فصلنامه اقیانوس شناسی
پیاپی 56 (زمستان 1402)

The aim of this study is to predict floods and investigate the impact of different digital elevation models (DEM) on simulating flood peaks using the WRF-Hydro model in the Polrud watershed on the southwestern coast of the Caspian Sea.

In this study, three different DEMs (HYDROSHEDS, MERIT with hydrological nature, and SRTM 30m with topographic and geological applications) were used as input data for pre-processing the WRF-Hydro model. Finally, for each pre-processing with different input DEMs, the parameters that have the most significant impact on the flood peak value and hydrograph shape were optimized. These parameters are REFDK (saturated hydraulic conductivity), REFKDT (infiltration parameter), and MANN (channel roughness coefficient), respectively. A probable range was estimated for each parameter value, and then in the next step, by comparing the simulated hydrograph with the observed hydrograph, the optimum value for each parameter was determined.  

Among the digital elevation models, MERIT DEM shows the best results, and the error rate for all three validation dates is 2.5%, 15.0%, and 33.3%, respectively. After MERIT DEM, SRTM USGS 30m with an error rate of 0.45, 4.4, and 2.14 for the three events respectively, provides the best results. Based on the output of the model and observational data, the two parameters REFDK and Manning's coefficient had the greatest effect on optimizing the model results. The Manning's coefficient has a significant effect on the flow time, so the lower the value of MANN, the faster the transfer time and the more flow generated.

Hydrology-based digital elevation models can have a better effect on the output results of the WRF-Hydro model. On the other hand, the optimization parameters of the WRF-Hydro model have a considerable impact on the results. In the study area, precipitation data, digital elevation models, and Geogrid resolution with better accuracy are very important. Combining numerical weather prediction models with hydrological models can increase flood warning time and have acceptable capabilities in predicting floods. Therefore, it is recommended to use the WRF model in combination with the WRF-Hydro hydrological model for flood prediction in flood-prone areas of the country in developing and expanding the flood warning system.

Background and Theoretical Foundations: 

The purpose of this research is to design and test the marketing model of port services based on the Foundation's data method.

The mixed exploratory research method and the statistical population of this research included two parts, in the qualitative part there were 20 experts and managers and experts in Amirabad port and in the quantitative part there were 110 people including the owners of goods and services and investors in the special economic zone of Amirabad port. The data collection tool was a researcher-made questionnaire, which was compiled with 88 items based on the theoretical foundations and conducted interviews.

From the results of the research in the field of port services, 22 components were obtained. In this model, the main and central category is creating value for the customer in providing services to customers in the port. Price, distribution, advertising and employees are causal factors and customer orientation, processes, information management, customers and electronicization of services, contextual factors and physical facilities, brand and branding and communication are intervening factors. Improvement of management structures, improvement of marketing strategies, market orientation, human resources management and improvement of service methods are model strategies and finally, more and more established presence in the market, improvement of structure and realization of internal marketing are the consequences of the model. The analysis of the performed paths showed with a confidence level of 95% that the causal factors to the main category of creating value for the customer at the rate of 0.66 and creating value for the customer to the strategies at the rate of 0.28 and interfering factors to the strategies at the rate of 0.44 and Background factors have an effect on strategies to the extent of 0.31, and finally, strategies have an effect on the results to the extent of 0.71. The greatest impact on the path of strategies related to outcomes was estimated at 0.71.

and this means that if the recommended and extracted strategies are well implemented in Amirabad port, they will improve performance in the field of port services.

Background and Theoretical Foundations:

 An ocean economy with a focus on enhancing social fairness and human well-being while lowering environmental dangers is known as a "water economy." In order to increase economic development, improve quality of life and employment opportunities, and maintain the health of ocean ecosystems, the term "water economy" is used. Iran has access to the sea, and by using these resources and potentials, it may move toward economic development and progress. Access to open waters, small and large islands, port cities with various commercial, fishing, touristic, and industrial functions, shipbuilding, maritime tourism, maritime transportation, underground resources, oil and gas mines, refineries, ports, piers, and marine structures, bunkering (fueling ships), and environmental activities are just a few of the potentials of the nation in the field of sea-based economy. The sea-oriented economy is one of the untapped development opportunities in the nation. Because the sea-oriented development and the sea economy have recently drawn more attention than in the past, it is important to paint a clear picture of them. In this study, an effort has been made to lay out the realities of the sea-based economy in the nation. The water economy, which has lately garnered increasing attention which is also addressed in the seventh development plan, may have an economic impact. Important economic sectors that are taken into account include aquaculture and maritime transport which has significant economic benefits for Iran. In light of this, the current study aims to identify these advantages. The primary research question is: What impact does emphasizing the sea-based economy have on welfare, changes in the nation's trade balance, and employment?

