M. Alavinezhad, M. Ghodsi Hassanabad, M. Ketabdari, Masood Nekooei
1 PhD student, Department of Marine Industries, Science and Research Branch, Islamic Azad University, Tehran, Iran; alavi.mehdi@yahoo.com 2* Assistant professor, Department of Marine Industries, Science and Research Branch, Islamic Azad University, Tehran, Iran; m.ghodsi@srbiau.ac.ir 3 Associate Professor, Department of Maritime Engineering, Amirkabir University of Technology, Tehran, Iran; ketabdar@aut.ac.ir 4 Assistant professor, Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran; nekooei@srbiau.ac.ir
{"title":"Damage localization and quantification in the Catwalk of Foroozan offshore complex using improved modal strain energy method","authors":"M. Alavinezhad, M. Ghodsi Hassanabad, M. Ketabdari, Masood Nekooei","doi":"10.52547/ijcoe.5.2.11","DOIUrl":"https://doi.org/10.52547/ijcoe.5.2.11","url":null,"abstract":"1 PhD student, Department of Marine Industries, Science and Research Branch, Islamic Azad University, Tehran, Iran; alavi.mehdi@yahoo.com 2* Assistant professor, Department of Marine Industries, Science and Research Branch, Islamic Azad University, Tehran, Iran; m.ghodsi@srbiau.ac.ir 3 Associate Professor, Department of Maritime Engineering, Amirkabir University of Technology, Tehran, Iran; ketabdar@aut.ac.ir 4 Assistant professor, Department of Civil Engineering, Science and Research Branch, Islamic Azad University, Tehran, Iran; nekooei@srbiau.ac.ir","PeriodicalId":33914,"journal":{"name":"International Journal of Coastal and Offshore Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70686811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Article History: Received: 07 Dec. 2020 Accepted: 01 Jun. 2021 In this study, a numerical third-generation wave model was performed to generate 10 years (2000-2010) of wave hindcast in the Persian Gulf. The modified wind field data of European Center for Medium Range Weather Forecasts (ECMWF) and bathymetry data were used as the input data to model. In situ measurements and satellite-derived wave height were performed for model calibration, and validation the results. The results show that the overall accuracy is more than 80% over the whole Persian Gulf. Geographical Information System (GIS) was used to handle all datasets through a userfriendly software which provides required tools for data visualization and manipulation. Data management was carried on using the integration of Relational Database Management Systems (RDBMS) and GIS components.
{"title":"Integration of geographical information system and Wave Hindcast model - case study: Persian Gulf","authors":"M. Moradi","doi":"10.52547/ijcoe.5.2.47","DOIUrl":"https://doi.org/10.52547/ijcoe.5.2.47","url":null,"abstract":"Article History: Received: 07 Dec. 2020 Accepted: 01 Jun. 2021 In this study, a numerical third-generation wave model was performed to generate 10 years (2000-2010) of wave hindcast in the Persian Gulf. The modified wind field data of European Center for Medium Range Weather Forecasts (ECMWF) and bathymetry data were used as the input data to model. In situ measurements and satellite-derived wave height were performed for model calibration, and validation the results. The results show that the overall accuracy is more than 80% over the whole Persian Gulf. Geographical Information System (GIS) was used to handle all datasets through a userfriendly software which provides required tools for data visualization and manipulation. Data management was carried on using the integration of Relational Database Management Systems (RDBMS) and GIS components.","PeriodicalId":33914,"journal":{"name":"International Journal of Coastal and Offshore Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2021-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"70686968","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Mehri Hashemi Devin, Abbas Ranjbar Saadat Abadi, E. Fattahi, S. Karami, Saviz Sehat Kashani
A strong low level jet (LLJ) in the northern region of the Persian Gulf (PG) observed on 5th Jun 2020 that sank the Behbahan cargo vessel. In this article, we have used the WRF-V3 model and reanalysis ERA5 data to study the vertical structure, diurnal variation and intensity of the LLJs. The aimed topography’s region, the pressure gradient and the land-sea breeze are the essential key factors in analyzing the diurnal variation of the LLJ over the PG that is known as the Shamal wind. The low terrain height in the northern of the PG and Zagros Mountains channelized the northwest winds and increased the pressure gradient that increased the wind speed. The decreasing friction over the PG during nighttime and the differences in temperature and specific heat capacity between water and land cause an increase in the LLJ intensity. The LLJ’s core 22-24 ms - 1 was located over the study region in 925hPa on 4th and 5th June at 18 and 00 UTC respectively. Thereafter core’s wind speed decreased to 10-14 ms -1 at 12UTC on 5th June. The mix-down of momentum from the LLJ level to the surface caused an increase in wind speed and wave height over the PG which sank the Behbahan cargo vessel at early morning of 5th June. The LLJ at some regions like Kuwait formed at lower heights (under 950 hPa) and at the other points LLJ formed at levels upper than 950 hPa during nighttime of 4th Jun to afternoon of 5th Jun.
