Browsing by Author "Amarouche, Khalid"

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Assessment of storm events along the Algiers coast and their potential impacts
(Pergamon-Elsevier Science, 2020-08-15) Amarouche, Khalid; Çakmak, Recep Emre; Houma, Fouzia; İslam, Bachari Nour El; Akpınar, Adem; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği.; 0000-0002-9042-6851; AAC-6763-2019; 23026855400
Knowledge of coastal storm regimes is essential to ensure an economic and sustainable development in the coastal area. In recent decades, wave storms have been responsible for several fatalities and economic losses along the Algiers coast. The aim of this paper is to present a detailed analysis on wave storm events during the past 40 years, including an assessment of the potential impacts of various storm events along the Algiers coasts according to their intensity and direction based on the different historical events. Thus, this paper gives an estimation of return periods of extreme significant wave heights and extreme storm events. For this purpose, the wave storm events occurring in the Algiers coasts, based on the storm power index (SPI) developed by Dolan and Davis (1992), were characterized and classified. Five storm categories were defined in terms of their power index, subdivided into 31 categories, taking into consideration their propagation directions. The temporal analysis shows a progressive increase in the number of storm events and their intensity during the last decade, which explains the increased damage recorded recently in the Algiers coastlines. A spatial analysis of these extreme and catastrophic storms being responsible in these damages has shown that the nature of coastal storm damages on the local scale depends on several factors, mainly power of these storms and their direction; in view of the complex morphology of the Algiers coastlines. These two factors were considered during the extreme value analysis, and allowed us to estimate the return period of the storm events already observed based on their SPI and direction. A return period of 59 years has been estimated for the catastrophic storm of 2015, which caused significant erosion resulting a loss of more than 15 000 m2 of coastal lands.
Assessment of swan and wavewatch-iii models regarding the directional wave spectra estimates based on eastern black sea measurements
(Pergamon-elsevier Science Ltd, 2023-02-16) Rybalko, Aleksandra; Myslenkov, Stanislav; Akpınar, Adem; AKPINAR, ADEM; Amarouche, Khalid; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0001-7983-4611; 0000-0002-9042-6851; AFR-7886-2022; AAC-6763-2019
The spectral wave models are often calibrated or validated based on bulk wave data derived from spectral in-formation such as the significant wave height (Hs) and mean period (Tm). However, the precision in the hind-casted spectral data was not evaluated in many seas, such as the Black Sea, due to the lack of spectral wave measurements. As part of this study, a spectral wave measuring buoy was installed near the cape Small Utrish to collect the spectral measurement data. The study objective is to assess the SWAN and WAVEWATCH-III (WWIII) models regarding the directional wave spectra estimates based on measurements conducted in the eastern Black Sea. For this purpose, the estimated spectral density distribution and spectral mean direction in terms of spectral frequency bins are assessed for both SWAN and WWIII outputs. The biases in variance densities are firstly calculated for both models at each frequency based on 14 710 spectral measurements, as well as the biases in the annual and seasonal averages. In addition, the correlation coefficients and root mean squared errors at each frequency are calculated and discussed. The accuracies in the mean direction at each spectral shape over the whole measurement period are secondly evaluated. Thirdly, the annual and seasonal averaged two-dimensional wave spectrums are discussed compared to measurements. The performances of both models are lastly verified based on bulk data measured at 8 locations on different coasts of the Black Sea. The results show that SWAN output fits better the average variance density shape at all frequency ranges f > 0.08Hz. However, it slightly overestimates the variance density in the 0.13-0.17 Hz range. In contrast to the SWAN model, WWIII data show only better correspondence in the 0.13-0.17 Hz frequency range but underestimate the lower frequency energies and overestimate higher frequency ranges. The SWAN model is therefore recommended for the spectral density estimate at seasonal and annual scales.
