Subsurface phytoplankton vertical structure observations using offshore fixed platform-based lidar in the Bohai Sea for offshore responses to Typhoon Bavi.

Subsurface phytoplankton vertical structure was observed using an offshore fixed platform-based lidar in the Bohai Sea for the first time. The lidar obtained two periods of continuous day-and-night measurements for a week. A hybrid retrieval method for the optical properties and chllorophyll-a concentration vertical structure of seawater using lidar data was developed. We studied offshore subsurface phytoplankton vertical variation responses to Typhoon Bavi. Significant changes in the intensity and depth of the subsurface phytoplankton maximum layer in the Bohai Sea may result from horizonal advection, light availability, and rainfall dilution following Typhoon Bavi. Preliminary results suggested that lidar measurements provide a new approach for understanding oceanic dynamics mechanisms at the submeso-mesoscale.