TY - JOUR
T1 - High-resolution quantitative precipitation forecasts and simulations by the Cloud-Resolving Storm Simulator (CReSS) for Typhoon Morakot (2009)
AU - Wang, Chung Chieh
AU - Kuo, Hung Chi
AU - Yeh, Tien Chiang
AU - Chung, Chao Hsuan
AU - Chen, Yu Han
AU - Huang, Shin Yi
AU - Wang, Yi Wen
AU - Liu, Ching Hwang
N1 - Funding Information:
The authors wish to thank Prof. Russ Elsberry of the Naval Postgraduate School and the anonymous reviewers for their constructive comments. Thanks are also to the National Science and Technology Center for Disaster Reduction (NCDR) of Taiwan for providing the radar data used in Fig. 3 . The real-time forecast runs in 2009 were carried out on the High-Performance Computer (HPC) of the Chinese Culture University, Taiwan. This study was supported by the National Science Council of Taiwan jointly under Grants NSC-99-2111-M-003-004-MY3, NSC-100-2625-M-003-002, NSC-100-2111-M-002-004-MY3, and NSC-101-2625-M-003-001.
PY - 2013/12/9
Y1 - 2013/12/9
N2 - Typhoon Morakot (2009) struck Taiwan during 7-9 August 2009, and brought extreme rainfall up to 2855. mm and the worst damages in the past 50. years. The operational models showed deficiency and serious under-prediction in rainfall amount at real time. This study demonstrates that the Cloud-Resolving Storm Simulator (CReSS), a state-of-the-art, high-resolution model, at a grid size of 3. km and starting as early as 0000 UTC 4 August, can successfully simulate and reproduce the event with high accuracy, including the distribution and timing of heavy rainfall in Taiwan. In the simulation starting at 0000 UTC 6 August, for example, the threat scores for 24-h rainfall for 8 August (with extreme amounts >1450. mm) reach 0.8-0.4 even at thresholds of 100-500. mm. This result is only possible due to small track error and the phase-locking mechanism of the Taiwan topography to heavy rainfall.Furthermore, real-time forecast and hindcast integrations of the CReSS model show that high-quality quantitative precipitation forecasts (QPFs) with peak total amount 67-80% of the true value are also obtained from initial conditions at 0000 UTC 6 August, which is about 2. days prior to the beginning of the heaviest rainfall in southern Taiwan. In these integrations, typhoon track errors in the global model forecasts used as boundary conditions are the major error source that prevent more ideal QPF results before and at 1200 UTC 5 August. When properly configured, it is believed that other similar cloud-resolving models can achieve comparable performance. Thus, the importance of and potential benefits from deterministic high-resolution forecasts is stressed, which may give an extended lead-time when the track error is small. With potentially longer time window for emergency action just prior to extreme rainfall events when it matters the most, such forecasts may ultimately lead to reduced losses in lives and properties.
AB - Typhoon Morakot (2009) struck Taiwan during 7-9 August 2009, and brought extreme rainfall up to 2855. mm and the worst damages in the past 50. years. The operational models showed deficiency and serious under-prediction in rainfall amount at real time. This study demonstrates that the Cloud-Resolving Storm Simulator (CReSS), a state-of-the-art, high-resolution model, at a grid size of 3. km and starting as early as 0000 UTC 4 August, can successfully simulate and reproduce the event with high accuracy, including the distribution and timing of heavy rainfall in Taiwan. In the simulation starting at 0000 UTC 6 August, for example, the threat scores for 24-h rainfall for 8 August (with extreme amounts >1450. mm) reach 0.8-0.4 even at thresholds of 100-500. mm. This result is only possible due to small track error and the phase-locking mechanism of the Taiwan topography to heavy rainfall.Furthermore, real-time forecast and hindcast integrations of the CReSS model show that high-quality quantitative precipitation forecasts (QPFs) with peak total amount 67-80% of the true value are also obtained from initial conditions at 0000 UTC 6 August, which is about 2. days prior to the beginning of the heaviest rainfall in southern Taiwan. In these integrations, typhoon track errors in the global model forecasts used as boundary conditions are the major error source that prevent more ideal QPF results before and at 1200 UTC 5 August. When properly configured, it is believed that other similar cloud-resolving models can achieve comparable performance. Thus, the importance of and potential benefits from deterministic high-resolution forecasts is stressed, which may give an extended lead-time when the track error is small. With potentially longer time window for emergency action just prior to extreme rainfall events when it matters the most, such forecasts may ultimately lead to reduced losses in lives and properties.
KW - Cloud-resolving model
KW - Morakot (2009)
KW - Quantitative precipitation forecasts (QPFs)
KW - Taiwan
KW - Topography
KW - Typhoon
UR - http://www.scopus.com/inward/record.url?scp=84888044065&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84888044065&partnerID=8YFLogxK
U2 - 10.1016/j.jhydrol.2013.02.018
DO - 10.1016/j.jhydrol.2013.02.018
M3 - Article
AN - SCOPUS:84888044065
SN - 0022-1694
VL - 506
SP - 26
EP - 41
JO - Journal of Hydrology
JF - Journal of Hydrology
ER -