The newly developed Coupled Ocean-Atmosphere-Wave-Sediment Transport(COAWST) Modeling System is applied to investigate typhoon-ocean interactions in this study. The COAWST modeling system represents the state-of-the-a...The newly developed Coupled Ocean-Atmosphere-Wave-Sediment Transport(COAWST) Modeling System is applied to investigate typhoon-ocean interactions in this study. The COAWST modeling system represents the state-of-the-art numerical simulation technique comprising several coupled models to study coastal and environmental processes. The modeling system is applied to simulate Typhoon Muifa(2011), which strengthened from a tropical storm to a super typhoon in the Northwestern Pacific, to explore the heat fluxes exchanged among the processes simulated using the atmosphere model WRF, ocean model ROMS and wave model SWAN. These three models adopted the same horizontal grid. Three numerical experiments with different coupling configurations are performed in order to investigate the impact of typhoon-ocean interaction on the intensity and ocean response to typhoon. The simulated typhoon tracks and intensities agree with observations. Comparisons of the simulated variables with available atmospheric and oceanic observations show the good performance of using the coupled modeling system for simulating the ocean and atmosphere processes during a typhoon event. The fully coupled simulation that includes a ocean model identifies a decreased SST as a result of the typhoon-forced entrainment. Typhoon intensity and wind speed are reduced due to the decrease of the sea surface temperature when using a coupled ocean model. The experiments with ocean coupled to atmosphere also results in decreased sea surface heat flux and air temperature. The heat flux decreases by about 29% compared to the WRF only case. The reduction of the energy induced by SST decreases, resulting in weakening of the typhoon. Coupling of the waves to the atmosphere and ocean model induces a slight increase of SST in the typhoon center area with the ocean-atmosphere interaction increased as a result of wave feedback to atmosphere.展开更多
A 72-h fine-resolution atmosphere-wave-ocean coupled forecasting system was developed for the South China Sea and its adjacent seas. The forecasting model domain covers from from 15°S to 45°N in latitude and...A 72-h fine-resolution atmosphere-wave-ocean coupled forecasting system was developed for the South China Sea and its adjacent seas. The forecasting model domain covers from from 15°S to 45°N in latitude and 99°E to135°E in longitude including the Bohai Sea, the Yellow Sea, the East China Sea, the South China Sea and the Indonesian seas. To get precise initial conditions for the coupled forecasting model, the forecasting system conducts a 24-h hindcast simulation with data assimilation before forecasting. The Ensemble Adjustment Kalman Filter(EAKF) data assimilation method was adopted for the wave model MASNUM with assimilating Jason-2 significant wave height(SWH) data. The EAKF data assimilation method was also introduced to the ROMS model with assimilating sea surface temperature(SST), mean absolute dynamic topography(MADT) and Argo profiles data. To improve simulation of the structure of temperature and salinity, the vertical mixing scheme of the ocean model was improved by considering the surface wave induced vertical mixing and internal wave induced vertical mixing. The wave and current models were integrated from January 2014 to October 2015 driven by the ECMWF reanalysis 6 hourly mean dataset with data assimilation. Then the coupled atmosphere-wave-ocean forecasting system was carried out 14 months operational running since November 2015. The forecasting outputs include atmospheric forecast products, wave forecast products and ocean forecast products. A series of observation data are used to evaluate the coupled forecasting results, including the wind, SHW, ocean temperature and velocity.The forecasting results are in good agreement with observation data. The prediction practice for more than one year indicates that the coupled forecasting system performs stably and predict relatively accurate, which can support the shipping safety, the fisheries and the oil exploitation.展开更多