{"title":"A Study on the Structural and Formation of the Low-Level Jet Stream over the Northern Persian Gulf (Case study on sinking the Behbahan cargo vessel)","authors":"Mehri Hashemi Devin, Abbas Ranjbar Saadat Abadi, E. Fattahi, S. Karami, Saviz Sehat Kashani","doi":"10.29252/ijcoe.4.1.55","DOIUrl":"https://doi.org/10.29252/ijcoe.4.1.55","url":null,"abstract":"A strong low level jet (LLJ) in the northern region of the Persian Gulf (PG) observed on 5th Jun 2020 that sank the Behbahan cargo vessel. In this article, we have used the WRF-V3 model and reanalysis ERA5 data to study the vertical structure, diurnal variation and intensity of the LLJs. The aimed topography’s region, the pressure gradient and the land-sea breeze are the essential key factors in analyzing the diurnal variation of the LLJ over the PG that is known as the Shamal wind. The low terrain height in the northern of the PG and Zagros Mountains channelized the northwest winds and increased the pressure gradient that increased the wind speed. The decreasing friction over the PG during nighttime and the differences in temperature and specific heat capacity between water and land cause an increase in the LLJ intensity. The LLJ’s core 22-24 ms - 1 was located over the study region in 925hPa on 4th and 5th June at 18 and 00 UTC respectively. Thereafter core’s wind speed decreased to 10-14 ms -1 at 12UTC on 5th June. The mix-down of momentum from the LLJ level to the surface caused an increase in wind speed and wave height over the PG which sank the Behbahan cargo vessel at early morning of 5th June. The LLJ at some regions like Kuwait formed at lower heights (under 950 hPa) and at the other points LLJ formed at levels upper than 950 hPa during nighttime of 4th Jun to afternoon of 5th Jun.","PeriodicalId":33914,"journal":{"name":"International Journal of Coastal and Offshore Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2020-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45238860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Article History: Received: 04 Jan. 2020 Accepted: 10 May. 2020 Today complicated and risky environment makes risk assessment and identification one of the main steps of proper project management and realization of project objectives. Marine construction projects are key and strategic projects, and their specific nature adds to their importance. This study aimed to propose a method for risk assessment and ranking critical risks in marine construction projects in Iran. To this end, the risk assessment team was formed to identify serious marine construction project risks using risk breakdown structure. Afterward, the team defined risk assessment measures. All risks were assessed in each criterion based on the Taguchi loss function. It allowed decision-makers to define a measurable risk threshold for each criterion and assess risks by developing a common language called loss score. Finally, critical risks were determined based on their priority. The results can be used to improve effective risk management, and consequently, project management.
