scholarly journals Assessment of Current Influence on the Wind Wave Parameters in the Black Sea based on Numerical Modeling

2020 ◽  
Author(s):  
А. D. Rybalko ◽  
S. A. Myslenkov ◽  
◽  
◽  
◽  
...  
Keyword(s):  
Wave Height ◽  
Black Sea ◽  
Wind Waves ◽  
The Black Sea ◽  
Spatial And Temporal Variability ◽  
Positive Contribution ◽  
Wave Parameters ◽  
Wave Heights ◽  
The Mean ◽  
Average Wave

Currents affect wind waves parameters. The issue of significance of this influence for the Black Sea has not been studied properly. The purpose of this paper is to study the scale, spatial and temporal variability of influence of sea currents on the wave height in the Black Sea. The research was carried out based on simulation using SWAN wave model and an irregular computational grid. Two datasets were used as input data: the NCEP/CFSv2 wind reanalysis and current data taken from the Remote Sensing Department's archive of the Marine Hydrophysical Institute of RAS. It is shown that the average wave height mainly decreases when sea current is considered. These changes are insignificant relative to the average values of wave heights. The greatest negative changes are typical of the western and northeast parts of the Black Sea. Here, the consideration of circulation reduces the average annual wave heights by up to 0.1 m. A slight increase in the average wave height is typical of the southern and southeast parts of the sea as well as the northwest shelf. The positive contribution to the mean annual wave heights is up to 0.02 m. When taken into account, currents change wave parameters at a maximum in winter months and at a minimum in late spring and summer. Currents change the mean monthly wave heights by –0.04…0.06 m in January and February in most parts of the sea. The contribution of currents is close to zero in June and July. The maximum changes in wave height reach 6–10 % of the monthly average.

scholarly journals Wind waves in the Black Sea: results of a hindcast study

2014 ◽  
Vol 14 (11) ◽  
pp. 2883-2897 ◽  
Author(s):  
V. S. Arkhipkin ◽  
F. N. Gippius ◽  
K. P. Koltermann ◽  
G. V. Surkova
Keyword(s):  
Black Sea ◽  
Initial Conditions ◽  
Wind Waves ◽  
Total Duration ◽  
Wave Model ◽  
Wave Parameter ◽  
The Black Sea ◽  
Storm Activity ◽  
Significant Wave ◽  
Wave Parameters

Abstract. In this study we describe the wind wave fields in the Black Sea. The general aims of the work were the estimation of statistical wave parameters and the assessment of interannual and seasonal wave parameter variability. The domain of this study was the entire Black Sea. Wave parameters were calculated by means of the SWAN wave model on a 5 × 5 km rectangular grid. Initial conditions (wind speed and direction) for the period between 1949 and 2010 were derived from the NCEP/NCAR reanalysis. According to our calculations the average significant wave height on the Black Sea does not exceed 0.7 m. Areas of most significant heavy sea are the southwestern and the northeastern parts of the sea as expressed in the spatial distribution of significant wave heights, wave lengths and periods. Besides, long-term annual variations of wave parameters were estimated. Thus, linear trends of the annual total duration of storms and of their quantity are nearly stable over the hindcast period. However, an intensification of storm activity is observed in the 1960s–1970s.

scholarly journals Influence of water area depth on wind waves

2020 ◽  
Vol 36 (4) ◽  
pp. 77-88
Author(s):  
Vitalii V. Yakovlev ◽  
Volodymyr A. Voskoboinick ◽  
Vitalii V. Khomicky ◽  
Viktor O. Tkachenko ◽  
Oleksandr A. Voskoboinyk ◽  
...  
Keyword(s):  
Wind Velocity ◽  
Black Sea ◽  
Wind Wave ◽  
Wind Waves ◽  
Water Area ◽  
Wave Transformation ◽  
The Black Sea ◽  
The North ◽  
Wave Parameters ◽  
North Eastern

