A Robust Estimate of Continental‐Scale Terrestrial Carbon Sinks Using GOSAT XCO₂ Retrievals

Satellite XCO2 retrievals could improve the estimates of surface carbon fluxes, but it remains unknown on what scales these are robust. Here, we use time-dependent Bayesian synthesis top-down method and prior net ecosystem exchanges (NEEs) from 12 terrestrial biosphere models (TBMs) to infer monthly fluxes 51 land regions with constraints by GOSAT retrievals. We find that uncertainty (standard deviation TBMs) reduction rates (uncertainty rate (URR)) decrease significantly at decreasing spatial scales. On continental-scale, mean URR is about 57%, annual seasonal cycle NEE rather The evaluation shows posterior CO2 concentrations improved continental scale. Our study suggests can only promise a robust continental-scale estimate, improving accuracy an effective way achieve smaller under current coverage.