International Journal of Coastal, Offshore and Environmental Engineering
Volume:8 Issue: 3, Summer 2023

Ultraviolet radiation can have a significant impact on human health, thus its prediction is necessary and important. In this study, the Tropospheric Ultraviolet and Visible (TUV) Radiation model was used to predict the UltraViolet Index (UVI). This model requires the total ozone column, albedo and Aerosol Optical Depth (AOD) data to forecast UVI. The Global Forecasting System (GFS) data was used for the total ozone column and albedo data, and the Whole Atmosphere Community Climate Model (WACCM) was used for AOD data. In this study, 102 case studies were selected for the coastal stations and islands of the Persian Gulf and Oman Sea in 2019, 2020 and 2021. Due to the lack of access to the actual value of UVI, the Ozone Monitoring Instrument (OMI) data were assumed as observational data. The verification results showed that in the warmer seasons of the year, when UVI levels are higher than in cold seasons, the forecast error is higher. Furthermore, when the AOD value is high, the forecast error is also high, but generally, the forecast is very accurate. For all selected case studies, the ME, MAE, RMSE and R values are -0.81, 1.07, 1.83 and 0.75 respectively, indicating the high accuracy of the UVI forecasts.

Due to the need of the maritime community to reduce meteorological calculations on maritime routes, ship weather routing has attracted a lot of attention in recent years, both in the university and in the maritime industry. The problems in this field are finding the optimal route and speed of navigation for a certain voyage, taking into account the environmental conditions of wind and waves. Goals are usually considered to minimize operating costs, fuel consumption, or safety. The main methods used to solve the weather routing problem are the Isochrone method, dynamic programming, calculus of variation, use of routing, and exploration algorithms, while in recent years, artificial intelligence and machine learning applications have also increased. Most of these methods are well established and have not changed significantly over the years, although programs with a combination of these methods have been used. In this research first, the great circle route is calculated for the vessel between the departure and the destination positions, and using the Rhumb line method, the network points around the great circle route are created. Next, it is necessary to number the network points and network connections, and finally, using Dijkstra's algorithm and defining a cost function, the network efficiency is proved. The results and innovations of this research, the use of up-to-date methods in calculating the great circle route and turning points on it, creating minimal connections between network points.

This study focused on improving the Princeton Ocean Model (POM) by proposing and implementing a new algorithm for its external mode, which solves depth-averaged two-dimensional equations of continuity and momentum transport. The goal of the new algorithm was to reduce the numerical diffusion of the model and enable the use of larger time steps for calculations. To achieve this, the Projection method was used along with the implicit discontinuity of the gravity terms in the governing equations of the two-dimensional solution of the model. The new algorithm was then evaluated for its efficiency in simulating tidal currents in the Persian Gulf. The results of the modified model were compared with those of the original model, as well as tidal fluctuations measured at several tidal stations in the Persian Gulf. The comparison showed that the modified algorithm successfully reduced the calculation time while increasing the accuracy and reducing numerical diffusion in the results.

Waves propagating to the shore can experience breaking in the near-shore zone which can cause sediment transport due to the large vortices and turbulence generated by broken waves. The pattern of sediment transport can be affected by the presence of slender cylindrical members forming the major components of many coastal and offshore structures. In this paper an experimental investigation was performed to measure the bed morphology due to the breaking wave impact on a slender vertical cylinder. Exact and rapid measurement of bed topography is very important in experimental hydraulics as it helps understanding of these complex processes and measured bed mapping. This can substantially aid in the design of particular projects. This paper gives a brief description of the close-range photogrammetry method that is currently available for bed mapping in hydraulic modeling. Digital Elevation Models (DEMs) and 3D maps are created; thus 3D bed figures and scouring patterns are determined.

Island nations around the world are vulnerable to natural coastal dynamics and the anticipated effects of climate change given their geographic locations and size. It is critical for such states to assess and quantify the probable consequences of coastal dangers in order to preserve their assets and protect their lives. Technological advancement these past years has changed the discipline of vulnerability assessment so much that today detailed and accurate results of impacts can be obtained and used for management practices. This study aimed at reviewing the literature on coastal vulnerability assessment methods used in the Atlantic, Indian Ocean and South China Sea Region and analyze the evolution in tools used over the years as a measure of island nations’ resolution to adapt to future changes. Using a series of specific keywords such as ‘coastal vulnerability assessment’ + ‘Maldives’ to grab relevant materials in Google Scholar and Google search engine for the period 1987 to 2019, over 100 papers were analyzed and filtered for relevancy to the topic. The results revealed an evolution in coastal vulnerability assessment tools in the AIMS region from paper based CVI methods to more robust models like GIS. Despite the vulnerability of AIMS SIDS to coastal hazards, financial resources and technical expertise, they are engaging in assessing their vulnerability to external hazards. This review sheds light on the various coastal vulnerability assessment tools used in island nations thereby forming a knowledge base for policy and decision makers, researchers and scientists involved in coastal management.

Many appropriate and necessary phenomena and mechanisms have essential roles for transfer and diffusion of arriving solar radiation, from tropical regions to high latitudes in northern hemisphere and low latitudes in southern hemisphere. Atmospheric movements (winds) and oceanic movements (currents) are some parts of these mechanisms. Even different shear of them (movements) including vertical shear of them; have basic roles in the subject. Our goal in this research is familiarizing with oceanic efforts for transfer of sensible heat via dense current that is vertical shear of geostrophic current. In connection with the subject; three versions of dense current were introduced. Furthermore; baroclinic environment, geostrophic current and variation of it with respect to depth, definition of dense current, deriving of dense current vector in Cartesian Coordinates System, the other view to derive other equations of dense current, relation between dense current and geopotential thickness, other view of relation between dense current and geopotential thickness, and other subject related to dense current; have discussed expanded upon the research. Also, study of dense current can enlighten deep sea dynamics and helps to better understanding climate of deep oceans.