In this study, the Compound and overtide constituents resulted from nonlinear triad interactions were evaluated using Bispectral method at the eastern Iranian coasts of Makran. It was found that the most significant Compound constituents at the studies area were KO2, KP2, MS4 and MN4. Also, the overtides of M4 and S4 were detectable by means of implemented method. The superiority of Bispectral method comparing with least square method (harmonic analysis) is in recognizing some of Compound tides such as KO2, which is never identifiable using least square method. The corresponding Fourier harmonic frequencies to main tidal constituents were identified by comparing the results of the least square method and the Fourier analysis. Finally, the analysis was performed with d. o. f. s of 16, 32 and 64. The repeated significant bicoherence values in all three d. o. f. s and in the main tidal constituent frequencies range were regarded as the intensive and effective interactions.

The regional waters in Singapore Strait are characterized by complex hydrodynamic phenomena as a result of the combined effect of three large water bodies viz. the South China Sea, the Andaman Sea, and the Java Sea. This leads to anomalies in water levels and generates residual currents. Numerical hydrodynamic models are generally used for predicting water levels in the ocean and seas. But their correctness is typically limited by several factors, namely the complexity associated with the coastal geometry and uncertainty in the flow forcing factors like (winds, pressure and deep ocean tides). Modeling of ocean dynamics in the Malacca strait and Singapore regional waters is particularly challenging due to the presence of large number of smaller islands and strongly nonlinear tidal interactions. The complexity is further enhanced due to the composite local bathymetry and geometry variations around the Singapore Island and meteorological effects on different scales. This study acknowledges the enhancement and better prediction of tides and surges through the use of data assimilation. Through a portable interface OpenDA, an ensemble Kalman filter is integrated with a hydrodynamic model to enhance the model predictions. To assess the sensitivity and evaluate model enhancement, a twin experiment is designed to improve tidal boundary forcing effect in a semienclosed estuary. The key outcomes of this study signify that the model results can be significantly improved in this complex flow regime.

In this study a numerical model was developed to determine the tidal regime and its power in any location of the seas and the oceans. The methodology employed is firstly to use the measured water level data for a limited period and then to use the least square method and low pass FIR filter with a suitable cut frequency, to calculate components and phases of tides. Next by using the calculated amplitudes of tidal components the tide form number of the study area is calculated. In this way the type of tide of the area and its efficient component and astronomical period is determined. Finally using these information as well as gravity acceleration and water density the tidal power is estimated. In a case study the change of water level was measured in Bandar Abbas Coast of Persian Gulf for 29 days. Then using the developed model the tidal power in the study area was estimated. Considering this power it can be decided if devices for absorbing tidal energy can be economical to install in this area.

Hydrodynamic models are widely used for simulating water level and oceanic current; however due to uncertainties involved in this process such as accuracy of input data or realization of the governing equations, there are some errors in the simulation results. Data assimilation is one of the effective solutions to avoid and to limit some of these errors. This manuscript evaluates how Ensemble Kalman filter, one of the most advance assimilation techniques, can enhance water elevation predictions in the Persian Gulf. The open source Delft3D FM was used as a hydrodynamic model and open source code of Open DA was employed to apply Kalman Filter. The Open DA was coupled inside the code of hydrodynamic model to improve its performance. We have setup several experiments to estimate the best number of groups, error parameter of observations, error parameter of open boundary, and the most effective station for assimilation. The results show that the data assimilation can effectively improve the hydrodynamic model results and can be used for real applications.

In this study an annual report of water height in Torat-Bakhakh station was investigated. No tidal calculation including identification of tidal constituents and its modeling has been done so far. Therefore, the results of this research along with the methods used can be effective and useful. In this study five tidal constituents of M2, Mf, O1, K1, and K2 were identified. The strongest element in this spot was M2 and it reveals that major changes of tides are related to the moon location. According to the American scale, the f-number is f=0.36 which indicates a semi-diurnal type of tides, because this quantity is less than 0.5. Hence, the tide of this area represents the powerful influence of the sea.

