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Influence of mesoscale eddies on primary production in the South China Sea during spring inter-monsoon period 被引量:18
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作者 HU Zifeng TAN Yehui +4 位作者 SONG Xingyu ZHOU Linbin LIAN Xiping HUANG Liangmin HE Yinghui 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2014年第3期118-128,共11页
Mesoscale eddies have been suggested to have an impact on biological carbon fixation in the South China Sea (SCS). However, their overall contribution to primary production during the spring inter-monsoon pe riod is... Mesoscale eddies have been suggested to have an impact on biological carbon fixation in the South China Sea (SCS). However, their overall contribution to primary production during the spring inter-monsoon pe riod is still unknown. Based on large-scale biological and environmental in situ observations and synchro nous remote sensing data, the distribution patterns of phytoplankton biomass and the primary production, and the role of mesoscale eddies in regulating primary production in different eddy-controlled waters were investigated. The results suggested that the surface chlorophyll a concentrations and water column inte grated primary production (IPP) are significantly higher in cyclonic eddies and lower in the anticyclonic eddies as compared to that in non-eddy waters. Although eddies could affect various environmental factors, such as nutrients, temperature and light availability, nutrient supply is suggested to be the most important one through which mesoscale eddies regulated the distribution patterns of phytoplankton biomass and pri mary production. The estimated IPP in cyclonic and anticyclonic eddies are about 29.5% higher and 16.6% lower than the total average in the whole study area, respectively, indicating that the promotion effect of mesoscale cold eddies on the primary production was much stronger than the inhibition effect of the warm eddies per unit area. Overall, mesoscale eddies are crucial physical processes that affect the biological car bon fixation and the distribution pattern of primary production in the SCS open sea, especially during the spring inter-monsoon period. 展开更多
关键词 mesoscale eddies chlorophyll a primary production vertically generalized production model remote sensing South China Sea
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Mesoscale eddies in the South China Sea and their impact on temperature profiles 被引量:11
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作者 WANGGuihua SUJilan LIRongfeng 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2005年第1期39-45,共7页
Some life history statistics of the mesoscale eddies of the South China Sea (SCS) derived from altimetry data will be further discussed according their different formation periods. A total of three ATLAS (autonomous t... Some life history statistics of the mesoscale eddies of the South China Sea (SCS) derived from altimetry data will be further discussed according their different formation periods. A total of three ATLAS (autonomous temperature line acquisition system)mooring buoys data will be analyzed to discuss eddies' impact on temperature profiles.They identify that the intraseasonal variation of SCS thermocline is partly controlled by mesoscale eddies. 展开更多
关键词 mesoscale eddies ATLAS South China Sea
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Seasonal variability of mesoscale eddies in the Banda Sea inferred from altimeter data 被引量:4
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作者 Baiyang Chen Lingling Xie +4 位作者 Quanan Zheng Lei Zhou Lei Wang Baoxin Feng Zipeng Yu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2020年第12期11-20,共10页
Using the mesoscale eddy trajectory atlas product derived from satellite altimeter data from 1993 to 2016,this study analyzes statistical characteristics and seasonal variability of mesoscale eddies in the Banda Sea o... Using the mesoscale eddy trajectory atlas product derived from satellite altimeter data from 1993 to 2016,this study analyzes statistical characteristics and seasonal variability of mesoscale eddies in the Banda Sea of the Indonesian seas.The results show that there were 147 mesoscale eddies that occurred in the Banda Sea,of which 137 eddies were locally generated and 10 originated from outside.The total numbers of cyclonic eddies(CEs,clockwise)and anticyclonic eddies(AEs,anticlockwise)are 76 and 71,respectively.Seasonally,the number of CEs(AEs)is twice larger than the number of AEs(CEs)in winter(summer).In winter,CEs are distributed in the southern and AEs in the northern basins,respectively,but the opposite thing occurs in summer,i.e.,the polarities of mesoscale eddies observed at the same location reverse seasonally.The mechanisms of polarity distribution reversal(PDR)of mesoscale eddies are examined with reanalysis data of ocean currents and winds.The results indicate that the basin-scale vorticity,wind stress curl,and the meridional shear of zonal current reverse seasonally,which are favorable to the PDR of mesoscale eddies.The possible generation mechanisms of mesoscale eddies include direct wind forcing,barotropic and baroclinic instabilities,of which the direct wind forcing should play the dominant role. 展开更多
