevier}},
  series       = {{Agricultural and Forest Meteorology}},
  title        = {{Seasonal divergence in the sensitivity of carbon and water fluxes to climate variability in terrestrial ecosystems}},
  url          = {{http://dx.doi.org/10.1016/j.agrformet.2025.110916}},
  doi          = {{10.1016/j.agrformet.2025.110916}},
  volume       = {{376}},
  year         = {{2025}},
}