The problem of the possibility of knowledge is one of the main issues in epistemology, which dates back to the beginning of philosophy. In this regard, some Western philosophers have embarked to solve the problem by presupposing the possibility of knowledge, some others by accepting the claims posed by skeptics, still some others by appealing to theology and again some others, through a new explanation of objectivity which has led to deepening the gap between the subject and the object, and have, thus, supported one of its two aspects. All these viewpoints are based on the assumption of contrast between the subject and the object and definition of knowledge as something in which no error is admitted; more over, they are deprived of any philosophical reasoning in favor of the possibility of knowledge, and have bore no results but tides of skepticism.      

The present investigation was undertaken to determine temporal and spatial distribution of macrofauna in low tide regions of Bushehr province in the northern Persian Gulf. Sampling was seasonally carried out by a box corer of 0.0225 m2 in six stations including Genaveh, Farakeh, Shif, Bandargah, Rostami and Asalouyeh from summer 2008 until spring 2009. In this study, 752 specimens belonging to 29 genera were collected. Polychaetes were dominant both in terms of genus number (22) and relative abundance (77.1% of total macrofaunal abundance). The other dominant groups were crustaceans, bivalves and turbellaria. The highest number of Prinospio and Solen specimens were found in Genaveh, Farakeh, Bandargah, Rostami and Asalouyeh stations with sandy substratum; however Capitella sp. and Nicomache specimens were collected only in silt–clay substratum of Shif station. The highest (888.89 ind. m-2) and lowest (37.03 ind. m-2) annual average density of macrofauna were found in Farakeh and Asalouyeh regions, respectively. R- square in quadratic Regression equation between temperature and macrofauna density and Shannon wiener species diversity index were assessed to be 0.988 (P=0.044) and 0.992 (P=0.09), respectively. The annual Principal Component Analysis indicated that in stations 1- 5, the organic matter content, sediment texture and temperature have had the most influence on the macrofauna assemblage, but comparison of species composition, density and Shannon wiener species diversity index of macrofauna in Asalouyeh with previous recorded data of the region showed that manmade factors such as gas and petrochemical industries have had the most effect on the macrofauna community structure during sampling period.

The purpose of this research is to show the use of neural networks in predicting the tides of the Caspian Sea. Forecasting the current level of seawater is very useful in the shipping industry and is one of the most important parameters in marine geodesy, oceanography, and geophysics. Sea level has been done in different ways. Among the factors that affect the instantaneous sea level changes, the tidal factor has been investigated in this research. Nowadays, artificial intelligence methods are used to predict tides, these methods can fill information gaps the above items are among the advantages of intelligent methods in analyzing and predicting tides. Accordingly, this study method has been used in the preparation of this research. The nature of this research is quantitative and applied, and a descriptive research method has been used. In this research, one of the types of artificial intelligence has been worked with, which is neural networks. Neural networks have been used to validate the primary data and predict the Caspian Sea tides in this research. According to the findings obtained by Geo Tide software and neural networks, the water level of the Caspian Sea is decreasing because is clear in this research. It was found that the neural networks are more effective for predicting the tides, the water level of the Caspian Sea will reach -28 meters from the open water level in the future.

Prediction of tides has been received a great attention from decades ago since its importance in admiralship, navigation, port designing and other related issues. The goal of this paper is to investigate the efficiency of predictive models based on Multiple Liner Regression (MLR) and feed-froward Artidicial Neural Networks (ANNs) using 3 learning algorithms of Gradient Descent (GD), Conjugate Gradient (CG) and Levenberg-Marquardt (LM). For this purpose, hourly observed data of Chabahar bay station in the Gulf of Oman and Kish Island and Imam-Khomeini port stations in the Persian Gulf were used. In the current study, the partial auto-correlation was used to determine the appropriate lag of input data. The results of models according to the criteria of RMSE and MAPE indicated that the ANN-LM has the highest accuracy in predicting tides in the 3 stations. This algorithm improved the prediction accuracy about 22%, 4% and 2% compared to MLR, GD and CG models. Finally, the residual analysis revealed the over-predictive behavior of ANNs in Kish Island and Imam Port stations while their under-predictive tendency in Chabahar Bay.