Creating an artificial neural network time series model for the prediction of daily solar radiation in oran
(Desalination Publ, 2022-04-01) Soukeur, El Hussein Iz El Islam; Chaabane, Djamal; Amarouche, Khalid; Bachari, Nour El Islam; AMAROUCHE, KHALID; Khalid Amarouche; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0001-7983-4611; AFR-7886-2022
Water and clean energies are currently a major scientific and political concern. The use of numerical prediction is often recommended in these areas, for optimal exploitation of renewable energy resources, mainly for seawater desalination and other energy and food security activities. In this study, we present an application of artificial neural networks (ANN), developed for daily solar energy forecasting. The ANN model developed is based on the multi-layer perceptron, the most widely used ANN type in renewable energy and time series forecasting. The developed model has two main properties: I. The ANN training is based on long-term reanalysis data, allowing the model to be trained even in areas where no radiation measurements are available, as is the case for marine areas and in the new desalination plants. II. The model allows automatic selection of the optimal ANN model architecture based on the training data. A thirty-nine-year time series of reanalysis data between 1980 and 2018 was used for training and model implementation. Thus, the model accuracy was evaluated based on one-year data (2019). The obtained error analysis results show that the developed model has a good performance in line with previous studies. The developed ANN models are characterized by reasonable daily prediction accuracy, with a root mean square error of 3.248 MJ/(m2 d) for solar radiation prediction. This verifies the accuracy and ability of the model to predict solar radiation to ensure optimal management of solar energy farms.
Evaluation of a high-resolution wave hindcast model SWAN for the West Mediterranean basin
(Elsevier Science, 2019-01-18) Amarouche, Khalid; Bachari, Nour El Islam; Houma, Fouzia; Akpınar, Adem; Çakmak, Recep Emre; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0002-9042-6851; 0000-0003-0700-8622; AAC-6763-2019; AAG-8624-2021; 23026855400; 57675048100
This study aims to present an evaluation and implementation of a high-resolution SWAN wind wave hindcast model forced by the CFSR wind fields in the west Mediterranean basin, taking into account the recent developments in wave modelling as the new source terms package ST6. For this purpose, the SWAN model was calibrated based on one-year wave observations of Azeffoune buoy (Algerian coast) and validated against eleven wave buoys measurements through the West Mediterranean basin. For the calibration process, we focused on the whitecapping dissipation coefficient C-ds and on the exponential wind wave growth and whitecapping dissipation source terms. The statistical error analysis of the calibration results led to conclude that the SWAN model calibration corrected the underestimation of the significant wave height hindcasts in the default mode and improved its accuracy in the West Mediterranean basin. The exponential wind wave growth of Komen et al (1984) and the whitecapping dissipation source terms of Janssen (1991) with C-ds = 1.0 have been thus recommended for the western Mediterranean basin. The comparison of the simulation results obtained using this calibrated parameters against eleven measurement buoys showed a high performance of the calibrated SWAN model with an average scatter index of 30% for the significant wave heights and 19% for the mean wave period. This calibrated SWAN model will constitute a practical wave hindcast model with high spatial resolution ((similar to)3 km) and high accuracy in the Algerian basin, which will allow us to proceed to a finer mesh size using the SWAN nested grid system in this area.
Global extreme wave estimates and their sensitivity to the analysed data period and data sources
(Elsevier Sci Ltd, 2023-07-13) Kamranzad, Bahareh; Khames, Ghollame-Ellah-Yacine; AKPINAR, ADEM; Amarouche, Khalid; AMAROUCHE, KHALID; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0002-9042-6851; AFR-7886-2022; AAC-6763-2019
In the absence of wave measuring buoys operating over extended periods, wave hindcast data or satellite observations are indispensable for estimating global extreme wave heights. However, the results may depend on the analysed wind wave sources and the period's length. The sensitivity of the estimated extreme significant wave heights (SWH) to the analysed data sources and periods is investigated in this study. Global extreme wave heights are estimated using ECMWF Reanalysis v5 data (ERA5), global wave hindcast developed based on Simulating WAves Nearshore forced by the Japanese 55-year Reanalysis (SWAN-JRA55), satellite altimeter observations, and long-term wave buoy measurements. Both Annual Maximum fitting to the Generalized Extreme Value Distribution (AM-GEV) and Peaks Over Threshold fitted to the Generalized Pareto Distribution (POT-GPD) models are used. The results show that the global extreme SWH estimates considerably depend on the analysed data sources. The relative differences observed between the analysed data sources are >20% in large parts of the world. Thus, the relative differences in extreme SWH are mainly lower by increasing the analysed data periods. However, they can reach 30% and are more critical using AM-GEV. Besides, by comparing the extreme values from reanalysis and hindcast wave data to those from long-term wave measurements, underestimations of up to 2 m are observed for a return period of 100 years in the North-West Atlantic and North-East Pacific.
