In situ autonomous optical radiometry measurements for satellite ocean color validation in the Western Black Sea

• Published in: Ocean science Vol. 11; no. 2; pp. 275 - 286
• Main Authors: Zibordi, G, Mélin, F, Berthon, J.-F, Talone, M
• Format: Journal Article
• Language: English
• Published: Katlenburg-Lindau Copernicus GmbH 26.03.2015; Copernicus Publications
• Subjects: Aerosol Robotic Network; Annual variations; Chlorophyll; Chlorophyll a; Climate; Coastal waters; Color; Comparative analysis; Equivalence; In situ measurement; Infrared radiometers; Investigations; Ocean color; Ocean colour; Oceans; Optical properties; Quality control; Quality standards; Radiance; Radiation measurement; Radiometers; Radiometry; Ratios; Salinity; Satellite ocean color data; Satellites; Spectroradiometers; Time series; Wavelengths; Black Sea
• ISSN: 1812-0792; 1812-0784; 1812-0792
• DOI: 10.5194/os-11-275-2015

The accuracy of primary satellite ocean color data products from the Moderate Resolution Imaging Spectroradiometer on-board Aqua (MODIS-A) and the Visible/Infrared Imager/Radiometer Suite (VIIRS) is investigated in the Western Black Sea using in situ measurements from the Gloria site included in the ocean color component of the Aerosol Robotic Network (AERONET-OC). The analysis is also extended to an additional well-established AERONET-OC site in the northern Adriatic Sea characterized by optically complex coastal waters exhibiting similarities to those observed at the Gloria site. Results from the comparison of normalized water-leaving radiance LWN indicate biases of a few percent between satellite-derived and in situ data at the center wavelengths relevant for the determination of chlorophyll a concentrations (443–547 nm, or equivalent). Remarkable is the consistency between the annual cycle determined with time series of satellite-derived and in situ LWN ratios at these center wavelengths. Contrarily, the differences between in situ and satellite-derived LWN are pronounced at the blue (i.e., 412 nm) and red (i.e., 667 nm, or equivalent) center wavelengths, confirming difficulties in confidently applying satellite-derived radiometric data from these spectral regions for quantitative analysis in optically complex waters.