The Role of the Inverted Barometer Effect in Observed and Modeled Extreme Sea Level

Understanding extreme sea level variability is crucial for mitigating and adapting to future sea level rise. The inverted barometer (IB) effect is an atmospheric-driven change in sea level due to variations in pressure, which can exacerbate periods of extreme sea level. The IB effect has been found to play a role in changing local distributions of sea level under future warming scenarios, but its effect on extreme sea level regimes has not yet been explored. This project analyzes the role of the IB effect during extreme sea level events and the effectiveness of models in representing these events by comparing tidal residuals of high-frequency tide gauge observations and coupled and ocean-only GFDL model simulations. With this comparison we can explore the impact of the IB on extremes through changes to statistical moments, quantile thresholds, with and without IB effect, and seasonality of threshold exceedances across a diverse selection of tide gauge locations. We find the IB effect does not change the seasonality of extreme sea level events, but is important for determining the magnitude of extreme events. Including the IB effect into climate model sea level output improves the tailedness and thresholds relative to observed distributions. Including the IB effect within global climate models better represents coastal extremes, and can play a valuable role in understanding extremes of undersampled coastal regions and future changes.