资源环境科技发展态势分析平台

Much uncertainty remains in measuring the inter-annual and longer–term dynamics of vegetation gross and net primary productivity (GPP, NPP) and the connected land carbon sink. Potential for better GPP estimation lies in newer satellite products representing different processes or vegetation states, but how they capture inter–annual GPP dynamics remains to be explored. Here we differentiate shorter– and longer–term vegetation dynamics and their drivers for several Earth-observation-based vegetation proxies and a GPP estimate using time series decomposition. We find that relations between proxies can significantly differ between time scales, along land cover and climate gradients. For GPP estimated at FLUXNET sites, seasonal and multi–annual slopes differ by at least 25% for half of the cases investigated, indicating considerable mismatch if multi–annual relations were derived from seasonal slopes. Considering time–scale–specific sensitivities between proxies of vegetation productivity may improve estimates of inter–annual variability in vegetation productivity.