珠江口洪季悬浮泥沙的浓度分布与输运通量受多种动力因素的影响,其中斜压效应不可忽视。本文采用Coupled Ocean-Atmosphere-Wave-Sediment Transport Modeling System(COAWST)海洋模型系统,以2022年6月份(洪季)的珠江口为例,研究斜压效...珠江口洪季悬浮泥沙的浓度分布与输运通量受多种动力因素的影响,其中斜压效应不可忽视。本文采用Coupled Ocean-Atmosphere-Wave-Sediment Transport Modeling System(COAWST)海洋模型系统,以2022年6月份(洪季)的珠江口为例,研究斜压效应对悬沙浓度分布与输运通量的影响。采用控制实验,研究有无斜压作用时悬沙浓度分布的变化;分析有无斜压作用时的泥沙输运通量与海底冲淤的变化情况,结果表明有斜压作用时悬浮泥沙的输运路径、通量均与无斜压时不同,伶仃洋的悬沙除向西口外输运外,还随着河口羽流的扩展向西南方向输运。有斜压作用时在伶仃洋的西南端及下游的西南沿岸均有明显的海底淤积,而无斜压作用时泥沙淤积主要发生于伶仃洋的西口附近及磨刀门口外落潮射流末端。利用悬沙输运方程进行诊断分析,揭示了斜压作用导致悬沙浓度分布与输运通量变化的动力机制,表明斜压作用虽然减小了底切应力与垂向混合系数,但由于增大的海底泥沙可侵蚀量及垂向悬沙梯度,悬沙输运方程中的再悬浮量与垂向混合通量要比无斜压时要大。本研究对河口区的悬沙输运过程与机理分析具有一定的指导意义。展开更多
This paper uses the Coupled Ocean-Atmosphere-Wave-Sediment Transport(COAWST)model to analyze the impact of typhoon‘Hongxia’on the velocity and position movement of the Kuroshio axis,the impact of typhoons on the Kur...This paper uses the Coupled Ocean-Atmosphere-Wave-Sediment Transport(COAWST)model to analyze the impact of typhoon‘Hongxia’on the velocity and position movement of the Kuroshio axis,the impact of typhoons on the Kuroshio intrusion into South China Sea(SCS),the corresponding water,heat,and salt fluxes,and the impact of Kuroshio water in the northeastern SCS.When typhoon‘Hongxia’passed,the Kuroshio intrusion into the SCS was the most significant at 21?N latitude.In the vertical direction,the Kuroshio intrusion was strongest in the subsurface layer,leading to the most significant changes in temperature and salinity in the northeastern part of the SCS in the subsurface layer.Under the influence of the southeastern monsoon in summer,a large amount of low-salinity water accumulates at the surface of the northeastern part of the SCS,and Kuroshio intrusive water remains in the bottom and middle portions of the subsurface layer.The westward deviation of the Kuroshio axis caused by the typhoon displays a certain lag compared with the hot and salty water intrusion into the SCS approximately 7 d later.The impact of the typhoon on the Kuroshio intrusion into the SCS lasts for 20 d.The typhoon caused increases in the water,heat,and salt fluxes associated with the Kuroshio intrusion into the SCS,and the contribution of the typhoon to these fluxes was as high as 40%.Under typhoon conditions,the maximum Kuroshio intrusion flux reached more than twice that before the typhoon.展开更多
基金supported by the Public Science and Technology Research Funds Projects of Ocean 201105018the National Natural Science Foundation of China 41106023
文摘The newly developed Coupled Ocean-Atmosphere-Wave-Sediment Transport(COAWST) Modeling System is applied to investigate typhoon-ocean interactions in this study. The COAWST modeling system represents the state-of-the-art numerical simulation technique comprising several coupled models to study coastal and environmental processes. The modeling system is applied to simulate Typhoon Muifa(2011), which strengthened from a tropical storm to a super typhoon in the Northwestern Pacific, to explore the heat fluxes exchanged among the processes simulated using the atmosphere model WRF, ocean model ROMS and wave model SWAN. These three models adopted the same horizontal grid. Three numerical experiments with different coupling configurations are performed in order to investigate the impact of typhoon-ocean interaction on the intensity and ocean response to typhoon. The simulated typhoon tracks and intensities agree with observations. Comparisons of the simulated variables with available atmospheric and oceanic observations show the good performance of using the coupled modeling system for simulating the ocean and atmosphere processes during a typhoon event. The fully coupled simulation that includes a ocean model identifies a decreased SST as a result of the typhoon-forced entrainment. Typhoon intensity and wind speed are reduced due to the decrease of the sea surface temperature when using a coupled ocean model. The experiments with ocean coupled to atmosphere also results in decreased sea surface heat flux and air temperature. The heat flux decreases by about 29% compared to the WRF only case. The reduction of the energy induced by SST decreases, resulting in weakening of the typhoon. Coupling of the waves to the atmosphere and ocean model induces a slight increase of SST in the typhoon center area with the ocean-atmosphere interaction increased as a result of wave feedback to atmosphere.
