[International Association of Geodesy Symposia] Fiducial Reference Measurements for Altimetry Volume 150 (Proceedings of the International Review Workshop on Satellite Altimetry Cal/Val Activities and Applications) ||

These proceedings include selected papers from the International Review Workshop on Satellite Altimetry Cal/Val Activities and Applications, held in Chania, Crete, Greece, on 23-26 April 2018. Organised in the context of the European Space Agency Project “Fiducial Reference Measurements for Altimetry” the workshop was cosponsored by the International Association of Geodesy (in particular by the IAG Commission 2, Gravity Field), the European Space Agency, the European Union (the Copernicus Programme), the European Organisation for the Exploitation of Meteorological Satellites (EUMETSAT), Space Geomatica P.C., and the Municipality of Chania. The workshop presented the latest research in the field of satellite altimetry calibration and altimetry applications for monitoring ocean changes and improving Earth observation in an objective, continuous, homogeneous and reliable manner, free of errors and biases. Further, it supported long-term monitoring of climate change by providing a better understanding of environmental changes in the world's oceans, terrestrial surface waters, and Arctic and Antarctic Regions. The outcome was the creation of a scientific roadmap with procedures, protocols, guidelines, and best practices to help international groups working on satellite altimetry to establish SI (Système International d'Unités) traceability of their measurements, results and data products. Preface Contents Fiducial Reference Measurements for Satellite Altimetry Calibration: The Constituents 1 Introduction 2 Constituents in Sea-Surface Calibration 2.1 Absolute Coordinates for the Cal/Val Site 2.2 Water Level Determination at the Cal/Val Site 2.3 Control Ties and Settings 2.4 Height Transfer from Cal/Val Site to Open Sea 2.5 Processing for Sea-Surface Calibration 3 Constituents in Transponder Calibration 3.1 Cal/Val Site Coordinate Determination 3.2 Time Reference 3.3 Control Ties and Settings 3.4 Transponder Data Processing 4 Conclusions References Practical Options for Time Tagging 1 TAI and UTC 2 Relativistic Timescales 3 GPS Timescales, and Other GNSS Timescales 4 Traceability to UTC 5 Time Transfer 6 Calibration 7 Conclusions References Time Reference, Calibration and Time Transfer Techniques for Satellite Altimetry 1 Introduction 1.1 UTC as a Reference 2 UTC(NPL) Time Transfer 3 Calibration Techniques and Uncertainties 4 Monitoring and Holdover 5 Relativistic Effects 6 Summary References Calibrating CryoSat-2 and Sentinel-3A Sea Surface Heights Along the German Coast 1 Introduction 2 Methodology and Data 3 Results 4 Discussion and Conclusion References Performance of Sentinel-3A SAR Altimetry Retrackers: The SAMOSA Coastal Sea Surface Heights for the Baltic Sea 1 Introduction 2 Theoretical Background 2.1 Satellite Altimetry 2.2 Tide Gauges 2.3 Hydrodynamic Models 3 Case Study 3.1 Study Area 3.2 Satellite Altimetry 3.3 Tide Gauges and Hydrodynamic Model 3.4 Regional Geoid Model 4 Evaluation Results 5 Conclusions and Further Studies References Sea Level Variability in the Strait of Gibraltar from Along-Track High Spatial Resolution Altimeter Products 1 Introduction 2 Study Area 3 Datasets and Methodology 3.1 Satellite Altimetry Data 3.2 In Situ Data 3.3 Absolute Dynamic Topography (ADT) 4 Results 4.1 ADT Profiles 4.2 Sea Level Variability Due To the Wind Regime 5 Final Remarks References Absolute Calibration of Sentinel-3A and Jason-3 Altimeters with Sea-Surface and Transponder Techniques in West Crete, Greece 1 Introduction 2 The Permanent Facility for Altimeter Calibration 2.1 Transponder Calibration at the CDN1 Cal/Val Site 2.2 Sea-Surface Calibration at the Gavdos Cal/Val Facility 3 Calibration Results 3.1 Sea-Surface and Transponder Results for Sentinel-3A 3.2 Sea-Surface and Transponder Results for Jason-3 3.3 Crossover Calibrations of Sentinel-3A and Jason-3 4 Conclusions References Multi-Mission Cross-Calibration of Satellite Altimeters 1 Introduction 2 Multi-Mission Cross-Calibration 3 Results and Discussion 4 Conclusion and Outlook References Improvement of the Arctic Ocean Bathymetry and Regional Tide Atlas: First Result on Evaluating Existing Arctic Ocean Bathymetric Models 1 Introduction 2 Arctic Bathymetry Datasets and Errors 2.1 Bathymetry Evaluation 2.1.1 Bathymetry Evaluation Using Hydrodynamic Tidal Modelling 2.1.2 Local Evaluation in the White Sea 3 Towards Improved Bathymetry from Gravity Inversions 4 Conclusions References Sea Level Trends and Variability in the Adriatic Sea and Around Venice 1 Introduction and Study Area 2 Data and Methods 3 Results 4 Discussion and Concluding Remarks References Sentinel-3A: Validation of Orbit Products at the Copernicus POD Service 1 Introduction 2 The Copernicus POD Service: Sentinel-3 3 Orbit Accuracy Validation Methods for Sentinel-3A 3.1 Processing Metrics 3.2 Orbit Overlap Analysis 3.3 Comparison to Other Orbit Solutions 3.4 External Validation 4 Conclusions and Future Plans for Improvement References The DTU17 Global Marine Gravity Field: First Validation Results 1 Gravity Field Update 2 Evaluation with Marine Gravity Observations 3 Marine Gravity Comparison in the Arctic Ocean 4 Conclusion 5 Data Availability References Global and Regional Evaluation of the First Year of Sentinel-3 1 Introduction 2 Data and Methods 3 Results 3.1 Mapping Signals with Shorter Wavelengths 3.2 Tide Models and MSS from Sentinel-3 3.3 Wet Tropospheric Correction 4 Conclusions References Arctic Freshwater Fluxes from Earth Observation Data 1 Introduction 2 Land Ice and Melt FWF 3 River FWF 4 Sea Ice FWF 5 Ocean FWF 6 Summary References Scientific and Operational Roadmap for Fiducial Reference Measurements in Satellite Altimetry Calibration & Validation 1 Introduction 2 FRM4ALT Site Selection 3 Facility Operational Performance Requirements 4 Instrumentation Requirements 5 Interface Control Documents 6 Conclusions References List of Reviewers Author Index