scholarly journals Quality of the Wind Wave Forecast in the Black Sea Including Storm Wave Analysis

2021 ◽  
Vol 13 (23) ◽  
pp. 13099
Author(s):  
Stanislav Myslenkov ◽  
Alexander Zelenko ◽  
Yuriy Resnyanskii ◽  
Victor Arkhipkin ◽  
Ksenia Silvestrova
Keyword(s):  
Black Sea ◽  
Wind Wave ◽  
Altimeter Data ◽  
The Black Sea ◽  
Bias Error ◽  
Regular Grid ◽  
Wavewatch Iii ◽  
Wave Forecast ◽  
Forecast Quality

This paper presents the results of wind wave forecasts for the Black Sea. Three different versions utilized were utilized: the WAVEWATCH III model with GFS 0.25 forcing on a regular grid, the WAVEWATCH III model with COSMO-RU07 forcing on a regular grid, and the SWAN model with COSMO-RU07 forcing on an unstructured grid. AltiKa satellite altimeter data were used to assess the quality of wind and wave forecasts for the period from 1 April to 31 December 2017. Wave height and wind speed forecast data were obtained with a lead time of up to 72 h. The presented models provide an adequate forecast in terms of modern wave modeling (a correlation coefficient of 0.8–0.9 and an RMSE of 0.25–0.3 m) when all statistics were analyzed. A clear improvement in the wave forecast quality with the high-resolution wind forecast COSMO-RU07 was not registered. The bias error did not exceed 0.5 m in an SWH range from 0 to 3 m. However, the bias sharply increased to −2 or −3 m for an SWH range of 3–4 m. Wave forecast quality assessments were conducted for several storm cases.

scholarly journals A study of long-term changes in Black Sea ecosystems based on data assimilation of remote measurements in a numerical model

2019 ◽  
Vol 46 (1) ◽  
pp. 58-69
Author(s):  
V. L. Dorofeev ◽  
L. I. Sukhikh
Keyword(s):  
Black Sea ◽  
Marine Ecosystem ◽  
Three Dimensional ◽  
The Black Sea ◽  
Regular Grid ◽  
Remote Measurements ◽  
Biogeochemical Parameters ◽  
Color Scanner

Herein, we present a simulation of the dynamics of Black Sea ecosystems using a three-dimensional interdisciplinary model that assimilates satellite color scanner measurements. Calculations were performed for the fifteen years from 1998 and a set of 3-d biogeochemical fields of the Black Sea were generated on a regular grid with a discreteness time of 1 day. Analyses of core biogeochemical parameters of the marine ecosystem were then performed. The qualities of received fields were evaluated using comparisons with existing data from in situ measurements.

Earth Observation products  for Science and Innovation in the Black Sea

2021 ◽  
Author(s):  
Marilaure Grégoire ◽  
Keyword(s):  
Black Sea ◽  
Earth Observation ◽  
Sea Surface Salinity ◽  
The Black Sea ◽  
Full Potential ◽  
Ocean Colour ◽  
Surface Salinity ◽  
Mesoscale Dynamics

