The Indonesian Throughflow(ITF),mainly through the Makassar Strait,transports amounts of water and salt from the tropical Pacific Ocean to the Indian Ocean,playing a crucial role in modulating heat and energy budget b...The Indonesian Throughflow(ITF),mainly through the Makassar Strait,transports amounts of water and salt from the tropical Pacific Ocean to the Indian Ocean,playing a crucial role in modulating heat and energy budget between two oceans.The South China Sea Throughflow(SCSTF)significantly contributes to the net transport of the ITF via Karimata Strait and Mindoro-Sibutu Passage.However,the specific proportion and variability of South China Sea(SCS)water joining the ITF are still unclear.Based on high-resolution reanalysis data and a Lagrangian particle tracking method-Connectivity Modelling System(CMS),we quantified the proportion and variability of SCS water joining the ITF in the Makassar Strait.The results show that about 16.41%of the particles released in the Makassar Strait could be back-tracked from the SCS and 42.45%from the western Pacific Ocean.The particles through Mindoro Strait and Karimata Strait are about 10.55%and 3.39%,respectively.About 14.56%and 15.42%particles are trapped in the Sulu and Sulawesi seas.The proportion of SCS water shows significant interannual variability,which is highly related to El Niño-Southern Oscillation(ENSO)events.The correlation coefficient between interannual change of SCS water volume proportion and the Niño 3.4 index is 0.75,with an increase of about 24%during El Niño years and a decrease of about−22%during La Niña years.The proportion also varies with the depth of particles released,showing two peaks at surface and subsurface depths of 5 m and 110 m,respectively.展开更多
The Indonesian Throughflow(ITF)plays important roles in global ocean circulation and climate systems.Previous studies suggested the ITF interannual variability is driven by both the El Niño-Southern Oscillation(E...The Indonesian Throughflow(ITF)plays important roles in global ocean circulation and climate systems.Previous studies suggested the ITF interannual variability is driven by both the El Niño-Southern Oscillation(ENSO)and the Indian Ocean Dipole(IOD)events.The detailed processes of ENSO and/or IOD induced anomalies impacting on the ITF,however,are still not clear.In this study,this issue is investigated through causal relation,statistical,and dynamical analyses based on satellite observation.The results show that the driven mechanisms of ENSO on the ITF include two aspects.Firstly,the ENSO related wind field anomalies driven anomalous cyclonic ocean circulation in the western Pacific,and off equatorial upwelling Rossby waves propagating westward to arrive at the western boundary of the Pacific,both tend to induce negative sea surface height anomalies(SSHA)in the western Pacific,favoring ITF reduction since the develop of the El Niño through the following year.Secondly,the ENSO events modulate equatorial Indian Ocean zonal winds through Walker Circulation,which in turn trigger eastward propagating upwelling Kelvin waves and westward propagating downwelling Rossby waves.The Rossby waves are reflected into downwelling Kelvin waves,which then propagate eastward along the equator and the Sumatra-Java coast in the Indian Ocean.As a result,the wave dynamics tend to generate negative(positive)SSHA in the eastern Indian Ocean,and thus enhance(reduce)the ITF transport with time lag of 0-6 months(9-12 months),respectively.Under the IOD condition,the wave dynamics also tend to enhance the ITF in the positive IOD year,and reduce the ITF in the following year.展开更多
The Indonesian Throughflow(ITF), which connects the tropical Pacific and Indian oceans, plays important roles in the inter-ocean water exchange and regional or even global climate variability. The Makassar Strait is t...The Indonesian Throughflow(ITF), which connects the tropical Pacific and Indian oceans, plays important roles in the inter-ocean water exchange and regional or even global climate variability. The Makassar Strait is the main inflow passage of the ITF, carrying about 77% of the total ITF volume transport. In this study, we analyze the simulated ITF in the Makassar Strait in the Simple Ocean Data Assimilation version 3(SODA3) datasets. A total of nine ensemble members of the SODA3 datasets, of which are driven by different surface forcings and bulk formulas, and with or without data assimilation, are used in this study. The annual mean water transports(i.e.,volume, heat and freshwater) are related to the combination of surface forcing and bulk formula, as well as whether data assimilation is employed. The phases of the seasonal and interannual variability in water transports cross the Makassar Strait, are basically consistent with each other among the SODA3 ensemble members. The interannual variability in Makassar Strait volume and heat transports are significantly correlated with El Ni?oSouthern Oscillation(ENSO) at time lags of-6 to 7 months. There is no statistically significant correlation between the freshwater transport and the ENSO. The Makassar Strait water transports are not significantly correlated with the Indian Ocean Dipole(IOD), which may attribute to model deficiency in simulating the propagation of semiannual Kelvin waves from the Indian Ocean to the Makassar Strait.展开更多
