Diffuse attenuation coefficient for downwelling irradiance at 490 nm and its spectral characteristics in the Black Sea upper layer: modeling, in situ measurements and ocean color data

2017 ◽  
Author(s):  
T. Ya. Churilova ◽  
Vyacheslav Suslin ◽  
Violeta K. slabakova
Keyword(s):  
Attenuation Coefficient ◽  
Black Sea ◽  
Spectral Characteristics ◽  
Ocean Color ◽  
In Situ Measurements ◽  
The Black Sea ◽  
Diffuse Attenuation Coefficient ◽  
Color Data ◽  
Downwelling Irradiance

Regional empirical algorithm for an improved retrieval of chlorophyll a concentrations in the Black Sea using Sentinel 3 ocean color data

2021 ◽  
Author(s):  
Violeta Slabakova ◽  
Snejana Moncheva ◽  
Nataliya Slabakova ◽  
Nina Dzembekova
Keyword(s):  
Remote Sensing ◽  
Chlorophyll A ◽  
Black Sea ◽  
Ocean Color ◽  
The Black Sea ◽  
Ocean Color Remote Sensing ◽  
Color Data ◽  
Cubic Polynomial ◽  
Polynomial Formulation

<p>The Black Sea is an extraordinarily complex water body for ocean color remote sensing, as it belong to Case 2 waters, which are characterized by relatively high absorption by Colored Dissolved Organic Matter (CDOM) while the concentration of non-pigmented particulate matter does not co-vary in a predictable manner with chlorophyll <em>a</em> . The optical complexity of the Black Sea is the reason why the standard bio-optical algorithms developed for Case 1 waters, are the source of large uncertainties (of the order of hundreds of percent) of chlorophyll <em>a</em> concentration in the coastal and shelf regions. In the framework of ESA contract “BIO-OPTICS FOR OCEAN COLOR REMOTE SENSING OF THE BLACK SEA - Black Sea Color” we developed empirical ocean color algorithm for chlorophyll<em> a </em>retrieval from Sentinel 3A/OLCI primary ocean color products using the <em>in situ </em>reference bio-optical datasets collected in the Black Sea in the period 2012-2019. Results obtained from the assessment of operational S3A/OLCI chlorophyll products, highlighted and confirmed that the specific regional algorithm is essential for the Black Sea. The coefficients of the regional algorithm were derived from the regression of log-transformed pigment concentrations and remote sensing reflectance ratio at 490nm and 560 nm with determination coefficient R<sup>2</sup> =0.88 and number of samples N=186. The algorithm predicts chlorophyll a values using a cubic polynomial formulation. The result of assessment of the regional chlorophyll <em>a</em> product against independent in situ measurements from the data utilized for algorithm development, showed relatively high accuracy (31.7%), fewer underestimations (MPD=-9.2%) and a good agreement (R<sup>2</sup>=0.66) between datasets indicating that the regional algorithm is more effective in reproducing the  pigment concentration in the Black Sea waters in comparison to the standard Sentinel 3A/OLCI algorithms. Our analysis revealed the importance of providing regional algorithms strictly required to suit the peculiar bio-optical properties featuring this basin. However, this requires collection of accurate<em> in situ </em>measurements in the different parts of the Black Sea. The validity of the reported empirical algorithm obviously depends on the size of the dataset used for its development. The Black Sea waters vary at a basin level due to the sub-regional features, environmental factors and seasonal variability, consequently the presented regional algorithm might have a limited generalization capability. Clearly, more<em> in situ</em> data with improved spatial and temporal coverage are critically needed for further calibration and validation of the ocean color products in the Black Sea.</p>

scholarly journals Assessment of Applicability of Satellite-Derived Ocean Color Data for Studying Variability of Total Suspended Matter in the Surface Layer of the Deep Part of the Black Sea

2020 ◽  
Vol 27 (5) ◽  
Author(s):  
A. S. Kukushkin ◽  
V. V. Suslin ◽  
Keyword(s):  
Surface Layer ◽  
Black Sea ◽  
Suspended Matter ◽  
Temporal Variability ◽  
Ocean Color ◽  
Total Suspended Matter ◽  
The Black Sea ◽  
Backscattering Coefficient ◽  
Color Data

Purpose. Studies of spatial-temporal variability of total suspended matter are necessary for understanding the biochemical processes which form and support stable functioning of a marine ecosystem. The aim of the work is to assess applicability of satellite data for studying total suspended matter variability in the surface layer of the deep part of the Black Sea. Methods and Results. Application of the regression analysis yielded the linear regression equations that unite the in situ measurements of the total suspended matter concentrations in the surface layer in the northeastern (June, 2005–2015) and western (November, 2016, 2017 and December, 2017) deep sea areas, and the regional satellite products (the particulate backscattering coefficient, the absorption coefficient of colored detrital matter and the chlorophyll a concentration). Based on the measured and calculated data arrays, the maps of the total suspended matter concentrations in the surface layer of the northeastern Black Sea were constructed. The interannual changes in the in situ measured concentrations of the total suspended and lithogenic matters, as well as in the quasi-synchronous satellite regional products (the light absorption coefficient of colored detrital matter at 490 nm and the particulate backscattering coefficient at 555 nm) in June, 2005–2015 were considered. High total suspended matter concentrations were noted in 2012, just when extreme growth of the coccolithophorid population was observed in the Black Sea. The correlation coefficients were used to evaluate whether the relation between the total suspended matter concentration and the individual analyzed parameters was fast. Conclusions. Spatial distributions of the measured and calculated total suspended matter contents showed satisfactory agreement. In course of the whole observation period, difference between the values of the measured and calculated total suspended matter concentrations was on average 6–23 %. Possibility of application of the satellite-derived ocean color data for studying spatial-temporal variability of the total suspended matter content is shown.

Satellite monitoring of coccolithophore blooms in the Black Sea from ocean color data

2014 ◽  
Vol 146 ◽  
pp. 113-123 ◽  
Author(s):  
O. Kopelevich ◽  
V. Burenkov ◽  
S. Sheberstov ◽  
S. Vazyulya ◽  
M. Kravchishina ◽  
...  
Keyword(s):  
Black Sea ◽  
Ocean Color ◽  
Satellite Monitoring ◽  
The Black Sea ◽  
Color Data

Photosynthetically available radiation on surface of the Black Sea based on ocean color data

2015 ◽  
Author(s):  
V. V. Suslin ◽  
S. N. Korolev ◽  
A. A. Kucheryaviy ◽  
T. Ya. Churilova ◽  
O. V. Krivenko
Keyword(s):  
Black Sea ◽  
Ocean Color ◽  
The Black Sea ◽  
Photosynthetically Available Radiation ◽  
Color Data

Internal waves in the Black Sea: satellite observations and in-situ measurements

2014 ◽  
Author(s):  
Olga Yu. Lavrova ◽  
Marina I. Mityagina ◽  
Andrey N. Serebryany ◽  
Konstantin D. Sabinin ◽  
Nina A. Kalashnikova ◽  
...  
Keyword(s):  
Internal Waves ◽  
Black Sea ◽  
In Situ Measurements ◽  
Satellite Observations ◽  
The Black Sea
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