Oceanographic surveying has been one of the key missions of the Chinese National Antarctic Research Expedition since 1984. Using the field data obtained in these surveys and the results from remote sensing and numeric...Oceanographic surveying has been one of the key missions of the Chinese National Antarctic Research Expedition since 1984. Using the field data obtained in these surveys and the results from remote sensing and numerical models, Chinese physical oceanographers have investigated the water masses, fronts and circulation patterns in the Southern Ocean. The results of nearly 30 years of research are summarized in this paper. Most oceanographic observations by Chinese researchers have been con- ducted in Prydz Bay and the adjacent seas. CTD （Conductivity Temperature and Depth） data, collected during the past 20 years, have been applied to study several features of the water masses in this region： The spatial variation of warm summer surface water, the northward extension of shelf water, the flow of ice shelf water from the cavity beneath the Amery Ice Shelf, the upweUing of the Circumpolar Deep Water, and the formation of the Antarctic Bottom Water. The circulation and its dynamic factors have been analyzed with dynamic heights calculated from CTD data as well as by numerical models. The structure and strength of the fronts in the southeast Indian Ocean and the Drake Passage were investigated with underway XBT/XCTD （Expendable Bathythermo- graph/Expendable CTD） and ADCP （Acoustic Doppler Current Profiler） data. Their interaunual variations have been determined and the factors of influence, especially the atmospheric forcing and mesoscale oceanic processes, were studied using remote sens- ing data. The dynamic mechanism of the Antarctic Circumpolar Current （ACC） was analyzed by theoretical models. The transport and pattern of the ACC have been well reproduced by coupled sea ice-ocean models. Additional details of ACC variability were identified based on satellite altimeter data. The response of the ACC to climate change was studied using reanalysis data. Prospects for future research are presented at the end of this paper.展开更多
As a part of the National Report of China for the International Association for Physical Science of Ocean （IAPSO）, the main research results of Chinese scientists in Arctic physical oceanography during 2007-2010 are...As a part of the National Report of China for the International Association for Physical Science of Ocean （IAPSO）, the main research results of Chinese scientists in Arctic physical oceanography during 2007-2010 are reviewed in this paper. This period overlaps with the International Polar Year （IPY）, which is a catalyst for nations to emphasize activities and research in the polar regions. The Arctic also experienced a rapid change in sea ice, ocean, and climate during this time. China launched two Arctic cruises with the R/V XUE LONG icebreaker, in 2008 and 2010, which provided more opportunities for Chinese scientists to investigate the Arctic Ocean and its change. During this period, Chinese scientists participated in more than ten other cruises with international collaborations. The main research covered in this paper includes the upper ocean characteristic, ocean and sea ice optics, kinematics of sea ice and the Arctic impact on global climate change. The progress in sea ice optics, the observation technologies and Arctic Oscillation are especially remarkable.展开更多
The Yellow Sea and Bohai Sea are among the global shelf seas susceptible to typhoons every year.Using observations and high-resolution numerical simulations,the current study investigates the dramatic changes in tempe...The Yellow Sea and Bohai Sea are among the global shelf seas susceptible to typhoons every year.Using observations and high-resolution numerical simulations,the current study investigates the dramatic changes in temperature and ocean heat content(OHC)of the Yellow Sea and Bohai Sea caused by Super Typhoon Maysak in early September 2020,which is representative of northward/northeastward-bypassing typhoons with centers just to the east of the study area.Temperature shows spatially coherent cooling in the upper mixed layer but warming in the subsurface layer in the majority of the offshore waters,due to wind-enhanced vertical mixing.In lower layers from the thermocline to sea bottom,temperature experiences significant warming in northeastern coastal waters of the Shandong Peninsula and in regions just off the Subei Shoal,but significant cooling in western coastal waters of the Korean Peninsula and southern coastal waters of the Shandong Peninsula.Significant temperature warming/cooling in lower layers is caused by coastal downwelling/upwelling.The total OHC of the study area decreases rapidly during Typhoon Maysak(2020)’s passage,which is generated comparably by latent heat loss at the sea surface and southward heat advection out of the study area at the southern boundary.Reduced shortwave radiation contributes positively but secondarily to the decreasing OHC during the first day.A numerical experiment suggests that Typhoon Maysak(2020)-induced OHC decline could have greatly affected the regional climate evolution in the following seasons.More studies are needed to fully understand the impacts of typhoons on regional climate changes in shelf seas at different time scales.展开更多
In this study, the micro-and macro-physical properties, thermal structure and precipitation characteristics of cyclone eye walls and their surrounding spiral clouds were analysed with Cloud Sat and TRMM data for five ...In this study, the micro-and macro-physical properties, thermal structure and precipitation characteristics of cyclone eye walls and their surrounding spiral clouds were analysed with Cloud Sat and TRMM data for five tropical cyclones(TCs) in 2013. The results show that the ice-phase clouds of a mature TC are mainly above 5 km. With increasing altitude, the cloud droplet effective radius decreases, and the particle number concentration increases. Ice water content first increases and then decreases with increasing height. In the eye area, in addition to the well-known warm-core area, another warm core is also apparent around the eye at a height of 8 to 15 km. The horizontal distribution of precipitation is characterized by large-scale stratiform precipitation mixed with independent convective precipitation. The height of precipitation is mostly below 7.5 km, and the heavy rain is mainly below 5 km. When the peripheral convective clouds are strong enough, ice particles would be generated, thus providing conditions that are favourable for the formation of precipitation below.展开更多
The melting of seasonal sea ice in Antarctica plays a pivotal role in the region’s carbon cycle,influencing global carbon storage and the exchange of carbon between the atmosphere and the ocean.However,the impact of ...The melting of seasonal sea ice in Antarctica plays a pivotal role in the region’s carbon cycle,influencing global carbon storage and the exchange of carbon between the atmosphere and the ocean.However,the impact of variability in the timing of seasonal sea ice retreat on the flux and composition of sinking particulate matter remains to be elucidated.In this study,we deployed sediment traps in Prydz Bay during the austral summers of 2019/2020 and 2020/2021,noting that sea ice melting occurred approximately one and a half months earlier in the former summer compared to the latter.We analyzed sediment trap data,which included total mass flux(TMF),particulate organic carbon(POC),biogenic silica(BSi),particulate inorganic carbon,and lithogenic particle(Litho)fluxes,as well as the stable isotopesδ^(13)C andδ^(15)N of particulate organic matter(POM).Additionally,we incorporated remote sensing data on sea ice concentration and chlorophyll a.This dramatic delay in sea ice melting timing could result in a significant increase in TMF,BSi and POC fluxes in the summer of 2020/2021 compared to 2019/2020.Elevated BSi fluxes and more ^(13)C-depleted POC in the austral summer of 2020/2021 suggest that the delayed melting of sea ice may have stimulated the productivity of centric diatoms.Furthermore,the higher BSi/POC ratio and more negativeδ^(15)N values of POM,along with a reduced presence of krill in the traps,indicate a diminished grazing pressure from zooplankton,which collectively enhanced the sedimentation efficiency of POC during the austral summer of 2020/2021.These findings highlight the critical role of sea ice melting timing in regulating productivity,flux and composition of sinking particulate matter in the Prydz Bay ecosystem,with significant implications for carbon cycling in polar oceans.展开更多