关键词 mesoscale eddies polarity distribution reversal(PDR) meridional shear Banda Sea Indonesian seas
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Mean properties of mesoscale eddies in the Kuroshio recirculation region 被引量:3
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作者 马利斌 王强 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2014年第3期681-702,共22页
Using a 19-year altimetric dataset, the mean properties and spatiotemporal variations of eddies in the Kuroshio recirculation region are examined. A total of 2 001 cyclonic tracks and 1 847 anticyclonic tracks were id... Using a 19-year altimetric dataset, the mean properties and spatiotemporal variations of eddies in the Kuroshio recirculation region are examined. A total of 2 001 cyclonic tracks and 1 847 anticyclonic tracks were identifi ed using a geometry-based eddy detection method. The mean radius was 57 km for cyclonic eddies and was 61 km for anticyclonic eddies, respectively, and the mean lifetime was about 10 weeks for both type eddies. There were asymmetric spatial distributions for eddy generation and eddy termination, which were domain-dependent. Mean eddy generation rates were 2.0 per week for cyclonic eddies and were 1.9 per week for anticyclonic eddies. Both type eddies tended to deform during their lifetime and had different propagation characteristics, which mainly propagated westward and southwestward with velocities 4.0–9.9 cm/s, in the Kuroshio recirculation region. Further discussion illustrates that the eddy westward speed maybe infl uenced by the combined effect of vertical shear of horizontal currents and nonlinearity of eddy. To better understand the evolution of eddy tracks, a total of 134 long-lived tracks(lifetime ≥20 weeks) were examined. Comparison between short-span eddies(lifetime ≥4 weeks and <20 weeks) and long-lived eddies is also conducted and the result shows that the short-span and long-lived eddies have similar time evolution. Finally, eddy seasonal variations and interannual changes are discussed. Correlation analysis shows that eddy activity is sensitive to the wind stress curl and meridional gradient of sea surface temperature on interannual timescales. Besides, the strength and orientation of background fl ows also have impacts on the eddy genesis. 展开更多
关键词 mesoscale eddies spatial distributions temporal variations potential factors
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Inversion of the three-dimensional temperature structure of mesoscale eddies in the Northwest Pacific based on deep learning 被引量:3
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作者 Fangjie Yu Zeyuan Wang +1 位作者 Shuai Liu Ge Chen 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第10期176-186,共11页
Mesoscale eddies,which are mainly caused by baroclinic effects in the ocean,are common oceanic phenomena in the Northwest Pacific Ocean and play very important roles in ocean circulation,ocean dynamics and material en... Mesoscale eddies,which are mainly caused by baroclinic effects in the ocean,are common oceanic phenomena in the Northwest Pacific Ocean and play very important roles in ocean circulation,ocean dynamics and material energy transport.The temperature structure of mesoscale eddies will lead to variations in oceanic baroclinity,which can be reflected in the sea level anomaly(SLA).Deep learning can automatically extract different features of data at multiple levels without human intervention,and find the hidden relations of data.Therefore,combining satellite SLA data with deep learning is a good way to invert the temperature structure inside eddies.This paper proposes a deep learning algorithm,eddy convolution neural network(ECN),which can train the relationship between mesoscale eddy temperature anomalies and sea level anomalies(SLAs),relying on the powerful feature extraction and learning abilities of convolutional neural networks.After obtaining the temperature structure model through ECN,according to climatic temperature data,the temperature structure of mesoscale eddies in the Northwest Pacific is retrieved with a spatial resolution of 0.25°at depths of 0–1000 m.The overall accuracy of the ECN temperature structure is verified using Argo profiles at the locations of cyclonic and anticyclonic eddies during 2015–2016.Taking 10%error as the acceptable threshold of accuracy,89.64%and 87.25%of the cyclonic and anticyclonic eddy temperature structures obtained by ECN met the threshold,respectively. 展开更多
关键词 mesoscale eddies temperature structure convolutional neural network Northwest Pacific Ocean
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Automatic detection of oceanic mesoscale eddies in the South China Sea 被引量:1
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作者 夏琼 申辉 《Chinese Journal of Oceanology and Limnology》 SCIE CAS CSCD 2015年第5期1334-1348,共15页
