Monitoring Coastal Sea Level and Reconstructing Sea-Land Link by Using Satellite Altimetry(2/2)

The proposed research aims to construct an improved land-sea link, in terms of a seamless digital elevationmodel (DEM) across ocean and land, by integrating multiple altimetry satellite data and global DEMs. Wepropose to utilize past and current satellites, including TOPEX/Poseidon, Jason-1, Envisat, Jason-2,SARAL/AltiKa, and Cryosat-2 for reconstruction of decadal sea-level change record near the coasts ofTaiwan. Following sea level analysis, the systematic error (or bias) between ocean and land can beestimated from ICESat laser altimetry data and thus the accuracy in absolution elevation of each DEM canbe investigated. The global DEMs examined in this project include SRTM C-band/X-band, GMTED2010,and ASTER GDEM2. After removing bias along the coast, these DEMs will be validated by high-resolutionregional DEM (5–40 m) archived by the Ministry of the Interior, and then used for flood hazard mapping.We propose to produce a web-based presentation of our research outcomes with graphical user interface(GUI) that end-users could obtain a high-frequency (18–40 Hz) altimetry time series at selected grid insurrounding oceans, where the altimetry elevation data have been processed by novel waveform retrackingalgorithms. Along the coast we will generate a historical change of coastlines and its current/projectedpositions. Over land, we will use refined DEM as a reference to map potential area prone to be inundateddue to storm surge and saltwater intrusion. This simulation solely from altimetry data and DEMs isindependent of other agency’s product thus can be used for cross-examination to leverage each of theproducts. This research will be benefit to local administration for their decision-making process and help onnatural hazards mitigation/adaptation in areas identified under risk. Once an integrated observation systemhas been properly established, it can be applied to low-lying deltas in the world that face similar problems,such as Bangladesh. Our approach including spaceborne observation and geographic information is todiscern sea-level rise and land motion and to improve coastal vulnerability projection.