Volume 2, Number 3, October 2004

PARI CONDUCTING REAL-TIME TYPHOON-CAUSED STORM SURGE
PREDICTION FOR JAPANESE MAJOR PORTS
After the storm surge that resulted in the loss of 5,000 lives in 1959, the Japanese Government
constructed coastal defenses such as dikes and seawalls on the major bay coasts. These facilities
significantly reduced loss of lives and properties, however tidal level may exceed the design level.
Hence, the reason why real-time prediction of the storm surge at each port and coast is essential tomitigate coastal disasters.
Following the above-mentioned situation, since 2001 the Port and Airport Research Institute (PARI)
has been improving their storm surge model based on long wave approximation with an empiricaltyphoon pressure and wind field model and also forecasting the storm surges at the major ports. For
effective forecasting the spatial grid interval of computation domains has been optimized between 0.6
km and 1.8 km around the target ports, because fine grid mesh gives the accurate result but requires
longer computation time. The figure below shows a part of the result for Typhoon 0418 (SONGDA).
In 2004, the storm surges from five typhoons were forecasted and three typhoons triggered severe
coastal disasters in west Japan. Just after these disasters, PARI began to model the storm surges for theactual typhoon tracks with finer spatial resolution and also investigated the damages of coastal
defenses and the inundation heights at more than 20 ports in Japan. These results will make the storm
surge forecasting more accurate.
Contact: Mr. Hiroyasu Kawai, Senior Researcher, Coastal Disaster Prevention Assessment, MarineEnvironment and Engineering Department, Port and Airport Research Institute, kawai@pari.go.jp

CBKobeSep. 79hr
21hr
15hr

Sep. 69hr

Seto Inland Sea

2Astorm surge (m)9hr D
Sep. 81.5
1forecast (track A)
forecast (track B)
forecast (track C)
forecast (track D)
obs

Kobe

0.5
0-0.5

9 12 15 18 21 0 3 6
Sep 6

9 12 15 18 21 0 3 6 9
Sep 7
Sep 8

COASTAL INUNDATION CAUSED BY STORM SURGE
The Port and Airport Research Institute (PARI) in
cooperation with Ministry of Land, Infrastructure andTransportation conducted field investigations ondamage due to storm surge and high waves caused byTyphoon CHABA in some coastal cities and towns.
The typhoon struck the south part of Kyushu islandaround 0900 on 30 August 2004 and traveled throughthe west part of Honshu island (Figure 1). The storm
surge caused serious inundation to Takamatsu City. The
peak of the storm surge was 1.3 m and occurred at thesame time of high spring tide near 2400 on 30 August.
The resultant sea level reached T.P.+2.46 m, which
exceeded the previous highest record by 0.54 m.
Seawater overflowed some low-lying areas as shown in
Picture 1. Water flooded a downtown section of the city.
Inundation depth was over 1 m (Picture 2). Two
persons died from the flooding and more than 15 000
houses were damaged.
In addition to Takamatsu City, the storm surge and highwaves caused by Typhoon CHABA resulted in damage
to many coastal cities and towns. Another typhoon,
SONGDA, in early September 2004 produced damage
to many Japan cities and towns. PARI has conducted
field surveys and numerical simulations on their storm
surge and high waves, and plan to report detailed
investigation results as soon as possible.
Contact: Dr. Takashi Tomita, Head of Storm Surge andTsunami Division, Marine Environment andEngineering Department, Port and Airport ResearchInstitute, tomita@pari.go.jp

Figure 1. Route of Typhoon CHABA

Picture 1. Maximum seawater level due
to storm surge by Typhoon CHABA

Picture 2. Inundation in the city