Ocean mixing is a consequence of essential dynamic processes such as internal tides and lee waves that occur near the seafloor topography.Internal tides and lee waves are generated by barotropic tidal currents and geo...Ocean mixing is a consequence of essential dynamic processes such as internal tides and lee waves that occur near the seafloor topography.Internal tides and lee waves are generated by barotropic tidal currents and geostrophic flows,respectively.Ocean current is composed of multiple flows;thus,internal tides and lee waves occur concurrently in the real ocean.In this paper,the Massachusetts Institute of Technology general circulation model(MITgcm)is used to conduct 2D numerical experiments.By varying background flow intensities,the energy and dissipation relationship between internal tides and lee waves are investigated.The results reveal that the internal tide beams become asymmetric due to the influence of Doppler shift.The lee wave structure gradually leads the wave field when the background flow velocity rises constantly.The presence of a background flow increases the energy portion of the high-mode wave by up to 15%-20%.Moreover,strong shear,owing to the background flow,considerably increases dissipation.When the background flow velocity is higher than the barotropic tidal current velocity,the isopycnal overturn triggered by the lee wave generates a dissipation of the same order of magnitude as the shear.展开更多
The Pacific Meridional Mode(PMM)and the Atlantic Meridional Mode(AMM)are key modes of interannual sea surface temperature(SST)variability in the Pacific and Atlantic Oceans,respectively.Analysis of CMIP6 model outputs...The Pacific Meridional Mode(PMM)and the Atlantic Meridional Mode(AMM)are key modes of interannual sea surface temperature(SST)variability in the Pacific and Atlantic Oceans,respectively.Analysis of CMIP6 model outputs reveals a robust intensification of the PMM under global warming,whereas the AMM exhibits no consensus among models.These different responses are attributed to mid-to-high latitude atmospheric forcing and subtropical feedback mechanisms.Changes in the upper-level westerly jet drive distinct atmospheric variability over the North Pacific and Atlantic,amplifying sea-level pressure variations associated with the PMM but weakening those linked to the AMM.The SST response to atmospheric forcing shows an increase in the Pacific and a decrease in the Atlantic,both of which are significantly positively correlated with the respective changes in each mode.The enhanced wind-evaporation-SST(WES)feedback,primarily driven by rising background SSTs,positively impacts the intensification of both modes.In the subtropical Pacific,the PMM is further strengthened by an increasing latent heat flux response.The enhancement of the PMM is principally connected to intensified atmospheric forcing and strengthened subtropical feedback.Although the WES feedback is enhanced to some extent,wind anomalies that oppose the climatological state reduce latent heat flux.Combined with the weakening of atmospheric forcing over the Atlantic,this phenomenon contributes to the uncertainty in the AMM's response to global warming.展开更多
The Antarctic Slope Current(ASC)links the processes occurring in the coast area with the global ocean by modulating the flow across the continental slope,which influences global overturning circulation and the mass ba...The Antarctic Slope Current(ASC)links the processes occurring in the coast area with the global ocean by modulating the flow across the continental slope,which influences global overturning circulation and the mass balance of the Antarctic ice shelves.This paper aims to explore the effects of wind and buoyancy fluxes on the long-term changes in the ASC using observation and reanalysis datasets.From 1993 to 2022,the ASC accelerated in all seasons,particularly in austral autumn,and was accompanied with the advancement of the strong flow.The positive buoyancy flux anomaly generates a low-density anomaly,which is accumulated by the prevailing surface easterly,maintaining a sharp density front along the continental slope.The heat flux intensifies the positive trend of buoyancy flux in summer and autumn,increasing the input of the lighter density anomaly into the ocean and advancing the strong flow of ASC.Compared with the annual mean,the additional acceleration of the ASC in autumn is mainly due to the contribution of the barotropic component,which could be explained by the local momentum input from the weakly enhanced local surface wind.The acceleration of the ASC is primarily driven by the positive trend of the buoyancy flux,while the influence of the wind on its seasonal variability becomes more significant due to the contribution of the local surface wind in autumn.展开更多
Under ongoing global warming,reliable projections of Arctic sea-ice conditions and future navigability are of strategic significance.Using a combination of observational and physical constraints,we systematically eval...Under ongoing global warming,reliable projections of Arctic sea-ice conditions and future navigability are of strategic significance.Using a combination of observational and physical constraints,we systematically evaluated the performance of 48 Coupled Model Intercomparison Project 6(CMIP6)models in simulating Arctic sea ice and selected 12 skillful models for detailed analysis.Navigability of the Northeast Passage(NEP),Northwest Passage(NWP),and Transpolar Sea Route(TSR)during 2015–2100 was assessed under Shared Socioeconomic Pathways(SSP)2-4.5 and SSP5-8.5 scenarios.Results indicate that for open water vessels under the SSP2-4.5,TSR is not projected to become navigable until 2029.In contrast,under the SSP5-8.5 scenario,both NWP and NEP are expected to support year-round navigation by the late 21st century,while TSR is not anticipated to become fully operational until after 2090.Polar Class 6 vessels achieve near year-round navigation by 2100 under SSP2-4.5,and full-year operation as early as 2048 under SSP5-8.5.展开更多
This study systematically examined phytoplankton community structure and its spatial distribution across euphotic and deep-water layers in the northeastern South China Sea(ne-SCS),elucidating their responses to physic...This study systematically examined phytoplankton community structure and its spatial distribution across euphotic and deep-water layers in the northeastern South China Sea(ne-SCS),elucidating their responses to physical processes including eddy dynamics and Kuroshio intrusions.Our observations revealed a significant reorganization in phytoplankton community structure,with the harmful algal bloom(HAB)—forming dinoflagellate Scrippsiella acuminata now dominating euphotic zone assemblages,followed by Nitzschia spp.The pronounced shift toward HAB species dominance elevates ecological risks associated with dinoflagellate blooms,while the concurrent decline in diatom abundance may indicate reduced marine primary productivity.Phytoplankton communities displayed clear spatial segregation,characterized by cyanobacterial dominance in Kuroshio intrusion zones,preferential distribution of dinoflagellates in warm eddy regions,and diatom prevalence in cold eddy systems and deep-current environments.Phytoplankton community composition showed distinct spatial patterns,driven primarily by temperature and nutrient gradients.Deep-sea phytoplankton communities,characterized by elevated diatom-to-dinoflagellate ratios and dominance of fast-sinking species,play a significant role in organic carbon export and biogeochemical cycling processes.展开更多
In recent years, with the development of technologies such as the Internet of Things(Io T), big data and cloud computing, digital twin technology has gradually been applied in marine research. The digital twin realize...In recent years, with the development of technologies such as the Internet of Things(Io T), big data and cloud computing, digital twin technology has gradually been applied in marine research. The digital twin realizes real-time monitoring, analysis and optimization of the state and behavior of a physical object or system by creating a virtual model. Research shows that digital twin technology has extensive application potential in ship design, marine resource development, marine equipment engineering design and optimization, marine ecological protection and early warning of disasters. Although digital twin technology has great potential in marine research, it also faces many challenges, including the complexity of data acquisition and processing, the accuracy and real-time performance of model construction, and the need for multidisciplinary cross-integration. An in-depth analysis of the technical bottlenecks and future development directions will provide an important reference for subsequent research and promote the further application and development of digital twin technology in marine research.展开更多
