Determination of the Concentration of Seawater Components based on Upwelling Radiation Spectrum

Abstract

Results of seawater reflectance measurements carried out in the Black Sea coastal waters in the summer-autumn season, 2002-2014 on the oceanographic platform of the Experimental Department of MHI are discussed. The data were obtained using the spectrophotometer developed in the Marine Optics Department of MHI. Special measuring technique allows one to take into account the light reflected by the sea surface that eliminates necessity in sub-surface probing and provides higher accuracy as compared to the results of the model simulations. The measurements show that in the summer-autumn period the sea reflectance spectra are of almost constant shape with a smooth peak in the range 480-500 nm. The peak values usually lie within between 1% (October) and 2% (July), except for the spectra measured during the coccolythophore bloom in 2012 when the peak values reached 6.6% (4.5% on average). The semi-analytical algorithm of reflectance data processing permits to obtain inherent optical properties of seawater including the phytoplankton pigments' concentration, absorption by nonliving organic matter and scattering by marine particles, and also to detect the auxiliary photosynthetic pigments from the reconstructed phytoplankton absorption spectrum. Special optimization technique permitting to simplify and to stabilize calculations is introduced. The chlorophyll-a concentrations obtained using the algorithm are in good agreement with direct biological data. Simultaneous measurements of reflectance and chlorophyll-a concentration performed during the sub-satellite experiment in [2002][2003][2004] have shown that discrepancy between the modeled and the measured concentrations was about 10%. The considered method permits to carry out operational sub-satellite monitoring of marine environment and, in particular, to validate the algorithms for processing remote sensing data.

Seasonal Stages of Chlorophyll‐a Vertical Distribution and Its Relation to the Light Conditions in the Black Sea From Bio‐Argo Measurements

“…This is due to the impact of other optical constituents on the light attenuation, among which dissolved organic matter, is one of the most important. One of the main source of the dissolved organic matter in the semiclosed Black Sea basin is high river discharge (Churilova et al, 2009;Lee et al, 2015;Mankovsky et al, 2010;Vladimirov et al, 1997;Xing et al, 2017). On the other hand, the seasonal variability of the dissolved organic matter in the most upper layers is largely related to the phytoplankton blooms.…”

Correlations between the Parameters of the Light Volume Scattering Functions in the Mediterranean Sea Surface Waters

“…Information on the light scattering characteristics is necessary to solve many problems related to ocean optics, for example [1][2][3]. Hence, the study the light scattering in waters of different regions of the World Ocean [4][5][6][7][8][9][10][11][12][13][14][15] is relevance.…”