As an integral part of the internal air system of aero-engines,the axial throughflow of the cooling air can interact with the cavity flow between the rotating compressor disks,forming a threedimensional,unsteady,and u...As an integral part of the internal air system of aero-engines,the axial throughflow of the cooling air can interact with the cavity flow between the rotating compressor disks,forming a threedimensional,unsteady,and unstable flow field.The flow characteristics in an engine-like rotating multi-stage cavity with throughflow were investigated using particle image velocimetry,flow visualization technology and three-dimensional unsteady Reynolds-Averaged Navier-Stokes (RANS)simulations.The focus of current research was to understand the distribution of the mean swirl ratio and its variation with a wide range of non-dimensional parameters in the co-rotating cavity with high inlet pre-swirl axial throughflow.The maximum axial Reynolds number and rotational Reynolds numbers could reach 4.41×10^(4)and 1.24×10^(6),respectively.The velocity measurement results indicate that the mean swirl ratio is greater than 1 and decreases with an increase in the radial position.The flow structure is dominated by the Rossby number,and two different flow patterns (flow penetration and flow stratification) are identified and confirmed by flow visualization images.In the absence of buoyancy,the flow penetration caused by the precession of the throughflow makes it easier for the throughflow to reach a high radius region.Satisfactory consistency of results between measurements and numerical calculations is obtained.This study provides a theoretical basis and data support for toroidal vortex breakdown,which is of practical significance for the design of high-pressure compressor cavities.展开更多
印尼贯穿流连接热带太平洋和印度洋,对区域和全球气候系统至关重要,但在印尼贯穿流的长期变化研究中非常缺乏长时间序列。利用第六次国际耦合模式比较计划历史模拟数据对卷积神经网络深度学习模型进行训练和测试,基于海表面温度反演了...印尼贯穿流连接热带太平洋和印度洋,对区域和全球气候系统至关重要,但在印尼贯穿流的长期变化研究中非常缺乏长时间序列。利用第六次国际耦合模式比较计划历史模拟数据对卷积神经网络深度学习模型进行训练和测试,基于海表面温度反演了印尼贯穿流的体积输运。结果表明,该模型反演的印尼贯穿流可再现其总方差的80%左右。进而结合数据,首次构建了1870~2023年长达154 a的印尼贯穿流流量时间序列。通过与潜标观测数据对比发现,反演结果与国际努沙登拉层化和输运计划(the international Nusantara stratification and transport,INSTANT)、印尼贯穿流监测项目(monitoring Indonesian throughflow,MITF)观测数据的相关系数分别为0.56与0.69,验证了该时间序列的可靠性。使用梯度加权类激活映射(gradient-weighted class activation mapping,Grad-CAM)与注意力机制研究了该模型中影响印尼贯穿流反演技巧的敏感性区域。展开更多
Besides the Indonesian throughflow(ITF), the South China Sea throughflow(SCSTF) also contributes to the water transport from the Pacific to the Indian Ocean. However, this South China Sea(SCS) branch at the Karimata S...Besides the Indonesian throughflow(ITF), the South China Sea throughflow(SCSTF) also contributes to the water transport from the Pacific to the Indian Ocean. However, this South China Sea(SCS) branch at the Karimata Strait is poorly observed until 2007, even though its importance has been suggested by numerical studies for decades. In this paper, we review the nearly 10-year field measurement in the Karimata Strait by the execution of the projects of "SCS-Indonesian Seas Transport/Exchange(SITE) and Impacts on Seasonal Fish Migration" and "The Transport, Internal Waves and Mixing in the Indonesian Throughflow regions(TIMIT) and Impacts on Marine Ecosystem", which extend the observations from the western Indonesian seas to the east to include the main channels of the ITF, is introduced. Some major achievements from these projects are summarized.展开更多