Fog is a highly complex weather phenomenon influenced by numerous factors.This study investigated the impact of the Changbai Mountains’topography on the formation and development of spring fog in the Bohai Sea.From 1...Fog is a highly complex weather phenomenon influenced by numerous factors.This study investigated the impact of the Changbai Mountains’topography on the formation and development of spring fog in the Bohai Sea.From 12 to 14 May 2021,the Bohai region experienced a sea fog event.Utilizing Himawari-8 satellite data,ERA5 reanalysis dataset,land and sea station observations,the WRF model,a topography sensitivity experiment,and backward trajectory tracking,the influence of the Changbai Mountains’topography on the evolution of this sea fog event was assessed.Results indicated that the Changbai Mountains’topography significantly impacted the propagation and concentration of the sea fog through dual effects—namely,the Venturi Effect and Foehn Clearance Effect.Comparative simulations incorporating and excluding the Changbai Mountains revealed that its topography favored weak convergence(Venturi Effect)of low-level airflow over the Bohai Sea induced by a high-pressure system,promoting westward fog expansion.Additionally,the backward trajectory analysis further indicated that the Foehn Clearance Effect of the Changbai Mountains extended its influence far beyond the immediate lee side,contributing to significant changes in atmospheric conditions such as reductions in relative humidity and increases in potential temperature.The dry,warm foehn contributed to a reduction in the liquid water content,ultimately leading to the weakening or even dissipation of the sea fog in the region close to the Changbai Mountains.This study emphasizes the crucial role of the Changbai Mountains’topography in the development and evolution of fog,providing valuable insights for forecasting fog in regions with complex terrain.展开更多
The year,2024,marks the 40th anniversary of Chinese research expeditions in the polar regions and the 25th anniversary of its Arctic research expeditions.China has conducted 14 national Arctic research expeditions.Wit...The year,2024,marks the 40th anniversary of Chinese research expeditions in the polar regions and the 25th anniversary of its Arctic research expeditions.China has conducted 14 national Arctic research expeditions.With the increase of understandings on the global impacts of the changes of Arctic climate system,especially on China’s weather and climate,and demands for commercial utilization of the Arctic sea routes,Chinese scientists have made great progresses on in site and remote sensing observation technologies for Arctic Ocean,interaction mechanisms between atmosphere,sea ice,and ocean,the connection mechanism between the Arctic Ocean and other regions,and have achieved a series of research results.This study summarizes the research achievements by Chinese scientists in the above-mentioned aspects or beyond,identifies knowledge gaps,and based on this,discusses prospects and provides suggestions.From a perspective of observation,improving the observation capabilities of the Arctic Ocean in winter and the ocean under the ice,as well as floe-scale processes of sea ice and mesoscale and submesoscale processes of the ocean,is an urgent task to be addressed.Strengthening international cooperation is necessary for building a monitoring network for the Arctic marine environment.From a perspective of numerical simulation,the descriptive ability and parameterization scheme of sub-grid processes based on observational evidence need to be developed.From a perspective of cross-sphere interactions,in addition to the multi-media coupling within the Arctic Ocean that this review focuses on,the interaction between the Arctic Ocean and land or ice sheet(Greenland),especially the water cycle process,is also a scientific domain that needs to be considered,in the context of Arctic warming and humidification.From a perspective of climate effects,the physical mechanisms that affect the robustness of teleconnection need to be clarified.展开更多
In November 1984,China launched its first expedition to the Southern Ocean and the Antarctic continent,culminating in the establishment of its first year-round research station—Great Wall Station—on the Antarctic Pe...In November 1984,China launched its first expedition to the Southern Ocean and the Antarctic continent,culminating in the establishment of its first year-round research station—Great Wall Station—on the Antarctic Peninsula in February 1985.Forty years later,in February 2024,China’s fifth research station,Qinling Station,commenced operations on Inexpress-ible Island near Terra Nova Bay.展开更多
Predicting monsoon climate is one of the major endeavors in climate science and is becoming increasingly challenging due to global warming. The accuracy of monsoon seasonal predictions significantly impacts the lives ...Predicting monsoon climate is one of the major endeavors in climate science and is becoming increasingly challenging due to global warming. The accuracy of monsoon seasonal predictions significantly impacts the lives of billions who depend on or are affected by monsoons, as it is essential for the water cycle, food security, ecology, disaster prevention, and the economy of monsoon regions. Given the extensive literature on Asian monsoon climate prediction, we limit our focus to reviewing the seasonal prediction and predictability of the Asian Summer Monsoon (ASM). However, much of this review is also relevant to monsoon predictions in other seasons and regions. Over the past two decades, considerable progress has been made in the seasonal forecasting of the ASM, driven by an enhanced understanding of the sources of predictability and the dynamics of seasonal variability, along with advanced development in sophisticated models and technologies. This review centers on advances in understanding the physical foundation for monsoon climate prediction (section 2), significant findings and insights into the primary and regional sources of predictability arising from feedback processes among various climate components (sections 3 and 4), the effects of global warming and external forcings on predictability (section 5), developments in seasonal prediction models and techniques (section 6), the challenges and limitations of monsoon climate prediction (section 7), and emerging research trends with suggestions for future directions (section 8). We hope this review will stimulate creative activities to enhance monsoon climate prediction.展开更多
This paper reviews recent progress made by Chinese scientists on the pathways of influence of the Northern Hemisphere mid-high latitudes on East Asian climate within the framework of a“coupled oceanic-atmospheric(lan...This paper reviews recent progress made by Chinese scientists on the pathways of influence of the Northern Hemisphere mid-high latitudes on East Asian climate within the framework of a“coupled oceanic-atmospheric(land-atmospheric or seaice-atmospheric)bridge”and“chain coupled bridge”.Four major categories of pathways are concentrated upon,as follows:Pathway A—from North Atlantic to East Asia;Pathway B—from the North Pacific to East Asia;Pathway C—from the Arctic to East Asia;and Pathway D—the synergistic effects of the mid-high latitudes and tropics.In addition,definitions of the terms“combined effect”,“synergistic effect”and“antagonistic effect”of two or more factors of influence or processes and their criteria are introduced,so as to objectively investigate those effects in future research.展开更多