A semi-empirical technique for calculating the parameters of wind waves at variable sea depths along the wind acceleration has been developed and presented. This technique allows you to determine the average values of wind wave heights, their length and period depending on the wind velocity, taking into account and without taking into account the heaping of water by wind. Within the framework of the described method, the calculations of wind wave parameters suitable for isobaths d = 20 m were performed for a specific study area of the Bistre (Novostambulske) branch of the Danube estuary, for the north-eastern and eastern wind directions. Numerical simulations were performed for the Black Sea in the location of the protection dam of the Maritime approach channel of the Danube-Black Sea deep-sea navigation. Numerical calculations of wind wave transformation in the water area near the protection dam for the most dangerous wind directions in stormy conditions were performed. For mathematical simulation, the maximum values of wind velocity and wave height were used, which were observed during the whole period of research of the Black Sea water area in the region of the dam. Within the framework of refraction theory, wave transformation calculations have been performed for the most wave-hazardous wind acceleration directions, namely, the north-eastern and eastern wind directions. It is shown that taking into account the heaping of water by wind leads to an increase in the parameters of gravitational waves. The results of numerical simulations have shown that with the increase of wind acceleration exceeding the limit values, the parameters of the waves reach constant values. These values depend on the bathymetry of the seabed, wind velocity and direction. It was found that the increase in the deviation of the free surface of the sea from the undisturbed level significantly depends on the heaping of water by wind. It was found that the relative increase in the wave parameters is observed higher in the east wind direction than in the northeast wind direction in the study area of the Black Sea.

scholarly journals Wind waves on the Black Sea: results of a hindcast study

2014 ◽  
Vol 2 (2) ◽  
pp. 1193-1221 ◽  
Author(s):  
V. S. Arkhipkin ◽  
F. N. Gippius ◽  
K. P. Koltermann ◽  
G. V. Surkova
Keyword(s):  
Black Sea ◽  
Initial Conditions ◽  
Wind Waves ◽  
Total Duration ◽  
Wave Model ◽  
The Black Sea ◽  
Storm Activity ◽  
Annual Variations ◽  
The North ◽  
Wave Parameters

Abstract. In this study we describe the wind waves fields on the Black Sea. The general aims of the work were the estimation of statistical wave parameters and the assessment of interannual and seasonal storm variability. The domain of this study was the entire Black Sea. Wave parameters were calculated by means of the SWAN wave model on a 5 km × 5 km rectangular grid. Initial conditions (wind speed and direction) for the period between 1948 and 2010 were derived from the NCEP/NCAR reanalysis. In our calculations the average significant wave height on the Black Sea does not exceed 0.7 m. Areas of most significant storminess are the south-western and the north-eastern corners as expressed in the spatial distribution of wave heights, wave lengths and periods. Besides that, long-term annual variations of storminess were estimated. Thus, linear trends of the annual total duration of storms and of their quantity are nearly stable over the reanalysis period. However, an intensification of storm activity is observed in the 1960s–1970s.

scholarly journals Reconstruction of Diffusion Coefficients and Power Exponents from Single Lagrangian Trajectories

Fluids ◽  
2021 ◽  
Vol 6 (3) ◽  
pp. 111
Author(s):  
Leonid M. Ivanov ◽  
Collins A. Collins ◽  
Tetyana Margolina
Keyword(s):  
Black Sea ◽  
Diffusion Coefficients ◽  
Current System ◽  
Mean Square Displacement ◽  
California Current ◽  
The Black Sea ◽  
Mean Square ◽  
California Current System ◽  
The Mean ◽  
Non Gaussian