{"title":"Risk assessment of marine construction projects using Taguchi Loss Function","authors":"A. Valyani, N. Farahmand, S. Iranzadeh","doi":"10.29252/ijcoe.3.3.33","DOIUrl":"https://doi.org/10.29252/ijcoe.3.3.33","url":null,"abstract":"Article History: Received: 04 Jan. 2020 Accepted: 10 May. 2020 Today complicated and risky environment makes risk assessment and identification one of the main steps of proper project management and realization of project objectives. Marine construction projects are key and strategic projects, and their specific nature adds to their importance. This study aimed to propose a method for risk assessment and ranking critical risks in marine construction projects in Iran. To this end, the risk assessment team was formed to identify serious marine construction project risks using risk breakdown structure. Afterward, the team defined risk assessment measures. All risks were assessed in each criterion based on the Taguchi loss function. It allowed decision-makers to define a measurable risk threshold for each criterion and assess risks by developing a common language called loss score. Finally, critical risks were determined based on their priority. The results can be used to improve effective risk management, and consequently, project management.","PeriodicalId":33914,"journal":{"name":"International Journal of Coastal and Offshore Engineering","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47822358","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Subsea pipelines due to the reduction of transfer costs and expedite the offshore operations is one of the all-purpose structures in marine industries. Subsea pipelines are exposed to a variety of hazards, including corrosion and fatigue Etc. Free span exacerbates the fatigue required parameters due to a phenomenon called the Vortex Induced Vibration (VIV). In this research, the influence of the span's length on the free span subsea pipeline has been reviewed with ABAQUS standard code. In this study the previous result has been expanded. The results of the VIV fatigue life are extensible to all of the depth. Achieved Results indicate that the fatigue life of the pipeline even in the worst condition is much higher than the required amount that it represents the upstream design of DNV-RP-F105. In this study the backrest pipeline has been investigated and result show that the pipeline under the different conditions in the backrest, by creating more vibration and displacement on one side of the pipeline reduces the fatigue life of 113 percent compared to snap. The VIV fatigue life has undergone a lot of changes due to span length changes, maximum changes occur between cable and behavioral which the amount of these changes is reduced by 75%. The free span length is another factor in VIV fatigue. VIV fatigue life will be increased by reducing the span length. As well as increasing the flow velocity that is the main factor in creating the VIV is increased fatigue. Therefore, in terms of the accuracy in the choice of the existing conditions of very high importance for the pipeline. Comparison between effect parameters in VIV fatigue life was shown that span length is the most effective parameter.
{"title":"Evaluation of Vortex Induced Vibration Effective Parameters on Free-Span Subsea Pipelines","authors":"S. Sharifi, M. Tasdighi","doi":"10.29252/ijcoe.3.3.9","DOIUrl":"https://doi.org/10.29252/ijcoe.3.3.9","url":null,"abstract":"Subsea pipelines due to the reduction of transfer costs and expedite the offshore operations is one of the all-purpose structures in marine industries. Subsea pipelines are exposed to a variety of hazards, including corrosion and fatigue Etc. Free span exacerbates the fatigue required parameters due to a phenomenon called the Vortex Induced Vibration (VIV). In this research, the influence of the span's length on the free span subsea pipeline has been reviewed with ABAQUS standard code. In this study the previous result has been expanded. The results of the VIV fatigue life are extensible to all of the depth. Achieved Results indicate that the fatigue life of the pipeline even in the worst condition is much higher than the required amount that it represents the upstream design of DNV-RP-F105. In this study the backrest pipeline has been investigated and result show that the pipeline under the different conditions in the backrest, by creating more vibration and displacement on one side of the pipeline reduces the fatigue life of 113 percent compared to snap. The VIV fatigue life has undergone a lot of changes due to span length changes, maximum changes occur between cable and behavioral which the amount of these changes is reduced by 75%. The free span length is another factor in VIV fatigue. VIV fatigue life will be increased by reducing the span length. As well as increasing the flow velocity that is the main factor in creating the VIV is increased fatigue. Therefore, in terms of the accuracy in the choice of the existing conditions of very high importance for the pipeline. Comparison between effect parameters in VIV fatigue life was shown that span length is the most effective parameter.","PeriodicalId":33914,"journal":{"name":"International Journal of Coastal and Offshore Engineering","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42760144","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A fundamental challenge facing security professionals is preventing loss; be that asset, production, or third-party losses. This is not dissimilar to what safety professionals have to face. Techniques and methodologies used by the safety professionals could potentially benefit the security experts. Physical security is about taking physical measures to protect personnel and prevent unauthorized access to installations, material, and documents, which also include protection against sabotage, willful damage, and theft. The characteristics of physical security controls include measures for deterrence, detection, delay, and responses aimed at risk mitigation and enhanced operational effectiveness.This paper outlines a systems engineering framework for implementing security goals, which are suitable for meeting the challenge of providing physical security for complex systems, which includes oil and gas facilities. The proposed framework builds security requirements into system requirements and moves it in parallel with the system development for the entire system’s life cycle; particularly during the concept and design phases. This is a top-down process for use by a multidisciplinary team of security, operations, and industry experts to identify and prevent the system from entering into vulnerable states which could lead to losses. This framework shifts the focus of the security analysis away from threats, being the immediate cause of losses, and focuses instead on the barriers, i.e. safeguards that prevent systems from entering into vulnerable states, which would allow an unfolding event to disrupt the system leading to loses.The need for such a method comes from the recent experience of the securing complex systems that combine a large amount of hardware, software hazardous materials, and control elements. The method takes advantage of systems engineering and encourages the use of goal-based security requirements instead of using a strict prescriptive approach that is common among security professionals. Using this framework helps both to identify threats associated with the system, as well as weak points within the system. This framework also encourages communication between the security professional, safety engineers, and system designers. This paper draws from the existing literature as listed in the references.
