Application Of Continual Assimilation Of Satellite Data In Simulation Of Typhoon Processes

Using the mesoscale weather forecasting model WRF,by continuous assimilation of AMSU-A microwave radiation data through WRFDA model and the Community Radiative Transfer Model(CRTM),super typhoon “Ramasoon” is simulated to assess the effect of satellite data assimilation.SWAN and FVCOM are applied to further explore the effect of wind field assimilation on wave field,flow field and temperature field simulation.The simulation program is applied to the “Rainbow” process simulation to further verify the rationality of the simulation scheme.The main contents and conclusions are as follows:Using the weather model WRF,WRFDA assimilation module and the Community Radiative Transfer Model(CRTM),by continuous assimilation of AMSU-A microwave radiation data,super typhoon “Ramasoon” is simulated.The results show that the continuous data assimilation of satellite data can improve the simulation effect of typhoon.The wind and pressure fileds are analyzed based on the simulated results.It is shown that the wind speed to the right of the center of the typhoon is greater than the left.When the typhoon is near the land,the wind speed of the typhoon is obviously weakened,but the distribution of the pressure field is less affected.The wave,flow and sea surface filed of the "Ramasoon" process were simulated by SWAN and FVCOM.The comparison of the wave height with the satellite data shows that the wave field driven by the assimilation test wind field is more reasonable than the non-assimilation experiment.Wind field assimilation can effectively improve the simulation effect of typhoon waves.The characteristics of wave field driven by typhoon are analyzed.It is show that the wave height to the right of the center of the wave field is greater than the left,which is consistent with the wind field,and the wave field has a time delay compared to wind field.The vertical distribution of the ocean temperature is verified by the measured data.Model can reasonably reflect the characteristics of the right-deviation and delay response of the flow field,and the characteristics of sea surface temperature drop during typhoon.The wind,field and temperature field in "Rainbow" process is simulated by the simulation program adopted by "Ramasoon" to further verify the rationality of the wind field assimilation scheme.The characteristics of wave field,flow field and temperature field in the process of typhoon "Rainbow" are analyzed based on the simulated results.It is shown that the scheme can simulate the rainbow typhoon path,intensity,wave field and ocean temperature vertical distribution well,which shows that the simulation scheme has wide applicability to typhoons in the South China Sea.