Oral Presentation AMOS Annual Meeting and International Conference on Tropical Meteorology and Oceanography

Understanding Recent and Near-term Future Change in Australian Tropical Cyclone Activity Using Decadal Prediction Ensembles (#59)

Abigail Jaye 1 , Cindy Bruyere 1 , James Done 1 , Erin Towler 1 , Greg Holland 1 , Bruce Buckley 2 , Peter Chan 2 , Mark Leplastrier 2
  1. NCAR, Boulder, CO, United States
  2. IAG, Sydney, Australia

The short historical record of tropical cyclones (TCs) combined with the rarity of occurrences in any given location makes it challenging to evaluate past changes in TC impacts, and to predict future changes. Statistical modeling gets around the rarity of occurrence, but these models are commonly based on past storm tracks, and therefore largely ignore recent and near-term future changes in storm tracks.

For this study, the NCAR CESM Decadal Prediction Large Ensemble Project (DPLE) dataset is used to explore how TC activity has changed in the recent climate, and how they are predicted to change in the next 5 to 10 years. The DPLE comprises 40-member ensembles initialized every year from 1954 to 2017. Each prediction extends out 10 years resulting in 25000 years of model data spanning past, current, and near future climates. TC-like vortices are tracked in the predictions using an automated tracking algorithm called TempestExtremes (Ullrich and Zarzycki 2017). Using these tracked TCs, the performance of the ensemble will be shown for different lead years of the ensemble and TC intensity distributions will be investigated. In addition, recent and near-term future changes in TC frequencies will be presented.

  1. Ullrich, P. A. and Zarzycki, C. M.: TempestExtremes: a framework for scale-insensitive pointwise feature tracking on unstructured grids, Geosci. Model Dev., 10, 1069-1090, https://doi.org/10.5194/gmd-10-1069-2017, 2017