Output of CCDAS, assimilating the SIO CO2 concentrations and ESA CCI surface soil moisture data

The two phases of El-Niño-Southern Oscillation (ENSO) impact both regional and global terrestrial vegetation productivity on inter-annual scales. However, the relationships between different phases of ENSO and the regional terrestrial carbon cycle, as well as the major controlling factors, remain unclear. We herein disentangled the impacts of ENSO on regional carbon cycle using multiple sources of datasets, and found that soil water dominantly accounts for ~40% of the variability of regional vegetation productivity during ENSO. Our results showed that the satellite-derived vegetation productivity proxies (VPPs), gross primary productivity (GPP) from data-driven model and observation-constrained ecosystem models are generally consistent in depicting the contribution of soil water and air temperature in modulating regional vegetation productivity and the ensemble of weakly constrained ecosystem models used in global climate assessments exhibits contrasting results in extra-tropical regions. This study highlights the significance of water in regulating regional vegetation productivity during ENSO and suggests that the regional response of vegetation productivity to ENSO may be underrepresented by the loosely constrained models.