Super typhoons Rammasun(No.1409) and Hato(No.1713) both underwent rapidly intensification(RI) in the northern part of South China Sea before they made landfall. Forecast skills and service performance of tropical cycl...Super typhoons Rammasun(No.1409) and Hato(No.1713) both underwent rapidly intensification(RI) in the northern part of South China Sea before they made landfall. Forecast skills and service performance of tropical cyclones' RI process in the real-time operation is analyzed in this study. TCs are prone to intensify rapidly in the South China Sea, which is a complex process concluding complicated interaction between large scale environmental systems and tropical cyclone inner-core structure. The forecast performance of Rammasun and Hato shown that the subjective forecast of CMA has defect in the intensity forecast especially for the long-rang more than 48-hr. However, forecasters have chance to capture the signal of RI besides numerical operational models, which contribute to gain precious time for disaster reduction affairs. The role of local sea surface temperature and the warm core structure revealed by the numerical simulations are highlighted in doing comprehensive analysis in real-time forecast.展开更多
Typhoon Hato (2017) went through a rapid intensification (RI) process before making landfall in Zhuhai,Guangdong Province, as the observational data shows. Within 24 hours, its minimum sea level pressure deepened by35...Typhoon Hato (2017) went through a rapid intensification (RI) process before making landfall in Zhuhai,Guangdong Province, as the observational data shows. Within 24 hours, its minimum sea level pressure deepened by35hPa and its maximum sustained wind speed increased by 20m s-1. According to satellite observations, Hato encountered a large area of warm water and two warm core rings before the RI process, and the average sea surface temperature cooling (SSTC) induced by Hato was only around 0.73℃. Air-sea coupled simulations were implemented to investigate the specific impact of the warm water on its RI process. The results showed that the warm water played an important role by facilitating the RI process by around 20%. Sea surface temperature budget analysis showed that the SSTC induced by mixing mechanism was not obvious due to the warm water. Besides, the cold advection hardly caused any SSTC, either. Therefore, the SSTC induced by Hato was much weaker compared with that in general cases. The negative feedback between ocean and Hato was restrained and abundant heat and moisture were sufficiently supplied to Hato. The warm water helped heat flux increase by around 20%, too. Therefore, the warm water influenced the structure and the intensity of Hato. Although there might be other factors that also participated in the RI process, this study focused on air-sea interaction in tropical cyclone forecast and discussed the impact of warm water on the intensity and structure of a tropical cyclone.展开更多
Super Typhoon Mangkhut hit Hong Kong on September 16,2018,necessitating the issuance of the highest tropical cyclone warning signal,No.10 Hurricane Signal.Packing ferocious winds and record-breaking storm surge,Mangkh...Super Typhoon Mangkhut hit Hong Kong on September 16,2018,necessitating the issuance of the highest tropical cyclone warning signal,No.10 Hurricane Signal.Packing ferocious winds and record-breaking storm surge,Mangkhut brought the most serious and widespread destruction to the territory in the recent three decades.A series of post event information search,field visits and damage surveys has been conducted by the Hong Kong Observatory(HKO)and the findings on the damages and impacts caused by Mangkhut in different parts of the territory are documented in this paper.Moreover,by analyzing the economic loss data reported by various government departments,public utilities and organizations in Hong Kong and the statistics on insurance claims from the Hong Kong Federation of Insurers(HKFI),the estimated direct economic loss due to Mangkhut in Hong Kong is about HK$4.60 billion,which is about 3.8 times to that of Super Typhoon Hato in 2017.On the contrary,in the Guangdong-Hong Kong-Macao Greater Bay Area,the estimated direct economic loss due to Hato is significantly higher than that of Mangkhut.This could be attributed to the early and effective warnings for Mangkhut,increased public awareness and typhoon preparedness for Mangkhut in 2018 since the fierce attack of Hato in 2017,and infrastructure enhancement of the major impact areas.展开更多
基金jointly funded by National Key Research and Development Program of China (2017YFC1501604) "Study of Key Dynamical and Thermal Process of Typhoon Intensity or Structural Change and Forecasting Theory"National Natural Science Foundation of China (41775048) "Study on the Mechanism of the Influence of the Middle and Upper Level Non-adiabatic Heating of the Troposphere on the Rapidly Intensification of Offshore Tropical Cyclones in China"
文摘Super typhoons Rammasun(No.1409) and Hato(No.1713) both underwent rapidly intensification(RI) in the northern part of South China Sea before they made landfall. Forecast skills and service performance of tropical cyclones' RI process in the real-time operation is analyzed in this study. TCs are prone to intensify rapidly in the South China Sea, which is a complex process concluding complicated interaction between large scale environmental systems and tropical cyclone inner-core structure. The forecast performance of Rammasun and Hato shown that the subjective forecast of CMA has defect in the intensity forecast especially for the long-rang more than 48-hr. However, forecasters have chance to capture the signal of RI besides numerical operational models, which contribute to gain precious time for disaster reduction affairs. The role of local sea surface temperature and the warm core structure revealed by the numerical simulations are highlighted in doing comprehensive analysis in real-time forecast.