The role of the Indonesian Throughflow （ITF） in the influence of the Indian Ocean Dipole （IOD） on ENSO is investigated using version 2 of the Parallel Ocean Program （POP2） ocean general circulation model. We dem...The role of the Indonesian Throughflow （ITF） in the influence of the Indian Ocean Dipole （IOD） on ENSO is investigated using version 2 of the Parallel Ocean Program （POP2） ocean general circulation model. We demonstrate the results through sensitivity experiments on both positive and negative IOD events from observations and coupled general circulation model simulations. By shutting down the atmospheric bridge while maintaining the tropical oceanic channel, the IOD forcing is shown to influence the ENSO event in the following year, and the role of the ITF is emphasized. During positive IOD events, negative sea surface height anomalies （SSHAs） occur in the eastern Indian Ocean, indicating the existence of upwelling. These upwelling anomalies pass through the Indonesian seas and enter the western tropical Pacific, resulting in cold anomalies there. These cold temperature anomalies further propagate to the eastern equatorial Pacific, and ultimately induce a La Nifia- like mode in the following year. In contrast, during negative IOD events, positive SSHAs are established in the eastern Indian Ocean, leading to downwelling anomalies that can also propagate into the subsurface of the western Pacific Ocean and travel further eastward. These downwelling anomalies induce negative ITF transport anomalies, and an E1 Nifio-like mode in the tropical eastern Pacific Ocean that persists into the following year. The effects of negative and positive IOD events on ENSO via the ITF are symmetric. Finally, we also estimate the contribution of IOD forcing in explaining the Pacific variability associated with ENSO via ITE展开更多
A quasi-global eddy permitting oceanic GCM, LICOM1.0, is run with the forcing of ERA40 daily wind stress from 1958 to 2001. The modelled Indonesian Throughflow (ITF) is reasonable in the aspects of both its water sour...A quasi-global eddy permitting oceanic GCM, LICOM1.0, is run with the forcing of ERA40 daily wind stress from 1958 to 2001. The modelled Indonesian Throughflow (ITF) is reasonable in the aspects of both its water source and major pathways. Compared with the observation, the simulated annual mean and seasonal cycle of the ITF transport are fairly realistic. The interannual variation of the tropical Pacific Ocean plays a more important role in the interannual variability of the ITF transport. The relationship between the ITF and the Indian Ocean Dipole (IOD) also reflects the influence of ENSO. However, the relationship between the ITF transport and the interannual anomalies in the Pacific and Indian Oceans vary with time. During some years, (e.g., 1994), the effect of a strong IOD on the ITF transport is more than that from ENSO.展开更多
Based on the high-resolution Eulerian fields of an ocean general circulation model simulation, the heat contribution of the Indonesian throughflow(ITF) to the Indian Ocean is estimated by Lagrangian tracing method.The...Based on the high-resolution Eulerian fields of an ocean general circulation model simulation, the heat contribution of the Indonesian throughflow(ITF) to the Indian Ocean is estimated by Lagrangian tracing method.The heat transport of each particle of ITF waters is calculated by tracing temperature change along the trajectory until the particle exits the Indian Ocean. The simulation reveals that the ITF waters flow westward and branch near Madagascar, further showing the ITF waters are redistributed in both northern and southern Indian Ocean.Heat budget analysis indicates that the ITF waters gain 0.41 PW(Petawatts, 1015 W) in the northern Indian Ocean and lose 0.56 PW in the southern Indian Ocean, respectively. As a result, the ITF waters warm the whole Indian Ocean basin with only 0.15 PW, which shows an "insignificant" role of ITF on the Indian Ocean because of the heat exchange compensation between northern and southern Indian Ocean. Furthermore, the tracing pathways show that the ITF waters mainly flow out the Indian Ocean at both sides of the basin via Agulhas Current and Leeuwin Current. About 89% of the ITF waters leave along western boundary and the rest 11% along eastern boundary. Compared to seeding section, 0.10 PW and 0.05 PW are released to the Indian Ocean, respectively.展开更多
In this study the interannual variability of the upper-ocean heat content in the South China Sea （SCS） was revisited using simple ocean data assimilation （SODA） combined with objective analyzed data sets that incl...In this study the interannual variability of the upper-ocean heat content in the South China Sea （SCS） was revisited using simple ocean data assimilation （SODA） combined with objective analyzed data sets that included the horizontal and vertical structures. The results confirmed that the upper-ocean heat content in the SCS is lower than normal during the mature phase of E1 Nifio events, and two super E1 Nifio events, 1982/1983 and 1997/1998 were also included. The variability of the heat content was consistent with the variability of the dynamic height anomalies. The SCS throughflow （SCSTF） plays an important role in regulating the interannual variability of the heat content, especially during the mature phase of E1 Nifio events.展开更多
