Case Study of Using Satellite Altimetry to Improve the Simulation of Typhoon Storm Surge

Satellite altimeters can capture storm surges generated by typhoons and tropical storms, if the satellite flies over at the right time. In this case study, we show that the TOPEX/Poseidon altimeter observed Typhoon Seth storm surges off Southeast China on 10 October 1994. We then use a three-dimensional, barotropic, finite-volume community ocean model (FVCOM) to simulate storm surges. An innovative aspect is that satellite data are used to calibrate the storm surge model to improve model performance, by adjusting model wind forcing fields (the National Center for Environment Prediction (NCEP) reanalysis product) in reference to the typhoon best-track data. The calibration reduces along-track root-mean-square (RMS) difference between model and altimetric data from 0.15 to 0.10 m. It also reduces the RMS temporal difference from 0.21 to 0.18 m between model and tide-gauge data at Xiamen. In particular, the calibrated model produces a peak storm surge of 1.01 m at 6:00, October 10, 1994 at Xiamen, agreeing with tide gauge data; while the peak storm surge with the NCEP forcing is 0.71 m only. We further show that the interaction between storm surges and astronomical tides contributes to the peak storm surge by 34% and that the storm surge propagates southwestward as a coastally trapped Kelvin wave.