Xu, XJ; Zhou, GM; Du, HQ; Mao, FJ; Xu, L; Li, XJ; Liu, LJ (2020). Combined MODIS land surface temperature and greenness data for modeling vegetation phenology, physiology, and gross primary production in terrestrial ecosystems. SCIENCE OF THE TOTAL ENVIRONMENT, 726, 137948.

Vegetation phenology such as the start (SOS) and end (EOS) of the growing season, physiology (represented by seasonal maximum capacity of carbon uptake, GPPmax), and gross primary production (GPP) are sensitive indicators formonitoring ecosystemresponse to environmental change. However, uncertainty and disagreement between models limit the use phenologymetrics and GPP derived fromremote sensing data. Statistical models for estimating phenology and physiologywere constructed based on key predictor variables derived from enhanced vegetation index (EVI) and land surface temperature (LST) data. Then, a statistical model that integrated remote sensing-based phenology and physiology (RS-SMIPP) datawas constructed to estimate seasonal and annual GPP. Thesemodelswere calibrated and validatedwith GPP observations from512 site-years of FLUXNET data covering four plant functional types (PFTs) in the northern hemisphere: deciduous broadleaf forest, evergreen needle-leaf forest, mixed forest, and grassland. Our results showed that phenology and physiologywere accurately estimated with relative root mean squared error (RMSEr) <20%, and the errors varied among the PFTs. Spring EVI was an important factor in explaining variation of GPPmax. The RS-SMIPP model outperformed the MOD17 algorithm in accurately estimating seasonal and annual GPP and reduced RMSEr from 25.34%-43.44% to 9.53%-26.19% for annual GPP of the different PFTs. These findings demonstrate that remote sensing-based phenological and physiological indicators could be used to explain the variations of seasonal and annual GPP, and provide an efficient way for improving GPP estimations at a global scale. (C) 2020 Elsevier B.V. All rights reserved.