Changes in the Indonesian Throughflow （ITF） and the South China Sea throughflow-measured by the Luzon Strait Transport （LST）-associated with the 1976/77 regime shift are analyzed using the Island Rule theory and t...Changes in the Indonesian Throughflow （ITF） and the South China Sea throughflow-measured by the Luzon Strait Transport （LST）-associated with the 1976/77 regime shift are analyzed using the Island Rule theory and the Simple Ocean Data Assimilation dataset. Results show that LST increased but ITF transport decreased after 1975. Such changes were induced by variations in wind stress associated with the regime shift. The strengthening of the easterly wind anomaly east of the Luzon Strait played an important role in the increase of LST after 1975, while the westerly wind anomaly in the equatorial Pacific contributed significantly to the decrease in ITF transport after 1975; accounting for 53% of the change. After 1975, the Kuroshio Current strengthened and the Mindanao Current weakened in response to a decrease in the total transport of the North Equatorial Current. Both the North Equatorial Countercurrent and the South Equatorial Current weakened after 1975, and an anomalous cyclonic circulation in the western equatorial Pacific prevented the tropical Pacific water from entering the Indian Ocean directly.展开更多
Prior studies have revealed that,as a part of the Pacific tropical gyre,the South China Sea throughflow（SCSTF） is strongly influenced by the Pacific low-latitude western boundary current（LLWBC）.In this study,ocean...Prior studies have revealed that,as a part of the Pacific tropical gyre,the South China Sea throughflow（SCSTF） is strongly influenced by the Pacific low-latitude western boundary current（LLWBC）.In this study,ocean general circulation model（OGCM） experiments with and without connection to the South China Sea（SCS） were performed to investigate the impact of the SCSTF on the Pacific LLWBC.These model experiments show that if the SCS is blocked,seasonal variability of the Kuroshio and Mindanao Current becomes stronger,and the meridional migration of the North Equatorial Current（NEC） bifurcation latitude is enhanced.Both in seasonal and interannual time scales,stronger Luzon Strait transport（LST） induces a stronger Kuroshio transport combined with a southward shift of the NEC bifurcation,which is unfavorable for a further increase of the LST;a weaker LST induces a weaker Kuroshio transport and a northward shifting NEC bifurcation,which is also unfavorable for the continuous decrease of the LST.展开更多
So far, large uncertainties of the Indonesian throughflow(ITF) reside in the eastern Indonesian seas, such as the Maluku Sea and the Halmahera Sea. In this study, the water sources of the Maluku Sea and the Halmahera ...So far, large uncertainties of the Indonesian throughflow(ITF) reside in the eastern Indonesian seas, such as the Maluku Sea and the Halmahera Sea. In this study, the water sources of the Maluku Sea and the Halmahera Sea are diagnosed at seasonal and interannual timescales and at different vertical layers, using the state-of-the-art simulations of the Ocean General Circulation Model(OGCM) for Earth Simulator(OFES). Asian monsoon leaves clear seasonal footprints on the eastern Indonesian seas. Consequently, the subsurface waters(around 24.5σ_θ and at ～150 m) in both the Maluku Sea and the Halmahera Sea stem from the South Pacific(SP) during winter monsoon, but during summer monsoon the Maluku Sea is from the North Pacific(NP), and the Halmahera Sea is a mixture of waters originating from the NP and the SP. The monsoon impact decreases with depth, so that in the Maluku Sea, the intermediate water(around 26.8σ_θ and at ～480 m) is always from the northern Banda Sea and the Halmahera Sea water is mainly from the SP in winter and the Banda Sea in summer. The deep waters(around27.2σ_θ and at ～1 040 m) in both seas are from the SP, with weak seasonal variability. At the interannual timescale,the subsurface water in the Maluku Sea originates from the NP/SP during El Ni?o/La Ni?a, while the subsurface water in the Halmahera Sea always originates from the SP. Similar to the seasonal variability, the intermediate water in Maluku Sea mainly comes from the Banda Sea and the Halmahera Sea always originates from the SP. The deep waters in both seas are from the SP. Our findings are helpful for drawing a comprehensive picture of the water properties in the Indonesian seas and will contribute to a better understanding of the ocean-atmosphere interaction over the maritime continent.展开更多
基金The Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)under contact No.SML2021SP309the National Natural Science Foundation of China under contract Nos 42276005,42430402,and 92158204.