In this study, the economic effects of concentrating on the sea-based economy (aquaculture sector and maritime transport), due to the multi-regional calculable general equilibrium model (GTAP) and version 10 of its database, during 3 scenarios, 1. 100% reduction in rates Bilateral tariff of the two sectors of aquaculture and marine transportation, 2. Increasing the productivity of the workforce working in two sectors of aquaculture and marine transportation, and 3. Increasing the productivity of intermediate inputs in two sectors of aquaculture and marine transportation) was analyzed with GEMPACK software package.

The study's findings indicate that lowering the aquaculture sector's tariff will result in a decline in production volume, an improvement in Iran's welfare due to increased productivity of intermediate inputs used in both the aquaculture and marine transportation sectors, and an improvement in the trade balance between these two industries due to increased productivity of labor and intermediate inputs.

According to the research's findings, the most crucial policy advice for the nation is that marine transportation may be seen of as a viable choice. The findings of this study may assist the nation's planners and policy makers in adopting suitable investment and workforce training strategies, which would eventually result in higher economic growth and increased exports of this industry. Production may rise as a result of worker productivity and training in sea-oriented industries. Investment in sea-oriented industries is one of the factors that might affect productivity. Iran has a unique maritime edge; thus it is important to develop economic activity via domestic investment as well as by attracting outside investors. The capability of the private sector in the marine and port sectors was best used by the foreigner.

The Persian Gulf hosts a variety of marine ecosystems, including mangrove forests, seagrass beds, and coral reefs, which have adapted to the challenging environmental conditions of the region to some extent. These ecosystems are increasingly influenced by rapid population growth, economic development in the countries surrounding the Persian Gulf, as well as, the impact of climate change in the region. They are facing mounting pressure from human activities. The influx of nutrients, coupled with the warming of the Persian Gulf, can result in a reduction in the dissolved oxygen concentration in the water. Consequently, the simultaneous occurrence of warming, reduced oxygen, and acidification in the Persian Gulf has become a significant challenge for its valuable ecosystems. According to studies, hypoxic areas in the Persian Gulf in mid-autumn can extend to more than 50,000 square kilometers. The occurrence of hypoxia in the Persian Gulf during late summer is confined to two primary areas in the western and central regions. In the eastern Strait of Hormuz, hypoxic conditions are observed in the near-bottom layer from early summer to mid-winter in areas distant from the Gulf's outflow. The reconstruction of dissolved oxygen concentrations in recent decades also indicates a declining trend accompanied by an increase in the extent and duration of hypoxia in the Persian Gulf. The degradation of water quality in the Persian Gulf, in addition to its adverse effects on its valuable ecosystems and consequently on fisheries and aquaculture in the Gulf, can significantly impact the Gulf of Oman and even the Arabian Sea in various ways, exacerbating the conditions of Oxygen Minimum Zones (OMZ) in these expansive seas. The Gulf of Oman and the Arabian Sea naturally and permanently host the widest and thickest OMZ in the world ocean. Depths exceeding 400 meters in the Gulf of Oman exhibit suboxic conditions (oxygen concentration less than 6 µmol/kg) during both summer and winter. The OMZ in the Arabian Sea and the Gulf of Oman has intensified over the past few decades. Oxygen levels recorded in 1960 in the core of the OMZ in the Arabian Sea and the Gulf of Oman ranged from 6 to 12 µmol/kg but have now dropped to levels below 6 µmol/kg (suboxic). This intensification of the OMZ in the Arabian Sea and the Gulf of Oman has adverse effects on the ecosystems of this region and the livelihoods of dependent populations. Marine organisms residing in the near-bottom layer or surface sediments are most affected by the expansion and intensification of hypoxic and suboxic conditions. Oxygen deficiency leads to a decline in the biodiversity of benthic communities, promoting resilient species such as polychaeta in surface sediments. The reduction in oxygen levels in the Arabian Sea has significantly influenced the composition of phytoplankton communities, the vertical migration of zooplankton, and myctophidae in the water column. The expansion and intensification of the OMZ, with its adverse impacts on fishing and aquaculture, also carry socio-economic implications for residents of the coastal areas of the Indian Ocean, the Gulf of Oman, and the Arabian Sea. Considering the prevalence of seasonal hypoxic conditions in the Persian Gulf and permanent suboxic conditions in the Gulf of Oman, addressing this trend and mitigating its environmental and economic impacts in the region is crucial. Management and policy strategies to halt or reduce the effects of oxygen depletion in the Persian Gulf and the Gulf of Oman can be classified into three main categories: a) ecosystem-based mitigation measures for environmental restoration and protection, b) adaptation-based measures to restore and protect marine organisms and fisheries, c) implementation and maintenance of monitoring programs and analysis of the information obtained. In essence, efforts to integrate research, management, and policy actions in oceans and seas across all biological, geochemical, and physical disciplines, addressing all climate change-related issues such as warming, acidification, and oxygen reduction, and involving all academic, industrial, governmental, and regulatory sectors, constitute the most effective roadmap recommended for combating the impacts of climate change on marine resources.

