An improved estimate of soil carbon pool and carbon fluxes in the Qinghai-Tibetan grasslands using data assimilation with an ecosystem biogeochemical model

•Three parameterization strategies to reduce C modelling uncertainties were compared.•Soil samples and EC measurements were assimilated to constrain the CENTURY model.•Patterns and magnitudes of SOCD and NEP in the QTP grasslands are estimated.•The estimates by process-based model were compared with existing datasets.