文摘The Indonesian Throughflow(ITF),mainly through the Makassar Strait,transports amounts of water and salt from the tropical Pacific Ocean to the Indian Ocean,playing a crucial role in modulating heat and energy budget between two oceans.The South China Sea Throughflow(SCSTF)significantly contributes to the net transport of the ITF via Karimata Strait and Mindoro-Sibutu Passage.However,the specific proportion and variability of South China Sea(SCS)water joining the ITF are still unclear.Based on high-resolution reanalysis data and a Lagrangian particle tracking method-Connectivity Modelling System(CMS),we quantified the proportion and variability of SCS water joining the ITF in the Makassar Strait.The results show that about 16.41%of the particles released in the Makassar Strait could be back-tracked from the SCS and 42.45%from the western Pacific Ocean.The particles through Mindoro Strait and Karimata Strait are about 10.55%and 3.39%,respectively.About 14.56%and 15.42%particles are trapped in the Sulu and Sulawesi seas.The proportion of SCS water shows significant interannual variability,which is highly related to El Niño-Southern Oscillation(ENSO)events.The correlation coefficient between interannual change of SCS water volume proportion and the Niño 3.4 index is 0.75,with an increase of about 24%during El Niño years and a decrease of about−22%during La Niña years.The proportion also varies with the depth of particles released,showing two peaks at surface and subsurface depths of 5 m and 110 m,respectively.
基金The Fund of Laoshan Laboratory under contract No.LSKJ202202700the Basic Scientific Fund for National Public Research Institutes of China under contract No.2024Q02+1 种基金the National Natural Science Foundation of China under contract Nos 42076023 and 42430402the Global Change and Air-Sea InteractionⅡProject under contract No.GASI-01-ATP-STwin.
文摘The Indonesian Throughflow(ITF)plays important roles in global ocean circulation and climate systems.Previous studies suggested the ITF interannual variability is driven by both the El Niño-Southern Oscillation(ENSO)and the Indian Ocean Dipole(IOD)events.The detailed processes of ENSO and/or IOD induced anomalies impacting on the ITF,however,are still not clear.In this study,this issue is investigated through causal relation,statistical,and dynamical analyses based on satellite observation.The results show that the driven mechanisms of ENSO on the ITF include two aspects.Firstly,the ENSO related wind field anomalies driven anomalous cyclonic ocean circulation in the western Pacific,and off equatorial upwelling Rossby waves propagating westward to arrive at the western boundary of the Pacific,both tend to induce negative sea surface height anomalies(SSHA)in the western Pacific,favoring ITF reduction since the develop of the El Niño through the following year.Secondly,the ENSO events modulate equatorial Indian Ocean zonal winds through Walker Circulation,which in turn trigger eastward propagating upwelling Kelvin waves and westward propagating downwelling Rossby waves.The Rossby waves are reflected into downwelling Kelvin waves,which then propagate eastward along the equator and the Sumatra-Java coast in the Indian Ocean.As a result,the wave dynamics tend to generate negative(positive)SSHA in the eastern Indian Ocean,and thus enhance(reduce)the ITF transport with time lag of 0-6 months(9-12 months),respectively.Under the IOD condition,the wave dynamics also tend to enhance the ITF in the positive IOD year,and reduce the ITF in the following year.
基金The Fund of Laoshan Laboratory under contract No. LSKJ202202700the National Natural Science Foundation of China under contract Nos 42076023, 42076024 and 41876027the Global Change and Air-Sea Interaction Ⅱ Project under contract No.GASI-01-AIP-STwin。
文摘The Indonesian Throughflow(ITF), which connects the tropical Pacific and Indian oceans, plays important roles in the inter-ocean water exchange and regional or even global climate variability. The Makassar Strait is the main inflow passage of the ITF, carrying about 77% of the total ITF volume transport. In this study, we analyze the simulated ITF in the Makassar Strait in the Simple Ocean Data Assimilation version 3(SODA3) datasets. A total of nine ensemble members of the SODA3 datasets, of which are driven by different surface forcings and bulk formulas, and with or without data assimilation, are used in this study. The annual mean water transports(i.e.,volume, heat and freshwater) are related to the combination of surface forcing and bulk formula, as well as whether data assimilation is employed. The phases of the seasonal and interannual variability in water transports cross the Makassar Strait, are basically consistent with each other among the SODA3 ensemble members. The interannual variability in Makassar Strait volume and heat transports are significantly correlated with El Ni?oSouthern Oscillation(ENSO) at time lags of-6 to 7 months. There is no statistically significant correlation between the freshwater transport and the ENSO. The Makassar Strait water transports are not significantly correlated with the Indian Ocean Dipole(IOD), which may attribute to model deficiency in simulating the propagation of semiannual Kelvin waves from the Indian Ocean to the Makassar Strait.