This study focuses on the spatial and temporal distribution characteristics of mesoscale eddies in the South China Sea(SCS). An automatic eddy detection method,based on the geometry of velocity vectors,was adopted to ... This study focuses on the spatial and temporal distribution characteristics of mesoscale eddies in the South China Sea(SCS). An automatic eddy detection method,based on the geometry of velocity vectors,was adopted to obtain an eddy dataset from 21 years of satellite altimeter data. Analysis revealed that the number of anticyclonic eddies was nearly equal to cyclonic eddies; in the SCS,cyclonic eddies are generally stronger than anticyclonic eddies and anticyclonic eddies are larger and longer-lived than cyclonic eddies. Anticyclonic eddies tend to survive longer in the spring and summer,while cyclonic eddies have longer lifetimes in the autumn and winter. The characteristics and seasonal variations of eddies in the SCS are strongly related to variations in general ocean circulation,in the homogeneity of surface wind stress,and in the unevenness of bottom topography in the SCS. The spatial and temporal variation of mesoscale eddies in the SCS could,therefore,be an important index for understanding local hydrodynamics and regional climate change. 展开更多
关键词 South China Sea mesoscale eddies eddy detection ALTIMETER STATISTICS
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Three-dimensional characteristics of mesoscale eddies simulated by a regional model in the northwestern Pacific Ocean during 2000–2008 被引量:1
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作者 Guijing Yang Xiayan Lin +3 位作者 Guoqing Han Yu Liu Gengxin Chen Jianhui Wang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2022年第10期74-93,共20页
Mesoscale eddies play vital roles in ocean processes.Although previous studies focused on eddy surface features and individual three-dimensional(3D)eddy cases in the northwestern Pacific Ocean,the analysis of unique e... Mesoscale eddies play vital roles in ocean processes.Although previous studies focused on eddy surface features and individual three-dimensional(3D)eddy cases in the northwestern Pacific Ocean,the analysis of unique eddy3D regional characteristics is still lacking.A 3D eddy detection scheme is applied to 9 years(2000-2008)of eddyresolving Regional Ocean Modeling System(ROMS)output to obtain a 3D eddy dataset from the surface to a depth of 1000 m in the northwestern Pacific Ocean(15°-35°N,120°-145°E).The 3D characteristics of mesoscale eddies are analyzed in two regions,namely,Box1(Subtropical Countercurrent,15°-25°N,120°-145°E)and Box2(Southern Kuroshio Extension,25°-35°N,120°-145°E).In Box1,the current is characterized by strong vertical shear and weak horizontal shear.In Box2,the current is characterized by the strong Kuroshio,topographic effect,and the westward propagation of Rossby waves.The results indicate the importance of baroclinic instability in Box1,whereas in Box2,both the barotropic and baroclinic instability are important.Moreover,the mesoscale eddies’properties in Box1 and Box2 are distinct.The eddies in Box1 have larger number and radius but a shorter lifetime.By contrast,Box2 has fewer eddies,which have smaller radius but longer lifetime.Vertically,more eddies are detected at the subsurface than at the surface in both regions;the depth of 650 m is the turning point in Box1.Above this depth,the number of cyclonic eddies(CEs)is larger than that of anticyclonic eddies(AEs).In Box2,the number of CEs is dominant vertically.Eddy kinetic energy(EKE)and mean normalized relative vorticity in Box2are significantly higher than those in Box1.With increasing depth,the attenuation trend of EKE and relative vorticity of Box1 become greater than those of Box2.Furthermore,the upper ocean(about 300 m in depth)contains 68.6%of the eddies(instantaneous eddy).Only 16.6%of the eddies extend to 1000 m.In addition,about87%of the eddies are bowl-shaped eddies in the two regions.Only about 3%are cone-shaped eddies.With increasing depth of the eddies,the proportion of bowl-shaped eddies gradually decreases.Conversely,the coneand lens-shaped eddies are equal in number at 700-1000 m,accounting for about 30%each.Studying the 3D characteristics of eddies in two different regions of the northwestern Pacific Ocean is an important stepping stone for discussing the different eddy generation mechanisms. 展开更多
关键词 three-dimensional structures mesoscale eddies northwestern Pacific Ocean
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Model Simulations of Mesoscale Eddies and Deep Convection in the Labrador Sea
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作者 Jieshun ZHU Entcho DEMIROV +1 位作者 Ying ZHANG Ania POLOMSKA-HARLICK 《Advances in Atmospheric Sciences》 SCIE CAS CSCD 2014年第4期743-754,共12页
