Monitoring Vegetation Change in Abu Dhabi Emirate from 1996 to 2000 and 2004 using Landsat Satellite Imagery PDF

Keywords

vegetation monitoring, satellite imagery, Landsat Abu Dhabi image

Abstract

In the fall of 2001. a study was initiated to investigate vegetation changes in the Abu Dhabi Emirate The vast majority of vegetation present in the region is irrigated, and an analysis of vegetation change will support groundwater investigations in the region by indicating areas of increased groundwater use Satellite-based imaging systems provide a good source of data for such an analysis. The recent analysis was completed between February and November 2002 using Landsat Thematic Mapper satellite imagery acquired in 1996 and Landsat Enhanced Thematic Mapper Plus imagery acquired in 2000 These assessments were augmented in 2004 with the study of Landsat 7 imagery acquired in early 2004. The total area of vegetation for each of seven study areas was calculated using the Normalized Difference Vegetation Index (NDVI) technique. Multi-band classification was used to differentiate general vegetation types. Change analysis consisted of simple NDVI image differencing and post-classification change matrices. Measurements of total vegetation area for the Abu Dhabi Emirate indicate an increase from 77,200 hectares in 1996 to 162,700 hectares in 2000 (110% increase). Based on comparison with manual interpretation of satellite imagery, the amount of under-reporting of irrigated land is estimated at about 15 percent of the actual area. From the assessment of the 2004 Landsat imagery, it was found that the growth of irrigated vegetation in most areas of the Emirate had stabilized and had actually slightly decreased in some cases. The decreases are probably due to variability in the measurement technique and not due to actual decreases in area of vegetation