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

Abstract

Abstract. Accurate tidal height data for the seas around Antarctica are much needed, given the crucial role of tidal processes as represented in regional and global climate, ocean and marine cryosphere models. Though obtaining long term sea level records for traditional tidal predictions is extremely difficult around ice affected coasts. This study evaluates the ability of a relatively new, tidal species based approach, the Complete Tidal Species Modulation with Tidal Constant Corrections (CTSM+TCC) method, to accurately predict tides for a temporary tidal station in the Ross Sea, Antarctica using records from a nearby reference station characterized by a different regime. Predictions for the 'mixed, mainly diurnal' regimes of Jang Bogo Antarctic Research Station (JBARS) were made and evaluated based on summertime (2017; and 2018 to 2019) short-term (25 h) observations at this temporary station, along with tidal prediction data derived from yearlong observations (2013) from the nearby, 'diurnal' regime of Cape Roberts (ROBT). Results reveal the CTSM+TCC method can produce accurate (to within ~ 5 cm Root Mean Square Errors) tidal predictions for JBARS when using short-term (25 h) tidal data from periods with higher than average tidal ranges (i.e. tropic-spring periods). Predictions were successful due to the similar relationships between the main tidal constituents' (K1 and O1 tides) phase-lag differences at the prediction and reference stations, and despite these tidal stations being characterized by different tidal regimes according to their form factors (i.e. mixed, mainly diurnal versus diurnal). We demonstrate how to determine optimal short-term data collection periods based on the Moon's declination. The importance of using long period tides to improve tidal prediction accuracy is also considered, along with the characteristics of the different decadal scale tidal variations around Antarctica, from the four major FES2014 tidal harmonic constants.