OS046-0003
On the use of partitions to assess the influence of atmospheric indices in the New Zealand area

Wednesday, 16 December 2020
Poster
Joao Albuquerque1, Jose A.A. Antolinez2, Fernando J. Mendez3 and Giovanni Coco1, (1)University of Auckland, School of Environment, Auckland, New Zealand, (2)Delft University of Technology, Department of Hydraulic Engineering, Faculty of Civil Engineering and Geosciences, Delft, Netherlands, (3)University of Cantabria, Ciencias y Tecnicas del Agua y del Medio Ambiente, Santander, Spain
Abstract:
The effects of climate indices such as the Southern Annular Mode (SAM), Indian Ocean Dipole (IOD) and Southern Oscillation Index (SOI) along the south-western Pacific Ocean have been assessed in a number of studies. However, the development of spectral partitioning algorithms allows the observation of wave systems that are not normally identified in the integrated (bulk) wave spectrum or instrumental data that was used in the previous investigations.

In this study, we used a 20-year partitioned hindcast to separate the swell and wind sea wave systems into directional sectors and applied a regression model to establish the correlation between each wind sea/swell directional sector and atmospheric index along the whole New Zealand area.

Results allowed us to identify how each index influences the local and remote wind-wave generation, as well as how the wave systems that are not identifiable in the bulk spectrum representation oscillate in response to these anomalies. Studies regarding beach erosion and sediment transport can benefit from these findings.

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