This study examined the characteristics and vertical propagation of near inertial waves(NIWs)induced by Typhoon Linfa(2015),based on in situ observations conducted southeast of Dongsha Islands in the South China Sea.T...This study examined the characteristics and vertical propagation of near inertial waves(NIWs)induced by Typhoon Linfa(2015),based on in situ observations conducted southeast of Dongsha Islands in the South China Sea.The results demonstrate that the near inertial currents induced by Linfa had velocities up to 35 cm s^-1 in the mixed layer and 20 cm s^-1 in the ocean interior.The near inertial currents were polarized with predominantly clockwise-rotating components,the magnitudes of which were about 10 times larger than the counter-clockwise rotating components.The energy density spectrum showed that the emergence of NIWs resulted in energy redistribution from the diurnal band to the near inertial band.The wavenumber spectrum and the downward/upward current decomposition demonstrated that the NIWs and energy flux propagated mainly downward.The estimated vertical phase velocity and group velocity are 1.44 and 0.48 m h-1,respectively,corresponding to a vertical wavelength of 49.7 m.The e-folding time scale was 7.5 d based on the near inertial kinetic energy in the ocean interior.We found no obvious wave–wave interaction during the decay process of the NIWs.The frequency was blue-shifted,being 0.03 f0 higher than the local inertial frequency,which was caused by the background vorticity.The normal mode analysis suggests that the higher mode plays a dominant role in the propagation stage of the NIWs.展开更多
The influences of the three types of reanalysis wind fields on the simulation of three typhoon waves occurred in2015 in offshore China were numerically investigated.The typhoon wave model was based on the simulating w...The influences of the three types of reanalysis wind fields on the simulation of three typhoon waves occurred in2015 in offshore China were numerically investigated.The typhoon wave model was based on the simulating waves nearshore model(SWAN),in which the wind fields for driving waves were derived from the European Centre for Medium-Range Weather Forecasts(ECMWF)Re-Analysis-Interim(ERA-interim),the National Centers for Environmental Prediction climate forecast system version 2(CFSv2)and cross-calibrated multi-platform(CCMP)datasets.Firstly,the typhoon waves generated during the occurrence of typhoons Chan-hom(1509),Linfa(1510)and Nangka(1511)in 2015 were simulated by using the wave model driven by ERA-interim,CFSv2 and CCMP datasets.The numerical results were validated using buoy data and satellite observation data,and the simulation results under the three types of wind fields were in good agreement with the observed data.The numerical results showed that the CCMP wind data was the best in simulating waves overall,and the wind speeds pertaining to ERA-Interim and CCMP were notably smaller than those observed near the typhoon centre.To correct the accuracy of the wind fields,the Holland theoretical wind model was used to revise and optimize the wind speed pertaining to the CCMP near the typhoon centre.The results indicated that the CCMP wind-driven SWAN model could appropriately simulate the typhoon waves generated by three typhoons in offshore China,and the use of the CCMP/Holland blended wind field could effectively improve the accuracy of typhoon wave simulations.展开更多
基金supported by the National Key Research and Development Program of China (No. 2017YFC1404201)the National Natural Science Foundation of China (Nos. 41706035, 41876027 and 41876029)+2 种基金the Laboratory for Regional Oceanography and Numerical Modeling, Qingdao National Laboratory for Marine Science and Technology (No. 2017A01)China Postdoctoral Science Foundation (No. 2017M622111)the NSFC-Shandong Joint Fund for Marine Science Research Centers (No. U1606405)
文摘This study examined the characteristics and vertical propagation of near inertial waves(NIWs)induced by Typhoon Linfa(2015),based on in situ observations conducted southeast of Dongsha Islands in the South China Sea.The results demonstrate that the near inertial currents induced by Linfa had velocities up to 35 cm s^-1 in the mixed layer and 20 cm s^-1 in the ocean interior.The near inertial currents were polarized with predominantly clockwise-rotating components,the magnitudes of which were about 10 times larger than the counter-clockwise rotating components.The energy density spectrum showed that the emergence of NIWs resulted in energy redistribution from the diurnal band to the near inertial band.The wavenumber spectrum and the downward/upward current decomposition demonstrated that the NIWs and energy flux propagated mainly downward.The estimated vertical phase velocity and group velocity are 1.44 and 0.48 m h-1,respectively,corresponding to a vertical wavelength of 49.7 m.The e-folding time scale was 7.5 d based on the near inertial kinetic energy in the ocean interior.We found no obvious wave–wave interaction during the decay process of the NIWs.The frequency was blue-shifted,being 0.03 f0 higher than the local inertial frequency,which was caused by the background vorticity.The normal mode analysis suggests that the higher mode plays a dominant role in the propagation stage of the NIWs.
基金The Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)under contract No.GML2019ZD0403the Program for Guangdong Introducing Innovative and Enterpreneurial Teams under contract No.2019ZT08L213the Guangdong Provincial Key Laboratory Project under contract No.2019B121203011
文摘The influences of the three types of reanalysis wind fields on the simulation of three typhoon waves occurred in2015 in offshore China were numerically investigated.The typhoon wave model was based on the simulating waves nearshore model(SWAN),in which the wind fields for driving waves were derived from the European Centre for Medium-Range Weather Forecasts(ECMWF)Re-Analysis-Interim(ERA-interim),the National Centers for Environmental Prediction climate forecast system version 2(CFSv2)and cross-calibrated multi-platform(CCMP)datasets.Firstly,the typhoon waves generated during the occurrence of typhoons Chan-hom(1509),Linfa(1510)and Nangka(1511)in 2015 were simulated by using the wave model driven by ERA-interim,CFSv2 and CCMP datasets.The numerical results were validated using buoy data and satellite observation data,and the simulation results under the three types of wind fields were in good agreement with the observed data.The numerical results showed that the CCMP wind data was the best in simulating waves overall,and the wind speeds pertaining to ERA-Interim and CCMP were notably smaller than those observed near the typhoon centre.To correct the accuracy of the wind fields,the Holland theoretical wind model was used to revise and optimize the wind speed pertaining to the CCMP near the typhoon centre.The results indicated that the CCMP wind-driven SWAN model could appropriately simulate the typhoon waves generated by three typhoons in offshore China,and the use of the CCMP/Holland blended wind field could effectively improve the accuracy of typhoon wave simulations.
