Understanding Recent and Near-Term Future Change in Tropical Cyclone Activity Using Decadal Prediction Ensembles

The coastlines around the world are heavily urbanized and densely populated. The northeast US coastline, for example, is home to ~33% of the US population and hosts one the world's largest economies. These are also regions where Tropical Cyclones (TCs) are amongst the most damaging natural disasters.

The short historical record 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 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 2015. 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 and recent and near-term future changes in TC frequencies will be presented.