<p>The Black Sea is a small enclosed basin where coastal regions have a large influence and mesoscale signals dominate the dynamics (the Rossby radius of deformation is about 20km). Large riverine inputs, mainly on the northwestern shelf, induce well-marked horizontal gradients in the distribution of the Black Sea salinity and optical characteristics: coastal and shelf waters have very low salinity and contain large amounts of optically active materials (e.g. coloured dissolved organic matter) and its oligotrophic deep sea has a salinity around 18.2. The presence of these contrasting water characteristics in a relatively small enclosed environment, combined with land contamination and the specificities of its atmospheric composition(e.g. high cloud coverage, aerosols) make the Black Sea a challenging area for the development of high quality satellite products. </p><p> </p><p>We present first results from a 2-year on-going ESA-funded project, EO4SIBS (Earth Observation for Science and Innovation in the Black Sea) dedicated to the development, and subsequent scientific analysis, of new algorithms and products. In particular, ocean colour products (chlorophyll-a and total suspended matter concentrations, turbidity) were produced from Sentinel 3 (S3) OLCI data combining different algorithms selected based on an automatic water mass classification procedure (case-1 versus case-2 waters). In specific areas, S3-OLCI and Sentinel 2-MSI data were merged to address local features. A revised gridded altimetry product based on 5-Hz along track data (combining Cryosat and S3 SAR) was produced and validated in the coastal zone with tide gauge data. Sea Surface Salinity was derived from the L-Band measured by SMOS and compared with in-situ surface salinity data from field sampling and Argo. </p><p> </p><p>All these products are now being integrated to further understand the Black Sea physical and biogeochemical functioning (e.g., plume and productivity patterns, mesoscale dynamics, deoxygenation). For instance, the Black Sea mesoscale dynamics are inferred from the 5-Hz altimetry product using an eddy detection and tracking algorithm. The quality of the eddy mapping is assessed by comparison with visible and infrared satellite products while the derived velocities are compared with drifters. Also, the benefit of assimilating ocean colour data in the Black Sea operational model (also known as CMEMS BS-MFC BIO) for the prediction of the Black Sea ecosystem will  be illustrated.</p><p> </p><p>Gridded products are archived as CF-compliant NetCDF files and disseminated through ncWMS protocol. In-situ data are modeled as vector points in a PostGIS database. A web portal is being implemented in order to propose an efficient spatiotemporal exploration of both data sources in a user-friendly interface, including interactive map layers and export possibilities.</p><p> </p><p>We conclude with a set of recommendations for observational requirements needed  to increase the quality of satellite products in the Black Sea and to be able to use the full potential of current and new information provided by  satellites. </p><p> </p>

IMPROVEMENT OF THE BIOLOGICAL EFFECTIVENESS OF FAT FROM THE LIVER OF THE BLACK SEA SHARK-KATRAN

2021 ◽  
Author(s):  
Е.Е. ИВАНОВА ◽  
Е.А. ДУБИНЕЦ ◽  
А.Л. БОЧАРОВА-ЛЕСКИНА
Keyword(s):  
Fatty Acids ◽  
Iodine Number ◽  
Black Sea ◽  
Liquid Fraction ◽  
Saturated Fatty Acids ◽  
Biologically Active ◽  
The Black Sea ◽  
Omega 3 ◽  
Biological Effectiveness

Для стабилизации показателя биологической эффективности исследована возможность повышения количества полиненасыщенных жирных кислот (ПНЖК) за счет снижения количества насыщенных жирных кислот (НЖК) в жирнокислотном составе жира из печени черноморской акулы-катрана в летний период вылова (с мая по октябрь). С целью повышения содержания омега-3 ПНЖК в продукте применен способ винтеризации. Кристаллизацию жира из печени акулы-катрана проводили в специальном охладителе при температуре от 0 до –5°С. Во время охлаждения жир медленно перемешивали (скорость вращения мешалки 20–25 об/мин) для равномерного охлаждения по всему объему. Полная кристаллизация НЖК при этих условиях проходила за 5–6 ч. Охлажденный жир немедленно направляли на осадительную центрифугу. В качестве параметров оптимизации процесса были выбраны: качество жира – прозрачность при температуре 15°С и степень ненасыщенности – йодное число жира. Установлено, что факторами, существенно влияющими на йодное число и органолептические показатели жира, являются: температура охлажденного жира, продолжительность центрифугирования, число оборотов барабана центрифуги. Для моделирования значений йодного числа и органолептического показателя в области изменения указанных факторов применена схема полного факторного двухуровневого эксперимента, в результате которого определены натуральные значения факторов, отвечающие наилучшему значению показателя качества жира: температура охлаждения жира –4°С, продолжительность центрифугирования 30 мин, частота вращения барабана центрифуги 6000 об/мин. Общая ненасыщенность жидкой фракции возросла с 122,2–138,0 до 131,0–145,0% йодного числа жира. Полученный очищенный жир был прозрачен, имел светло-желтый цвет, низкие значения кислотного и перекисного чисел. Содержание ПНЖК в полученном продукте увеличилось на 10–30%. Содержание неомыляемых веществ в нем, в том числе биологически активных веществ алкилглицеролов, при этом не снизилось. Биологическая эффективность жира увеличилась с 0,6 до 0,9. To stabilize the increased biological effectiveness the possibility of increasing the amount of polyunsaturated fatty acids (PUFA) by reducing the amount of saturated fatty acids (SFA) in the fatty acid composition of fat from the liver of the black sea shark-katran in the summer fishing period (May – October) is investigated. With the aim of increasing the content of omega-3 PUFA in the product method of winterization was applied. Crystallization of fat from the liver of sharks-katran dogfish was conducted in a special chiller with temperature from 0 to –5°C. During cooling, the fat is slowly stirred (speed of rotation of the mixer 20–25 rpm) for uniform cooling throughout. Full crystallization of SFA under these conditions was held for 5–6 h. The cooled fat was immediately sent to precipitating in the centrifuge. Quality of fat – transparency at a temperature of 15°C and unsaturation – iodine number of fat was selected as the optimization parameters of the process. It is established that: the temperature of the refrigerated fat, the duration of centrifugation, the number of drum rotations of the centrifuge are factors that significantly affect the iodine number and the organoleptic indicators of fat. Scheme two-level full factorial experiment was applied for modeling the values of iodine number and organoleptic indicator in changing these factors. Natural values of factors corresponding to the best value of indicator of the quality of the fat: temperature of cooling fat –4°C, duration of centrifugation 30 min, and the speed of rotation of the drum centrifuge 6000 rpm were determined in the experiment. The result of this treatment, the total unsaturation of the liquid fraction increased from 122,2–138,0 up to 131,0–145,0% of iodine number. The purified obtained fat was transparent, had a light yellow color, low acid value and peroxide values. In the obtained product the content of PUFA increased by 10–30%. The content of unsaponifiables in it, including biologically active substances alkylglycerols, was not decreased. The biological effectiveness of fat increased from 0,6 to 0,9.