文摘As an integral part of the internal air system of aero-engines,the axial throughflow of the cooling air can interact with the cavity flow between the rotating compressor disks,forming a threedimensional,unsteady,and unstable flow field.The flow characteristics in an engine-like rotating multi-stage cavity with throughflow were investigated using particle image velocimetry,flow visualization technology and three-dimensional unsteady Reynolds-Averaged Navier-Stokes (RANS)simulations.The focus of current research was to understand the distribution of the mean swirl ratio and its variation with a wide range of non-dimensional parameters in the co-rotating cavity with high inlet pre-swirl axial throughflow.The maximum axial Reynolds number and rotational Reynolds numbers could reach 4.41×10^(4)and 1.24×10^(6),respectively.The velocity measurement results indicate that the mean swirl ratio is greater than 1 and decreases with an increase in the radial position.The flow structure is dominated by the Rossby number,and two different flow patterns (flow penetration and flow stratification) are identified and confirmed by flow visualization images.In the absence of buoyancy,the flow penetration caused by the precession of the throughflow makes it easier for the throughflow to reach a high radius region.Satisfactory consistency of results between measurements and numerical calculations is obtained.This study provides a theoretical basis and data support for toroidal vortex breakdown,which is of practical significance for the design of high-pressure compressor cavities.
文摘印尼贯穿流连接热带太平洋和印度洋,对区域和全球气候系统至关重要,但在印尼贯穿流的长期变化研究中非常缺乏长时间序列。利用第六次国际耦合模式比较计划历史模拟数据对卷积神经网络深度学习模型进行训练和测试,基于海表面温度反演了印尼贯穿流的体积输运。结果表明,该模型反演的印尼贯穿流可再现其总方差的80%左右。进而结合数据,首次构建了1870~2023年长达154 a的印尼贯穿流流量时间序列。通过与潜标观测数据对比发现,反演结果与国际努沙登拉层化和输运计划(the international Nusantara stratification and transport,INSTANT)、印尼贯穿流监测项目(monitoring Indonesian throughflow,MITF)观测数据的相关系数分别为0.56与0.69,验证了该时间序列的可靠性。使用梯度加权类激活映射(gradient-weighted class activation mapping,Grad-CAM)与注意力机制研究了该模型中影响印尼贯穿流反演技巧的敏感性区域。
基金The National Key Research and Development Program of China under contract No.2016YFC1402604the Marine S&T Fund of Shandong Province for Pilot National Laboratory for Marine Science and Technology(Qingdao)under contract No.2015ASKJ01+4 种基金the SOA Program on Global Change and Air-Sea Interactions under contract Nos GASI-IPOVAI-03,GASI-IPOVAI-02 and GASI-IPOVAI-01-02the National Natural Science Foundation of China under contract Nos 40476025,41506036 and 41876027the NSFC-Shandong Joint Fund for Marine Science Research Centers under contract No.U1606405the Office of Naval Research of United States under contract No.N00014-08-01-0618the China-Indonesia Maritime Cooperation Fund
文摘Besides the Indonesian throughflow(ITF), the South China Sea throughflow(SCSTF) also contributes to the water transport from the Pacific to the Indian Ocean. However, this South China Sea(SCS) branch at the Karimata Strait is poorly observed until 2007, even though its importance has been suggested by numerical studies for decades. In this paper, we review the nearly 10-year field measurement in the Karimata Strait by the execution of the projects of "SCS-Indonesian Seas Transport/Exchange(SITE) and Impacts on Seasonal Fish Migration" and "The Transport, Internal Waves and Mixing in the Indonesian Throughflow regions(TIMIT) and Impacts on Marine Ecosystem", which extend the observations from the western Indonesian seas to the east to include the main channels of the ITF, is introduced. Some major achievements from these projects are summarized.