In this study, a sea fog event which occurred on 27 March 2005 over the Yellow and Bohai Seas was investigated observationally and numerically. Almost all available observational data were used, including satellite im...In this study, a sea fog event which occurred on 27 March 2005 over the Yellow and Bohai Seas was investigated observationally and numerically. Almost all available observational data were used, including satellite imagery of Geostationary Operational Environmental Satellite （GOES）-9, three data sets from station observations at Dandong, Dalian and Qingdao, objectively reanalyzed data of final run analysis （FNL） issued by the National Center for Environmental Prediction （NCEP） and Regional Atmospheric Modeling System （RANIS） results. Synoptic conditions and fog characteristics were analyzed. The fog formed when warm, moist air was advected northwards over the cool water of the Yellow and Bohai Seas, and dissipated when a cold front brought northerly winds and cool, dry air. In order to better understand the fog formation mechanism, a high-resolution RAMS modeling with a 6km×6km grid, initialized and validated by FNL data, was designed. A 48h modeling that started from 12 UTC 26 March 2005 reproduced the main characteristics of this sea fog event. The simulated lower visibility area agreed reasonably well with the sea fog region identified from the satellite imagery. Advection cooling effect seemed to play a significant role in the fog formation.展开更多
On the basis of data of drifting bottles＇ tracks and the current measured in anchored stations, as well as temperature and salinity observed in cruise investigations and coastal stations, ADCP current data and AVHRR ...On the basis of data of drifting bottles＇ tracks and the current measured in anchored stations, as well as temperature and salinity observed in cruise investigations and coastal stations, ADCP current data and AVHRR surface sea temperature （SST） data on the western coast of Guangdong, synthetic results of analysis showed that the coastal currents in the west of the mouth of the Zhujiang River were mainly westward in summer, which constituted the north branch of cyclonic gyre in the east of the Qiongzhou Straits. Part of its water flowed westward into the Beibu Gulf through the Qiongzhou Straits. The coastal current pattern was not identical with the traditional current system which flowed westward in the Qiongzhou Straits in winter and eastward in summer. The summertime＇s coastal current was always westward, maybe temporarily turning northeast only when the southwest wind was strong. The important characteristics of coastal current on the western coast of Guangdong, in the Qiongzhou Straits and in the north of the Beibu Gulf were analyzed and their mechanisms also were explained.展开更多
The Argo data are used to calculate eddy（turbulence） heat transport（EHT） in the global ocean and analyze its horizontal distribution and vertical structure.We calculate the EHT by averaging all the v ′,T ′ profi...The Argo data are used to calculate eddy（turbulence） heat transport（EHT） in the global ocean and analyze its horizontal distribution and vertical structure.We calculate the EHT by averaging all the v ′,T ′ profiles within each 2 ×2 bin.The velocity and temperature anomalies are obtained by removing their climatological values from the Argo ＂instantaneous＂ values respectively.Through the Student＇s t-test and an error evaluation,we obtained a total of 87% Argo bins with significant depth-integrated EHTs（D-EHTs）.The results reveal a positive-and-negative alternating D-EHT pattern along the western boundary currents（WBC） and Antarctic Circumpolar Current（ACC）.The zonally-integrated D-EHT（ZI-EHT） of the global ocean reaches 0.12 PW in the northern WBC band and –0.38 PW in the ACC band respectively.The strong ZI-EHT across the ACC in the global ocean is mainly caused by the southern Indian Ocean.The ZI-EHT in the above two bands accounts for a large portion of the total oceanic heat transport,which may play an important role in regulating the climate.The analysis of vertical structures of the EHT along the 35 N and 45 S section reveals that the oscillating EHT pattern can reach deep in the northern WBC regions and the Agulhas Return Current（ARC） region.It also shows that the strong EHT could reach 600 m in the WBC regions and 1 000 m in the ARC region,with the maximum mainly located between 100 and 400 m depth.The results would provide useful information for improving the parameterization scheme in models.展开更多
Wave climate analysis and other applications for the Pacific Ocean require a reliable wave hindcast. Five source and sink term packages in the Wavewatch III model （v3.14 and v4.18） are compared and assessed in this ...Wave climate analysis and other applications for the Pacific Ocean require a reliable wave hindcast. Five source and sink term packages in the Wavewatch III model （v3.14 and v4.18） are compared and assessed in this study through comprehensive observations, including altimeter significant wave height, advanced synthetic aperture radar swell, and buoy wave parameters and spectrum. In addition to the evaluation of typically used integral parameters, the spectra partitioning method contributes to the detailed wave system and wave maturity validation. The modified performance evaluation method （PS） effectively reduces attribute numbers and facilitates the overall assessment. To avoid possible misleading results in the root mean square error-based validations, another indicator called HH （indicating the two authors） is also calculated to guarantee the consistency of the results. The widely used Tolman and Chalikov （TC） package is still generally efficient in determining the integral properties of wave spectra but is physically deficient in explaining the dissipation processes. The ST4 package performs well in overall wave parameters and significantly improves the accuracy of wave systems in the open ocean. Meanwhile, the newly published ST6 package is slightly better in determining swell energy variations. The two packages （ACC350 and BIA） obtained from Wavewatch III v3.14 exhibit large scatters at different sea states. The three most ideal packages are further examined in terms of reproducing wave- induced momentum flux from the perspective of transport. Stokes transport analysis indicates that ST4 is the closest to the NDBC-buoy-spectrum-based transport values, and TC and ST6 tend to overestimate and underestimate the transport magnitude, respectively, in swell mixed areas. This difference must be considered, particularly in air-wave-current coupling research and upper ocean analysis. The assessment results provide guidance for the selection of ST4 for use in a background Pacific Ocean hindcast for high wave climate research and China Sea swell type analysis.展开更多
基金supported by the Chinese Polar Environment Comprehensive Investigation and Assessment Programmes (Grant nos.CHINARE2013-04-01,CHINARE2013-04-04)the National High-tech Research & Development Program of China (Grant no.2010CB950301)
文摘Oceanographic surveying has been one of the key missions of the Chinese National Antarctic Research Expedition since 1984. Using the field data obtained in these surveys and the results from remote sensing and numerical models, Chinese physical oceanographers have investigated the water masses, fronts and circulation patterns in the Southern Ocean. The results of nearly 30 years of research are summarized in this paper. Most oceanographic observations by Chinese researchers have been con- ducted in Prydz Bay and the adjacent seas. CTD （Conductivity Temperature and Depth） data, collected during the past 20 years, have been applied to study several features of the water masses in this region： The spatial variation of warm summer surface water, the northward extension of shelf water, the flow of ice shelf water from the cavity beneath the Amery Ice Shelf, the upweUing of the Circumpolar Deep Water, and the formation of the Antarctic Bottom Water. The circulation and its dynamic factors have been analyzed with dynamic heights calculated from CTD data as well as by numerical models. The structure and strength of the fronts in the southeast Indian Ocean and the Drake Passage were investigated with underway XBT/XCTD （Expendable Bathythermo- graph/Expendable CTD） and ADCP （Acoustic Doppler Current Profiler） data. Their interaunual variations have been determined and the factors of influence, especially the atmospheric forcing and mesoscale oceanic processes, were studied using remote sens- ing data. The dynamic mechanism of the Antarctic Circumpolar Current （ACC） was analyzed by theoretical models. The transport and pattern of the ACC have been well reproduced by coupled sea ice-ocean models. Additional details of ACC variability were identified based on satellite altimeter data. The response of the ACC to climate change was studied using reanalysis data. Prospects for future research are presented at the end of this paper.