基金The National Key Research and Development Program of China under contract No.2017YFC1404201the NSFCShandong Joint Fund for Marine Science Research Centers under contract No.U1606405+1 种基金the SOA Program on Global Change and AirSea Interactions under contract Nos GASI-IPOVAI-03 and GASI-IPOVAI-02the National Natural Science Foundation of China under contract Nos 41606040,41876029,41776016,41706035 and 41606036
文摘A 72-h fine-resolution atmosphere-wave-ocean coupled forecasting system was developed for the South China Sea and its adjacent seas. The forecasting model domain covers from from 15°S to 45°N in latitude and 99°E to135°E in longitude including the Bohai Sea, the Yellow Sea, the East China Sea, the South China Sea and the Indonesian seas. To get precise initial conditions for the coupled forecasting model, the forecasting system conducts a 24-h hindcast simulation with data assimilation before forecasting. The Ensemble Adjustment Kalman Filter(EAKF) data assimilation method was adopted for the wave model MASNUM with assimilating Jason-2 significant wave height(SWH) data. The EAKF data assimilation method was also introduced to the ROMS model with assimilating sea surface temperature(SST), mean absolute dynamic topography(MADT) and Argo profiles data. To improve simulation of the structure of temperature and salinity, the vertical mixing scheme of the ocean model was improved by considering the surface wave induced vertical mixing and internal wave induced vertical mixing. The wave and current models were integrated from January 2014 to October 2015 driven by the ECMWF reanalysis 6 hourly mean dataset with data assimilation. Then the coupled atmosphere-wave-ocean forecasting system was carried out 14 months operational running since November 2015. The forecasting outputs include atmospheric forecast products, wave forecast products and ocean forecast products. A series of observation data are used to evaluate the coupled forecasting results, including the wind, SHW, ocean temperature and velocity.The forecasting results are in good agreement with observation data. The prediction practice for more than one year indicates that the coupled forecasting system performs stably and predict relatively accurate, which can support the shipping safety, the fisheries and the oil exploitation.
文摘珠江口洪季悬浮泥沙的浓度分布与输运通量受多种动力因素的影响,其中斜压效应不可忽视。本文采用Coupled Ocean-Atmosphere-Wave-Sediment Transport Modeling System(COAWST)海洋模型系统,以2022年6月份(洪季)的珠江口为例,研究斜压效应对悬沙浓度分布与输运通量的影响。采用控制实验,研究有无斜压作用时悬沙浓度分布的变化;分析有无斜压作用时的泥沙输运通量与海底冲淤的变化情况,结果表明有斜压作用时悬浮泥沙的输运路径、通量均与无斜压时不同,伶仃洋的悬沙除向西口外输运外,还随着河口羽流的扩展向西南方向输运。有斜压作用时在伶仃洋的西南端及下游的西南沿岸均有明显的海底淤积,而无斜压作用时泥沙淤积主要发生于伶仃洋的西口附近及磨刀门口外落潮射流末端。利用悬沙输运方程进行诊断分析,揭示了斜压作用导致悬沙浓度分布与输运通量变化的动力机制,表明斜压作用虽然减小了底切应力与垂向混合系数,但由于增大的海底泥沙可侵蚀量及垂向悬沙梯度,悬沙输运方程中的再悬浮量与垂向混合通量要比无斜压时要大。本研究对河口区的悬沙输运过程与机理分析具有一定的指导意义。
基金Tianjin Key Laboratory for Oceanic Meteorology for its support via the 2020 Open Fund Project(No.2020TKLOMZD01).
文摘This paper uses the Coupled Ocean-Atmosphere-Wave-Sediment Transport(COAWST)model to analyze the impact of typhoon‘Hongxia’on the velocity and position movement of the Kuroshio axis,the impact of typhoons on the Kuroshio intrusion into South China Sea(SCS),the corresponding water,heat,and salt fluxes,and the impact of Kuroshio water in the northeastern SCS.When typhoon‘Hongxia’passed,the Kuroshio intrusion into the SCS was the most significant at 21?N latitude.In the vertical direction,the Kuroshio intrusion was strongest in the subsurface layer,leading to the most significant changes in temperature and salinity in the northeastern part of the SCS in the subsurface layer.Under the influence of the southeastern monsoon in summer,a large amount of low-salinity water accumulates at the surface of the northeastern part of the SCS,and Kuroshio intrusive water remains in the bottom and middle portions of the subsurface layer.The westward deviation of the Kuroshio axis caused by the typhoon displays a certain lag compared with the hot and salty water intrusion into the SCS approximately 7 d later.The impact of the typhoon on the Kuroshio intrusion into the SCS lasts for 20 d.The typhoon caused increases in the water,heat,and salt fluxes associated with the Kuroshio intrusion into the SCS,and the contribution of the typhoon to these fluxes was as high as 40%.Under typhoon conditions,the maximum Kuroshio intrusion flux reached more than twice that before the typhoon.
