Spatial-Temporal Assessment of Drought in Hoa Vang district, Da Nang City, Vietnam Using Remote Sensing and Google Earth Engine

The objective of this research was to map the drought risk in Hoa Vang district, Da Nang city, and analyze the variability of drought events from 1991 to 2020 using remote sensing imagery. To achieve this, remote sensing and GIS methods were utilized to gather information on land surface temperature and the Normalized Difference Vegetation Index (NDVI). The study effectively employed the Google Earth Engine which is a cloud-based computing platform to analyze image sequences from Landsat 5 and OLI sensors spanning the period from 1991 to 2020. This analysis aimed to extract the remote sensing indices and applied them for drought assessment and monitoring. The study employed land surface temperature (LST) and Normalized Difference Vegetation Index (NDVI) to derive the Temperature Condition Index (TCI), Vegetation Condition Index (VCI), and Vegetation Health Index (VHI). These indices were utilized to assess drought conditions in Hoa Vang district, Da Nang city, over the period from 1991 to 2020. The research findings reveal that the drought values in Hoa Vang district exhibited variations throughout the studied period. Notably, regions at risk of drought during the later periods exhibited an increasing trend compared to the initial periods. This suggests a potential escalation in drought severity in the study area over time. The outcomes of this study provide essential background for evaluating the impacts of drought on agricultural production in Hoa Vang district, Da Nang city.