پديد آورندگان :
پرهيزكار، فاطمه دانشگاه تبريز - دانشكده ي جغرافيا و برنامه ريزي - گروه ژئومرفولوژي , رجبي، معصومه دانشگاه تبريز - دانشكده ي جغرافيا و برنامه ريزي - گروه ژئومرفولوژي , يماني، مجتبي دانشگاه تهران - دانشكده ي جغرافيا - گروه جغرافيا طبيعي , مختاري، داوود دانشگاه تبريز - دانشكده ي جغرافيا و برنامه ريزي - گروه ژئومرفولوژي
چكيده لاتين :
1- Introduction
Coastal systems are very dynamic, and their movement is relatively fast due to the collision of
onshore and marine environment. The majority of the world's population is concentrated along
with the coastal areas. Hormuz Strait coasts are affected by morphological variables due to the
hydrodynamics of the sea and the dynamics of coastal and onshore environments. Destruction,
transport, and displacement of sediments, Settlement of destruction's materials, are the most
prominent features of this case study. Coastal areas of Bandar Abbas are occupied by the dense
of human constructions and residential people. The northern coast of the Hormoz strait has the
highest tidal range in comparison with the shoreline of the Oman Sea and the Persian Gulf.
Therefore, the effects of seawater in this area are more obvious than other places, and all of
these factors cause coastal changes. In general, the research goal is to study the shoreline
changes in a 47 years period and also find the most important factor in shoreline changes in
that period, finally to predict the shoreline changes in the future.
2- Methodology
In this study, Landsat satellite images, MSS, TM, ETM +, OLI sensors from 1972 to 2019
were used to monitoring the shoreline changes in the northwest and west of the Hormuz Strait.
In the next step, the necessary preprocesses (radiometric and atmospheric corrections) were
applied to the images in ENVI 5.3 software. Next, the NDWI index was used to process
satellite images and to separate water and land index. After that, to improve the clarity of
shoreline changes, the High Pass filter was applied on each image. After applying the filter, the
shoreline was extracted in each year. After extracting the shoreline, the shoreline zones turned
into Vector in ENVI software and then moved to Arc GIS10.5 software. After transferring to
Arc GIS10.5 software, the coast was divided into 4 zones, by using satellite images and field
visits and also according to natural and human factors. Furthermore, Digital Shoreline Analysis
System (DSAS) was used to analyze the shoreline variations. After calculating shoreline
variations through the Digital Shoreline Analysis System, the MAPE and RMSE criteria were
used to evaluate the error in the change ratio, accuracy, and positioning of shorelines in 2029
and 2039.
3- Results
Linear Regression Rate (LRR) is derived from fitting the position of the shoreline to the
shoreline time. The slope of the linear regression equation shows the displacement rate in
meters per year at a confidence level of 95%. For zone A, which includes the Delta of Hasan
Langi and the Shur river, the coastal displacement rate is between 0.05 to 11.04 meters per
year. The positive value of the slope in the regression equation indicates the progression of the
shoreline to the sea (the sedimentation process). This progress is related to the extension of two
important rivers, Hasan Langhi and Shur, and the amount of sediment carried by these rivers.
For zone B, the shoreline displacement is between 1.78 to 7.7 meters per year, which the
coastal constructions that have expanded over the past 30 to 40 years are one of the most
important factors in this case. The study of transects in this zone shows the stability of this
zone because most of the shoreline changes are less than 1 meter per year. For zone C, which
includes the Kol river delta, the shoreline displacement is between -0.9 to 8.58 meter per year,
which the sedimentation was seen in different parts of this zone by calculations and the review
of transects. In zone D that covers the area of Mangrove forests and the Mehran river delta, the
shoreline displacement from -3.6 to 6.84 meter per year. Due to the values obtained from the
validation of LRR and EPR parameters, the EPR parameter has less error in both MAPE and
RMSE criteria and is more proper for shoreline prediction.
4- Discussion & Conclusions
During the 47 years, Linear Regression Rate (LRR) in the zones of A, B, C, and D was
respectively 12.6, 1.65, 2.63 and 0.8 meters per year. According to the results, shorelines have
more progress toward the sea, showing that the sedimentation is more than erosion. The
changes were calculated by the transect method during four periods, and then using the
statistical analysis, and finally the calculation of MAPE and RMSE. As a result, the EPR
parameter was selected as the basis for predicting shorelines. The predicted shorelines for the
next 10 to 20 years also show the progress of the shoreline toward the sea and the continuation
of this sedimentation process. In addition, it is not possible to ignore the zones that the erosion
process occurred, especially in the Hara forests in the Khour Khoran and parts of the Kol River
delta and in the west zone of Bandar Abbas. The results of this study give an indication of the
vulnerability of various coastal areas and essential needs for planning to protect the shoreline in
different zones.
