جستجوی مقالات مرتبط با کلیدواژه « satellite imagery » در نشریات گروه « محیط زیست »

Wetlands, as one of the most important types of ecosystems in the world, are extremely threatened. In addition to being part of Iran's protected areas, the Parishan wetland is also known as an international wetland and biosphere reserve. Understanding the process of changing in this wetland, can be very helpful in improving its future status. Therefore, the purpose of the present study is to monitor the changes in the over a 30-year period.

For the purpose of the research, Landsat satellite images were prepared for four time periods of 1987, 1998, 2007 and 2016 along with other required data. By performing the required preprocessing in ENVI 4.7 software, Parishan wetland land-cover maps was extracted using Normalized Difference Vegetation Index and Normalized Difference Water Index combining with Decision Tree method in three class including water-body, vegetation and others land-cover.

The results showed that after 30 years only 13 hectares of 1963 hectares of Parishan wetland water-body remained. Monitoring of changes shows that Parishan wetland water-body has decreased by 1950 hectare in comparison to 1987, 3605 hectare in comparison to 1998 and 2272 hectare in comparison to 2007.

using satellite data and remote sensing techniques along with Decision Tree classification model indicate the capability of this method for identifying and classifying land-cover in wetland areas where vegetation and water are intertwined.

Quantitative and qualitative monitoring of vegetation is one of the main applications of remote sensing knowledge. Estimating the area of vegetation and agricultural lands in the traditional way is time consuming. Remote sensing is of great importance for providing up-to-date information, duplicate coverage, sensing in different spectral ranges, quantitative and digital sensing of surface phenomena. This study was conducted to estimate the level of vegetation and agricultural lands of Babolsar county through Sentinel 2 satellite images using NDVI index.

The present research method is descriptive-analytical based on the data of Sentinel 2 satellite images of 2019. These images were extracted from the USGS website. After extraction, the images are processed in remote sensing software systems and geographic information systems, and the required results have been extracted.

After receiving the Sentinel 2 satellite images, the bands 2, 3, 4, 8, which have a spatial resolution of 10 meters, after preprocessing and atmospheric corrections, based on IDL programming language, using NDVI index, Sentinel 2 ROI were obtained, then output. Threshold was calculated between a maximum of 1 and a minimum of 0.5 and with a Shape file output in ENVI and Arc Map software, the area of vegetation and the area under cultivation of agricultural lands in Babolsar county were calculated and concluded on the date of obtaining satellite images. Discussion and

The results showed that the area of arable land and vegetation of Babolsar city is estimated to be more than 52%. Overall accuracy of 95% and kappa coefficient of 89% by evaluating the output of NDVI index showed that Sentinel 2 images can be used to extract vegetation and arable lands.

Remote sensing science plays a crucial role in the management of water resources, particularly in monitoring changes in these resources. Recently, Zarivar lake has garnered attention from various environmental organizations due to concerns about its future based on observed changes. The objective of this study is to monitor and evaluate changes in the surface area of Zarivar lake using remote sensing techniques.

In order to achieve this objective, Landsat satellite images from 1985 to 2015 were obtained and subjected to radiometric processing, classification, and extraction of vegetation indices. This allowed for the separation of the lake water surface from surrounding vegetation and soil.

Analysis of the data revealed that there was no significant difference in the change of water level in Zarivar Lake over the 30-year period studied.

Despite concerns about Zarivar lake's future, our findings suggest that there has been no significant change in its water level over time. However, it is important to note that sediment buildup on the lake floor and elimination of its margins have resulted in a decrease in volume without a corresponding decrease in surface area.