Examining the impact of Green Riyadh Project on alleviating urban heat island effects

Abstract

The increase of land surface temperature (LST) because of the urban growth and spatial expansion specially in developing country have shown many negative impacts on the health and quality of life of people, nowadays some cities experience much warmer temperatures than nearby rural areas, causes what is known as the urban heat island (UHI) phenomenon. This study investigates alterations in vegetation and land surface temperature over space and time due to the Green Riyadh Project, employing remote sensing techniques. Multi-temporal Landsat images of the study area from 2018 and 2022, were processed in order to derive The Normalized Difference Vegetation Index (NDVI) and LST are being considered. Change detection methods were used to indicate the changes between the two time periods. Based on the results of this study, NDVI values show that the vegetated areas in Riyadh have not increased between (2018 and 2022). While the LST values show that the total area of UHIs has increased between (2018 and 2022). The change detection in vegetation indicates that there was a decrease in vegetation, mostly in urban areas. Where the change detection of surface temperature indicates huge areas where temperature has increased, mostly in the rural are-as, leaving few areas where the temperature has decreased. This means that the present amount of vegetation has still not made an impact in terms of decreasing the LST. Therefore, there is a need for more effort to be made in increasing the green areas within the urban environment of Riyadh.