Internal solitary waves(ISWs)are an essential dynamic process in the ocean due to their large amplitude and long propagation distance.Traditional satellite observations provide only twodimensional observations of ocea...Internal solitary waves(ISWs)are an essential dynamic process in the ocean due to their large amplitude and long propagation distance.Traditional satellite observations provide only twodimensional observations of ocean signatures induced by ISWs.The Surface Water and Ocean Topography(SWOT)satellite has drawn significant attention due to its high resolution and threedimensional observation capabilities.SWOT can generate high-precision three-dimensional sea surface topography,capture sea surface undulations,and reveal ISW-related surface oscillations,thus offering a new perspective for studying ISWs.We collected 43 SWOT observations with clear ISW signatures in the Lombok Strait from August 2023 to June 2024.Based on collected data,the ISW imaging characteristics and distributions were analyzed,and the ISW-related sea level anomaly(SLA)data were measured by the SWOT to calculate the ISW amplitude and reveal the amplitude variations during the propagation along the wave crest.The ISW amplitudes generally range between 10 and 100 m,with most ISW amplitudes between 20 and 40 m.By analyzing two consecutive generated ISW packets,we identified the spreading effect along ISW wave crests,which manifests as ISW amplitude decrease with increase in propagation distance,and the amplitude distribution is non-uniform along the wave crest.Further analysis of the propagation paths of the maximum amplitude of ISW moving northward through the Lombok Strait revealed that these maxima are predominantly oriented in northeast direction.Finally,the relationship between the amplitude of ISW and the resulting SLA was analyzed.The Pearson correlation coefficient between these two variables is as high as 0.90,which suggests a strong positive correlation between amplitude and SLA.Furthermore,this relationship is closely related to the water depth,indicating that the three-dimensional sea surface observations provided by SWOT offer crucial observational data for the inversion of amplitudes of ISW.展开更多
The internal solitary wave(ISW)represents a frequent and severe oceanic dynamic phenomenon observed in the South China Sea,exposing marine structures to sudden loads.This paper examines the prediction model of interac...The internal solitary wave(ISW)represents a frequent and severe oceanic dynamic phenomenon observed in the South China Sea,exposing marine structures to sudden loads.This paper examines the prediction model of interaction loads between ISW and FPSO,accounting for varying attack angles and incorporating ISW theories.The research demonstrates that the horizontal and transverse forces on FPSO under internal solitary waves(ISWs)comprise wave pressure difference force and viscous force,while the vertical force primarily consists of vertical wave pressure difference force.The wave pressure difference force is determined using the Froude-Krylov equation.The viscous force is derived from the tangential particle velocity induced by ISW and the viscous coefficient.The viscous coefficient formula is obtained through regression analysis of experimental data with different ISW attack angles.The research reveals that the horizontal viscous coefficient C_(vx)decreases as Reynolds number(R_(e))increases,while the transverse viscous coefficient C_(vy)initially increases and subsequently decreases with the growth of the Keulegan-Carpenter number(KC).Moreover,changes in wave propagation direction significantly affect the extreme magnitudes of both horizontal and transverse forces,and simultaneously modify the transverse force orientation,while having minimal impact on the vertical force.Additionally,the forces increase with the ISW’s amplitude.For horizontal and transverse forces,a thinner upper fluid layer generates larger forces.Comparative analysis of experimental,numerical,and theoretical results indicates strong agreement between theoretical predictions and experimental and numerical outcomes.展开更多
Internal solitary waves(ISWs)have considerable energy to drive the mixing of water masses in the Sulu Sea.The propagation speed is one of the critical parameters in quantifying the energy budget of the ISWs.We collect...Internal solitary waves(ISWs)have considerable energy to drive the mixing of water masses in the Sulu Sea.The propagation speed is one of the critical parameters in quantifying the energy budget of the ISWs.We collected 1354 groups of ISWs’speeds from tandem satellite remote sensing images with temporal intervals shorter than 25 min and analyzed their spatial and multi-scale temporal variations in the Sulu Sea.We found that water depth plays an important role in modulating the spatial variation of wave speeds,which increase exponentially