基金supported by the National Department Public Benefit Research Foundation (Grant no.201105022)the National Natural Science Foundation of China(Grant nos. 40876006, 40976111)
文摘As a part of the National Report of China for the International Association for Physical Science of Ocean （IAPSO）, the main research results of Chinese scientists in Arctic physical oceanography during 2007-2010 are reviewed in this paper. This period overlaps with the International Polar Year （IPY）, which is a catalyst for nations to emphasize activities and research in the polar regions. The Arctic also experienced a rapid change in sea ice, ocean, and climate during this time. China launched two Arctic cruises with the R/V XUE LONG icebreaker, in 2008 and 2010, which provided more opportunities for Chinese scientists to investigate the Arctic Ocean and its change. During this period, Chinese scientists participated in more than ten other cruises with international collaborations. The main research covered in this paper includes the upper ocean characteristic, ocean and sea ice optics, kinematics of sea ice and the Arctic impact on global climate change. The progress in sea ice optics, the observation technologies and Arctic Oscillation are especially remarkable.
基金supported by the National Key Research and Development Program of China(Grant Nos.2022YFF0801400 and 2021YFF0704002)the Shandong Provincial Natural Science Foundation(Grant No.ZR2024LQX002)the National Science Foundation of China(Grant No.42176016).
文摘The Yellow Sea and Bohai Sea are among the global shelf seas susceptible to typhoons every year.Using observations and high-resolution numerical simulations,the current study investigates the dramatic changes in temperature and ocean heat content(OHC)of the Yellow Sea and Bohai Sea caused by Super Typhoon Maysak in early September 2020,which is representative of northward/northeastward-bypassing typhoons with centers just to the east of the study area.Temperature shows spatially coherent cooling in the upper mixed layer but warming in the subsurface layer in the majority of the offshore waters,due to wind-enhanced vertical mixing.In lower layers from the thermocline to sea bottom,temperature experiences significant warming in northeastern coastal waters of the Shandong Peninsula and in regions just off the Subei Shoal,but significant cooling in western coastal waters of the Korean Peninsula and southern coastal waters of the Shandong Peninsula.Significant temperature warming/cooling in lower layers is caused by coastal downwelling/upwelling.The total OHC of the study area decreases rapidly during Typhoon Maysak(2020)’s passage,which is generated comparably by latent heat loss at the sea surface and southward heat advection out of the study area at the southern boundary.Reduced shortwave radiation contributes positively but secondarily to the decreasing OHC during the first day.A numerical experiment suggests that Typhoon Maysak(2020)-induced OHC decline could have greatly affected the regional climate evolution in the following seasons.More studies are needed to fully understand the impacts of typhoons on regional climate changes in shelf seas at different time scales.
基金Young Scientists Fund of National Natural Science Foundation of China Grant(41505013,41575017)Natural Science Foundation of Shandong Province(BS2015HZ019)
文摘In this study, the micro-and macro-physical properties, thermal structure and precipitation characteristics of cyclone eye walls and their surrounding spiral clouds were analysed with Cloud Sat and TRMM data for five tropical cyclones(TCs) in 2013. The results show that the ice-phase clouds of a mature TC are mainly above 5 km. With increasing altitude, the cloud droplet effective radius decreases, and the particle number concentration increases. Ice water content first increases and then decreases with increasing height. In the eye area, in addition to the well-known warm-core area, another warm core is also apparent around the eye at a height of 8 to 15 km. The horizontal distribution of precipitation is characterized by large-scale stratiform precipitation mixed with independent convective precipitation. The height of precipitation is mostly below 7.5 km, and the heavy rain is mainly below 5 km. When the peripheral convective clouds are strong enough, ice particles would be generated, thus providing conditions that are favourable for the formation of precipitation below.
基金The National Key Research and Development Program of China under contract No.2022YFE0136500the Scientific Research Fund of the Second Institute of Oceanography,Ministry of Natural Resources,under contract Nos JG2212 and JG2211+2 种基金the National Natural Science Foundation of China under contract Nos 42276255,41976228,and 42176227the National Polar Special Program“Impact and Response of Antarctic Seas to Climate Change”under contract Nos IRASCC 01-01-02 and IRASCC 02-02the China Scholarship Council under contract No.201704180017.
文摘The melting of seasonal sea ice in Antarctica plays a pivotal role in the region’s carbon cycle,influencing global carbon storage and the exchange of carbon between the atmosphere and the ocean.However,the impact of variability in the timing of seasonal sea ice retreat on the flux and composition of sinking particulate matter remains to be elucidated.In this study,we deployed sediment traps in Prydz Bay during the austral summers of 2019/2020 and 2020/2021,noting that sea ice melting occurred approximately one and a half months earlier in the former summer compared to the latter.We analyzed sediment trap data,which included total mass flux(TMF),particulate organic carbon(POC),biogenic silica(BSi),particulate inorganic carbon,and lithogenic particle(Litho)fluxes,as well as the stable isotopesδ^(13)C andδ^(15)N of particulate organic matter(POM).Additionally,we incorporated remote sensing data on sea ice concentration and chlorophyll a.This dramatic delay in sea ice melting timing could result in a significant increase in TMF,BSi and POC fluxes in the summer of 2020/2021 compared to 2019/2020.Elevated BSi fluxes and more ^(13)C-depleted POC in the austral summer of 2020/2021 suggest that the delayed melting of sea ice may have stimulated the productivity of centric diatoms.Furthermore,the higher BSi/POC ratio and more negativeδ^(15)N values of POM,along with a reduced presence of krill in the traps,indicate a diminished grazing pressure from zooplankton,which collectively enhanced the sedimentation efficiency of POC during the austral summer of 2020/2021.These findings highlight the critical role of sea ice melting timing in regulating productivity,flux and composition of sinking particulate matter in the Prydz Bay ecosystem,with significant implications for carbon cycling in polar oceans.