Using discrete wavelets, a novel technique is developed to estimate turbulent diffusion coefficients and power exponents from single Lagrangian particle trajectories. The technique differs from the classical approach (Davis (1991)’s technique) because averaging over a statistical ensemble of the mean square displacement (<X2>) is replaced by averaging along a single Lagrangian trajectory X(t) = {X(t), Y(t)}. Metzler et al. (2014) have demonstrated that for an ergodic (for example, normal diffusion) flow, the mean square displacement is <X2> = limT→∞τX2(T,s), where τX2 (T, s) = 1/(T − s) ∫0T−s(X(t+Δt) − X(t))2 dt, T and s are observational and lag times but for weak non-ergodic (such as super-diffusion and sub-diffusion) flows <X2> = limT→∞≪τX2(T,s)≫, where ≪…≫ is some additional averaging. Numerical calculations for surface drifters in the Black Sea and isobaric RAFOS floats deployed at mid depths in the California Current system demonstrated that the reconstructed diffusion coefficients were smaller than those calculated by Davis (1991)’s technique. This difference is caused by the choice of the Lagrangian mean. The technique proposed here is applied to the analysis of Lagrangian motions in the Black Sea (horizontal diffusion coefficients varied from 105 to 106 cm2/s) and for the sub-diffusion of two RAFOS floats in the California Current system where power exponents varied from 0.65 to 0.72. RAFOS float motions were found to be strongly non-ergodic and non-Gaussian.

scholarly journals Extreme wind waves in the Black Sea

Oceanologia ◽  
2020 ◽  
Vol 62 (1) ◽  
pp. 23-30
Author(s):  
Boris V. Divinsky ◽  
Vladimir V. Fomin ◽  
Ruben D. Kosyan ◽  
Yuri D. Ratner
Keyword(s):  
Black Sea ◽  
Wind Waves ◽  
The Black Sea ◽  
Extreme Wind

scholarly journals Recent Sea Level Change in the Black Sea from Satellite Altimetry and Tide Gauge Observations

2020 ◽  
Vol 9 (3) ◽  
pp. 185 ◽  
Author(s):  
Nevin Avşar ◽  
Şenol Kutoğlu
Keyword(s):  
Sea Level Rise ◽  
Sea Level ◽  
Black Sea ◽  
Satellite Altimetry ◽  
Tide Gauge ◽  
The Black Sea ◽  
Sea Level Changes ◽  
Early 19Th Century ◽  
Mean Sea Level ◽  
The Mean

Global mean sea level has been rising at an increasing rate, especially since the early 19th century in response to ocean thermal expansion and ice sheet melting. The possible consequences of sea level rise pose a significant threat to coastal cities, inhabitants, infrastructure, wetlands, ecosystems, and beaches. Sea level changes are not geographically uniform. This study focuses on present-day sea level changes in the Black Sea using satellite altimetry and tide gauge data. The multi-mission gridded satellite altimetry data from January 1993 to May 2017 indicated a mean rate of sea level rise of 2.5 ± 0.5 mm/year over the entire Black Sea. However, when considering the dominant cycles of the Black Sea level time series, an apparent (significant) variation was seen until 2014, and the rise in the mean sea level has been estimated at about 3.2 ± 0.6 mm/year. Coastal sea level, which was assessed using the available data from 12 tide gauge stations, has generally risen (except for the Bourgas Station). For instance, from the western coast to the southern coast of the Black Sea, in Constantza, Sevastopol, Tuapse, Batumi, Trabzon, Amasra, Sile, and Igneada, the relative rise was 3.02, 1.56, 2.92, 3.52, 2.33, 3.43, 5.03, and 6.94 mm/year, respectively, for varying periods over 1922–2014. The highest and lowest rises in the mean level of the Black Sea were in Poti (7.01 mm/year) and in Varna (1.53 mm/year), respectively. Measurements from six Global Navigation Satellite System (GNSS) stations, which are very close to the tide gauges, also suggest that there were significant vertical land movements at some tide gauge locations. This study confirmed that according to the obtained average annual phase value of sea level observations, seasonal sea level variations in the Black Sea reach their maximum annual amplitude in May–June.

scholarly journals Heavy metal contamination of Pleuronectiformes species from Sinop coasts of the Black Sea

