Optimal primary production model and parameterization in the eastern East China Sea

Abstract

Integrated primary production (IPP) datasets from the eastern East China Sea (ECS) were used to validate the depth dependent and time integrated model (TIM), the empirical model (EM), and the vertically generalized production model (VGPM). Employing constant maximum chlorophyll-a (Chl-a) specific carbon fixation rate (P opt B ), the original TIM could not explain measured IPP variance, while the low P opt B estimated using P opt B models originally embedded in the EM were responsible for original EM low estimations. The disparity between P opt B expressions originally embedded in the VGPM and that observed in this study was responsible for the low accuracy of the original VGPM. After locally tuning on the P opt B model, TIM and VGPM could predict well, whereas EM still gave low estimates. This was probably due to the fact that, unlike TIM and VGPM, EM employs a constant factor instead of a light dependent function in describing the depth of light-saturation primary production. The high accuracy of TIM was limited by the complexity of estimating many variable inputs. EM, as a simplest model, should be used with caution in the eastern ECS. Global VGPM with locally adjusted P opt B seemed to be an effective model for estimating IPP in the eastern ECS.