Deep convection in the Labrador Sea is confined within a small region in the southwest part of the basin.The strength of deep convection in this region is related to the local atmospheric and ocean characteristics,whi... Deep convection in the Labrador Sea is confined within a small region in the southwest part of the basin.The strength of deep convection in this region is related to the local atmospheric and ocean characteristics,which favor processes of deep convection preconditioning and intense air-sea exchange during the winter season.In this study,we explored the effect of eddy-induced flux transport on the stratification of the Labrador Sea and the properties of deep convection.Simulations from an eddy-resolving ocean model are presented for the Labrador Sea.The general circulation was well simulated by the model,including the seasonal cycle of the deep Labrador Current.The simulated distribution of the surface eddy kinetic energy was also close to that derived from Topex-Poseidon satellite altimeter data,but with smaller magnitude.The energy transfer diagnostics indicated that Irminger rings are generated by both baroclinic and barotropic processes; however,when they propagate into the interior basin,the barotropic process also disperses them by converting the eddy energy to the mean flow.In contrast to eddy-permitting simulations,deep convection in the Labrador Sea was better represented in the eddyresolving model regarding their lateral position.Further analysis indicated that the improvement might be due to the lateral eddy flux associated with the resolved Irminger rings in the eddy-resolving model,which contributes to a realistic position of the isopycnal dome in the Labrador Sea and correspondingly a realistic site of deep convection. 展开更多
关键词 mesoscale eddies deep convection labrador Sea model simulation
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Contribution of Mesoscale Eddies to the Subduction and Transport of North Pacific Eastern Subtropical Mode Water
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作者 YANG Zhitong LUO Yiyong 《Journal of Ocean University of China》 SCIE CAS CSCD 2020年第1期36-46,共11页
This study investigates the contribution of mesoscale eddies to the subduction and transport of North Pacific Eastern Subtropical Mode Water(ESTMW)using the high-frequency output of an eddy-resolved ocean model spanni... This study investigates the contribution of mesoscale eddies to the subduction and transport of North Pacific Eastern Subtropical Mode Water(ESTMW)using the high-frequency output of an eddy-resolved ocean model spanning the period 1994–2010.Results show that the subduction induced by mesoscale eddies accounts for about 31%of the total subduction of ESTMW formation.The volume of ESTMW trapped by anticyclonic eddies is slightly larger than that trapped by cyclonic eddies.The ESTMW trapped by all eddies in May reaches up to about 2.8×1013m3,which is approximately 16%of the total ESTMW volume.The eddy-trapped ESTMW moves primarily westward,with its meridional integration at 18°–30°N reaching about 0.17Sv,which is approximately 18%of the total zonal ESTMW transport in this direction,at 140°W.This study highlights the important role of eddies in carrying ESTMW westward over the northeastern Pacific Ocean. 展开更多
关键词 mesoscale eddies SUBDUCTION TRANSPORT North Pacific Eastern Subtropical Mode Water
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Mesoscale eddies and their dispersive environmental impacts in the Persian Gulf
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作者 Amin Raeisi Abbasali Bidokhti +1 位作者 Seyed Mohammad Jafar Nazemosadat Kamran Lari 《Chinese Physics B》 SCIE EI CAS CSCD 2020年第8期363-371,共9页
As the mesoscale eddies in oceans and semi-enclosed seas are significant in horizontal dispersion of pollutants,we investigate the seasonal variations of these eddies in the Persian Gulf(PG)that are usually generated ... As the mesoscale eddies in oceans and semi-enclosed seas are significant in horizontal dispersion of pollutants,we investigate the seasonal variations of these eddies in the Persian Gulf(PG)that are usually generated due to seasonal winds and baroclinic instability.The sea surface height(SSH)data from 2010 to 2014 of AVISO are used to identify and track eddies,using the SSH-based method.Then seasonal horizontal dispersion coefficients are estimated for the PG,using the properties of eddies.The results show an annual mean of 78 eddies with a minimum lifetime of one week.Most of the eddies are predominantly cyclonic(59.1%)and have longer lifetimes and higher diffusion coefficients than the anti-cyclonic eddies.The eddy activity is higher in warm seasons,compared to that of cold seasons.As locations with high eddy diffusion coefficients are high-risk areas by using maps of horizontal eddy diffusion coefficients,perilous times and locations of the release of pollutants are specified to be within the longitude from 51.38°E to 55.28°E.The mentioned areas are located from the Strait of Hormuz towards the northeast of the PG,closer to Iranian coast.Moreover,July can be considered as the most dangerous time of pollution release. 展开更多
关键词 Persian Gulf mesoscale eddies marine pollution horizontal eddy diffusion coefficient
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A three-dimensional ocean general circulation model for mesoscale eddies——Ⅱ Diagnostic analysis
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作者 Moto Ikeda 《Acta Oceanologica Sinica》 SCIE CAS CSCD 1997年第1期29-43,共15页