The Mediterranean-Arab (Arab-Med) Corridor of India to Europe is an emerging multi-faceted trade corridor that could fundamentally alter trade patterns between the Indian Ocean region, the Middle East, and Europe by creating a crescent of trade connectivity on the southern edge of Eurasia from the coasts. The Arabian Sea of India will change to the eastern Mediterranean coast of Greece. For India, this new corridor is a strategic paradigm shift with huge geopolitical implications that could change its role in the Eurasian economic order. Based on this, the current research, which was carried out in a descriptive-analytical way, seeks to answer the question of what effect does the Arab-fashion corridor have on the new architecture in the trans-regional connection? The hypothesis of this research is that the Arab-Med Corridor is creating an alternative trans-regional trade architecture in which the UAE ports can act as the connecting point of the Indian Ocean to create a separate trade corridor from India to Europe and India to The title introduces a new power to the world with the ability to create transregional commercial architecture. The establishment of a Mediterranean terminal - from Haifa to the European mainland at the Greek port of Piraeus - means that Indian goods sent to UAE ports can reach the main markets and production centers of Europe.

Ophiolite complexes are interpreted as remnants of oceanic lithosphere that have emplacement along the edges of continents after an oceanic basin close. Iranian ophiolites, considered as remnants of closure of the Tethys (or Neo-Tethys) Ocean and its branches. These ophiolites are outcrop in two distinct regions: 1) Ophiolites coeval with the Zagros orogenic belt, and 2) Ophiolitic assemblages surrounding the Central Iranian Microcontinent. The comparison of these two ophiolite complexes indicates noticeable differences between them. Therefore, in order to understanding the tectonic sitting of their formation, initially, the geological, petrological, geochemical features, and the age of these rock units were examined and compared. Subsequently, to delineate the boundary between the two mentioned ophiolite complexes, field surveys were conducted, and geological maps of the region were prepared.Based on results, the ophiolite complexes surrounding the Central Iranian Microcontinent include the Sabzevar ophiolites in the north, the Neyriz-Dehshir-Baft ophiolites in the west, the Kahnuj ophiolites in the southwest, the Makran ophiolites in the south, and the Turbat Heydariyeh - Tchehel-Kureh ophiolitic belt in the east demonstrate similar features and it seems they have formed in a same tectonic environment. They exhibit fundamental differences from the Zagros ophiolites and have formed at different geological time, too. The ophiolites around the Central Iranian Microcontinent mark remnants of oceanic lithosphere that formed as a result of the opening of a rift basin between two continental blocks and its expansion into an intracontinental oceanic basin that known as a branch of Tethyan Ocean. This Ring Ocean existed during late Mesozoic, and as a result of its closure, these ophiolite complexes were formed