2019 ◽  
Vol 7 (2) ◽  
Author(s):  
Levent Bat ◽  
Fatih Şahin ◽  
Ayşah Öztekn
Keyword(s):  
Heavy Metals ◽  
Black Sea ◽  
Heavy Metal Contamination ◽  
Scophthalmus Maximus ◽  
Essential Amino Acids ◽  
The Black Sea ◽  
Limit Values ◽  
Fish Samples ◽  
The Mean ◽  
Cu And Zn

In the Turkish Black Sea coasts fish is particularly consumed because of high protein supplies, essential amino acids, vitamin, and mineral content. Fish are exposed to contaminants such as heavy metals in polluted waters. The aims of the study are to determine heavy metals in Pleuronectiformes species from Sinop coasts of the Black Sea and determine the health risks due to the consumption of contaminated fish. Pleuronectiformes species Scophthalmus maximus (Linnaeus, 1758) belonging to Scophthalmidae family, Arnoglossus laterna (Walbaum, 1792) belonging to Bothidae family and Pegusa lascaris (Risso, 1810) belonging to Soleidae family were collected from Sinop coasts of the Black Sea in fishing season of 2016. Heavy metals (Hg, Cd, Pb, Cu and Zn) in edible tissues were determined by ICP-MS (Agilent 7700x). The limit values given by the international and national organizations did not exceed in the muscle tissues of turbot, Mediterranean scald fish and sand sole. Overall Zn was detected in higher concentrations in all species followed by Cu, Pb, Hg and Cd. The results obtained from the analyses of the maximum levels of the metals except Hg were found in turbot. The highest Hg (0.021±0.007 µg g-1 wet wt.) was found in sand sole. However, the high amounts of Cd, Pb, Cu and Zn in turbot were 0.011±0.004, 0.07±0.005,1.32±0.28 and 14±3 µg g-1 wet wt., respectively. The EDIs and EWIs of the metals were estimated taking into account the mean of metal in all fish samples and the mean consumption of fish per day/week for adults. These results are normally significantly lower than the recommended values of FAO/WHO. Estimated HIs of all the considered metals were below the value of 1, therefore the metals in fish samples do not toxic any apparent threat to the population and these fishes are healthy for consumption.Keywords: Scophthalmus maximus, Arnoglossus laterna, Pegusa lascaris, heavy metals, Black Sea

scholarly journals Wave directional measurement in Patos Lagoon, RS, Brazil

RBRH ◽  
2017 ◽  
Vol 22 (0) ◽  
Author(s):  
Natália Lemke ◽  
◽  
Lauro Julio Calliari ◽  
José Antônio Scotti Fontoura ◽  
Déborah Fonseca Aguiar
Keyword(s):  
Wave Height ◽  
Significant Wave Height ◽  
Wave Climate ◽  
Coastal Protection ◽  
Peak Period ◽  
Patos Lagoon ◽  
Significant Wave ◽  
Wave Parameters ◽  
Wave Heights ◽  
Significant Wave Heights

ABSTRACT The wave climate characterization in coastal environments is essentially important to oceanography and coastal engineering professionals regarding coastal protection works. Thus, this study aims to determine the most frequent wave parameters (significant wave height, peak period and peak direction) in Patos Lagoon during the period of operation of a directional waverider buoy (from 01/27/2015 to 06/30/2015). The equipment was moored at approximately 14 km from the São Lourenço do Sul coast at the geographic coordinates of 31º29’06” S and 51º55’07” W, with local depth of six meters, registering significant wave height, peak period and peak direction time series. During the analyzed period, the greatest wave frequencies corresponded to short periods (between 2 and 3.5 seconds) and small values of significant wave heights (up to 0.6 meters), with east peak wave directions. The largest wave occurrences corresponded to east peak wave directions (33.3%); peak wave periods between 2.5 and 3 seconds (25.6%) and between 3 and 3.5 seconds (22.1%); and to significant wave heights of up to 0.3 meters (41.2%) and from 0.3 to 0.6 meters (38%). This research yielded unprecedented findings to Patos Lagoon by describing in detail the most occurring wave parameters during the analyzed period, establishing a consistent basis for several other studies that might still be conducted by the scientific community.

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