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
Positive SST anomalies usually appear in remote ocean such as the China seas during an ENSO event. By analyzing the monthly data of HadISST from 1950 to 2007, it shows that the interannual component of SST anomalies p...Positive SST anomalies usually appear in remote ocean such as the China seas during an ENSO event. By analyzing the monthly data of HadISST from 1950 to 2007, it shows that the interannual component of SST anomalies peak approximately 10 months after SST anomalies peak in the eastern equatorial Pacific. As the ENSO event progresses, the positive SST anomalies spread throughout the China seas and eastward along the Kuroshio extension. Atmospheric reanalysis data demonstrate that changes in the net surface heat flux entering into the China seas are responsible for the SST variability. During E1 Nifio, the western north Pacific anticyclone is generated, with anomalous southwester lies prevailing along the East Asian coast. This anticyclone reduces the mean surface wind speed which decreases the surface heat flux and then increases the SST. The delays between the developing of this anticyclone and the south Indian Ocean anticyclone with approximately 3-6 months cause the 2-3 months lag of the surface heat flux between the China seas and the Indian Ocean. The northwestern Pacific anticyclone is the key process bridging the warming in the eastern equatorial Pacific and that in the China seas.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 Natural Science Foundation of China under contact No.41106023the State Oceanic Administration Marine Science Foundation for Youth of China under contact No.2012204the Open Research Program of the Key Laboratory of Ocean Circulation and Wave,Institute of Oceanology,Chinese Academy of Sciences,under contact No.KLOCAW1102
文摘Positive SST anomalies usually appear in remote ocean such as the China seas during an ENSO event. By analyzing the monthly data of HadISST from 1950 to 2007, it shows that the interannual component of SST anomalies peak approximately 10 months after SST anomalies peak in the eastern equatorial Pacific. As the ENSO event progresses, the positive SST anomalies spread throughout the China seas and eastward along the Kuroshio extension. Atmospheric reanalysis data demonstrate that changes in the net surface heat flux entering into the China seas are responsible for the SST variability. During E1 Nifio, the western north Pacific anticyclone is generated, with anomalous southwester lies prevailing along the East Asian coast. This anticyclone reduces the mean surface wind speed which decreases the surface heat flux and then increases the SST. The delays between the developing of this anticyclone and the south Indian Ocean anticyclone with approximately 3-6 months cause the 2-3 months lag of the surface heat flux between the China seas and the Indian Ocean. The northwestern Pacific anticyclone is the key process bridging the warming in the eastern equatorial Pacific and that in the China seas.