基金National Basic R&D Project(973 Program)of China(2015CB452805)National Natural Science Foundation of China(61827901)+3 种基金National Key R&D Program of China(2017YFC1501602)Open Research Program of the State Key Laboratory of Severe Weather(2019LASW-A08)Basic Research Fund of CAMS(2016Z003,2018Y013)Program of the National Satellite Meteorological Centre(FY3(02P)-MAS-1803)。
文摘Typhoon Hato (2017) went through a rapid intensification (RI) process before making landfall in Zhuhai,Guangdong Province, as the observational data shows. Within 24 hours, its minimum sea level pressure deepened by35hPa and its maximum sustained wind speed increased by 20m s-1. According to satellite observations, Hato encountered a large area of warm water and two warm core rings before the RI process, and the average sea surface temperature cooling (SSTC) induced by Hato was only around 0.73℃. Air-sea coupled simulations were implemented to investigate the specific impact of the warm water on its RI process. The results showed that the warm water played an important role by facilitating the RI process by around 20%. Sea surface temperature budget analysis showed that the SSTC induced by mixing mechanism was not obvious due to the warm water. Besides, the cold advection hardly caused any SSTC, either. Therefore, the SSTC induced by Hato was much weaker compared with that in general cases. The negative feedback between ocean and Hato was restrained and abundant heat and moisture were sufficiently supplied to Hato. The warm water helped heat flux increase by around 20%, too. Therefore, the warm water influenced the structure and the intensity of Hato. Although there might be other factors that also participated in the RI process, this study focused on air-sea interaction in tropical cyclone forecast and discussed the impact of warm water on the intensity and structure of a tropical cyclone.
文摘Super Typhoon Mangkhut hit Hong Kong on September 16,2018,necessitating the issuance of the highest tropical cyclone warning signal,No.10 Hurricane Signal.Packing ferocious winds and record-breaking storm surge,Mangkhut brought the most serious and widespread destruction to the territory in the recent three decades.A series of post event information search,field visits and damage surveys has been conducted by the Hong Kong Observatory(HKO)and the findings on the damages and impacts caused by Mangkhut in different parts of the territory are documented in this paper.Moreover,by analyzing the economic loss data reported by various government departments,public utilities and organizations in Hong Kong and the statistics on insurance claims from the Hong Kong Federation of Insurers(HKFI),the estimated direct economic loss due to Mangkhut in Hong Kong is about HK$4.60 billion,which is about 3.8 times to that of Super Typhoon Hato in 2017.On the contrary,in the Guangdong-Hong Kong-Macao Greater Bay Area,the estimated direct economic loss due to Hato is significantly higher than that of Mangkhut.This could be attributed to the early and effective warnings for Mangkhut,increased public awareness and typhoon preparedness for Mangkhut in 2018 since the fierce attack of Hato in 2017,and infrastructure enhancement of the major impact areas.