A three-dimensional density field associated with mesoscaie unstable waves generated by the 3-D, primitive-equation model (Wang and Ikeda, 1996) is provided to the quasi-geostrophic pressure tendency and ω-equations,... A three-dimensional density field associated with mesoscaie unstable waves generated by the 3-D, primitive-equation model (Wang and Ikeda, 1996) is provided to the quasi-geostrophic pressure tendency and ω-equations, and to the (ageostrophic) Q-vector equation. Diagnostic analyses, analogous to the approaches in meteorology: ω-equation and Q-vector method, are for the first time developed to examine the mesoscaie dynamical processes and mechanisms of the unstable waves propagating in the mid-latitude ocean. The weaknesses and strengths of these two diagnostic approaches are evaluated and compared to the model results. The Q-vector method is then recommended to diagnose the vertical motion associated with the mesoscaie dynamics from a hydrographic CTD (conductivity-temperature-depth) array, while the quasi-geostrophic equations produce some small-scale features (errors) in the diagnosed fields. 展开更多
关键词 Diagnostic analysis A three-dimensional ocean general circulation model for mesoscale eddies
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Modal Wave Number Spectrum for Mesoscale Eddies
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作者 KANG Ying, PENG LinhuiDepartment of Physics, Ocean University of China, Qingdao 266071, P.R.China 《Journal of Ocean University of Qingdao》 2003年第2期218-223,共6页
The variations of ocean environmental parameters invariably result in variations of local modal wave numbers of a sound pressure field. The asymptotic Hankel transform with a short sliding window is applied to the com... The variations of ocean environmental parameters invariably result in variations of local modal wave numbers of a sound pressure field. The asymptotic Hankel transform with a short sliding window is applied to the complex sound pressure field in the water containing a mesoscale eddy to examine the variation of local modal wave numbers in such a range-dependent environment. The numerical simulation results show that modal wave number spectra obtained by this method can reflect the location and strength of a mesoscale eddy, therefore it can be used to monitor the strength and spatial scale of ocean mesoscale eddies. 展开更多
关键词 nomal mode wave number spectrum mesoscale eddies
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Derivation of the thermal characteristics of mesoscale eddies
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作者 CHEN Xuan PAN Jing +2 位作者 ZHENG Chongwei ZHANG Xi HE Ming 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2017年第3期8-13,共6页
This study aims at explaining the relationship between thermodynamic characteristics and direction of rotation of mesoscale eddies(MEs). The geometric characteristics of the MEs are under the following assumptions:... This study aims at explaining the relationship between thermodynamic characteristics and direction of rotation of mesoscale eddies(MEs). The geometric characteristics of the MEs are under the following assumptions: the structure of the MEs is symmetrical, and changes of oceanic physical variables are close to linear features in the radial direction in the ME regions. Based on these assumptions, by using primitive equations without friction under a cylindrical coordinate system, the thermodynamic characteristics of the MEs are derived, showing that the conventional relationship of warm anticyclonic eddies with high sea surface height(SSH) and cold cyclonic eddies with low SSH is not consistent with the SSH and sea surface temperature(SST) observations of eddies. The results show that the symmetrical form is an ideal approximation for the geometric characteristics of MEs. In consideration of the above assumptions, there are advantages for derivation of the characteristics of the MEs under a cylindrical coordinate. 展开更多
关键词 mesoscale eddies thermodynamic characteristics symmetry
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A statistical analysis of mesoscale eddies in the Bay of Bengal from 22–year altimetry data 被引量:15
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作者 CUI Wei YANG Jungang MA Yi 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2016年第11期16-27,共12页
Eddy properties in the Bay of Bengal are studied from 22 a archiving, validation and interpretation of satellite oceanographic(AVISO) data using a sea level anomaly(SLA)-based eddy identification. A geographical d... Eddy properties in the Bay of Bengal are studied from 22 a archiving, validation and interpretation of satellite oceanographic(AVISO) data using a sea level anomaly(SLA)-based eddy identification. A geographical distribution and an eddy polarity, an eddy lifetime and propagation distances, eddy origins and terminations,eddy propagation directions and trajectories, eddy kinetic properties, the evolution of eddy properties,seasonal and interannual variabilities of eddy activities are analyzed in this area. Eddies exist principally in the western Bay of Bengal and most of them propagate westward. The polarity distribution of eddies shows cyclones prefer to occur in the northwest and south of the Bay of Bengal, while anticyclones mainly occur in the east of the bay. Five hundred and sixty-five cyclones and 389 