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 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
利用WRF(Weather Research and Forecast)模式及WRFDA(WRF model data assimilation system)系统,针对2017年台风“天鸽”个例通过同化雷达径向速度(Vr)和反射率因子(RF),研究水凝物控制变量的雷达资料同化对台风分析预报的影响。研究表...利用WRF(Weather Research and Forecast)模式及WRFDA(WRF model data assimilation system)系统,针对2017年台风“天鸽”个例通过同化雷达径向速度(Vr)和反射率因子(RF),研究水凝物控制变量的雷达资料同化对台风分析预报的影响。研究表明:雷达径向速度的直接同化有效地改进了模式初始场中台风涡旋区的中小尺度信息,分析场中产生了气旋性的风场增量,对模式背景场中的台风有显著增强作用。通过在传统控制变量中扩展针对水凝物的控制变量可有效地同化雷达反射率因子资料,对初始场的水物质进行调整,并对随后确定性预报的台风路径和强度都有一定的正效果。此外,相比没有水凝物控制变量的雷达同化试验,加入了水凝物控制变量的雷达资料同化试验降水预报效果更好。这为将我国近海的地基多普勒天气雷达用于台风初始化分析和预报提供了一定的技术支撑和保障。展开更多
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.
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.
文摘利用WRF(Weather Research and Forecast)模式及WRFDA(WRF model data assimilation system)系统,针对2017年台风“天鸽”个例通过同化雷达径向速度(Vr)和反射率因子(RF),研究水凝物控制变量的雷达资料同化对台风分析预报的影响。研究表明:雷达径向速度的直接同化有效地改进了模式初始场中台风涡旋区的中小尺度信息,分析场中产生了气旋性的风场增量,对模式背景场中的台风有显著增强作用。通过在传统控制变量中扩展针对水凝物的控制变量可有效地同化雷达反射率因子资料,对初始场的水物质进行调整,并对随后确定性预报的台风路径和强度都有一定的正效果。此外,相比没有水凝物控制变量的雷达同化试验,加入了水凝物控制变量的雷达资料同化试验降水预报效果更好。这为将我国近海的地基多普勒天气雷达用于台风初始化分析和预报提供了一定的技术支撑和保障。
