Influence of the Subtropical Ridge on Directional Wave Power in the Southeast Indian Ocean — Australian Meteorological and Oceanographic Society
  1. Schedule
  2. 01. Impact of wind driven sea and swell waves
  3. Influence of the Subtropical Ridge on Directional Wave Power in the Southeast Indian Ocean

Influence of the Subtropical Ridge on Directional Wave Power in the Southeast Indian Ocean (#11)

Thomas Mortlock 1 2 , Zak Baillie 2 3 4 , Ian D Goodwin 2 5 , Stuart Browning 2
  1. Risk Frontiers, St Leonards, NSW, Australia
  2. Department of Environmental Sciences, Macquarie University, Sydney, NSW, Australia
  3. School of Science, University of New South Wales Canberra, Canberra, ACT, Australia
  4. ARC Centre of Excellence for Climate Extremes, University of New South Wales Canberra , Canberra, ACT, Australia
  5. UWA Oceans Institute, University of Western Australia, Perth, Western Australia, Australia

Changes in the intensity and position of subtropical anticyclones are major drivers of wave climate around Australia. Here we decompose the directional wave climate along the Western Australian Shelf (WAS) into three primary modes of variability using a statistical-synoptic typing approach, and relate the wave power signatures of each to movements in the Subtropical Ridge (STR). We find a significant reduction in wave power along the WAS over the past 35 years. This is synonymous with an intensification of the STR resulting in the blocking of powerful Southern Ocean low wave conditions, a small increase in weaker anticyclonic waves, and a reduction in total wave power. A persistent intensification and/or poleward shift in the STR, associated with anthropogenic warming, may result in a continued decrease and anticlockwise rotation in wave power along the WAS. The approach taken in this paper relates empirical changes in wave climate to movements in large-scale climate drivers as an alternative to dynamically downscaling Global Climate Model projections for exploring future scenarios of wave climate change.

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