2025/05/27 by Weize Tang, Fangyue Zhang, Paul C. Stoy +3 · 1 voice
Earth and Planetary Sciences · Environmental Science · #Atmospheric and Environmental Gas Dynamics #Atmospheric chemistry and aerosols #Meteorological Phenomena and Simulations
paper · doi:10.1111/pce.15638
openalex publication_date 2025/05/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/25
ABSTRACT Gross primary productivity (GPP) is the key pathway for CO 2 uptake by terrestrial ecosystems. Diurnal variation in atmospheric CO 2 concentration ([CO 2 ]) can reach 5%–15%, yet the extent to which (CO 2 ) contributes to diurnal GPP variations across biomes and how this contribution varies across climate gradients remain unclear. Here, we used global half‐hourly eddy covariance observations to quantify the importance of (CO 2 ) in driving diurnal GPP variations and investigated the environmental factors influencing this response. On average, the relative contribution of (CO 2 ) to diurnal GPP variations, calculated through multivariate regression, was 11% across all sites, comparable to the contributions of vapour pressure deficit (13%) and soil moisture (11%). We also observed systematic differences in the contribution of (CO 2 ) to GPP variability across ecosystems with different plant functional types and climate conditions. Variation in the contribution of (CO 2 ) to GPP is primarily driven by temperature‐related variables. At long‐term sites, we identified a significant upward trend in (CO 2 ) influence on GPP over time, suggesting an increasing role of (CO 2 ) in explaining GPP variations. This study quantified the importance of (CO 2 ) to the diurnal variations of GPP across globally distributed ecosystems and highlighted that it makes a significant contribution to diurnal GPP patterns.