with water depth with a power of 0.26.Tidal currents,ocean stratification,background circulation,and climate affect the temporal variations of wave speeds from days to months or years.The fortnightly spring/neap tidal currents cause daily variations of wave speeds up to 40%by modulating the ISW amplitudes.In addition to the well-accepted results that monthly variations of wave speeds are related to density stratification,we found that enhanced stratification increases wave speeds,and the background circulation leads to a maximum decrease of 0.27 m/s in the linear counterparts of wave speed.Moreover,the averaged wave speed collected in October is lower than the corresponding linear one possibly due to some unknown dynamical processes or underestimation of background current.As for the interannual variations,we show that wave speed increases in La Niña years and decreases in El Niño years as a result of the climatic modulation on the depth of the maximum value of buoyancy frequency.展开更多
Optical remote sensing has been widely used to study internal solitary waves(ISWs).Wind speed has an important effect on ISW imaging of optical remote sensing.The light and dark bands of ISWs cannot be observed by opt...Optical remote sensing has been widely used to study internal solitary waves(ISWs).Wind speed has an important effect on ISW imaging of optical remote sensing.The light and dark bands of ISWs cannot be observed by optical remote sensing when the wind is too strong.The relationship between the characteristics of ISWs bands in optical remote sensing images and the wind speed is still unclear.The influence of wind speeds on the characteristics of the ISWs bands is investigated based on the physical simulation experiments with the wind speeds of 1.6,3.1,3.5,3.8,and 3.9 m/s.The experimental results show that when the wind speed is 3.9 m/s,the ISWs bands cannot be observed in optical remote sensing images with the stratification of h_(1)∶h_(2)=7∶58,ρ_(1)∶ρ_(2)=1∶1.04.When the wind speeds are 3.1,3.5,and 3.8 m/s,which is lower than 3.9 m/s,the ISWs bands can be obtained in the simulated optical remote sensing image.The location of the band’s dark and light extremum and the band’s peak-to-peak spacing are almost not affected by wind speed.More-significant wind speeds can cause a greater gray difference of the light-dark bands.This provided a scientific basis for further understanding of ISW optical remote sensing imaging.展开更多
基金Supported by the National Key Research and Development Program of China(No.2021YFB3901304)the Shandong Provincial Natural Science Foundation(No.ZR2024QD054)+2 种基金the National Key Research and Development Program of China(No.2019YFA0606702)the National Natural Science Foundation of China(Nos.41906157,42306194,42306195)the Oceanographic Data Center,Chinese Academy of Sciences and the platform of Sino-Indonesian Joint Laboratory for Marine Sciences(SIMS)。
文摘Internal solitary waves(ISWs)are an essential dynamic process in the ocean due to their large amplitude and long propagation distance.Traditional satellite observations provide only twodimensional observations of ocean signatures induced by ISWs.The Surface Water and Ocean Topography(SWOT)satellite has drawn significant attention due to its high resolution and threedimensional observation capabilities.SWOT can generate high-precision three-dimensional sea surface topography,capture sea surface undulations,and reveal ISW-related surface oscillations,thus offering a new perspective for studying ISWs.We collected 43 SWOT observations with clear ISW signatures in the Lombok Strait from August 2023 to June 2024.Based on collected data,the ISW imaging characteristics and distributions were analyzed,and the ISW-related sea level anomaly(SLA)data were measured by the SWOT to calculate the ISW amplitude and reveal the amplitude variations during the propagation along the wave crest.The ISW amplitudes generally range between 10 and 100 m,with most ISW amplitudes between 20 and 40 m.By analyzing two consecutive generated ISW packets,we identified the spreading effect along ISW wave crests,which manifests as ISW amplitude decrease with increase in propagation distance,and the amplitude distribution is non-uniform along the wave crest.Further analysis of the propagation paths of the maximum amplitude of ISW moving northward through the Lombok Strait revealed that these maxima are predominantly oriented in northeast direction.Finally,the relationship between the amplitude of ISW and the resulting SLA was analyzed.The Pearson correlation coefficient between these two variables is as high as 0.90,which suggests a strong positive correlation between amplitude and SLA.Furthermore,this relationship is closely related to the water depth,indicating that the three-dimensional sea surface observations provided by SWOT offer crucial observational data for the inversion of amplitudes of ISW.