anticyclones with the lifetime that exceeds 30 d are detected during the 22 a period, and there is a preference for the cyclones for all lifetime and propagation distances. The kinetic properties of all observed eddies show the average amplitude of the cyclones is larger than that of the anticyclones, whereas that is opposite for average radius, and their average velocities are basically the same. Moreover, the evolution of eddies properties reveals that the eddies with a long lifetime that exceeds 90 d have a significant double-stage feature of the former 50 d growth period and the dying period after 50 d. For the seasonal variability of the eddies, the cyclones occur more often in spring while the anticyclones occur more often in summer. The analysis of long-lived eddy seasonal distributions shows that there is the obvious seasonal variation of the eddy activities in the Bay of Bengal. The interannual variability of an eddy number shows an obvious negative correlation with the EKE variation. 展开更多
关键词 mesoscale eddy altimetry data Bay of Bengal eddy characteristics seasonal variabilit3 interannual variability
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Characterizing the capability of mesoscale eddies to carry drifters in the northwest Pacific 被引量:6
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作者 WANG Huizan LIU Ding +2 位作者 ZHANG Weimin LI Jiaxun WANG Bo 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2020年第6期1711-1728,共18页
Mesoscale eddies are common oceanic phenomena.Although many related studies have been conducted,the ability for mesoscale eddies to carry real particles remains poorly addressed.We considered the drifters as real part... Mesoscale eddies are common oceanic phenomena.Although many related studies have been conducted,the ability for mesoscale eddies to carry real particles remains poorly addressed.We considered the drifters as real particles to characterize the capability of mesoscale eddies to carry particles.Firstly,mesoscale eddies in the northwest Pacific(99°E-180°E,0°-66°N)were identified using sea level anomaly(SLA)data from 1993 to 2015.Secondly,three important parameters(the carrying days,the number of circles the drifter revolving around the eddy center,and the carrying distances)were calculated by colocalizing eddy data with drifters.Finally,statistical analysis and composite analysis were conducted,reflecting the capability of mesoscale eddies to carry particles.The mechanisms on the carrying capability of eddies were also discussed.Results show that(1)the motion of carried drifters reflects the upper limit of rotational speed of eddies that the drifters revolve around the eddy center by≤90°for one day in most cases;(2)the drifters tend to be carried for a longer time when their minimal distances to the eddy center measured with normalized distance are small;(3)there are two types of eddies(cyclonic and anticyclonic eddies)in different subregions of northwest Pacific,and each has a different carrying capability(on average,similar in the tropical ocean and Subtropical Countercurrent,cyclonic eddies tend to have stronger carrying capability in Southern Kuroshio Extension,and anticyclonic eddies tend to have stronger carrying capability in Northern Kuroshio Extension and Subarctic Gyre);(4)on average,the carried drifters tend to travel for a longer time around the normalized eddy radii ranging from 0.41 to 0.76;(5)the carrying days are related to the Rossby number of the eddy(in general when the Rossby number is smaller,the carrying days are longer). 展开更多
关键词 mesoscale eddy DRIFTER Rossby number composite analysis carrying capability
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Effects of mesoscale eddies on the internal solitary wave propagation 被引量:4
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作者 LIAO Guanghong YANG Chenghao +3 位作者 XU Xiaohua SHI Xingang YUAN Yaochu HUANG Weigen 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2012年第5期26-40,共15页
The mesoscale eddy and internal wave both are phenomena commonly observed in oceans. It is aimed to investigate how the presence of a mesoscale eddy in the ocean affects wave form deformation of the internal solitary ... The mesoscale eddy and internal wave both are phenomena commonly observed in oceans. It is aimed to investigate how the presence of a mesoscale eddy in the ocean affects wave form deformation of the internal solitary wave propagation. An ocean eddy is produced by a quasi-geostrophic model in f-plane, and the one-dimensional nonlinear variable-coefficient extended Korteweg-de Vries (eKdV) equation is used to simulate an internal solitary wave passing through the mesoscale eddy field. The results suggest that the mode structures of the linear internal wave are modified due to the presence of the mesoscale eddy field. A cyclonic eddy and an anticyclonic eddy have different influences on the background environment of the internal solitary wave propagation. The existence of a mesoscale eddy field has almost no prominent impact on the propagation of a smallamplitude internal solitary wave only based on the first mode vertical structure, but the mesoscale eddy background field exerts a considerable influence on the solitary wave propagation if considering high-mode vertical structures. Furthermore, whether an internal solitary wave first passes through anticyclonic eddy or cyclonic eddy, the deformation of wave profiles is different. Many observations of solitary internal waves in the real oceans suggest the formation of the waves. Apart from topography effect, it is shown that the mesoscale eddy background field is also a considerable factor which influences the internal solitary wave propagation and deformation. 展开更多
