Abstract
The latest satellite and in situ data are a fundamental source for tidal model evaluations. In this work, the satellite missions TOPEX/Poseidon, Jason-1, Jason-2 and Sentinel-3A, together with tide gauge data, were used to investigate the performance of recent regional and global tidal models over the Great Barrier Reef, Australia. Ten models, namely, TPXO8, TPXO9, EOT11a, HAMTIDE, FES2012, FES2014, OSUNA, OSU12, GOT 4.10 and DTU10, were considered. The accuracy of eight major tidal constituents (i.e., K1, O1, P1, Q1, M2, S2, N2 and K2) and one shallow water constituent (M4) were assessed based on the analysis of sea-level observations from coastal tide gauges and altimetry data (TOPEX series). The outcome was compared for four different subregions, namely, the coastline, coastal, shelf and deep ocean zones. Sea-level anomaly data from the Sentinel-3A mission were corrected using the tidal heights predicted by each model. The root mean square values of the sea level anomalies were then compared. According to the results, FES2012 compares more favorably to other models with root mean square (RMS) values of 10.9 cm and 7.7 cm over the coastal and shelf zones, respectively. In the deeper sections, the FES2014 model compares favorably at 7.5 cm. In addition, the impact of sudden fluctuations in bottom topography on model performances suggest that a combination of bathymetric variations and proximity to the coast or islands contributes to tidal height prediction accuracies of the models.
Highlights
The Great Barrier Reef (GBR), Australia, is the largest reef system in the world
The coastline consists of only tide gauge stations, while the other zones consist of only altimetry a2l.o1n
While other available software packages require special treatments for irregularly spaced observations, Unified Tidal Analysis and Prediction (UTide) has the ability to analyze time series containing time gaps. Another method to derive harmonic constants was used because the altimeter background noise of T/P series is within a few centimeters [45] and only extracts constituents with a global root mean square (RMS) above the noise level (e.g., M2, S2, N2, K1 and O1)
Summary
The Great Barrier Reef (GBR), Australia, is the largest reef system in the world. It comprises over 2500 coral reefs and stretches for more than 2000 km along the northeastern Australian coastline, ranging in width from 100 to 200 km [1]. The lack of sufficient information regarding the shallow water constituents (including both compound and overtide components) in existing tidal models leads to the absence of a comprehensive picture of tides and circulations in the area [18]. These tidal components, which are the consequences of interactions between bottom topography and major tidal constants, exhibit large variations in the presence of the reefs.
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