Ecological environment quality evaluation of the Sahel region in Africa based on remote sensing ecological index

Abstract

Long-term monitoring of the ecological environment changes is helpful for the protection of the ecological environment. Based on the ecological environment of the Sahel region in Africa, we established a remote sensing ecological index (RSEI) model for this region by combining dryness, moisture, greenness, and desertification indicators. Using the Moderate-resolution Imaging Spectroradiometer (MODIS) data in Google Earth Engine (GEE) platform, this study analyzed the ecological environment quality of the Sahel region during the period of 2001-2020. We used liner regression and fluctuation analysis methods to study the trend and fluctuation of RSEI, and utilized the stepwise regression approach to analyze the contribution of each indicator to the RSEI. Further, the correlation analysis was used to analyze the correlation between RSEI and precipitation, and Hurst index was applied to evaluate the change trend of RSEI in the future. The results show that RSEI of the Sahel region exhibited spatial heterogeneity. Specifically, it exhibited a decrease in gradient from south to north of the Sahel region. Moreover, RSEI in parts of the Sahel region presented non-zonal features. Different land-cover types demonstrated different RSEI values and changing trends. We found that RSEI and precipitation were positively correlated, suggesting that precipitation is the controlling factor of RSEI. The areas where RSEI values presented an increasing trend were slightly less than the areas where RSEI values presented a decreasing trend. In the Sahel region, the areas with the ecological environment characterized by continuous deterioration and continuous improvement accounted for 44.02% and 28.29% of the total study area, respectively, and the areas in which the ecological environment was changing from improvement to deterioration and from deterioration to improvement accounted for 12.42% and 15.26% of the whole area, respectively. In the face of the current ecological environment and future change trends of RSEI in the Sahel region, the research results provide a reference for the construction of the ''Green Great Wall'' (GGW) ecological environment project in Africa.

Analysis and Evaluation of Ecological Environment Monitoring Based on PIE Remote Sensing Image Processing Software

“…In order to comprehensively monitor the ecological environment, it is usually necessary to obtain more information of ground targets with the help of geographic information system (GIS) and global positioning system (GPS). rough the integration of RS, GIS and GPS technology, we can accurately obtain the target attribute information and location information of the ground ecological area, and establish a spatial information database based on the superposition processing and statistical analysis of the spatial data, so as to effectively manage and query the spatial data [18].…”

Evaluation of Chabuga Mountain mine after ecological restoration based on remote sensing information processing

“…The total area of Chabuga mining area was known through the survey as 4.31km 2 , and the specific grading table is shown in Table 4 below [12] . By using the raster data classification that comes with ENVI, the area corresponding to different stratification in the RSEI image can be calculated [13], as follows Table 5 shows the statistics of the area of the whole mine ecological environment grading, the broken ring inside the mine is serious, and the surrounding ecological environment is affected accordingly, before the ecological restoration project was carried out in 19 years, the area of the local ecological environment that is above medium (Grade 3~5) in the grading was counted a total of 2181670m 2 , accounting for 16.9% of the overall area, the area of the part of poor ecological environment(Grade 1~2) totaled 10791478m 2 , accounting for 83.1% of the total statistical area, and after the ecological restoration project in 2022, the area of the part of the with ecological grade above medium was only 31%, while the part of poor ecological environment totaled 69% of the area. The area of the ecological grade above medium expands from 2181670m 2 to 4025701m 2 , and the mean value of RSEI increases from 0.56509 in 19 years to 0.69072 in 22 years, from the data it can be observed that the effect of the ecological project has achieved some results and the ecological environment of the study area is gradually improved.…”

GIS-based sensitivity analysis of urban land ecology: a case study of Hangzhou City

“…The grading of evaluation indicators in ecological sensitivity assessment is an important link in related research. This article refers to previous research by relevant scholars [15][16] and divides the levels of various evaluation indicators into four levels: insensitive, low sensitive, moderately sensitive, and highly sensitive, with corresponding quantification scores of 1.3.5.7 assigned from low to high.…”