Driving force of Storm Surge along Ibaraki Coast of Japan in October 2006

Abstract

A strong low-pressure system passed along the coast of Pacific Ocean side of the northern part of Japan in October 2006. High tide level was recorded, many beaches and dunes were eroded and coastal defense systems were damaged on the Ibaraki coast by the low-pressure system. This high tide level due to the low-pressure system continued for over 24 hours with big wind waves and met astronomical high tide two or three times. The results of the numerical simulation in this paper show that Ekman transport was the main physical force to generate this high tide level. Unusual time and spatial distribution of winds around the low-pressure system affected the force considerably.

Dynamical Downscaling of Coastal Dynamics for Two Extreme Storm Surge Events in Japan

“…Additionally, on October 23, SLP was about 1,025 mbar and northward surface wind was about 5 m/s, which generated the reduced SSH with northward alongshore current. These magnitudes and directions of extreme coastal southward surface wind correspond well with the findings from Nobuoka et al (2007). Therefore, the results under this study might support their conclusion that Ekman transport was the main physical force that generated the high tide level on October 7 and possibly also on October 24.…”

“…Goda (2006) showed that various current driving forces other than waves are important for generating longshore currents. Nobuoka et al (2007) specifically analyzed the driving force of storm surge in the October 2006 event and the maximum water level recorded along the coast. They reported that the Ekman transport was the main physical force that generated this high tide level and that unusual time and spatial distribution of winds around the lowpressure system considerably affected the force.…”