Is Climate Change Redefining the Speed Limit of Tropical Cyclones?

This study addresses whether recent trends in tropical cyclone (TC) intensification rates can be explained by the natural variability of the climate system or if they are attributable to climate change. Two observational data sources, the International Best-Track Archive for Climate Stewardship (IBTRaCS) and the Hurricane Satellite Data-B1 Advanced Dvorak Technique (HURSAT-ADT), are used to calculate TC intensity changes, normalized by the total number of cases, over the period 1986-2015 and 1982-2009, respectively. In both datasets, Atlantic basin TC acceleration rates significantly increase, which is consistent with the well-documented growth of major hurricanes in this basin. Overall, there are strong positive correlations in most basins but there are significant variations depending on the basin.

The trends in the observational datasets are then compared to a pre-industrial multi-century simulation produced by the Geophysical Fluid Dynamics Laboratory (GFDL) High-Resolution Forecast-Oriented Low Ocean Resolution (HiFLOR) model. HiFLOR is a global coupled climate model that is able to simulate and predict category 4 and 5 (Saffir–Simpson scale) TCs and their interannual variations, and is therefore uniquely able to reproduce the entire TC intensification distribution. Monte Carlo techniques are utilized to determine if observed TC intensification rates are changing in a manner consistent with the natural variability in the HiFLOR run or if there is a detectable climate change signal.