Increasing trend on stormwave intensity in the western mediterranean
(MDPI AG, 2021-01) Amarouche, Khalid; Akpınar, Adem; Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği.; 0000-0001-7983-4611; 0000-0002-9042-6851; AFR-7886-2022; ABG-2101-2020; AAC-6763-2019; 57205453111; 23026855400
Annual trends in storm wave intensity over the past 41 years were evaluated during the present study. Storm wave intensity is evaluated in terms of total storm wave energy (TSWE) and storm power index (SPI) of Dolan and Davis (1992). Using an accurate long-term wave hindcast developed using a calibrated SWAN model, all storm wave events occurring over the past 41 years were characterized in terms of significant wave height (H-s) and total storm duration. Thus, both SPI and TSWE was computed for each storm wave event. The Theil-Sen slope estimator was used to estimate the annual slopes of the SPI and TSWE and the Mann-Kendall test was used to test the trend significance with different confidence levels. The present study is spatially performed for the western Mediterranean Sea basin considering 2308 grid points in a regular grid of 0.198 degrees resolution in both directions. Results allow as to define five hotspots covering a large area, experienced a significant increasing slope in both SPI and TSWE (annual maxima and average). The confidence level in this area exceed 95%, with a steep slope between 100 kWh center dot m(-1)center dot year(-1) and 240 kWh center dot m(-1)center dot year(-1) for annual max TSWE and between 28 m(2)center dot h center dot year(-1) and 49 m(2)center dot h center dot year(-1) for annual max SPI. Consideration of the present findings is strongly recommended for risk assessment and for sustainable development in coastal and offshore area and to identify areas sensitive to global climate change in the western Mediterranean Sea.
Increasing trends in spectral peak energy and period in a semi-closed sea
(Pergamon-elsevier Science Ltd, 2023-02-13) Acar, Emine; Akpınar, Adem; AKPINAR, ADEM; Kankal, Murat; KANKAL, MURAT; Amarouche, Khalid; AMAROUCHE, KHALID; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0002-9042-6851; 0000-0003-0897-4742; 0000-0001-7983-4611; JTU-9268-2023; AAC-6763-2019; AAZ-6851-2020; AFR-7886-2022
This study aims to investigate long-term trends in the Black Sea's spectral wave peak energy and periods. Improved Visualization of the Innovative Trend Analysis and the Mann-Kendal methods was applied to the maximum and mean spectral peak energies and peak periods between 1979 and 2020. Long-term spectral data are obtained from the ERA5 reanalysis and two spectral wave models, SWAN and WWIII. The innovative trend analysis method has the particularity to examine trends in higher and lower value categories. Studies of long-term changes in spectral wave characteristics are rare, and trends in spectral peak parameters are evaluated in this study for the first time in the Black Sea. It was detected that both spectral peak energies and peak periods tend to increase predominantly over most of the time scales. Furthermore, while the change rates for peak en-ergies do not exceed 40% annually and seasonally, change rates exceeding 100% are observed on a monthly basis. Besides, the change rates of the peak periods vary in the +/- 5% band and usually do not exceed 15%. Moreover, despite a few differences, trend analysis results obtained using SWAN and WWIII models were close to the global ERA5 results. The results may provide insight into the design and durable development of coastal and marine structures as well as the evaluation of wave climate change based on spectral wave data.
