A New Perspective for Future Precipitation Change from Intense Extratropical Cyclones

C Kodama,T Mauritsen,T Seiki,B Stevens,M Satoh

doi:10.1029/2019gl084001

Abstract

AbstractExtratropical cyclones, major contributors to precipitation in the midlatitudes, comprise mesoscale fronts and fine‐scale convective storms. Intense oceanic cyclones pose natural hazards, making reliable projections of their changes with global warming of great interest. Here, we analyze the first ever global climate simulations to resolve such mesoscale dynamics of extratropical cyclones. The present‐day structure, frequency, and precipitation of the oceanic extratropical cyclones compare well with reanalyses and new satellite datasets that resolve the multiscale cloud‐precipitation system. Simulated precipitation from intense oceanic cyclones increases at a rate of 7%/K1, following Clausius‐Clapeyron, with warming. The same scaling is apparent also in the interhemispheric contrast, suggesting that the latter could serve as a predictor of the former. Projected changes in precipitation from intense oceanic cyclones with warming may thus be testable using a reliable global observation network of precipitation in the present day.

Highlights

The day‐to‐day weather in the midlatitudes is shaped by extratropical cyclones (ECs)
To help assess the fitness of the model to study how ECs change with warming, as we do in section 3.2, we first evaluate the simulations of present‐day ECs, and the representation of EC structure, as compared to composites from satellite observations and reanalyses of meteorological data
Both the reanalysis and the simulation indicate that oceanic ECs generated in southern hemisphere (SH) are more intense than those in northern hemisphere (NH), even if the simulated ECs are somewhat deeper than those identified in the reanalysis

Summary

Introduction

The day‐to‐day weather in the midlatitudes is shaped by extratropical cyclones (ECs). Intense ECs are often associated with major weather hazards, including heavy precipitation and flash floods. ECs are associated with precipitation extremes, contributing more than half (regionally up to 80%) of extreme precipitation events (Pfahl & Wernli, 2012). In the Northeastern United States 93–100% of extreme precipitation in the winter comes from ECs (Agel et al, 2015). These are just some of the reasons why understanding how ECs, and the precipitation associated with them, will change with warming will be helpful for societies endeavoring to adapt to climate change (Bony et al, 2015)

Methods

Results

Discussion

Conclusion