4D structure of bio-optical characteristics of the upper 70 m layer of the Black Sea: Bio-Argo floats and ocean color scanners

Abstract

Assessment of the marine ecosystem function and energy and matter fluxes in marine food web requires the knowledge on light field in the sea upper layer. Detailed information about light field needed for correct assessment of the primary production in the sea. To describe downwelling irradiance in the sea the vertical distribution of the all in water optically active components should be known. The mean profile and two eigenvectors of chlorophyll-a concentration, particle backscattering coefficient, colored dissolved organic matter absorption coefficient and temperature have been derived from bio-Argo float data within 0–70 m layer with 5 m resolution. Long-term (2013–2018) dataset of bio-Argo float data have been used to get ten-days averaged parameter values - 37 data subsets/year. To get link between surface satellite data and statistics (parameter profiles) derived from bio-Argo float the chlorophyll-a concentration, light absorption coefficient of colored detrital matter at 490 nm and particle backscattering coefficient at 555 nm retrieved based on regional algorithms, temperature - standard satellite product have been related with statistics derived from bio-Argo float measurements of chlorophyll-a concentration, particle backscattering, colored dissolved organic matter and temperature in surface layer. The obtained relationships allowed to solve the task - to retrieve 4D fields (x,y,z,t) of parameters in the 0–70 m layer of the Black Sea.