{"title":"A Systems Engineering Approach to Physical Security of Oil & Gas Installations","authors":"S. Yasseri","doi":"10.29252/ijcoe.3.3.17","DOIUrl":"https://doi.org/10.29252/ijcoe.3.3.17","url":null,"abstract":"A fundamental challenge facing security professionals is preventing loss; be that asset, production, or third-party losses. This is not dissimilar to what safety professionals have to face. Techniques and methodologies used by the safety professionals could potentially benefit the security experts. Physical security is about taking physical measures to protect personnel and prevent unauthorized access to installations, material, and documents, which also include protection against sabotage, willful damage, and theft. The characteristics of physical security controls include measures for deterrence, detection, delay, and responses aimed at risk mitigation and enhanced operational effectiveness.This paper outlines a systems engineering framework for implementing security goals, which are suitable for meeting the challenge of providing physical security for complex systems, which includes oil and gas facilities. The proposed framework builds security requirements into system requirements and moves it in parallel with the system development for the entire system’s life cycle; particularly during the concept and design phases. This is a top-down process for use by a multidisciplinary team of security, operations, and industry experts to identify and prevent the system from entering into vulnerable states which could lead to losses. This framework shifts the focus of the security analysis away from threats, being the immediate cause of losses, and focuses instead on the barriers, i.e. safeguards that prevent systems from entering into vulnerable states, which would allow an unfolding event to disrupt the system leading to loses.The need for such a method comes from the recent experience of the securing complex systems that combine a large amount of hardware, software hazardous materials, and control elements. The method takes advantage of systems engineering and encourages the use of goal-based security requirements instead of using a strict prescriptive approach that is common among security professionals. Using this framework helps both to identify threats associated with the system, as well as weak points within the system. This framework also encourages communication between the security professional, safety engineers, and system designers. This paper draws from the existing literature as listed in the references.","PeriodicalId":33914,"journal":{"name":"International Journal of Coastal and Offshore Engineering","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"41837627","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A combination of linear and non-linear models results in a more accurate prediction in comparison with using linear or non-linear models individually to forecast time series data. This paper utilizes the linear autoregressive integrated moving average (ARIMA) model and non-linear artificial neural network (ANN) model to develop a new hybrid ARIMA-ANN model for prediction of container vessel traffic volume. The suggested hybrid method consists of an optimized feed-forward, back-propagation model with a hybrid training algorithm. The database of monthly traffic of Rajaee Port for thirteen years from 2005-2018 is taken into account. The performance of the developed model in forecasting short-term traffic volume is evaluated using various performance criteria such as correlation coefficient (R), mean absolute deviation (MAD), mean squared error (MSE) and mean absolute percentage error (MAPE). The developed model provides useful insights into container traffic behavior. Comparing the results with the real data-sets demonstrates the superior performance of the hybrid models than using models individually in forecasting traffic data.
