Storm Surge Modelling Results for Typhoon Vamei and Hagibis

1. Storm Surge Modelling Results for Typhoon Vamei and Hagibis Malaysian Meteorological Department Web address: www.met.gov.my

2. Outline • Implementation of JMA-MMD Storm Surge Model in Malaysian Meteorological Department • Case Studies: • Typhoon Vamei • Typhoon Hagibis • Future Improvement

3. JMA Storm Surge Model • Overview of the model : • Based on shallow water equations • two-dimensional model • linearized equations by eliminating advection terms • Computes storm surges due to wind setup and inverted barometer effect • Accepts two kinds of meteorological forcing data: • GRIB format files containing surface wind and pressure fields from Atmospheric Model (USGODAE,NCEP,GSM etc)‏

4. Tropical Cyclone Best Track Data provided by • RSMC Tokyo - Typhoon Center • Uses : Parametric Tropical Cyclone Model • Good for Ensemble Surge Forecast due to the uncertainty of forecasted typhoon track • Disadvantage : Always overestimate the wind speed when TC hit Land (No dampening of wind speed due to topographic effect)‏

5. Tropical Storm Vamei’s case (26-28 December 2001)‏ • Simulation using JMA Storm Surge Model with JMA GSM and Best Track Data • Period 00Z25122001 – 00Z29122001 for hourly output • Domain = 1˚S - 7 ˚N, 97 ˚E - 108 ˚E • Forcing Field = JMA GSM and Best Track Data for 2001

7. Best Track JMA GSM Overestimation occurred for Best track input field

8. Best Track JMA GSM

9. Implement Ensemble Storm Surge Prediction because of uncertainties in Typhoon Track forecast • Change in Typhoon Track will significantly change the affected area of storm surge • 5 members are considered :-fast, slow, most right, most left and centre • Uses the Best Track Data to create the members

10. 5 member Ensemble of Tropical Storm Vamei Best Track Data

11. Surge Prediction are also run using different meteorological forcing field • This give “Ensemble forecast” for various forcing field • Compute storm tide = Storm Surge + Astronomical tide and compare with observed sea level • Sea Level Residue is calculated and compared with storm Surge - Verification • Uses Harmonic Analysis of Tide Gauge Data and Ocean Tide Model

12. Uses the Harmonic Analysis of Tide Gauge from University of Hawaii Sea Level Centre to obtain the timeseries of sea level residue

13. Model output deviates from observation. Possible : over-estimate wind speed forecast (USGODAE) during Vamei Stations in Malaysia show slower wind….Vamei a TS/TY???

14. Case study of TY Hagibis (T0724)‏ This settlement is common in Coastal areas of Sabah (Borneo). Known as “Kampung Air” (Water Village)‏ Can extend to 1 km to the sea

15. Newspaper (Daily Express)‏ High tide phenomenon floods areas 26 November, 2007 Kota Kinabalu: Sea level rose on Saturday night causing several coastal areas here to be inundated with water. Food stalls at Anjung Selera, Likas Bay, saw several inches of the salty water surging into their premises. Although the water level did not rise to dangerous point following a high tide phenomenon, customers shied away from the eatery outlets. Scores of motorists also stopped by the road to catch a glimpse or take pictures of the rising water and waves pounding the beach. Affa, a stall worker, said water started rising as early 7pm to about 2.2 feet. "At 9.30pm, there was suddenly a blackout causing the entire area to be in pitch darkness," he said. However, he said such a phenomenon was not unusual since it normally happened in November and December. Affa said the water level was the highest last Monday, at 2.4 feet. On Sunday, stall operators began cleaning up their respective premises but one inch of seawater still remained at 11am. In TUARAN, several kampungs reportedly came under 0.6 to one metre of water on Saturday night. Most of the affected houses, built on water villages by the coastal areas, had the water level reaching the floor, particularly at Kampung Serusup, Kampung Tajau, Labuanya, Gayang and Mengkabong. The phenomenon was said to have occurred around 9.30pm and the residents feared they would be washed away to the sea, especially guests attending a wedding party in one of the villages. However, the water level fell as the tide receded by 12.30pm on Sunday.

16. Case study of TY Hagibis (T0724)‏ • Simulation period: 06Z19112007 – 00Z22122007 for hourly output • Domain = 0 - 20˚N, 105˚E - 125˚E • Forcing Field = JMA GSM Grib Data

18. Track shows on 26 Nov 2007 TY Hagibis moved further north. Simulation run shows highest surge of only 19 cm on 16Z 21 Nov 2007

19. High tide recorded on the 26 Nov 2007 about 1.86 meter

20. The flood occurred in Kota Kinabalu, Sabah on 26 November 2008 most probably due to : Slight Surge + High Tide + High Wave (2.5 – 3.5 meter)‏

21. Future Improvement Storm Surge Model • Improvement for existing JMA –MMD Storm Surge Model • Install and run separately the new version of Storm Surge Model • 1 minute arc Bathymetry • Hot start/Continuously run for realistic state of the sea for initial storm surge calculation purpose • Time series of Storm Surge and compare side by side with real time observation from tide gauge.

22. Use the output of Tide prediction field from Global Ocean Tide Prediction Model from Oregon State University • Use the Tide Harmonic Analysis from UHSLC to get the sea level residue (Observation)‏ • Run Ensemble Storm Surge forecast from Best Track data that is converted from RSMC Bulletin when TS is significantly near the Malaysian Waters for both Indian Ocean and South China Sea. • Use the JTWC Bulletin for Best Track since Malaysia is also vulnerable to Cyclone in Indian Ocean

23. Thank you VERY MUCH!!!!!!!!!!!! On Behalf of MALAYSIAN METEOROLOGICAL DEPARTMENT