A daily and 500 m coupled evapotranspiration and gross primary production product across China during 2000–2020

[摘要] Accurate high-resolution actual evapotranspiration (ET)and gross primary production (GPP) information is essential forunderstanding the large-scale water and carbon dynamics. However,substantial uncertainties exist in the current ET and GPP datasets in Chinabecause of insufficient local ground measurements used for model constraint. This study utilizes a water–carbon coupled model, Penman–Monteith–Leuning Version 2 (PML-V2), to estimate 500 m ET and GPP at a daily scale. The parameters of PML-V2(China) were well calibrated against observations of 26 eddy covariance flux towers across nine plant functional types in China,indicated by a Nash–Sutcliffe efficiency (NSE) of 0.75 and a root mean square error (RMSE) of 0.69 mm d −1 for daily ET, respectively, and a NSE of 0.82 and a RMSE of 1.71 g C m −2  d −1 for daily GPP. The model estimates get a small Bias of 6.28 % and a high NSE of 0.82 against water-balance annual ET estimatesacross 10 major river basins in China. Further evaluations suggest that thenewly developed product is better than other typical products (MOD16A2,SEBAL, GLEAM, MOD17A2H, VPM, and EC-LUE) in estimating both ET and GPP. Moreover, PML-V2(China) accurately monitors the intra-annual variations in ET and GPP in the croplands with a dual-cropping system. The new data showedthat, during 2001–2018, the annual GPP and water use efficiency experienced a significant ( p 0 .05) increase (0.43 mm yr −2 ). Thisindicates that vegetation in China exhibits a huge potential for carbonsequestration with little cost in water resources. The PML-V2(China) productprovides a great opportunity for academic communities and various agenciesfor scientific studies and applications, freely available at https://doi.org/10.11888/Terre.tpdc.272389 (Zhang and He, 2022).

[学科分类] 眼科学