Sally began her presentation with a video of Royal New Zealand Navy ships at sea in the Southern Ocean, showing why the RNZN and NZDF are interested in the Southern Ocean and Ross Sea wave climate.
The waves of the Southern Ocean and the Ross Sea are largely unstudied. The NZDF routinely operates in these areas and is currently engaged in a shipbuilding program which requires a detailed understanding of the wave climate for sea-keeping analysis and ice-belt design. Unlike other areas, the Southern Ocean and the Ross Sea have limited ship traffic and therefore limited wave observations from volunteer observing ships. Moreover, due to the difficult conditions and remote locations, limited scientific measurements of waves have been completed. In 2017, the NZDF deployed the first wave buoy in the open ocean south of 47oS anywhere in the world. In addition, 21 free-floating buoys were also deployed between 42oS and 67oS. This array has provided an understanding of wave characteristics across the Southern Ocean and the Ross Sea.
The data from these platforms have been used to optimise the WaveWatch III wave forecast model. The optimised setup was then used to create a 24-year hindcast wave atlas for the ice-free areas south of 31oS.
In the presentation, this previously unpublished wave atlas for the Southern Ocean and Ross Sea was presented. A limited comparison was also made between the wave statistics from both wave-buoy observations and the wave atlas in these regions with the bivariate frequency wave height–period occurrence tables recommended for the North Atlantic by the International Association of Classification Societies.
Question time was lengthy and elicited many more interesting points.
The “thank you” certificate was subsequently posted to Sally.
Sally’s presentation was recorded, and is expected to be available soon on the RINA YouTube channel.
[This was an updated version of Sally Garrett and Tom Durrant’s presentation on this topic at Pacific 2019 IMC, which was also published in the May 2020 issue of The Australian Naval Architect, with the addition of their latest work which is concentrating on the wave climate in ice-infested waters — Ed.]