نوع مقاله : مقاله پژوهشی
نویسنده
گروه جغرافیا، دانشکده علوم انسانی، دانشگاه زنجان، زنجان، ایـران
چکیده
کلیدواژهها
عنوان مقاله [English]
نویسنده [English]
Aim: The purpose of this research is to identify the area of sand dunes and its changes in desert areas using spectral indicators in Landsat 8 and Sentinel 2 satellites.
Material & Method: In this research, using four bands of Sentinel 2 data, a new spectral index named NDESI has been presented for the identification and recognition of sand dunes in Rig Jen area. This index uses the blue, red or red edge of vegetation and two short wave infrared bands SWIR1 and SWIR2 to produce the image. A threshold calculation method was used to create unique thresholds for each image.
Finding: Based on this, the threshold value for equation 1 and 2 in March and July 2023 of Sentinel 2 satellite was obtained as 0.261 and 0.217, respectively. This amount for Landsat 8 satellite in 2013, 2018 and 2023 was equal to 0.063, 0.0735 and 0.071 respectively. The extent of sand dunes in this area according to equation 1 of Sentinel 2 satellite in July 2023 was equal to 2262 square kilometers and for Landsat 8 satellite in the same year it was 2638 square kilometers. In the discussion of Pearson correlation, it was also observed that the highest correlation of 0.63 between NDESI index and band 7 of Landsat 8 satellite and the lowest correlation of -0.14 between this index and band 2 in equation 1 of Sentinel satellite 2 has been.
Conclusion: Finally, the accuracy evaluation on the images obtained from equations 1 and 2 showed the overall accuracy of 87.4 and 83.7 percent. This index has also been compatible with Landsat 8 data.
Innovation: The results of this research have been used in the investigation of sand dunes and their identification.
کلیدواژهها [English]
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