关键词 mesoscale eddy internal solitary wave variable-coefficient extended Korteweg-de Vries equation wave deformation
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Statistical characteristics and mechanisms of mesoscale eddies in the North Indian Ocean 被引量:2
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作者 Chunjian Sun Xidong Wang +3 位作者 Anmin Zhang Lianxin Zhang Caixia Shao Guosong Wang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2022年第5期27-40,共14页
The statistical characteristics and mechanisms of mesoscale eddies in the North Indian Ocean are investigated by adopting multi-sensor satellite data from 1993 to 2019.In the Arabian Sea(AS),seasonal variation of eddy... The statistical characteristics and mechanisms of mesoscale eddies in the North Indian Ocean are investigated by adopting multi-sensor satellite data from 1993 to 2019.In the Arabian Sea(AS),seasonal variation of eddy characteristics is remarkable,while the intraseasonal variability caused by planetary waves is crucial in the Bay of Bengal(BOB).Seasonal variation of the eddy kinetic energy(EKE)is distinct along the west boundary of AS,especially in the Somali Current region.In the BOB,larger EKE occurs at the northwest basin from March to May,to the east of Sri Lanka from June to September,and along the east coast of India from November to December.The wind stress work(WW)is further studied to figure out the direct influence of wind forcing on EKE.The WW exerts positive effects on EKE along the west boundary of AS and in the south of India/Sri Lanka during the two monsoon seasons.Besides,the WW also has impact on EKE along the east coast of India in November and December.Eventually,we investigate the characteristics and the driving mechanisms of long lifespan eddies.In the AS,long lifespan anti-cyclonic eddies(AEs)mainly generate in the Socotra,the West Indian Coastal Current and the East Arabian Current regions,while cyclonic eddies(CEs)are concentrated in the northwest region.In the BOB,long lifespan AEs mostly form near the west of Myanmar,while CEs are accumulated at the north and northwest basin.The instabilities caused by Rossby waves,coastal Kelvin waves,seasonal currents,together with wind stress forcing exert enormous efforts on the generation and evolution of these eddies. 展开更多
关键词 mesoscale eddy eddy characteristics North Indian Ocean satellite altimeter
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Distribution of reactive aluminum under the influence of mesoscale eddies in the western South China Sea 被引量:1
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作者 LIU Jiaxing ZHOU Linbin +5 位作者 TAN Yehui WANG Qionga HU Zifeng LI Jiajun JIANG Xin KE Zhixin 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2017年第6期95-103,共9页
To understand the distribution of aluminum (A1) under the influence of mesocale eddies in the western South China Sea (SCS), sea level anomaly, geostrophic current, environmental parameters and reactive A1 were in... To understand the distribution of aluminum (A1) under the influence of mesocale eddies in the western South China Sea (SCS), sea level anomaly, geostrophic current, environmental parameters and reactive A1 were investigated in the western SCS in August 2013. The highest reactive A1 concentration ((180±64) nmol/L) was observed in the surface waters, indicating a substantial atmospheric input. Vertically, the reactive A1 decreased from the surface high concentration to the subsurface minima at the depth of chlorophyll a (Chl a) maxima and then increased again with depth at most of the stations. The average concentration of reactive A1 in the upper 100 m water column was significantly lower in the cyclonic eddy ((137±6) nmol/L) as compared with that in the non- eddy waters ((180±21) nmol/L). By contrast, the average concentrations of Chl a and silicate in the upper 100 m water column were higher in the cyclonic eddy and lower in the anticyclonic eddy. There was a significant negative correlation between the average concentrations of reactive Al and Chl a in the upper 100 m water column. The vertical distribution of reactive AI and the negative correlation between reactive A1 and Chl a both suggest that the reactive A1 in the upper water column was significantly influenced by biological removal processes. Our results indicate that mesoscale eddies could regulate the distribution of reactive A1 by influencing the primary production and phytoplankton community structure in the western SCS. 展开更多
关键词 reactive aluminum mesoscale eddy chlorophyll a biological removal PHYTOPLANKTON primaryproduction western South China Sea
