Accuracy Assessment of Tide Models in Terra Nova Bay, East Antarctica, for Glaciological Studies of DDInSAR Technique

Abstract

: Accuracy assessment of tide models in polar ocean has to be performed to accurately analyze tidal response of glaciers by using Double-Differential Interferometric SAR (DDInSAR) technique. In this study, we used 120 DDInSAR images generated from 16 one-day tandem COSMOSkyMed DInSAR pairs obtained for 2 years and in situ tide height for 11 days measured by a pressure type wave recorder to assess the accuracy of tide models such as TPXO7.1, FES2004, CATS2008a and Ross_Inv in Terra Nova Bay, East Antarctica. Firstly, we compared the double-differential tide height (Δ . T) for Campbell Glacier Tongue extracted from the DDInSAR images with that predicted by the tide models. Tide height (T) from in situ measurement was compared to that of the tide models. We also compared 24-hours difference of tide height ( . T) from in situ tide height with that from the tide models. The root mean square error (RMSE) of Δ . T, T and .T decreased after the inverse barometer effect (IBE)-correction of the tide models, from which we confirmed that the IBE of tide models should be corrected requisitely. The RMSE of .T and Δ .T were smaller than that of T. This was because . T is the difference of tide height during temporal baseline of the DInSAR pairs (24 hours), in which the errors from mean sea level of the tide models and in situ tide, and the tide constituents of S2, K2, K1 and P1 used in the tide models were canceled. This confirmed that .T and Δ .T predicted by the IBE-corrected tide models can be used in DDInSAR technique. It was difficult to select an optimum tide model for DDInSAR in Terra Nova Bay by using in situ tide height measured in a short period. However, we could confirm that Ross_Inv is the optimum tide model as it showed the smallest RMSE of 4.1 cm by accuracy assessment using the DDInSAR images.

Differential InSAR for tide modelling in Antarctic ice-shelf grounding zones

“…1). This agrees well with the findings of Han et al (2013), who find that the Ross_Inv_2002 model is the optimum tide model for the Terra Nova Bay with a 4.1 cm RMSE against 11 days of tide gauge data. We therefore choose Ross_Inv_2002 for numerical modelling purposes to minimize any effects on a viscoelastic model, but use TPXO7.2 to reconstruct vertical displacement at the times of satellite overpasses as it fits best our GPS measurements.…”

Predicting tidal heights for extreme environments: From 25 h observations to accurate predictions at Jang Bogo Antarctic Research Station, Ross Sea, Antarctica

“…Our results compare favourably with those of Han et al (2013), who reviewed the tidal height prediction accuracy of 4 models for Terra Nova Bay, Ross Sea: that is, TPXO7.1 developed by Egbert and Erofeeva (2002) However, as shown in Figure 8, our results appear to contain a changing bias in estimates occurring at fortnightly timescales, with predictions slightly overestimating tides during the period from the equatorial to tropic tides (the ETT), and slightly underestimating tides from the period between the -tropic to equatorial tides (the TET). This error pattern likely resulted from our application of CTSM+TCC only considering 2 major tidal species, those representing diurnal and semi-diurnal constituents, whilst ignoring long period tides.…”

“…, FES2004 fromLyard et al (2006); the Circum-Antarctic Tidal Solution (CATS2008a) from byPadman et al (2008), and the Ross Sea Height-Based Tidal Inverse Model (Ross_Inv_2002) fromPadman et al (2003) Han et al (2013). compared the model datasets to 11 days of February 2011 in situ sea level observations, corrected for inverse barometer effects, and considered model usefulness for investigating tidal signals in satellite data from the Campbell Glacier tongue.…”