基金supported by JUST Start-up Fund for Science Research,the Jiangsu Natural Science Foundation(Grant No.BK20210885).
文摘The internal solitary wave(ISW)represents a frequent and severe oceanic dynamic phenomenon observed in the South China Sea,exposing marine structures to sudden loads.This paper examines the prediction model of interaction loads between ISW and FPSO,accounting for varying attack angles and incorporating ISW theories.The research demonstrates that the horizontal and transverse forces on FPSO under internal solitary waves(ISWs)comprise wave pressure difference force and viscous force,while the vertical force primarily consists of vertical wave pressure difference force.The wave pressure difference force is determined using the Froude-Krylov equation.The viscous force is derived from the tangential particle velocity induced by ISW and the viscous coefficient.The viscous coefficient formula is obtained through regression analysis of experimental data with different ISW attack angles.The research reveals that the horizontal viscous coefficient C_(vx)decreases as Reynolds number(R_(e))increases,while the transverse viscous coefficient C_(vy)initially increases and subsequently decreases with the growth of the Keulegan-Carpenter number(KC).Moreover,changes in wave propagation direction significantly affect the extreme magnitudes of both horizontal and transverse forces,and simultaneously modify the transverse force orientation,while having minimal impact on the vertical force.Additionally,the forces increase with the ISW’s amplitude.For horizontal and transverse forces,a thinner upper fluid layer generates larger forces.Comparative analysis of experimental,numerical,and theoretical results indicates strong agreement between theoretical predictions and experimental and numerical outcomes.
基金Supported by the National Natural Science Foundation of China(Nos.U23A2032,42006193)supported by the Hainan Provincial Excellent Talent Team Project(Space Observation of Deep-sea)。
文摘Internal solitary waves(ISWs)have considerable energy to drive the mixing of water masses in the Sulu Sea.The propagation speed is one of the critical parameters in quantifying the energy budget of the ISWs.We collected 1354 groups of ISWs’speeds from tandem satellite remote sensing images with temporal intervals shorter than 25 min and analyzed their spatial and multi-scale temporal variations in the Sulu Sea.We found that water depth plays an important role in modulating the spatial variation of wave speeds,which increase exponentially with water depth with a power of 0.26.Tidal currents,ocean stratification,background circulation,and climate affect the temporal variations of wave speeds from days to months or years.The fortnightly spring/neap tidal currents cause daily variations of wave speeds up to 40%by modulating the ISW amplitudes.In addition to the well-accepted results that monthly variations of wave speeds are related to density stratification,we found that enhanced stratification increases wave speeds,and the background circulation leads to a maximum decrease of 0.27 m/s in the linear counterparts of wave speed.Moreover,the averaged wave speed collected in October is lower than the corresponding linear one possibly due to some unknown dynamical processes or underestimation of background current.As for the interannual variations,we show that wave speed increases in La Niña years and decreases in El Niño years as a result of the climatic modulation on the depth of the maximum value of buoyancy frequency.
基金Supported by the National Natural Science Foundation of China(Nos.61871353,42006164)。
文摘Optical remote sensing has been widely used to study internal solitary waves(ISWs).Wind speed has an important effect on ISW imaging of optical remote sensing.The light and dark bands of ISWs cannot be observed by optical remote sensing when the wind is too strong.The relationship between the characteristics of ISWs bands in optical remote sensing images and the wind speed is still unclear.The influence of wind speeds on the characteristics of the ISWs bands is investigated based on the physical simulation experiments with the wind speeds of 1.6,3.1,3.5,3.8,and 3.9 m/s.The experimental results show that when the wind speed is 3.9 m/s,the ISWs bands cannot be observed in optical remote sensing images with the stratification of h_(1)∶h_(2)=7∶58,ρ_(1)∶ρ_(2)=1∶1.04.When the wind speeds are 3.1,3.5,and 3.8 m/s,which is lower than 3.9 m/s,the ISWs bands can be obtained in the simulated optical remote sensing image.The location of the band’s dark and light extremum and the band’s peak-to-peak spacing are almost not affected by wind speed.More-significant wind speeds can cause a greater gray difference of the light-dark bands.This provided a scientific basis for further understanding of ISW optical remote sensing imaging.