Long-term characterisation of directional wave spectra in the black sea and the sea of azov
(Elsevier, 2023-11-07) Amarouche, Khalid; Akpınar, Adem; AMAROUCHE, KHALID; AKPINAR, ADEM; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü; 0000-0001-7983-4611; 0000-0002-9042-6851; AFR-7886-2022; AAC-6763-2019
Directional wave spectra describe complex sea-states in frequency and directional domains and provide more detailed information than the bulk wave parameters. Using hourly directional wave spectra hindcasted for 42 years (1979-2020), this study aims to assess long-term spectral wave climate in the Black and Azov Seas. Variance densities are averaged over the frequencies and directions for annual, seasonal, and monthly scales to determine spectral wave climate. Furthermore, The individual wave systems observed in each directional wave spectra are determined by referring to the independent spectral peak at each observation. The different sea state conditions, including the uni-modal and multi-modal wave systems, are classified and analysed; The energy, frequency, and direction of the three first prominent individual wave system peaks are deeply evaluated as a function of the sea state conditions. Occurrences as the function of spectral peak density and directions of the prominent individual wave system peaks are also computed and discussed. The results reveal that multi-modal spectra are more frequent, although the highest peak density values and lowest peak frequencies were observed within the wave spectra of uni-modal sea states. The spectral peak densities, frequencies, and directions depend on the number of wave systems in the wave spectrum and geographic location. The first peaks in the wave spectra are primarily derived from two dominant directions, and similar to 54 % of the peaks had a density greater than 2 m(2)/Hz. In contrast, second and third peaks in the wave spectra are typically derived from three or more dominant directions and rarely exceed 2 m(2)/Hz density.
Spatial calibration of wavewatch iii model against satellite observations using different input and dissipation parameterizations in the black sea
(Pergamon-elsevier Science Ltd, 2022-06-01) Akpınar, Adem; AKPINAR, ADEM; Soran, Mehmet Burak; Amarouche, Khalid; AMAROUCHE, KHALID; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0001-7983-4611; 0000-0002-9042-6851; AFR-7886-2022; AAC-6763-2019
The quality of the third generation wave model WAVEWATCH III, referred WW3, using the different source term packages is investigated in the context of wave growth and dissipation in a semi-closed sea, Black Sea. Accuracy in wave height hindcast is tested for five different source term parameterizations ST1, ST2, ST3, ST4, and ST6 in WW3 against the 2020-year multi-mission satellite observations over the entire sea. The aims are to determine the most appropriate formulation and optimum tuneable coefficients for wind waves modelling in the Black Sea. For this purpose, significant wave heights (Hm0) are produced using five different source term packages implemented in the WW3 model. A sensitivity test was applied to define the tuneable parameters that contributes to the accuracy of the models, and subsequently the coefficient values of each parameters was turned to calibrate the WW3 models. The tuneable parameter allowing to obtain the most accurate result in each package are defined for each source term package. Comparing between model results and satellite observations, we found that the default WW3 model with all source terms as well as the calibrated ST2 model underestimate Hm0 in the entire domain and mainly in the eastern Black Sea region and are not suitable physical source term for the Black Sea. In the Black sea, the calibrated ST1, ST3 and ST4 forced with ERA5 wind are recommended for long term wave climate simulation, and the calibrated ST6 is recommended for extreme wave simulation.
Wave energy resource assessment along the Algerian coast based on 39-year wave hindcast
(Pergamon-Elsevier Science, 2020-02-11) Amarouche, Khalid; Houma, Fouzia; Bachari, Nour El Islam; Akpınar, Adem; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği.; 0000-0002-9042-6851; ABE-8817-2020; 23026855400
This study investigates a long-term assessment of the wave energy resource propagated along the Algerian basin, based on a 39-year wave hindcast. The wave energy hindcast dataset was developed using the Simulating WAve Nearshore (SWAN) model, calibrated and validated [1] against wave measurements performed on the Algerian coast. A detailed spatial and local analysis was performed following the hindcast results. We have determined several parameters including; hourly, monthly, seasonal and annual variations of wave energy resources, the probability of occurrence distribution for different wave power ranges with different directions, the probability of calm sea states, the wave energy development index (WEDI) and the total annual wave energy and their distribution as a function of significant wave height and energy period. All these results enabled a very important benchmark for decision making regarding the future implementation and design of wave energy converters (WECs) and other offshore structures in the Algerian basin. Our findings have shown that the Algerian coasts are characterized by a considerable wave energy potential with a large hotspot area in the eastern coasts. Thus, we have recorded a significant variability in the wave energy characteristics available in each zone along the Algerian coast. The western zone was characterized by an average energy of ∼7.5 kW/m with a low monthly and seasonal variation (<1.2), the central zone was characterized by a significant total annual wave energy of 63 MWh/m/year and a considerable WEDI of 0.019, and the eastern Algerian coast was characterized by one of the highest energy potential in the Mediterranean basin with a total annual energy exceeding 100 MWh/m for less than 15 km from the coast and a calm sea state probability lower than 18%. Thus, it has been concluded that since 1995, wave energy resources have tended to increase further.