基金supported by the National Natural Science Foundation of China(No.41876015)。
文摘Ocean mixing is a consequence of essential dynamic processes such as internal tides and lee waves that occur near the seafloor topography.Internal tides and lee waves are generated by barotropic tidal currents and geostrophic flows,respectively.Ocean current is composed of multiple flows;thus,internal tides and lee waves occur concurrently in the real ocean.In this paper,the Massachusetts Institute of Technology general circulation model(MITgcm)is used to conduct 2D numerical experiments.By varying background flow intensities,the energy and dissipation relationship between internal tides and lee waves are investigated.The results reveal that the internal tide beams become asymmetric due to the influence of Doppler shift.The lee wave structure gradually leads the wave field when the background flow velocity rises constantly.The presence of a background flow increases the energy portion of the high-mode wave by up to 15%-20%.Moreover,strong shear,owing to the background flow,considerably increases dissipation.When the background flow velocity is higher than the barotropic tidal current velocity,the isopycnal overturn triggered by the lee wave generates a dissipation of the same order of magnitude as the shear.
基金the National Natural Science Foundation of China(Nos.42230405,41975092)the National Key R&D Program of China(No.2023YFF0805100)+1 种基金the Shandong Natural Science Foundation Project(No.ZR2019ZD12)the Taishan Scholars Project of Shandong Province(No.tsqn202306095)。
文摘The Pacific Meridional Mode(PMM)and the Atlantic Meridional Mode(AMM)are key modes of interannual sea surface temperature(SST)variability in the Pacific and Atlantic Oceans,respectively.Analysis of CMIP6 model outputs reveals a robust intensification of the PMM under global warming,whereas the AMM exhibits no consensus among models.These different responses are attributed to mid-to-high latitude atmospheric forcing and subtropical feedback mechanisms.Changes in the upper-level westerly jet drive distinct atmospheric variability over the North Pacific and Atlantic,amplifying sea-level pressure variations associated with the PMM but weakening those linked to the AMM.The SST response to atmospheric forcing shows an increase in the Pacific and a decrease in the Atlantic,both of which are significantly positively correlated with the respective changes in each mode.The enhanced wind-evaporation-SST(WES)feedback,primarily driven by rising background SSTs,positively impacts the intensification of both modes.In the subtropical Pacific,the PMM is further strengthened by an increasing latent heat flux response.The enhancement of the PMM is principally connected to intensified atmospheric forcing and strengthened subtropical feedback.Although the WES feedback is enhanced to some extent,wind anomalies that oppose the climatological state reduce latent heat flux.Combined with the weakening of atmospheric forcing over the Atlantic,this phenomenon contributes to the uncertainty in the AMM's response to global warming.
基金The National Natural Science Foundation of China under contract Nos 42376256,42230405,and 41576020.
文摘The Antarctic Slope Current(ASC)links the processes occurring in the coast area with the global ocean by modulating the flow across the continental slope,which influences global overturning circulation and the mass balance of the Antarctic ice shelves.This paper aims to explore the effects of wind and buoyancy fluxes on the long-term changes in the ASC using observation and reanalysis datasets.From 1993 to 2022,the ASC accelerated in all seasons,particularly in austral autumn,and was accompanied with the advancement of the strong flow.The positive buoyancy flux anomaly generates a low-density anomaly,which is accumulated by the prevailing surface easterly,maintaining a sharp density front along the continental slope.The heat flux intensifies the positive trend of buoyancy flux in summer and autumn,increasing the input of the lighter density anomaly into the ocean and advancing the strong flow of ASC.Compared with the annual mean,the additional acceleration of the ASC in autumn is mainly due to the contribution of the barotropic component,which could be explained by the local momentum input from the weakly enhanced local surface wind.The acceleration of the ASC is primarily driven by the positive trend of the buoyancy flux,while the influence of the wind on its seasonal variability becomes more significant due to the contribution of the local surface wind in autumn.
基金supported by the National Natural Science Foundation of China(Grant no.42430411)the National Key Research and Development Program of China(Grant no.2019YFA0607004)+1 种基金the National Natural Science Foundation of China(Grant no.42075024)the Innovation and Development Program of China Meteorological Administration(Grant no.CXFZ2024J033).
文摘Under ongoing global warming,reliable projections of Arctic sea-ice conditions and future navigability are of strategic significance.Using a combination of observational and physical constraints,we systematically evaluated the performance of 48 Coupled Model Intercomparison Project 6(CMIP6)models in simulating Arctic sea ice and selected 12 skillful models for detailed analysis.Navigability of the Northeast Passage(NEP),Northwest Passage(NWP),and Transpolar Sea Route(TSR)during 2015–2100 was assessed under Shared Socioeconomic Pathways(SSP)2-4.5 and SSP5-8.5 scenarios.Results indicate that for open water vessels under the SSP2-4.5,TSR is not projected to become navigable until 2029.In contrast,under the SSP5-8.5 scenario,both NWP and NEP are expected to support year-round navigation by the late 21st century,while TSR is not anticipated to become fully operational until after 2090.Polar Class 6 vessels achieve near year-round navigation by 2100 under SSP2-4.5,and full-year operation as early as 2048 under SSP5-8.5.
基金The National Natural Science Foundation of China under contract No.32501444.
文摘This study systematically examined phytoplankton community structure and its spatial distribution across euphotic and deep-water layers in the northeastern South China Sea(ne-SCS),elucidating their responses to physical processes including eddy dynamics and Kuroshio intrusions.Our observations revealed a significant reorganization in phytoplankton community structure,with the harmful algal bloom(HAB)—forming dinoflagellate Scrippsiella acuminata now dominating euphotic zone assemblages,followed by Nitzschia spp.The pronounced shift toward HAB species dominance elevates ecological risks associated with dinoflagellate blooms,while the concurrent decline in diatom abundance may indicate reduced marine primary productivity.Phytoplankton communities displayed clear spatial segregation,characterized by cyanobacterial dominance in Kuroshio intrusion zones,preferential distribution of dinoflagellates in warm eddy regions,and diatom prevalence in cold eddy systems and deep-current environments.Phytoplankton community composition showed distinct spatial patterns,driven primarily by temperature and nutrient gradients.Deep-sea phytoplankton communities,characterized by elevated diatom-to-dinoflagellate ratios and dominance of fast-sinking species,play a significant role in organic carbon export and biogeochemical cycling processes.
