The Evaluation of the Result of Post-Processing Envisat Satellite Altimetry Data Used for Coastal Area Potential Flood Mapping (Case Study: Coastal Area of Buleleng Regency, Bali, Indonesia)

Post-processing result of Envisat satellite altimetry data was evaluated in this study to generate precise sea level height and sea level rise as the bases for the coastal area potential flood mapping, with case study of Buleleng regency, Bali, Indonesia. In the post-processing stage, three types of geophysical corrections that greatly affect the accuracy of altimetry data in coastal areas were used, namely: tide, tropospheric and ionospheric corrections. For evaluation purposes, these geophysical corrections were combined and classified as combination model I (ECMWF, GIM and FES2004 correction models), combination model II (MWR, Radiometer and GOT00.2b correction models) and combination model III (MWR, DORIS and GOT0.2b correction models). The evaluation of post-processing results was done by: 1). comparing the accuracy of Envisat data corrected by three combination models; 2). comparing the Envisat data corrected by three combination models with the tide gauge data from the Celuk Belawan tide gauge station. Determination of the most appropriate combination model was based on RMS error determination, correlation and significance values, and on a visual test. The results indicated that the most appropriate combination for geophysical correction is the combination model I (ECMWF, GIM, and FES2004). Based on the corrected Envisat data from the period of 2002 – 2009, it was found that the sea level increased about 5 cm/year. Finally, it was found that the prediction for the sea level increase for the year 2015 is about 25.5 cm so that the potential for coastal area flooding in Buleleng may reach about 7.396%.