Using remote sensing approach to analyze vegetation response to drought and landscape changes in arid regions

Abstract

Arid regions, characterized by low annual precipitation, unique vegetation, and distinctive hydrological cycles, play a significant role in maintaining ecological balance. However, these regions, with their hostile and remote environments, present unique challenges for field research. This study utilizes remote sensing technology, particularly the Normalized Difference Vegetation Index (NDVI), to evaluate the ecosystem's response to drought and understand the relationship between vegetation variability and other landscape features including elevation, soil type, and changes in land use or land cover. Six sites within the city, each of 100 square kilometers and representing diverse landscapes, were selected for the study. Key datasets describing land features were collected from official and authentic websites. A series of ArcGIS-based data processing methods were applied to discern patterns in the relationship between landscape features and vegetation variability, with a particular focus on periods of wet and dry years. The wet and dry years are identified as 2005 and 2009 respectively, based on average rainfall data. Notably, NDVI values in the wet year are consistently higher than in the dry year, with the greatest differences observed in undeveloped or shrubland areas (sites 3, 5, and 6). In terms of land cover, urban development increases in sites 1, 2, and 4 between 2004 and 2008, while shrubland decreases in sites 3, 5, and 6. This development corresponds to a contraction of vegetation cover. The study areas are primarily characterized by loamy soils, with variations in clay and sand composition. These findings underscore the impacts of rainfall and urban development on vegetation health in arid regions.