Extreme Cyclones and Storm Surges in the Past and Future Climates: A Sensitivity Study for the Baltic Sea Region.

The purpose of the paper is to analyse the possible parameters of extratropical cyclones (ETCs) as they would occur in the Baltic Sea area at the end of the 21st century and in the past during the Holocene thermal maximum. Using a modelling system composed of the Weather Research and Forecasting (ARW-WRF) atmospheric model, Finite Volume Community Ocean Model (FVCOM), and surrogate background conditions, the results showed that changes in cyclone parameters are more profound under steeper climate change scenarios (RCP8.5) and under higher air temperatures. Most likely, the North Atlantic ETCs will become slightly stronger, but also the uncertainty increases. Non-linear interactions between ice melt, North Atlantic current systems and atmospheric parameters probably induce an uncertainty both into future and past storminess reconstructions.