نوع مقاله : علمی - پژوهشی
نویسندگان
1 استاد یار گروه جغرافیا دانشگاه آزاد اسلامی لارستان
2 دانشجو کارشناسی ارشد سنجش از دور دانشگاه آزاد اسلامی واحد لارستان
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسندگان [English]
Sustainable coastal management requires awareness of the trend of shoreline changes. Detecting shoreline changes can help identify and analyze the extent of shoreline displacement. By determining the wave and coastal current patterns and their interaction on sediment transport, changes in coastal morphology can be investigated.
Shamkhi Ranjbar et al. (1401) have presented an article entitled Detection and investigation of river shoreline changes using remote sensing data. This study investigated the capabilities of IKONOS Sentinel-2A satellite images in extracting river features to identify and investigate changes in the shoreline of the Karun River in two periods between 2006 and 2018.
The objectives of the research are: Identifying the factors affecting the change in the course and geometric shape of the riverbed Investigating the extent of the impact of human intervention on the change in the course of the river
This research is a field and system research in terms of its applied purpose and in terms of its implementation method, which is carried out as a case study. In this research, the river course plan is extracted through Landsat remote sensing satellite images, and by applying geometric corrections and georeferencing these images in different time intervals, raster information from the river course will be classified in the ARCGIS software according to the times of image acquisition, and then by digitizing the river coastline, the geometric path of the river is drawn in each time period. This digital information is analyzed and examined in AutoCAD and ArcGis software.
Method used: Introducing the MIKE numerical model The MIKE mathematical model, which was prepared and developed by the Danish Hydraulic Institute (DHI), is capable of simulating unsteady flows in rivers, estuaries, irrigation networks and other similar hydraulic systems.
Results and Discussion of Satellite Image Analysis of the Research In this study, images from Landsat 5 and 8 satellites were used over a 20-year period. The images used were from frames 135-167 and 134, 134-166 of the above satellite and were from August. The sensor of these satellites in Landsat 5 has 7 bands, 6 of which are spectral and 1 is thermal. Two OLI and TIRS sensors are installed in Landsat 8, 4 bands in OLI and 2 bands in TIRS. At this stage, in order to study the changes in the coastline, the intersection of two consecutive classified images was used. The table and map show the land changes in the region from 2000 to 2020. With the help of this information, it is possible to study the relationship between the trends in changes in different classes with each other. In order to monitor the changes in the coastline, the images obtained from the previous stage, which have two classes of water and land and are intersected with each other, are periodically reviewed.
During this period, the total length of the coastline has increased from 74,772 meters in 2000 to 77,292 meters in 2020 (an increase of 2,520 meters). The maximum advance of the water class towards land is about 127.5 meters along the coastline and the maximum advance of land towards the water class is about 202.5 meters at the mouth of the Qara Aghaj River.
One of the most important graphical outputs of the numerical model is the distribution of the total sediment load, which is the sum of bed and suspended sediments in different directions. The figure shows the total sediment load of the studied coast. According to the results of the model, the maximum sediment load has occurred in the western areas of the Qara Aghaj River and the sediment distribution is also greater in this area. Therefore, special measures, including dredging, must be taken in these areas to ensure water flow. Also, the numerical values of the sediment transport rate in the study area, according to the numerical model, are shown in the table.
کلیدواژهها [English]
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