资源环境科技发展态势分析平台

Accurate estimation of the underwater light field associated with photosynthetically available radiation (PAR) is a critical ocean parameter necessary to compute phytoplankton growth rate, net primary production (NPP), and to assess photo‐physiological response of phytoplankton, such as changes in cellular pigmentation. However, methods to estimate PAR used in many previous studies lack in accuracy, likely resulting in significant bias in light‐dependent products such as NPP derived from remote sensing, model simulations, or autonomous platforms. Here we propose and validate a chlorophyll‐based model for more accurate estimation of the subsurface PAR profile which uses chlorophyll‐a as its input. Validation is performed using 1,744 BGC‐Argo profiles of chlorophyll fluorescence that are calibrated with surface satellite‐derived chlorophyll concentration over their lifetime. The independent verification with the float’s PAR sensors confirms the accuracy of satellite chlorophyll estimate worldwide and in the Southern Ocean in particular.