{"title":"Forecasting Short-term Container Vessel Traffic Volume Using Hybrid ARIMA-NN Model","authors":"Negar Sadeghi Gargari, H. Akbari, R. Panahi","doi":"10.29252/ijcoe.3.3.47","DOIUrl":"https://doi.org/10.29252/ijcoe.3.3.47","url":null,"abstract":"A combination of linear and non-linear models results in a more accurate prediction in comparison with using linear or non-linear models individually to forecast time series data. This paper utilizes the linear autoregressive integrated moving average (ARIMA) model and non-linear artificial neural network (ANN) model to develop a new hybrid ARIMA-ANN model for prediction of container vessel traffic volume. The suggested hybrid method consists of an optimized feed-forward, back-propagation model with a hybrid training algorithm. The database of monthly traffic of Rajaee Port for thirteen years from 2005-2018 is taken into account. The performance of the developed model in forecasting short-term traffic volume is evaluated using various performance criteria such as correlation coefficient (R), mean absolute deviation (MAD), mean squared error (MSE) and mean absolute percentage error (MAPE). The developed model provides useful insights into container traffic behavior. Comparing the results with the real data-sets demonstrates the superior performance of the hybrid models than using models individually in forecasting traffic data.","PeriodicalId":33914,"journal":{"name":"International Journal of Coastal and Offshore Engineering","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49179752","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
1 MSc. Student in Coastal Engineering, Faculty of Civil Engineering, Shahrood University of Technology, Shahrood, Iran; qanbari.ftm@gmail.com 2 Assistant Professor, Faculty of Civil Engineering, Shahrood University of Technology, Shahrood, Iran; adjami@shahroodut.ac.ir 3 PhD. Candidate in Coastal Engineering, Faculty of Civil Engineering, Shahrood University of Technology, Shahrood, Iran; ataei.h.s@gmail.com
{"title":"An Analytical Study on the Formation of Submerged Bars in the Southern Coasts of Caspian Sea","authors":"F. Ghanbari, M. Adjami, H. Ataei","doi":"10.29252/ijcoe.3.3.1","DOIUrl":"https://doi.org/10.29252/ijcoe.3.3.1","url":null,"abstract":"1 MSc. Student in Coastal Engineering, Faculty of Civil Engineering, Shahrood University of Technology, Shahrood, Iran; qanbari.ftm@gmail.com 2 Assistant Professor, Faculty of Civil Engineering, Shahrood University of Technology, Shahrood, Iran; adjami@shahroodut.ac.ir 3 PhD. Candidate in Coastal Engineering, Faculty of Civil Engineering, Shahrood University of Technology, Shahrood, Iran; ataei.h.s@gmail.com","PeriodicalId":33914,"journal":{"name":"International Journal of Coastal and Offshore Engineering","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46559442","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Article History: Received: 4 Jul. 2019 Accepted: 8 Sep. 2019 Assessing the impact of physical properties on active reaction changes in the coastal and offshore area is one the most important aspect of marine environment of the Caspian Sea. Therefore, updated techniques and modern instruments have been used in order to evaluating the coastal and offshore area conditions. In the current research, collected data with spatial and temporal variety have been evaluated for investigation on seawater characteristics in the shallow and intermediate layers over the southern Caspian Sea. Some phenomena such as mixing, turbulence, water column stability and stratification are the effective elements on variability of physical and natural structures of the sea. Active reaction and dissolved oxygen as two properties of seawater are very important items for coastal engineering, piping in seabed, breakwaters and port constructions. Thus, in the current study, the above mentioned parameters were assessed over the southern shelf of the Caspian Sea. Vertical and horizontal variations of chemical characteristics such as active reaction of seawater were observed in several stations between coastal and offshore stations across surface, intermediate and deep layers. Results of the field operations showed that the normal values of pH in the study almost varied around 7.9-8 while during some seasons increased ore decreased more than 0.5 units due to human activates.