scholarly journals How Does Solar Attenuation Depth Affect the Ocean Mixed Layer? Water Turbidity and Atmospheric Forcing Impacts on the Simulation of Seasonal Mixed Layer Variability in the Turbid Black Sea*

2005 ◽  
Vol 18 (3) ◽  
pp. 389-409 ◽  
Author(s):  
A. Birol Kara ◽  
Alan J. Wallcraft ◽  
Harley E. Hurlburt
Keyword(s):  
Solar Radiation ◽  
Black Sea ◽  
Mixed Layer ◽  
Sea Surface ◽  
Shortwave Radiation ◽  
Altimeter Data ◽  
The Black Sea ◽  
Upper Ocean ◽  
Clear Water ◽  
Water Turbidity

Abstract A fine-resolution (≈3.2 km) Hybrid Coordinate Ocean Model (HYCOM) is used to investigate the impact of solar radiation attenuation with depth on the predictions of monthly mean sea surface height (SSH), mixed layer depth (MLD), buoyancy and heat fluxes, and near-sea surface circulation as well. The model uses spatially and temporally varying attenuation of photosynthetically available radiation (kPAR) climatologies as processed from the remotely sensed Sea-Viewing Wide Field-of-View Sensor (SeaWiFS) to take water turbidity into account in the Black Sea. An examination of the kPAR climatology reveals a strong seasonal cycle in the water turbidity, with a basin-averaged annual climatological mean value of 0.19 m−1 over the Black Sea. Climatologically forced HYCOM simulations demonstrate that shortwave radiation below the mixed layer can be quite different based on the water turbidity, thereby affecting prediction of upper-ocean quantities in the Black Sea. The clear water constant solar attenuation depth assumption results in relatively deeper MLD (e.g., ≈+15 m in winter) in comparison to standard simulations due to the unrealistically large amount of shortwave radiation below the mixed layer, up to 100 W m−2 during April to October. Such unrealistic sub–mixed layer heating causes weaker stratification at the base of the mixed layer. The buoyancy gain associated with high solar heating in summer effectively stabilizes the upper ocean producing shallow mixed layers and elevated SSH over the most of the Black Sea. In particular, the increased stability resulting from the water turbidity reduces vertical mixing in the upper ocean and causes changes in surface-layer currents, especially in the easternmost part of the Black Sea. Monthly mean SSH anomalies from the climatologically forced HYCOM simulations were evaluated against a monthly mean SSH anomaly climatology, which was constructed using satellite altimeter data from TOPEX/ Poseidon (T/P), Geosat Follow-On (GFO), and the Earth Remote Sensing Satellite-2 (ERS-2) over 1993–2002. Model–data comparisons show that the basin-averaged root-mean-square (rms) difference is ≈4 cm between the satellite-based SSH climatology and that obtained from HYCOM simulations using spatial and temporal kPAR fields. In contrast, when all solar radiation is absorbed at the sea surface or clear water constant solar attenuation depth values of 16.7 m are used in the model simulations, the basin-averaged SSH rms difference with respect to the climatology is ≈6 cm (≈50% more). This demonstrates positive impact from using monthly varying solar attenuation depths in simulating upper-ocean quantities in the Black Sea. The monthly mean kPAR and SSH anomaly climatologies presented in this paper can also be used for other Black Sea studies.

