Sensitivity of a carbon-based primary production model on satellite ocean color products

Abstract

Satellite remote sensing plays a crucial role in estimating global primary production. One well-known model is the carbon-based production model (CbPM), which focuses on the estimation of carbon biomass (Cph) via particulate backscattering coefficient at 443 nm (bbp(443)) and emphasizes the physiological characteristics of phytoplankton. However, as there are various remote sensing algorithms for the estimation of bbp(443) and chlorophyll-a concentration (Chl), the impacts introduced by different bbp(443) and Chl products on the estimated water-column integrated primary production (PPeu) by CbPM are unknown, especially with the new CbPM version (CbPM08) (Westberry et al., 2008). In this study, we conducted analyses to examine the impact of Chl, bbp(443), and Kd(490) (the diffuse attenuation coefficient at 490 nm) that were derived from ocean color remote sensing on PPeu estimated by CbPM08. Our results revealed that Chl constitutes the primary source of model uncertainty, followed by Kd(490), while variations of bbp(443) exhibit negligible impact on the estimation of PPeu. Especially, between Chl and Cph, sensitivity studies indicate that the PPeu values estimated by CbPM08 are fundamentally driven by Chl, rather than by Cph (or bbp(443)). These results provide important insights on understanding the uncertainties associated with CbPM08-estimated PPeu and future directions for further improvement for the estimation of PPeu via this model, as well as its applications on estimating water-column primary production.