New determinations of tides on the north-western Ross Ice Shelf

New determinations of ocean tides are extracted from high-rate Global Positioning System (GPS) solutions at nine stations sitting on the Ross Ice Shelf. Five are multi-year time series. Three older time series are only 2-3 weeks long. These are not ideal, but they are still useful because they provide the only in situ tide observations in that sector of the ice shelf. The long tide-gauge observations from Scott Base and Cape Roberts are also reanalysed. They allow determination of some previously neglected tidal phenomena in this region, such as third-degree tides, and they provide context for analysis of the shorter datasets. The semidiurnal tides are small at all sites, yet M-2 undergoes a clear seasonal cycle, which was first noted by Sir George Darwin while studying measurements from the Discovery expedition. Darwin saw a much larger modulation than we observe, and we consider possible explanations - instrumental or climatic - for this difference.

Automated summary

New determinations of ocean tides are extracted from high-rate Global Positioning System (GPS) solutions at nine stations on the Ross Ice Shelf. These data provide context for analysis of tidal phenomena and show a clear seasonal cycle in the M-2 tide, which has been previously noted in historical measurements.