基金financially supported by the Key R&D Program of Shandong Province,China (Grant No. 2023ZLYS01)the National Natural Science Foundation of China (Grant No. 42106172)+8 种基金the Natural Science Foundation of Shandong Province (Grant Nos.ZR2024MD003, ZR2023QD023, ZR2023QD066 and ZR2023QD018)the Consulting and Researching Project of the Chinese Academy of Engineering(Grant Nos. 2024-DFZD-29, 2022-DFZD-35, 2022-XY-21, and 2021-XBZD-13-31)Qingdao Marine Science and Technology Innovation Project (Grant No. 23-1-3-hygg-6-hy)the Natural Science Foundation of Qingdao (Grant Nos. 23-2-1-58-zyyd-jch and 23-2-1-72-zyyd-jch)Project Plan of Pilot Project of Integration of Science,Education and Industry of Qilu University of Technology (Shandong Academy of Sciences)(Grant No. 2023PX035)the Visiting and Training Program for Teachers from Ordinary Undergraduate Universities in Shandong Provincethe Open Fund of Shandong Key Laboratory of Marine Ecological Environment and Disaster Prevention and Mitigation (Grant No. 202302)Major Innovation Project for the Science Education Industry Integration Pilot Project of Qilu University of Technology (Shandong Academy of Sciences)(Grant Nos. 2023HYZX01, and2023JBZ03)University-Industry Collaborative Education Program (Grant No. 202102245036)。
文摘In recent years, with the development of technologies such as the Internet of Things(Io T), big data and cloud computing, digital twin technology has gradually been applied in marine research. The digital twin realizes real-time monitoring, analysis and optimization of the state and behavior of a physical object or system by creating a virtual model. Research shows that digital twin technology has extensive application potential in ship design, marine resource development, marine equipment engineering design and optimization, marine ecological protection and early warning of disasters. Although digital twin technology has great potential in marine research, it also faces many challenges, including the complexity of data acquisition and processing, the accuracy and real-time performance of model construction, and the need for multidisciplinary cross-integration. An in-depth analysis of the technical bottlenecks and future development directions will provide an important reference for subsequent research and promote the further application and development of digital twin technology in marine research.
基金jointly supported by the National Natural Science Foundation of China[grant number 42205009]the Open Grants of the State Key Laboratory of Severe Weather[grant number 2024LASWB23]+1 种基金the Collaborative Innovation Project for Marine Meteorological Science and Technology in the Bohai Rim Region[grant number QYXM202315]the Research and Development Project of Hebei Provincial Meteorological Bureau[grant number 22ky26]。
文摘Fog is a highly complex weather phenomenon influenced by numerous factors.This study investigated the impact of the Changbai Mountains’topography on the formation and development of spring fog in the Bohai Sea.From 12 to 14 May 2021,the Bohai region experienced a sea fog event.Utilizing Himawari-8 satellite data,ERA5 reanalysis dataset,land and sea station observations,the WRF model,a topography sensitivity experiment,and backward trajectory tracking,the influence of the Changbai Mountains’topography on the evolution of this sea fog event was assessed.Results indicated that the Changbai Mountains’topography significantly impacted the propagation and concentration of the sea fog through dual effects—namely,the Venturi Effect and Foehn Clearance Effect.Comparative simulations incorporating and excluding the Changbai Mountains revealed that its topography favored weak convergence(Venturi Effect)of low-level airflow over the Bohai Sea induced by a high-pressure system,promoting westward fog expansion.Additionally,the backward trajectory analysis further indicated that the Foehn Clearance Effect of the Changbai Mountains extended its influence far beyond the immediate lee side,contributing to significant changes in atmospheric conditions such as reductions in relative humidity and increases in potential temperature.The dry,warm foehn contributed to a reduction in the liquid water content,ultimately leading to the weakening or even dissipation of the sea fog in the region close to the Changbai Mountains.This study emphasizes the crucial role of the Changbai Mountains’topography in the development and evolution of fog,providing valuable insights for forecasting fog in regions with complex terrain.
基金The National Natural Science Foundation of China under contract Nos 42325604 and 42276253the Program of Shanghai Academic/Technology Research Leader under contract No.22XD1403600the Fund of the Ministry of Industry and Information Technology of China under contract No.CBG2N21-2-1.
文摘The year,2024,marks the 40th anniversary of Chinese research expeditions in the polar regions and the 25th anniversary of its Arctic research expeditions.China has conducted 14 national Arctic research expeditions.With the increase of understandings on the global impacts of the changes of Arctic climate system,especially on China’s weather and climate,and demands for commercial utilization of the Arctic sea routes,Chinese scientists have made great progresses on in site and remote sensing observation technologies for Arctic Ocean,interaction mechanisms between atmosphere,sea ice,and ocean,the connection mechanism between the Arctic Ocean and other regions,and have achieved a series of research results.This study summarizes the research achievements by Chinese scientists in the above-mentioned aspects or beyond,identifies knowledge gaps,and based on this,discusses prospects and provides suggestions.From a perspective of observation,improving the observation capabilities of the Arctic Ocean in winter and the ocean under the ice,as well as floe-scale processes of sea ice and mesoscale and submesoscale processes of the ocean,is an urgent task to be addressed.Strengthening international cooperation is necessary for building a monitoring network for the Arctic marine environment.From a perspective of numerical simulation,the descriptive ability and parameterization scheme of sub-grid processes based on observational evidence need to be developed.From a perspective of cross-sphere interactions,in addition to the multi-media coupling within the Arctic Ocean that this review focuses on,the interaction between the Arctic Ocean and land or ice sheet(Greenland),especially the water cycle process,is also a scientific domain that needs to be considered,in the context of Arctic warming and humidification.From a perspective of climate effects,the physical mechanisms that affect the robustness of teleconnection need to be clarified.
文摘In November 1984,China launched its first expedition to the Southern Ocean and the Antarctic continent,culminating in the establishment of its first year-round research station—Great Wall Station—on the Antarctic Peninsula in February 1985.Forty years later,in February 2024,China’s fifth research station,Qinling Station,commenced operations on Inexpress-ible Island near Terra Nova Bay.
基金supported by the National Natural Science Foundation of China(Grant No.U2342208)support from NSF/Climate Dynamics Award#2025057。
文摘Predicting monsoon climate is one of the major endeavors in climate science and is becoming increasingly challenging due to global warming. The accuracy of monsoon seasonal predictions significantly impacts the lives of billions who depend on or are affected by monsoons, as it is essential for the water cycle, food security, ecology, disaster prevention, and the economy of monsoon regions. Given the extensive literature on Asian monsoon climate prediction, we limit our focus to reviewing the seasonal prediction and predictability of the Asian Summer Monsoon (ASM). However, much of this review is also relevant to monsoon predictions in other seasons and regions. Over the past two decades, considerable progress has been made in the seasonal forecasting of the ASM, driven by an enhanced understanding of the sources of predictability and the dynamics of seasonal variability, along with advanced development in sophisticated models and technologies. This review centers on advances in understanding the physical foundation for monsoon climate prediction (section 2), significant findings and insights into the primary and regional sources of predictability arising from feedback processes among various climate components (sections 3 and 4), the effects of global warming and external forcings on predictability (section 5), developments in seasonal prediction models and techniques (section 6), the challenges and limitations of monsoon climate prediction (section 7), and emerging research trends with suggestions for future directions (section 8). We hope this review will stimulate creative activities to enhance monsoon climate prediction.
