Methods of Analyzing Nonstationary Variability of the Black Sea Wave Climate

This study analyzes the evolution of the wave climate in the Black Sea basin in a 31-year long hindcast (1988-2018) performed with the third-generation wave model WaveWatchIII v5.16, forced by the ECMWF-ERA5 reanalysis winds at 30km of spatial resolution and 1-hour frequency. The wave model is implemented on a grid covering the whole Black Sea, with 3km grid step and is off-line coupled with a NEMO based hydrodynamical model. The wave spectrum is discretized using 24 directional sectors, and 30 frequencies, with 10% increment starting from 0.055Hz. The model is implemented to solve deep water processes, following the WAM Cycle4 model physics, with Ultimate Quickest propagation scheme and GSE alleviation, which is implemented in WWIII. Wind input and dissipation are based on Ardhuin et al. (2010), wave-wave interactions are based on Discrete Interaction Approximation. Currents and air-sea temperature difference are provided to the wave model to account for Doppler shift and atmospheric stability above the sea. Model validation and statistical analysis have been carried out to describe the wave climate of the Black sea, considering the following wave fields: significant wave height (Hs), mean wave period (Tm) and mean wave direction. Statistics as Mean, Maximum, 5th percentile and 95th statistics have been computed to produce monthly climatologies. The work considers also the evaluation of trends for Hs and Tm, and the evaluation of tendency in the occurrence frequency of mean and max fields for Hs and Tm.There is no evidence about an overall trend in Hs and Tm, but tendencies can be highlighted in some months and seasons. The most evident trend occurs in Summer on the whole wave spectrum, with reduction of Hs and Tm in the Eastern basin, and increasing in the South-Western basins. Even the evaluation of occurrence frequencies suggests that Black Sea is subjected to a change in the wave regime.

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A Comparative Analysis of the Wind and Wave Climate in the Black Sea Along the Shipping Routes

Water ◽

10.3390/w10070924 ◽

2018 ◽

Vol 10 (7) ◽

pp. 924 ◽

Cited By ~ 9

Author(s):

Liliana Rusu ◽

Alina Raileanu ◽

Florin Onea

Keyword(s):

Regional Climate Model ◽

Black Sea ◽

Climate Model ◽

Extreme Values ◽

Regional Climate ◽

Wave Model ◽

Wave Climate ◽

Reanalysis Data ◽

The Black Sea ◽

Wind Fields

The aim of the present work is to assess the wind and wave climate in the Black Sea while considering various data sources. A special attention is given to the areas with higher navigation traffic. Thus, the results are analyzed for the sites located close to the main harbors and also along the major trading routes. The wind conditions were evaluated considering two different data sets, the reanalysis data provided by NCEP-CFSR (U.S. National Centers for Environmental Prediction-Climate Forecast System Reanalysis) and the hindcast results given by a Regional Climate Model (RCM) that were retrieved from EURO-CORDEX (European Domain-Coordinated Regional Climate Downscaling Experiment). For the waves, there were considered the results coming from simulations with the SWAN (Simulating Wave Nearshore) model, forced with the above-mentioned two different wind fields. Based on these results, it can be mentioned that the offshore sites seem to show the best correlation between the two datasets for both wind and waves. As regards the nearshore sites, there is a good agreement between the average values of the wind data that are provided by the different datasets, except for the points located in the southern part of the Black Sea. The same trends noticed for the average values remain also valid for the extreme values. Finally, it can be concluded that the results obtained in this study are useful for the evaluation of the wind and wave climate in the Black Sea. Also, they give a more comprehensive picture on how well the wind field provided by the Regional Climate Model, and the wave model forced with this wind, can represent the features of a complex marine environment as the Black Sea is.

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Analysis of the Variability of Wave Energy Due to Climate Changes on the Example of the Black Sea

Energies ◽

10.3390/en11082020 ◽

2018 ◽

Vol 11 (8) ◽

pp. 2020 ◽

Cited By ~ 6

Author(s):

Yana Saprykina ◽

Sergey Kuznetsov

Keyword(s):

Black Sea ◽

Wave Energy ◽

Wave Climate ◽

Positive Phase ◽

The Black Sea ◽

Power Flux ◽

Teleconnection Patterns ◽

The North ◽

Wave Heights ◽

The North Atlantic Oscillation

An analysis of the variability of wave climate and energy within the Black Sea for the period 1960–2011 was made using field data from the Voluntary Observing Ship Program. Methods using wavelet analysis were applied. It was determined that the power flux of wave energy in the Black Sea fluctuates: the highest value is 4.2 kW/m, the lowest is 1.4 kW/m. Results indicate significant correlations among the fluctuations of the average annual wave heights, periods, the power flux of wave energy, and teleconnection patterns of the North Atlantic Oscillation (NAO), the Atlantic Multi-decadal Oscillation (AMO), the Pacific Decadal Oscillation (PDO) and the East Atlantic/West Russia (EA/WR). It was revealed that, in positive phases of long-term periods of AMO (50–60 years) as well as PDO, NAO, and AO (40 years), a decrease of wave energy was observed; however, an increase in wave energy was observed in the positive phase of a 15-year period of NAO and AO. The positive phase of changes of EA/WR for periods 50–60, 20–25, and 13 years led to an increase of wave energy. The approximation functions of the oscillations of the average annual wave heights, periods, and the power flux of wave energy for the Black Sea are proposed.

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Mediterranean and Black seas maximum waves climatology

10.5194/egusphere-egu21-7328 ◽

2021 ◽

Author(s):

Francesco Barbariol ◽

Arno Behrens ◽

Alvise Benetazzo ◽

Silvio Davison ◽

Gerhard Gayer ◽

...

Keyword(s):

Mediterranean Sea ◽

Wave Height ◽

Black Sea ◽

Atmospheric Stability ◽

Wave Model ◽

Wave Climate ◽

The Black Sea ◽

Positive Anomaly ◽

The Mediterranean ◽

Mediterranean And Black Seas

Reliable wave forecasts and hindcasts, together with long-term statistical analysis of extreme conditions, are of utmost importance for monitoring marine areas. Indeed, there is general consensus that high-quality predictions of extreme events during marine storms can substantially contribute to avoiding or minimizing human and material damage, especially in busy waterways such as the Mediterranean and Black Seas. So far, however, the wave climate characterization (average and anomaly relative to the average) has focused on the bulk characterization of the significant wave height Hs, and it has lacked a description of the individual waves, such as the maximum ones that may occur at a given location in the sea. To fill this gap, we provide the intensity and geographical distribution of the maximum waves in the Mediterranean and Black Seas over 27 years (1993-2019), by representing the average annual (1993-2018) and anomaly for 2019 relative to the average of the 99th percentile of the expected maximum wave height Hm and crest height Cm. The analysis combines wave model hindcasts available through CMEMS model setup and the wave model WAVEWATCH III&#174;, both forced with ECMWF ERA5 reanalysis winds. Results show that in 2019 maximum waves were smaller than usual in the Black Sea (anomalies of Hm up to -1.5 m), while in the Mediterranean Sea a markedly positive anomaly (+2.5 m for Hm) was found in the southern part of the basin. The peculiar 2019 configuration seems to be caused by a widespread atmospheric stability over the Black Sea and by depressions that rapidly passed over the Mediterranean Sea.

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