scholarly journals FUNCTIONAL STATE OF THE MARINE MICROALGAE CULTURES AS AN INDICATOR OF THE WATER POLLUTION LEVEL OF THE SEVASTOPOL BAY

2021 ◽  
pp. 83-90
Author(s):  
L.V. Stelmakh ◽  
◽  
I.M. Mansurova ◽  
Keyword(s):  
Functional State ◽  
Black Sea ◽  
Phaeodactylum Tricornutum ◽  
Inhibitory Effect ◽  
The Black Sea ◽  
Pollution Level ◽  
Sevastopol Bay ◽  
Algae Growth ◽  
Taxonomic Affiliation

The possibility of using cultures of Black Sea planktonic microalgae of different taxonomic affiliation to assess the quality of the aquatic environment based on the assessment of their functional state is shown. The research was carried out on the diatom Phaeodactylum tricornutum, three dinoflagellates species Prorocentrum cordatum, Prorocentrum pusillum and Gyrodinium fissum, as well as the coccolithopho-ride Emiliania huxleyi. It was found that the waters of the Sevastopol Bay in the period from May to August 2021 in 50% of cases had a weak inhibitory effect on the growth of the tested species. In other cases, algae growth was either stimulated or the effect of pollution on cultures was not revealed. The need for using several types of algae in carrying out complex work on water biotesting of the coastal are-as of the Black Sea is highlighted.

scholarly journals Operational numerical wind-wave model for the Black Sea

2000 ◽  
Vol 1 (1) ◽  
pp. 65
Author(s):  
A. KORTCHEVA ◽  
G. KORTCHEV ◽  
J. M. LEFEVRE
Keyword(s):  
Shallow Water ◽  
Real Time ◽  
Wave Height ◽  
Black Sea ◽  
Water Wave ◽  
Wind Wave ◽  
Wave Model ◽  
The Black Sea ◽  
Sea State ◽  
Height Data

In this paper the discrete spectral shallow water wave model named VAGBUHL1 is presented. This model is used for real-time Black Sea state forecasting. The model was verified against satellite ERS-2 altimeter wave height data.

scholarly journals Mean dynamic topography of the black sea, computed from altimetry, drifters measurements and hydrology data

2011 ◽  
Vol 8 (2) ◽  
pp. 701-722 ◽  
Author(s):  
A. A. Kubryakov ◽  
S. V. Stanichny
Keyword(s):  
Sea Level ◽  
Black Sea ◽  
The Black Sea ◽  
Dynamic Topography ◽  
Mean Dynamic Topography ◽  
Sea Level Anomalies ◽  
Temporal Features ◽  
Geostrophic Velocities ◽  
Mesoscale Processes

Abstract. Mean Dynamic Topography (MDT) is a crucial parameter for estimating dynamic topography, and, therefore, geostrophic circulation from satellite altimetry Sea Level Anomalies (SLA). In this work we use drifting buoy measurements, hydrographic profiles and SLA to reconstruct MDT of the Black Sea by "synthetic" method. Obtained mean dynamic topography shows higher gradients of sea level and resolves a lot of mesoscale processes in comparison to previous works, mostly based on climatic hydrological measurements. Verification of dynamic topography determined by altimetry SLA and estimated MDT, with independent dynamic heights and drifter buoy velocities shows good quantitative and qualitative coincidence for all Black Sea basin and improvements compare to previous fields of MDT. New MDT for the Black Sea will improve quality of altimetry derived geostrophic velocities for better understanding of the spatial and temporal features of the upper layer dynamics.

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