{"title":"Impact of Physical Properties on Distribution of Active Reaction in the Coastal and Offshore Areas of the Southern Caspian Basin","authors":"S. Jamshidi","doi":"10.29252/ijcoe.3.2.31","DOIUrl":"https://doi.org/10.29252/ijcoe.3.2.31","url":null,"abstract":"Article History: Received: 4 Jul. 2019 Accepted: 8 Sep. 2019 Assessing the impact of physical properties on active reaction changes in the coastal and offshore area is one the most important aspect of marine environment of the Caspian Sea. Therefore, updated techniques and modern instruments have been used in order to evaluating the coastal and offshore area conditions. In the current research, collected data with spatial and temporal variety have been evaluated for investigation on seawater characteristics in the shallow and intermediate layers over the southern Caspian Sea. Some phenomena such as mixing, turbulence, water column stability and stratification are the effective elements on variability of physical and natural structures of the sea. Active reaction and dissolved oxygen as two properties of seawater are very important items for coastal engineering, piping in seabed, breakwaters and port constructions. Thus, in the current study, the above mentioned parameters were assessed over the southern shelf of the Caspian Sea. Vertical and horizontal variations of chemical characteristics such as active reaction of seawater were observed in several stations between coastal and offshore stations across surface, intermediate and deep layers. Results of the field operations showed that the normal values of pH in the study almost varied around 7.9-8 while during some seasons increased ore decreased more than 0.5 units due to human activates.","PeriodicalId":33914,"journal":{"name":"International Journal of Coastal and Offshore Engineering","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48871374","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Article History: Received: 21 Jul. 2019 Accepted: 16 Sep. 2019 Cyclones are as one of the most dangerous meteorological phenomena of the tropical region that generate strong winds and heavy rainfall, impacting coastal regions. Behavior of tropical cyclone trajectories needs to be better understood in order to find predictable aspects of landfall potentially. This research aims to analyze the cyclone tracks statistically and then study of the associated meteorological effects of Gonu cyclone in June 2007 as an example. Using the cluster analysis (K-mean method) 5 principal clusters have been derived and spatial – temporal studies including the monthly variation of cyclone trajectories and their intensity and frequencies are performed. The 4th cluster indicated more spatial variability and expansion (4o-31oN and 48.5o-78oE). The second cluster showed the highest frequency with 349 events as well as the highest maximum intensity and standard deviation of 235.2km/h and 47.96km/h respectively. During 1-7 June 2007, the Gonu super cyclone traversed the Arabian Sea and reached the Iranian southern regions affecting the coastal infrastructures and communities. In this 7-day period the daily composite maps of different atmospheric levels showed that by intensifying of Gonu cyclone the axis of subtropical high pressures in the lower levels moved to the east and in the 500hp level they moved to the northward over the study region.
{"title":"The Tropical Cyclone Tracks and Formation over the Western Indian Ocean, And Impacts on the Iranian Southern Coasts","authors":"Mojtaba Zoljoodi","doi":"10.29252/ijcoe.3.2.41","DOIUrl":"https://doi.org/10.29252/ijcoe.3.2.41","url":null,"abstract":"Article History: Received: 21 Jul. 2019 Accepted: 16 Sep. 2019 Cyclones are as one of the most dangerous meteorological phenomena of the tropical region that generate strong winds and heavy rainfall, impacting coastal regions. Behavior of tropical cyclone trajectories needs to be better understood in order to find predictable aspects of landfall potentially. This research aims to analyze the cyclone tracks statistically and then study of the associated meteorological effects of Gonu cyclone in June 2007 as an example. Using the cluster analysis (K-mean method) 5 principal clusters have been derived and spatial – temporal studies including the monthly variation of cyclone trajectories and their intensity and frequencies are performed. The 4th cluster indicated more spatial variability and expansion (4o-31oN and 48.5o-78oE). The second cluster showed the highest frequency with 349 events as well as the highest maximum intensity and standard deviation of 235.2km/h and 47.96km/h respectively. During 1-7 June 2007, the Gonu super cyclone traversed the Arabian Sea and reached the Iranian southern regions affecting the coastal infrastructures and communities. In this 7-day period the daily composite maps of different atmospheric levels showed that by intensifying of Gonu cyclone the axis of subtropical high pressures in the lower levels moved to the east and in the 500hp level they moved to the northward over the study region.","PeriodicalId":33914,"journal":{"name":"International Journal of Coastal and Offshore Engineering","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-08-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48386605","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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