基金supported by the National Natural Science Foundation of China(41790474)the State Oceanic Administration International Cooperation Program on Global Change and Air–Sea Interactions(GASI-IPOVAI-03)
文摘This paper reviews recent progress made by Chinese scientists on the pathways of influence of the Northern Hemisphere mid-high latitudes on East Asian climate within the framework of a“coupled oceanic-atmospheric(land-atmospheric or seaice-atmospheric)bridge”and“chain coupled bridge”.Four major categories of pathways are concentrated upon,as follows:Pathway A—from North Atlantic to East Asia;Pathway B—from the North Pacific to East Asia;Pathway C—from the Arctic to East Asia;and Pathway D—the synergistic effects of the mid-high latitudes and tropics.In addition,definitions of the terms“combined effect”,“synergistic effect”and“antagonistic effect”of two or more factors of influence or processes and their criteria are introduced,so as to objectively investigate those effects in future research.
基金supported by the National Natural Science Foundation of China under the grant number 40675060the Chinese Ministry of Science and Technology under the 863 Project grant number 2006AA09Z151+2 种基金supported by the State Oceanic Administration under the grant 908-02-03-10the Chinese Meteorological Administration under the grant CMATG 2006M32supported by the National Science Foundation under grant number OISE-0229657.
文摘In this study, a sea fog event which occurred on 27 March 2005 over the Yellow and Bohai Seas was investigated observationally and numerically. Almost all available observational data were used, including satellite imagery of Geostationary Operational Environmental Satellite （GOES）-9, three data sets from station observations at Dandong, Dalian and Qingdao, objectively reanalyzed data of final run analysis （FNL） issued by the National Center for Environmental Prediction （NCEP） and Regional Atmospheric Modeling System （RANIS） results. Synoptic conditions and fog characteristics were analyzed. The fog formed when warm, moist air was advected northwards over the cool water of the Yellow and Bohai Seas, and dissipated when a cold front brought northerly winds and cool, dry air. In order to better understand the fog formation mechanism, a high-resolution RAMS modeling with a 6km×6km grid, initialized and validated by FNL data, was designed. A 48h modeling that started from 12 UTC 26 March 2005 reproduced the main characteristics of this sea fog event. The simulated lower visibility area agreed reasonably well with the sea fog region identified from the satellite imagery. Advection cooling effect seemed to play a significant role in the fog formation.
文摘On the basis of data of drifting bottles＇ tracks and the current measured in anchored stations, as well as temperature and salinity observed in cruise investigations and coastal stations, ADCP current data and AVHRR surface sea temperature （SST） data on the western coast of Guangdong, synthetic results of analysis showed that the coastal currents in the west of the mouth of the Zhujiang River were mainly westward in summer, which constituted the north branch of cyclonic gyre in the east of the Qiongzhou Straits. Part of its water flowed westward into the Beibu Gulf through the Qiongzhou Straits. The coastal current pattern was not identical with the traditional current system which flowed westward in the Qiongzhou Straits in winter and eastward in summer. The summertime＇s coastal current was always westward, maybe temporarily turning northeast only when the southwest wind was strong. The important characteristics of coastal current on the western coast of Guangdong, in the Qiongzhou Straits and in the north of the Beibu Gulf were analyzed and their mechanisms also were explained.
基金The Major Program of the National Natural Science Foundation of China under contact No.40890153The National High Tech-nology Research and Development Program of China(863 Program)under contact No.2008AA09A402
文摘The Argo data are used to calculate eddy（turbulence） heat transport（EHT） in the global ocean and analyze its horizontal distribution and vertical structure.We calculate the EHT by averaging all the v ′,T ′ profiles within each 2 ×2 bin.The velocity and temperature anomalies are obtained by removing their climatological values from the Argo ＂instantaneous＂ values respectively.Through the Student＇s t-test and an error evaluation,we obtained a total of 87% Argo bins with significant depth-integrated EHTs（D-EHTs）.The results reveal a positive-and-negative alternating D-EHT pattern along the western boundary currents（WBC） and Antarctic Circumpolar Current（ACC）.The zonally-integrated D-EHT（ZI-EHT） of the global ocean reaches 0.12 PW in the northern WBC band and –0.38 PW in the ACC band respectively.The strong ZI-EHT across the ACC in the global ocean is mainly caused by the southern Indian Ocean.The ZI-EHT in the above two bands accounts for a large portion of the total oceanic heat transport,which may play an important role in regulating the climate.The analysis of vertical structures of the EHT along the 35 N and 45 S section reveals that the oscillating EHT pattern can reach deep in the northern WBC regions and the Agulhas Return Current（ARC） region.It also shows that the strong EHT could reach 600 m in the WBC regions and 1 000 m in the ARC region,with the maximum mainly located between 100 and 400 m depth.The results would provide useful information for improving the parameterization scheme in models.
基金The National High Technology Research and Development Program(863 Program) of China under contract No.2013AA122803the Strategic Priority Research Program of the Chinese Academy of Sciences under contract No.XDA11010104
文摘Wave climate analysis and other applications for the Pacific Ocean require a reliable wave hindcast. Five source and sink term packages in the Wavewatch III model （v3.14 and v4.18） are compared and assessed in this study through comprehensive observations, including altimeter significant wave height, advanced synthetic aperture radar swell, and buoy wave parameters and spectrum. In addition to the evaluation of typically used integral parameters, the spectra partitioning method contributes to the detailed wave system and wave maturity validation. The modified performance evaluation method （PS） effectively reduces attribute numbers and facilitates the overall assessment. To avoid possible misleading results in the root mean square error-based validations, another indicator called HH （indicating the two authors） is also calculated to guarantee the consistency of the results. The widely used Tolman and Chalikov （TC） package is still generally efficient in determining the integral properties of wave spectra but is physically deficient in explaining the dissipation processes. The ST4 package performs well in overall wave parameters and significantly improves the accuracy of wave systems in the open ocean. Meanwhile, the newly published ST6 package is slightly better in determining swell energy variations. The two packages （ACC350 and BIA） obtained from Wavewatch III v3.14 exhibit large scatters at different sea states. The three most ideal packages are further examined in terms of reproducing wave- induced momentum flux from the perspective of transport. Stokes transport analysis indicates that ST4 is the closest to the NDBC-buoy-spectrum-based transport values, and TC and ST6 tend to overestimate and underestimate the transport magnitude, respectively, in swell mixed areas. This difference must be considered, particularly in air-wave-current coupling research and upper ocean analysis. The assessment results provide guidance for the selection of ST4 for use in a background Pacific Ocean hindcast for high wave climate research and China Sea swell type analysis.
