Doreh Mirheidar; Bahador Gholami; Zahra Pishgahifard; Ghasem Azizi; Amirhossein Ranjbarian
Abstract
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 ...
Read More
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. 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.
Morteza Miri; Ghasem Azizi; Hossein Mohammadi; Mahdi Pourhashemi
Abstract
Extended Abstract
Introduction
The limited access to the atmospheric and terrestrial data such as rainfall, temperature, humidity and soil temperature is the most important problem in studying many climatological and hydrological in many parts of the world, particularly in developing countries, rural ...
Read More
Extended Abstract
Introduction
The limited access to the atmospheric and terrestrial data such as rainfall, temperature, humidity and soil temperature is the most important problem in studying many climatological and hydrological in many parts of the world, particularly in developing countries, rural and mountainous areas. One of the solutions to overcome this obstacle is to use available gridded datasets that have proved their representativeness for many different parts of the world. Although the use of satellite data and gridded datasets is a reasonable alternative source for areas lacking station and data, since local effects can vary from region to region and can affect satellite and model performance, thus an dataset must be evaluated in a region before it is used as a decision-making tool in that region.
Materials and methods
The present study is aimed at the presentation of Global Land Data Assimilation System (GLDAS) and evaluates this model dataset against data measured by synoptic stations. The Global Land Data Assimilation System (GLDAS) has been developed jointly by scientists at the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center (GSFC) and the National Oceanic and Atmospheric Administration (NOAA) National Centers for Environmental Prediction (NCEP) in order to produce such fields. The goal of a land data assimilation system is to ingest satellite and ground-based observational data products, using advanced land surface modelling and data assimilation techniques. The uniqueness of GLDAS is that it is a global, high resolution, offline terrestrial modelling system incorporating ground and satellite observations. The temporal resolution for the GLDAS products is 3-hourly and Monthly with 0.25 and 1 degree spatial resolution its output is the result of four land surface models: the Community Land Model (CLM), NOAH, Mosaic, and the Variable Infiltration Capacity (VIC) model.The products are in Gridded Binary (GRIB) format and can be accessed through a number of interfaces.
The representativeness and performance of GLDAS in estimate temperature amount at 66 Iranian synoptic stations distributed across the country is herein examined. To evaluate the performance of the considered dataset when compared to the observed temperature records at the considered locations we have used R squared, the Nash–Sutcliffe model efficiency coefficient (EF), RMSE, Bias, B slope of the regression and the standardized RMSE indicators. The performance of the dataset was also graphically represented through scatter plots of the established regression between GLDAS and observation at the selected stations.
Results and discussion
The results of the statistical indicators were represented through plotting the indicators over the map of Iran to ease displaying spatial tendency of the indicators and explaining the possible geographical role in controlling the spatial variation of the indicators. According to the results of the evaluation, the GLDAS data performs well in all of the studied stations with strong correlation coefficient. However, the Special physiographic and climatic characteristics is one of the main reasons for this overestimation in the coastal areas of the Caspian Sea. very likely due to not properly taking into account the complex topography of the region in its model parameterization or not being able to remove the effect of sea atmosphere in the stations nearby the seas. However, since the cloud of the estimated data for this region are distributed along the regression line, it can be said that the observed over-estimation could be resolved through establishing a statistical relationship between the observed and modeled datasets; thus such a mismatch might not be considered as a drawback of the modeled dataset. Considering that this model output is produced through combination of the modeled, observed and remotely sensed data, it could be confidentially used for mountainous areas and deserts of Iran that suffer from lack of weather stations or substantial missing values. This data-set might be considered as a superior dataset to be used for many climatological and hydrological subjects in Iran and thus should be seen as a promising tool for extending hydrological and climatological research areas in the country.
Conclusion
Statistical comparisons indicate that the GLDAS data perform well in all of the studied stations with strong Accuracy. Due to the Global coverage of the model dataset, A large number of climate-hydrological variables, and the results of this research that indicate the Good accuracy of the GLDAS model in Iran, It is suggested that all variables in the model to be evaluated.
Hossein Mohammadi Hossein Mohammadi; Ghasem Azizi; Faramarz Khoshakhlagh; Mahdi Khazaei
Abstract
Abstract
Accurate and timely estimation of evapotranspiration has a significant and critical impact on the planning of water resources and agriculture. In this research, the estimation of evapotranspiration of sugarcane in Khuzestan province has been studied, and the data used, have been air temperature, ...
Read More
Abstract
Accurate and timely estimation of evapotranspiration has a significant and critical impact on the planning of water resources and agriculture. In this research, the estimation of evapotranspiration of sugarcane in Khuzestan province has been studied, and the data used, have been air temperature, relative humidity, wind speed and sunny hours since the establishment of synoptic station until 2014. For this purpose, the evapotranspiration values of the reference plant were first calculated using the FAO Penman-Monteith standard method and then, using available plant coefficients, the amount of sugarcane evapotranspiration was estimated at different stages of growth. The results of this study show that the average sugarcane evapotranspiration in Khuzestan province has been 3.35 mm / day in June and in the early stages of growth, 10.46 mm/day in the middle stages of growth, and 6.26 mm / day in the final stages of growth. The value of this parameter in July was estimated 3.59 mm/day in the early stages, 11.23 mm/day in the middle stages and 6.74 mm/day in the final stages of growth. Finally, the amount of evapotranspiration of sugarcane in August was estimated 3.56 mm per day in the early stages of growth, 11.12 mm/day in the middle stages and 6.67mm per day in the final stages of the growth. The maximum daily and monthly evapotranspiration has occurred in July and the minimum in June. Also, the highest daily and monthly fluctuations of sugarcane evapotranspiration have occurred in the middle stages of growth and the lowest in the early stages of growth.
