Three-way Coupled Modeling System for Storm Wave: A case study in Lake Superior

Session: Improving Model Predictions Through Coupled System and Data Assimilation (1)

Huang Chenfu, Michigan Technological University, [email protected]
Pengfei Xue, Michigan Tech, [email protected]

Abstract

This research provides an advanced modeling technique to study storm events in the Great Lakes Region. A remarkable extreme wave event happened in Lake Superior on October 24th, 2017 with the highest significant wave height (SWH) up to 30 feet (> 9 m). Our current wave modeling system driven by the prognostic wind field shows that the predicted SWH has 20% bias under extreme conditions compared with those observed and reported (i.e., buoys and overall lake pattern). To further evaluate this extreme wave event and improve the accuracy of wave hindcasting, we developed an integrated three-way coupled regional modeling system to resolve the strong air-lake interactions between the lower atmospheric boundary layer and lake surface and therefore improve modeling accuracy during the storm event. The coupled system consisted of three individual components: atmosphere modeling (WRF), lake circulation modeling (FVCOM) and spectral wave modeling (SWAN) that linked via OASIS3-MCT coupler. A model simulation under storm event is conducted to evaluate the developed modeling system. Preliminary results indicate that the three-way coupled system successfully reproduces the pattern of the extreme wave event, and improved the SWH prediction. The impact of wind-wave-current interactions on the improved model simulation will be discussed in detail.