基金sponsored by the National Public Benefit (Meteorology) Research Foundation of China (Grant No. GYHY 201306018)
文摘The role of the Indonesian Throughflow （ITF） in the influence of the Indian Ocean Dipole （IOD） on ENSO is investigated using version 2 of the Parallel Ocean Program （POP2） ocean general circulation model. We demonstrate the results through sensitivity experiments on both positive and negative IOD events from observations and coupled general circulation model simulations. By shutting down the atmospheric bridge while maintaining the tropical oceanic channel, the IOD forcing is shown to influence the ENSO event in the following year, and the role of the ITF is emphasized. During positive IOD events, negative sea surface height anomalies （SSHAs） occur in the eastern Indian Ocean, indicating the existence of upwelling. These upwelling anomalies pass through the Indonesian seas and enter the western tropical Pacific, resulting in cold anomalies there. These cold temperature anomalies further propagate to the eastern equatorial Pacific, and ultimately induce a La Nifia- like mode in the following year. In contrast, during negative IOD events, positive SSHAs are established in the eastern Indian Ocean, leading to downwelling anomalies that can also propagate into the subsurface of the western Pacific Ocean and travel further eastward. These downwelling anomalies induce negative ITF transport anomalies, and an E1 Nifio-like mode in the tropical eastern Pacific Ocean that persists into the following year. The effects of negative and positive IOD events on ENSO via the ITF are symmetric. Finally, we also estimate the contribution of IOD forcing in explaining the Pacific variability associated with ENSO via ITE
基金This work was jointly supported by the Chinese Academy of Sciences“Innovation Program”under Grant No.KZCX2-SW-210the National Key Basic Research of China under Grant No.G2000078502the National Natural Science Foundation of China under Grant Nos.40233031,40375030,and 40405017.
文摘A quasi-global eddy permitting oceanic GCM, LICOM1.0, is run with the forcing of ERA40 daily wind stress from 1958 to 2001. The modelled Indonesian Throughflow (ITF) is reasonable in the aspects of both its water source and major pathways. Compared with the observation, the simulated annual mean and seasonal cycle of the ITF transport are fairly realistic. The interannual variation of the tropical Pacific Ocean plays a more important role in the interannual variability of the ITF transport. The relationship between the ITF and the Indian Ocean Dipole (IOD) also reflects the influence of ENSO. However, the relationship between the ITF transport and the interannual anomalies in the Pacific and Indian Oceans vary with time. During some years, (e.g., 1994), the effect of a strong IOD on the ITF transport is more than that from ENSO.
基金The Strategic Priority Research Program of Chinese Academy of Sciences under contract Nos XDA20060502 and XDA11010301the National Key Research and Development Program of China under contract No.2016YFC1401401+2 种基金the National Natural Science Foundation of China under contract Nos 41676013,41521005 and 41731173the Independent Research Project Program of State Key Laboratory of Tropical Oceanography under contract No.LTOZZ1702the CAS/SAFEA International Partnership Program for Creative Research Teams
文摘Based on the high-resolution Eulerian fields of an ocean general circulation model simulation, the heat contribution of the Indonesian throughflow(ITF) to the Indian Ocean is estimated by Lagrangian tracing method.The heat transport of each particle of ITF waters is calculated by tracing temperature change along the trajectory until the particle exits the Indian Ocean. The simulation reveals that the ITF waters flow westward and branch near Madagascar, further showing the ITF waters are redistributed in both northern and southern Indian Ocean.Heat budget analysis indicates that the ITF waters gain 0.41 PW(Petawatts, 1015 W) in the northern Indian Ocean and lose 0.56 PW in the southern Indian Ocean, respectively. As a result, the ITF waters warm the whole Indian Ocean basin with only 0.15 PW, which shows an "insignificant" role of ITF on the Indian Ocean because of the heat exchange compensation between northern and southern Indian Ocean. Furthermore, the tracing pathways show that the ITF waters mainly flow out the Indian Ocean at both sides of the basin via Agulhas Current and Leeuwin Current. About 89% of the ITF waters leave along western boundary and the rest 11% along eastern boundary. Compared to seeding section, 0.10 PW and 0.05 PW are released to the Indian Ocean, respectively.
基金supported by the National Natural Science Foundation of China (GrantNo. 40806005)by the Chinese Academy of Sciences’Knowledge Innovation Program (Grant No. KZCX2-YW-Q11-02)partially supported under the South China Sea Institute of Oceanology (Grant No. SQ200814)
文摘In this study the interannual variability of the upper-ocean heat content in the South China Sea （SCS） was revisited using simple ocean data assimilation （SODA） combined with objective analyzed data sets that included the horizontal and vertical structures. The results confirmed that the upper-ocean heat content in the SCS is lower than normal during the mature phase of E1 Nifio events, and two super E1 Nifio events, 1982/1983 and 1997/1998 were also included. The variability of the heat content was consistent with the variability of the dynamic height anomalies. The SCS throughflow （SCSTF） plays an important role in regulating the interannual variability of the heat content, especially during the mature phase of E1 Nifio events.
