Combining Geodetic Techniques to Predict Tidal Inundation at Coastal Megacities.

Abstract:

We combine 2-m posting Digital Elevation (DEM) and Surface Models (DSM) with satellite laser altimetry and Differential Interferometric Synthetic Aperture Radar (DInSAR) observations to predict Perigean tidal inundation under a series of sea level rise scenarios. For the coastal topography DSMs are derived from along-track stereo images from very high resolution satellite imagery. Satellite lidar from ICESat-2 and the Global Ecosystem Dynamics Investigation (GEDI) provide returns that are as close to bare earth as possible filtered with ancillary data and machine learning techniques. DSMs edges are sharpened and converted to bare earth DEMs using segmentation techniques. DEMs are co-registered to the laser altimetry data. Mean sea level and coastal bathymetry is investigated using ICESat-2 returns. High tides are calculated using tidal models. We derive vertical land motions in and around cities using DInSAR, tied to GNSS rates of absolute motion where possible. We investigate the combination of geodetic techniques to improve predictions of extent and depth of inundation at and around global coastal megacities and compare our findings to published studies.