Development Project High Resolution Numerical Prediction of Landfalling Typhoon Rainfall (tentative title)

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1 A Proposal for the WMO/WWRP Research and Development Project High Resolution Numerical Prediction of Landfalling Typhoon Rainfall (tentative title) Yihong Duan WGTMR Proposed in the side meeting of the International High Level Forum on Rapid Change Phenomena in Tropical Cyclones held in Haikou, China in 2012.

2 Contents Why is high resolution prediction of landfalling typhoon rainfall important? Goals Plans

3 Apart from winds, the most damaging aspect of a typhoon is rainfall because of its effects on flooding and landslides. Typhoon Morakot (2009) Accumulated Rainfall (16 UTC Aug. 5 to 16 UTC Aug. 9) mm 619 killed, 76 missing, 16.4 billion of agricultural losses in Taiwan, China

4 Apart from winds, the most damaging aspect of a typhoon is rainfall because of its effects on flooding and landslides. 619 killed, 76 missing, 16.4 billion of agricultural losses in Taiwan, China

5 Currently, most of the operational forecasts of rainfall associated with typhoon landfalling are statistical in nature, showing quite limited capability in the prediction of extreme rainfall events for typhoon. Coarse resolution numerical forecasts of landfalling typhoon rainfall generally perform not well, thus not satisfying the needs of disaster prevention and mitigation. Physical processes that lead to different rainfall distributions associated with different typhoon landfall characteristics are not clear.

6 Typhoons Saola and Damrey (2012) Forecasts Observations Under estimation of rainfall by Typhoon DAMREY Wrong forecasts of torrential rainfall locations of Typhoon SAOLA

7 The precipitation (observation vs. forecast) by TC Haikui 2012 forecast observation Haikui s precipitation covered larger areas and lasted longer duration than that of forecast. The maximum precipitation observed in Huangshan, Anhui province 740.3mm, several hundred kilometers away from the landing point.

8 OBS ECMWF 0 24 OBS ECMWF 24 48

9 OBS ECMWF OBS ECMWF total

10 OBS JMA 0 24 OBS JMA 24 48

11 OBS JMA OBS JMA total

12 OBS NCEP 0 24 OBS NCEP 24 48

13 OBS NCEP OBS NCEP total

14 OBS CMA 0 24 OBS CMA 24 48

15 OBS CMA OBS CMA total

16 Rainfall of Typhoon Haikui (2012) during landfall Forecasts Observations Inaccurate forecasting of high rainfall coverage False forecasting of peak rainfall occurrence

17 More and more high resolution regional numerical models and ensemble prediction systems are developed and employed in operational forecasting in many forecasting and research centers. GRAPES TCM (Shanghai Typhoon Institute of CMA; resolution: ~10 km) High resolution Typhoon Prediction System (Chinese Academy of Meteorogical Sciences; resolution: 2 km) Regional Numerical Forecasting System (Central Weather Bureau of Taiwan, China; resolution: 5 km) Hong Kong Mesoscale Numerical Prediction System (Hong Kong Observatory; resolution: 2 km) JMA Mesoscale model (JMA; resolution: 5 km) Regional Prediction Model (KMA; resolution: 10 km).

18 72 h accumulated rainfall total of Typhoon Morakot over Taiwan, forecasted by 60 ensemble members Resolution: 4.5 km Zhang et al. (2010)

19 Contents Why is high resolution prediction of landfalling typhoon rainfall important? Goals Plans

20 Goals To understand the current capability of high resolution regional numerical weather prediction (NWP) models and ensemble prediction systems (EPSs) in predicting rainfall related to landfalling typhoons To improve the model settings for better NWP of landfalling typhoon rainfall.

21 Specific objectives To intercompare the performance of participating models on prediction of landfalling typhoon rainfall To better understand the effects of different data and assimilation techniques on high resolution NWP of landfalling typhoon rainfall To better understand the effects of different ensemble techniques on high resolution NWP of landfalling typhoon rainfall To better understand the effects of physical processes on highresolution NWP of landfalling typhoon rainfall To set up a prototype of model settings for future operational application To propose key scientific issues on further development of highresolution NWP and EPSs of landfalling typhoon rainfall

22 Contents Why is high resolution prediction of landfalling typhoon rainfall important? Goals Plans

23 The region of interest in this project will be the western North Pacific. Potential participants will be from the WMO Members surrounding the western North Pacific region and any other interested. Potential participants: China, Australia, Hongkong, China, Japan, the Philippines, ROK, Thailand, USA, Vietnam, and others.

24 The project should be jointly supported by the WGTMR, WGMWFR, and JWGFVR..and guided by an International Scientific Steering Committee, which will be co led by two Chief scientists, one from WGTMR and the other from WGMWFR. Several task teams should be formed to tackle specific objectives of the project. The sharing of data and products should be according to the WMO guidelines. The project need to collaborate with on going WMO RDPs (TLFDP, HIW.)

25 Thank you for your attention!