Climate change signal in Atlantic tropical cyclones today and near future

Abstract

This manuscript discusses the challenges in detecting and attributing recently observed trends in the Atlantic hurricanes and the epistemic uncertainty we face in assessing future hurricane risk. Data used here include synthetic storms downscaled from five CMIP5 models by the Columbia HAZard model (CHAZ), and directly simulated storms from high-resolution climate models. We examine three aspects of recent hurricane activity: the upward trend and multi-decadal oscillation of the annual frequency, the increase in storm wind intensity, and the downward trend in the forward speed. Some datasets suggest that these trends and oscillation are forced while others suggest that they can be explained by natural variability. Future projections under warming climate scenarios also show a wide range of possibilities, especially for the annual frequencies, which increase or decrease depending on the choice of moisture variable used in the CHAZ model and on the choice of climate model. The uncertainties in the annual frequency lead to epistemic uncertainties in the future hurricane risk assessment. Here, we investigate the reduction of epistemic uncertainties on annual frequency through a statistical practice – likelihood analysis. We find that historical observations are more consistent with the simulations with increasing frequency but we are not able to rule out other possibilities. We argue that the most rational way to treat epistemic uncertainty is to consider all outcomes contained in the results. In the context of hurricane risk assessment, since the results contain possible outcomes in which hurricane risk is increasing, this view implies that the risk is increasing.

Climate Change Signal in Atlantic Tropical Cyclones Today and Near Future

“…HighResMIP TC information can be found at https://catalogue.ceda.ac.uk/uuid/0b42715a7a804290afa9b7e31f5d7753 and https://catalogue.ceda.ac.uk/ uuid/438268b75fed4f27988dc02f8a1d756d (Roberts, 2019). Underlying data for this publications are at https:// doi.org/10.5281/zenodo.8417288 (Lee, 2023).…”

Contributions of Tropical Cyclones and Atmospheric Rivers to Extreme Precipitation Trends Over the Northeast US

“…First of all, TC frequency in the North Atlantic is projected to decline in the future in the majority of climate model studies (e.g., Knutson et al., 2020; Roberts et al., 2020a, 2020b; and references therein). However, this projected decrease in TC frequency is still highly uncertain (e.g., Hsieh et al., 2022, 2023; Jing et al., 2021; Knutson et al., 2020; Lee et al., 2023; Roberts et al., 2020b; Sobel et al., 2021; and references therein). For example, opposite results have been derived from some climate model projections (e.g., Bhatia et al., 2018; Murakami et al., 2014; Vecchi et al., 2019) and statistical‐dynamical downscaling (e.g., Emanuel, 2013, 2021; Lee et al., 2020, 2022).…”