Intercomparing atmospheric reanalysis products for hydrodynamic and wave modeling of extreme events during the open-water Arctic season

Abstract

The significant increase in the Arctic open-water extent along with the earlier sea-ice summer melt and later autumn freeze-up seasons observed in the last decades allow the formation of less fetch-limited waves and the further propagation of storm surges to new ice-free shores. Coupled hydrodynamic and wave models can be used to simulate these complex atmospheric–ocean interactions that often result in coastal flood hazards and extreme waves. However, the reliability of such simulations is intrinsically dependent on the quality of their main inputs, including wind and mean sea-level pressure products, which are usually extracted from reanalysis. This study evaluates the storm surge and significant wave height hindcasts from the coupled ADCIRC+SWAN numerical model forced by seven different reanalysis products during contrasting major storms. Model results show that the highest spatial resolution product CFSv2 led to the overall most accurate model simulations, performing particularly well at locations exposed to extreme surge and waves. Average root mean square error increases of up to 100 percent for storm surge and 157.55 percent for significant wave height were observed when using products other than CFSv2, thus highlighting the importance of selecting the proper wind and pressure reanalysis to be implemented as forcing in the hydrodynamic and wave numerical model.

Keywords

• Numerical modeling
• wind and pressure forcing
• Bering Sea
• ADCIRC+SWAN
• ice-free Alaskan coast