Extended Abstract Introduction Maritime territories and quasi-territories are, in fact, continuation of territories underwater, formedbased on rules and principles governing political systems, international law and international relationsin maritime environment. Place making, territoriality, delimitation and demarcation of territories in the seas are performed based on geographical factors (particularly physical geography). As one of many different physical geographic factors, tideplays a decisive role in maritime delimitation and territoriality. It is considered as the basis upon which boundaries of different maritime territories and quasi-territories in different countriesare demarcated and delimited and formalnautical maps are drawn. Each country of the worldapplies a different basisfor determining low water lineand thisresults in many issues and challenges in maritime territoriality. Meanwhile, sea level has risen due toclimate changesand is expected to increase in the future. Thiswill also affect the above mentioned phenomenon, and may cause serious challenges for demarcation of the existing boundaries. Thus, the present study employs a descriptive-analytical method toinvestigate the role and significance of tides in maritime delimitation andanalyze the impact of sea levelrise on delimitationand maritime territoriality process. Materials & Methods: The present study is an applied research following a descriptive-analytical method. Related data was collected through library and internet-based methods and the research follows a qualitative method of analysis. Moreover, GIS and mathematical map calculator known as the “ Raster Calculator” were used to draw the maps required for therise of sea levels. Based on the existing scenarios and their average values, the present study considers a two-meter rise for the sea level rise by the end of the 21st century. 􀀗 􀀖 ، پاییز 􀀏 􀀏 􀀏 ، شماره 􀀐 􀀖 دوره 􀀆 􀀇 لنامه علمی-پژوهشی اطلاعات جغرافیایی 􀂐 ف 4 / Scientific-Research Quarterly of Geographical Data (SEPEHR) Vo. 28, No. 111, Autumn 2019 Results & Discussion: Tideis the most significant factor based on which baselines are drawn. Setting low water line as a fixed basisused for delimitation of maritime territories and quasi-territories is only possible ifcoastline is stabilized at one level or in other words at a definite plate during tide. This function is carried out by the tidal datum. Datum is the reference level based on which all depths andcorresponding elevations are plotted. Therefore, tides play a significant role in determining the Law of the Sea. On flat coastlines, baseline is determined based on the low water line. On dented and jagged beaches, the base points are also determined according to the same phenomenon. Moreover, some features such as the low– tide elevations and islands are also identified based on the datum used. Selection of low water line (as opposed to high water line) leads outer limits of the territorial sea and consequently other areas toward the sea. This will expandmaritime area under sovereignty and jurisdiction of different countries. The country which uses a lower datum will expand its marine sovereignty and jurisdiction. In Persian sources, terms such as the lowest tide line have been used mistakenly as a translation for the term “ Low Water line” stipulated in Article 5 of the 1982 Convention. This is while lowest tide is only one type of low water lines, and though this concept plays the most important role in maritime territoriality, no clear reference has been mentioned for datum in the 1982 Convention. The convention stipulates thatdatum used in the official nautical charts published by different states is the tidal datum based on which normal baseline must be defined. Although the International Hydrographic Organization has proposed the lowest astronomical tide as the basis for determining the datum, there is a major difference between states in this regard and they use a variety of tidal base lines. However, coastal countries usually prefer to use the lowest datum. It seems that sea level rise, as the most important phenomenon resulting from climate change, has significant impacts on tides and boundaries delimitated based on tides. This is because low water line may retreat due to sea level rise, and as a result base points upon which baselines are drawn, along with marine territories and quasi-territories might also move closer to the land. However, states which have based their datum on higher averages oflow water will encounter fewer challenges caused by the retreating baseline compared to those that have selected the lowest low water line. However, evaluating a two-meter rise in sea level by the end of the 21st century shows that in different coastal regions of the world, the impact of sea level rise on low water line is not balanced and similar. Thus, given the spatial-geographical variations, only flat regions of the world will encounter submersion of coastlines and retreating low-water line. Conclusion Results indicate that sea level rise has dramatically changed tides and will challenge Political Geography of the Sea. However, a two-meter sea levelrise will severely affect tides in areas facing coastal retreat, and since normal baselines are drawn based on this geographic factor, a retreat in those baseline should also be expected. In case ofstraight baselines, if base points immerse due to two-meter rise in sea level, these lines will also retreat. Yet, this largely dependson the datum considered for drawing the baselines. On the other hand, the approach used bydifferent states, especially in areas in which maritime boundaries have been delimited, shows that low-water line drawn onformal maps is more referable than the actual low-water line and, therefore, maps can play a stabilizing role as the most important geographic instrumentin the future.