Wave power trends over the mediterranean sea based on innovative methods and 60-year ERA5 reanalysis
(Mdpi, 2023-05-22) Acar, Emine; Akpınar, Adem; Kankal, Murat; Amarouche, Khalid; Acar, Emine; AKPINAR, ADEM; KANKAL, MURAT; AMAROUCHE, KHALID; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü.; 0000-0002-9042-6851; 0000-0003-0897-4742; 0000-0001-7983-4611; AAZ-6851-2020; AAC-6763-2019; ABG-2101-2020; JTU-9268-2023; AFR-7886-2022
The present study aims to evaluate long-term wave power (P-wave) trends over the Mediterranean Sea using innovative and classical trend analysis techniques, considering the annual and seasonal means. For this purpose, the data were selected for the ERA5 reanalysis with 0.5 degrees x 0.5 degrees spatial resolution and 1 h temporal resolution during 60 years between 1962 and 2021. Spatial assessment of the annual and seasonal trends was first performed using the innovative trend analysis (ITA) and Mann-Kendall (MK) test. To obtain more detailed information, innovative polygon trend analysis (IPTA), improved visualization of innovative trend analysis (IV-ITA), and star graph methods were applied to annual, seasonal, and monthly mean Pwave at 12 stations selected. The results allow us to identify an increasing trend above the 10% change rate with the innovative method and above the 95% confidence level with the Mann-Kendall test in mean wave power in the Levantine basin and the Libyan Sea at all timescales. The use of various innovative methods offered similar results in certain respects and complemented each other.
Wave storm events in the western mediterranean sea over four decades
(Elsevier, 2022-01-14) Amarouche, Khalid; Akpınar, Adem; Semedo, Alvaro; AMAROUCHE, KHALID; AKPINAR, ADEM; Bursa Uludağ Üniversitesi/Mühendislik Fakültesi/İnşaat Mühendisliği Bölümü; 0000-0001-7983-4611; AAC-6763-2019; AFR-7886-2022
The rising intensity and recurrence of wave storm events can seriously impact navigation and coastal and offshore structures in the Western Mediterranean Sea. Therefore, the present study is focused on wave storm events in the Western Mediterranean Sea, over the last four decades. The spatial decadal variations of wave storm events are shown, considering variations in the parameters that characterise wave storms, such as significant wave height (SWH), wave storm duration, and wave storm direction. Additionally, the decadal variation in wave storm intensities is evaluated through the storm power index (SPI) and the total storm wave energy (TSWE). The study is based on a wave hindcast, developed using a calibrated SWAN model. The wave storm events are obtained based on the SWH time series for 24 325 locations, distributed over an unstructured grid, covering the entire Western Mediterranean Sea. The decadal variation in the number of wave storm events, maximum and mean wave storm duration, SPI, and TSWE were observed in large parts of the West Mediterranean Sea during the last four decades. However, variations in mean SWH during these storms are low, and do not show a real implication in the decadal changes in the wave storm intensity (SPI and TSWE). Locations of significant increasing changes in SPI and TSWE show a dependence on changes in the wave storm duration. They may be related to variations in wave storm direction in some areas. Increases in wave storm duration are mainly responsible for increases in wave storm intensities over the last decade.