[G02-6] Height systems

[G02-6-06] SAR and SARIN contribution to Height System Unification in Greece

Ourania Altiparmaki¹, ^○Georgios S. Vergos¹, Ole Andersen² (1.GravLab, Department of Geodesy and Surveying, Aristotle University of Thessaloniki, Greece, 2.DTU SPACE, National Space Institute, Technical University of Denmark, Denmark)

One of the most important research topics in physical geodesy nowadays, is height system unification (HSU), at both national and global levels. The innovative Cryosat-2 satellite mission and mainly the SAR and SARin drifting modes, offer dense cross-track spacing, which contributes to the improvement of spatial resolution in both open sea and coastal zones. Taking advantage of the above, this work focuses on the prediction of Sea Level Anomalies (SLAs) and Sea Surface Heights (SSHs), close to the coastline and specifically on tide gauges/GNSS benchmarks at the land/sea boundaries. The Greek region was chosen as the study area, as its complex structure with many isles and islands constitutes an interesting area of research for the evaluation of SAR and SARin data close to coastline. Furthermore, SAR and SARin data for this region are available from the mission start (April 2010) to the end of 2016. Two different cases are investigated in this work. First, the prediction at the TG BMs is achieved via interpolation on a grid and smoothing algorithms using the total set of SAR and SARin data. Then, only the along-track data close to each point of interest are used and contribute to the prediction using simple polynomial models (first to second order), splines and Least Squares Collocation. Different prediction cases are investigated based on the general structure of the prediction area, the distribution of points which act as input data and the corresponding accuracy of the SAR and SARin SLAs and SSHs. Finally, interpolation and prediction is carried out to ‘bridge' the data between SAR-SARin and LRM-SAR modes using novel algorithms, as well as to detect the existence of possible biases during the alternation of the mask mode.