Importance of ocean tidal load corrections for differential InSAR

Large time series of interferometric synthetic aperture radar (InSAR) measurements make it possible to detect slow tectonic motions of the Earth's surface on the order of millimeters per year. Here, we illustrate the importance of correcting InSAR data for the effects of ground displacements due to ocean tidal loads (OTL). These loads can cause displacement gradients greater than 3 cm per 100 km, which is larger than the accuracy of InSAR techniques and can be a significant percentage of the measured displacement due to slow tectonic processes. We demonstrate the importance of OTL with predicted displacements from selected regions of tectonic interest.

[1]  Peter J. Clarke,et al.  A comparison of GPS, VLBI and model estimates of ocean tide loading displacements , 2006 .

[2]  Y. Bock,et al.  Anatomy of apparent seasonal variations from GPS‐derived site position time series , 2001 .

[3]  Geoffrey Blewitt,et al.  GPS and Space-Based Geodetic Methods , 2007 .

[4]  T. Baker,et al.  Validating Earth and ocean tide models using tidal gravity measurements , 2003 .

[5]  M. Ooe,et al.  GOTIC2: A Program for Computation of Oceanic Tidal Loading Effect , 2001 .

[6]  Gerhard Beutler,et al.  Validating ocean tide loading models using GPS , 2005 .

[7]  C. Provost,et al.  FES99: A Global Tide Finite Element Solution Assimilating Tide Gauge and Altimetric Information , 2002 .

[8]  T. Baker,et al.  An estimate of the errors in gravity ocean tide loading computations , 2005 .

[9]  Mike P. Stewart,et al.  GPS height time series: Short‐period origins of spurious long‐period signals , 2007 .

[10]  Hans-Georg Scherneck,et al.  Assessing the accuracy of predicted ocean tide loading displacement values , 2008 .

[11]  P. Rosen,et al.  Interferometric Synthetic Aperture Radar Geodesy , 2007 .

[12]  Richard D. Ray,et al.  A Global Ocean Tide Model From TOPEX/POSEIDON Altimetry: GOT99.2 , 1999 .

[13]  Jean-Marie Nicolas,et al.  Ocean tide loading (OTL) displacements from global and local grids: comparisons to GPS estimates over the shelf of Brittany, France , 2008 .

[14]  M. Ooe,et al.  Ocean Tide Models Developed by Assimilating TOPEX/POSEIDON Altimeter Data into Hydrodynamical Model: A Global Model and a Regional Model around Japan , 2000 .

[15]  W. Farrell.  Deformation of the Earth by surface loads , 1972 .

[16]  G. Egbert,et al.  Efficient Inverse Modeling of Barotropic Ocean Tides , 2002 .

[17]  Duncan Carr Agnew,et al.  NLOADF: A program for computing ocean‐tide loading , 1997 .

[18]  Marie-Noëlle Bouin,et al.  GPS estimates of ocean tide loading in NW-France: Determination of ocean tide loading constituents and comparison with a recent ocean tide model , 2008 .

[19]  H. Scherneck.  A parametrized solid earth tide model and ocean tide loading effects for global geodetic baseline measurements , 1991 .