Using SRTM and GDEM2 data for assessing vulnerability to coastal flooding due to sea level rise in Lagos: a comparative study

Abstract

Climate change and its associated sea level rise is one of the recent challenging global issues especially in coastal areas, where a large percentage of the world population resides. Sealevel rise (SLR) is expected to increase coastal inundation and erosion. This may disrupt the physical and human processes including economic systems and social structures in coastal regions, which are densely populated. Digital Elevation Model (DEM) especially Shuttle Radar Topography Mission (SRTM) is a common source of elevation data for assessing the risk of flooding due to sea level rise. Recently, a new Advanced Space borne Thermal Emission and Reflection Radiometer (ASTER) Global DEM Version 2 (GDEM2) has been released to the public. This paper compares the flood risk estimations of SRTM and GDEM2. It examines different scenarios of sea level rise and its consequences on flooding in Mainland Lagos. It uses high resolution remote sensing data within Geographic Information System (GIS) environment to visualize the scenarios. The result shows that Lagos Mainland is vulnerable to sea level rise and SRTM (RMSE = 1.98) gives better flood risk estimations than GDEM2 (RMSE = 10.09).

Keywords: geospatial techniques; sea level rise, coastal flooding, SRTM, ASTER GDEM2 and flood risk estimations