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Statistical characteristics and thermohaline properties of mesoscale eddies in the Bay of Bengal 被引量:1
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作者 Wei Cui Chaojie Zhou +1 位作者 Jie Zhang Jungang Yang 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2021年第4期10-22,共13页
The statistical characteristics and vertical thermohaline properties of mesoscale eddies in the Bay of Bengal are studied from the view of satellite altimetry data and Argo profiles.Eddy propagation preferences in dif... The statistical characteristics and vertical thermohaline properties of mesoscale eddies in the Bay of Bengal are studied from the view of satellite altimetry data and Argo profiles.Eddy propagation preferences in different lifetimes,eddy evolution process,and geographical distribution of eddy kinetic properties are analyzed in this area.Eddies exist principally in the western Bay of Bengal,and most of them propagate westward.There is a clear southward(equatorward)preference for eddies with long lifetimes,especially for cyclones.Moreover,the eddies in different areas of the bay show different north-southward preferences.Evolution of eddy kinetic properties with lifetime shows that eddies have the significant three-stage feature:the growth period in the former one-fifth lifetime,the stable period in the middle two-fifth to four-fifth lifetime,and the dying period in the last one-fifth lifetime.Large-amplitude and high-intensity eddies occur only in the relatively confined regions of highly unstable currents,such as the East Indian Coastal Current and eastern Sri Lanka.Based on Argo profile data and climatology data,the eddy synthesis method was used to construct three-dimensional temperature and salt structures of eddies in this area.The mean temperature anomaly is negative/positive to the cyclonic/anticyclonic eddies in the upper 300×10^(4)Pa,and below this depth,the anomaly becomes weak.The salinity structures of positive anomalies inside cyclonic eddies and negative anomalies inside anticyclonic eddies in the Bay of Bengal are not consistent with other regions.Due to the special characteristics of the water mass in the bay,especially under the control of the low-salinity Bay of Bengal water at the surface and the Indian equatorial water in the deep ocean,the salinity of seawater shows a monotonic increase with depth.For regional varieties of temperature and salinity structures,as the eddies move westward,the temperature anomaly induced by the eddies increases,the effecting depth of the eddies deepens,and the salinity structures are more affected by inflows.In the north-south direction,the salinity structures of the eddies are associated with the local water masses,which comprise lowsalinity water in the northern bay due to the inflow of freshwater from rivers and salty water in the southern bay due to the invasion of Arabian Sea high-salinity water from the north Indian Ocean. 展开更多
关键词 mesoscale eddy Bay of Bengal thermohaline structures satellite altimetry Argo data
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Tracking the evolution processes and behaviors of mesoscale eddies in the South China Sea:a global nearest neighbor filter approach 被引量:1
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作者 YI Jiawei DU Yunyan +1 位作者 WANG Dongxiao ZHOU Chenghu 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2017年第11期27-37,共11页
The eddy tracking approach is developed using the global nearest neighbor filter(GNNF) to investigate the evolution processes and behaviors of mesoscale eddies in the South China Sea(SCS). Combining the Kalman fil... The eddy tracking approach is developed using the global nearest neighbor filter(GNNF) to investigate the evolution processes and behaviors of mesoscale eddies in the South China Sea(SCS). Combining the Kalman filter and optimal data association technologies, the GNNF algorithm is able to reduce pairing errors to 0.2% in tracking synthetic eddy tracks, outperforming other existing methods. A total of 4 913 eddy tracks that last more than a week are obtained by the GNNF during 1993–2012. The analysis of a growth and a decay based on 3 445 simple eddy tracks show that eddy radius, amplitude, and vorticity smoothly increase during the first half of lifetime and decline during the second half following a parabola opening downwards. The genesis of eddies mainly clusters northwest and southwest of Luzon Island whereas the dissipations concentrate the Xisha Islands where the underwater bay traps and terminates eddies. West of the Luzon Strait, northwest of Luzon Island, and southeast of Vietnam are regions where eddy splits and mergers are frequently observed. Short disappearances mainly distribute in the first two regions. Moreover, eddy splits generally result in a decrease of the radius and the amplitude whereas eddy mergers induce growing up. Eddy intensity and vorticity, on the contrary, are strengthened in the eddy splits and diminished in mergers. 展开更多
关键词 mesoscale ocean eddies eddy tracking eddy split eddy merger South China Sea
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