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The sensitivity of North American terrestrial carbon fluxes to spatial and temporal variation in soil moisture: an analysis using radar-derived estimates of root zone soil moisture
journal contribution
posted on 2023-06-09, 19:19 authored by Ke Zhang, Ashehad Ali, Alexander AntonarakisAlexander Antonarakis, Mahta Moghaddam, Sassan Saatchi, Alireza Tabatabaeenejad, Richard Chen, Sermsak Jaruwatanadilok, Richard Cuenca, Wade T Crow, Paul MoorcroftThis study examines the impact of variation in Root-Zone Soil Moisture (RZSM), a key component of the Earth's hydrologic cycle and climate system, on regional carbon fluxes across seven North American ecosystems. P-band Synthetic Aperture Radar-derived RZSM estimates were incorporated into the Ecosystem Demography (ED2) terrestrial biosphere model through a model-data blending approach. Analysis shows that the model qualitatively captures inter-daily and seasonal variability of observed RZSM at seven flux tower sites (r=0.59 ± 0.26 and r= 0.70 ± 0.22 for 0-10cm and 10-40cm soil layers, respectively; P<0.001). Incorporating the remotely-sensed RSZM estimates increases the accuracy (root-mean-square deviations decrease from 0.10 ± 0.07 m3m-3 and 0.09 ± 0.06 m3m-3 to 0.08 ± 0.05 m3m-3 and 0.07 ± 0.03 m3m-3 for 0-10 cm and 10-40 cm soil layers, respectively) of the model's RZSM predictions. The regional carbon fluxes predicted by the native and RZSM-constrained model were used to quantify sensitivities of gross primary productivity (GPP), autotrophic respiration (Ra), heterotrophic respiration (Rh) and net ecosystem exchange (NEE) to variation in RZSM. GPP exhibited the largest sensitivity (6.6 ± 10.7 kgCm-2 y-1?-1) followed by Ra (2.9 ± 7.3 kgCm-2 y-1?-1), Rh (2.6 ± 3.1kg Cm-2 y-1?-1), and NEE (-1.7 ± 7.8 kgCm-2 y-1?-1). Analysis shows that these carbon flux sensitivities varied considerably across regions, reflecting influences of canopy structure, soil properties, and the eco-physiological properties of different plant functional types. This study highlights (1) the importance of: improved terrestrial biosphere model predictions of RZSM to improve predictions of terrestrial carbon fluxes, (2) improved pedotransfer functions, and (3) improved understanding of how soil characteristics, climate, and vegetation composition interact to govern the responses of different ecosystems to changing hydrological conditions.
Funding
AirMOSS; National Aeronautical and Space Administration; NASA Earth Venture-1 09-EV109-0006
History
Publication status
- Published
File Version
- Accepted version
Journal
Journal of Geophysical Research: BiogeosciencesISSN
2169-8961Publisher
American Geophysical UnionExternal DOI
Issue
11Volume
124Page range
3208-3231Department affiliated with
- Geography Publications
Research groups affiliated with
- climate@sussex Publications
Full text available
- No
Peer reviewed?
- Yes
Legacy Posted Date
2019-10-11First Compliant Deposit (FCD) Date
2019-10-10Usage metrics
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