基金supported by the Chinese Academy of Sciences' Knowledge Innovation Program (Grant Nos.KZCX2-YW-214 and KZCX2-YW-BR-04)the National Natural Science Foundation of China (Grant Nos.40806005,40640420557 and 40625017)supported by a grant from the City University of Hong Kong (Project No. 7002329)
文摘Changes in the Indonesian Throughflow （ITF） and the South China Sea throughflow-measured by the Luzon Strait Transport （LST）-associated with the 1976/77 regime shift are analyzed using the Island Rule theory and the Simple Ocean Data Assimilation dataset. Results show that LST increased but ITF transport decreased after 1975. Such changes were induced by variations in wind stress associated with the regime shift. The strengthening of the easterly wind anomaly east of the Luzon Strait played an important role in the increase of LST after 1975, while the westerly wind anomaly in the equatorial Pacific contributed significantly to the decrease in ITF transport after 1975; accounting for 53% of the change. After 1975, the Kuroshio Current strengthened and the Mindanao Current weakened in response to a decrease in the total transport of the North Equatorial Current. Both the North Equatorial Countercurrent and the South Equatorial Current weakened after 1975, and an anomalous cyclonic circulation in the western equatorial Pacific prevented the tropical Pacific water from entering the Indian Ocean directly.
基金supported by the Ministry of Science and Technology of the People’s Republic of China (MOST) (Grant No. 2011CB403504)the National Natural Science Foundation of China (Grant Nos. 40625017 and 40806005)
文摘Prior studies have revealed that,as a part of the Pacific tropical gyre,the South China Sea throughflow（SCSTF） is strongly influenced by the Pacific low-latitude western boundary current（LLWBC）.In this study,ocean general circulation model（OGCM） experiments with and without connection to the South China Sea（SCS） were performed to investigate the impact of the SCSTF on the Pacific LLWBC.These model experiments show that if the SCS is blocked,seasonal variability of the Kuroshio and Mindanao Current becomes stronger,and the meridional migration of the North Equatorial Current（NEC） bifurcation latitude is enhanced.Both in seasonal and interannual time scales,stronger Luzon Strait transport（LST） induces a stronger Kuroshio transport combined with a southward shift of the NEC bifurcation,which is unfavorable for a further increase of the LST;a weaker LST induces a weaker Kuroshio transport and a northward shifting NEC bifurcation,which is also unfavorable for the continuous decrease of the LST.
基金The GASI Project under contract Nos GASI-IPOVAI-01-02 and GASI-02-SCS-YGST2-02the National Natural Science Foundation of China under contract Nos 41776034 and 41706025the Foundation of Guangdong Province for Outstanding Young Teachers in University under contract No.YQ201588
文摘So far, large uncertainties of the Indonesian throughflow(ITF) reside in the eastern Indonesian seas, such as the Maluku Sea and the Halmahera Sea. In this study, the water sources of the Maluku Sea and the Halmahera Sea are diagnosed at seasonal and interannual timescales and at different vertical layers, using the state-of-the-art simulations of the Ocean General Circulation Model(OGCM) for Earth Simulator(OFES). Asian monsoon leaves clear seasonal footprints on the eastern Indonesian seas. Consequently, the subsurface waters(around 24.5σ_θ and at ～150 m) in both the Maluku Sea and the Halmahera Sea stem from the South Pacific(SP) during winter monsoon, but during summer monsoon the Maluku Sea is from the North Pacific(NP), and the Halmahera Sea is a mixture of waters originating from the NP and the SP. The monsoon impact decreases with depth, so that in the Maluku Sea, the intermediate water(around 26.8σ_θ and at ～480 m) is always from the northern Banda Sea and the Halmahera Sea water is mainly from the SP in winter and the Banda Sea in summer. The deep waters(around27.2σ_θ and at ～1 040 m) in both seas are from the SP, with weak seasonal variability. At the interannual timescale,the subsurface water in the Maluku Sea originates from the NP/SP during El Ni?o/La Ni?a, while the subsurface water in the Halmahera Sea always originates from the SP. Similar to the seasonal variability, the intermediate water in Maluku Sea mainly comes from the Banda Sea and the Halmahera Sea always originates from the SP. The deep waters in both seas are from the SP. Our findings are helpful for drawing a comprehensive picture of the water properties in the Indonesian seas and will contribute to a better understanding of the ocean-atmosphere interaction over the maritime continent.
