Ocean Tides Observed from A GPS Receiver on Floating Sea Ice Near Chinese Zhongshan Station, Antarctica

ABSTRACT

Due to limit of coverage in TOPEX/Poseidon (T/P) satellite and sparseness of in-situ tide gauges around Antarctica, the accuracy of global ocean tide models in Antarctic seas is relatively poorer than in low- and mid-latitude regions. To better understand ocean tides in Prydz Bay, east Antarctica, a GPS receiver was deployed on floating sea ice to measure tide-induced ice motion in multiple campaigns. Four online Precise Point Positioning (PPP) services are used to process the GPS data in the kinematic PPP mode, and UTide software is used to separate the major tidal constituents. Comparison between results from different processing methods (relative processing solutions from Track, kinematic PPP solutions from online services) and with bottom pressure gauge (BPG) shows that, high-accuracy tidal information can be obtained from GPS observations on floating sea ice, the root-sum-square (RSS) for the eight major constituents (O1, K1, P1, Q1, M2, S2, N2, K2) is below 4 cm. We have also studied the impacts of data span and filter edge effects at daily boundaries on the accuracy of tide estimates, and found that to obtain reliable tide estimates and neglect the filter edge effects, continuous observation longer than 30 days is necessary. Our study suggests that GPS provides an independent method to estimate tides in Prydz Bay, and can be an alternative to tidal gauges, which are costly and hard to maintain in Antarctica.

KEYWORDS:

• GPS
• harmonic analysis
• kinematic PPP
• ocean tides

Acknowledgments

The authors acknowledge help from Zhao Jiechen, Hao Guanghua and other teammates in the 2012 and 2016 Chinese Antarctic campaigns. The authors also greatly appreciate the developers for 4 online PPP services, the MIT for TRACK and Daniel L. Codiga for UTide software.

Additional information

Funding

This research is partly supported by grants from National Key Research and Development Program of China (Grant No. 2017YFA0603104), from the Key Program of National Natural Science of China (Grant No. 41531069), and from the Independent research project of Wuhan University (Grant No. 2042017kf0209).