Physical Oceanography Physical Oceanography 1573-160X 20250508 Satellite hydrophysics Research Article Features of Results of Optical Observations of the Black Sea from Space in Summer 2015 https://orcid.org/0000-0001-7278-667X M-6879-2018 Suetin V. S. v.suetin@mhi-ras.ru https://orcid.org/0000-0001-5704-8863 M-6584-2018 Korolev S. N. s.korolev@mhi-ras.ru Marine Hydrophysical Institute of RAS Sevastopol Russian Federation 31 10 2025 32 5 690 702 21 11 2024 18 06 2025 11 07 2025 Copyright © 2025, V. S. Suetin, S. N. Korolev 2025 V. S. Suetin, S. N. Korolev https://creativecommons.org/licenses/by-nc/4.0/ https://physical-oceanography.ru/repository/issues/2025/05/08/

Purpose. The study aims to analyze the results of satellite observations of the Black Sea in summer 2015 during the period of increased chlorophyll a concentration in its deep-water region.

Methods and Results. We analyzed NASA archive products from MODIS and VIIRS optical data updated during the 2022 archive reprocessing. To ensure reliable conclusions, we compared synchronous observations from Aqua, Terra and Suomi NPP satellites and analyzed spectral dependencies of sea surface reflectance. Additionally, we compared chlorophyll a concentration estimates in the sea near-surface layer using two different methods: the standard NASA processing method and an alternative approach based on calculating the phytoplankton-related light absorption coefficient. This value is calculated using the GIOP (Generalized ocean color inversion model for retrieving marine Inherent Optical Properties) procedure and is included in the NASA archive among other products.

Conclusions. Analysis of satellite observations revealed the need to account for significant errors and distortions. After excluding erroneous data, we found that chlorophyll a concentrations in the eastern deep-water region at the end of summer 2015 reached anomalously high values of ~ 1–2 mg/m3.

 Black Sea satellite observations chlorophyll a concentration optical characteristics light absorption MODIS VIIRS GIOP phytoplankton yellow substance The study was carried within the framework of theme of state assignment of FSBSI FRC MHI FNNN-2024-0012 “Analysis, nowcast and forecast of the state of hydrophysical and hydrochemical fields of marine water areas based on mathematical modeling using the data of remote and contact measurement methods.”

Article text not included.

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