Because of their effect on climate,carbon dioxide(CO_(2)),methane(CH_(4)),nitrous oxide(N_(2)O),and dimethylsulfide(DMS)are collectively designated as climate-relevant gases(CRGs).CO_(2),CH_(4),and N_(2)O are greenhou...Because of their effect on climate,carbon dioxide(CO_(2)),methane(CH_(4)),nitrous oxide(N_(2)O),and dimethylsulfide(DMS)are collectively designated as climate-relevant gases(CRGs).CO_(2),CH_(4),and N_(2)O are greenhouse gases contributing to global warming(positive climate feedback).Conversely,DMS is involved in the generation of cloud condensation nuclei,thus in the formation of clouds that cool the boundary layer by reflecting incoming solar radiation(negative climate feedback).Despite their scarcity,field observations and model results have demonstrated the essential role of polar oceans in the budget of CRGs.For example,the Southern Ocean represents a substantial CO_(2)sink but a source of N_(2)O and DMS,thereby exerting variable feedback on climate change.Unfortunately,because of the severe environmental conditions at polar latitudes,substantial knowledge gaps remain,for example on the mechanisms underlying CRGs formation or on the strength and distribution of their sources and sinks in the Southern and Arctic Oceans.Here,we review the most recent research results on the distribution,production-loss processes,and abundance variations of CRGs in the polar oceans.We list the remaining knowledge gaps and propose future directions of research on CRGs in the polar oceans,as a useful reference for future studies.展开更多
There have always been academic debates regarding the timing and geodynamics of the superimposition and transformation between the Paleo-Pacific Ocean and the Paleo-Asian Ocean.To resolve the relevant issues over this...There have always been academic debates regarding the timing and geodynamics of the superimposition and transformation between the Paleo-Pacific Ocean and the Paleo-Asian Ocean.To resolve the relevant issues over this debate,the authors selected the Jilin–Heilongjiang high-pressure metamorphic belt(Ji–Hei HP Belt)between the Jiamusi–Khanka Block and the Songliao Block in NE China as the study area.This area preserves important records of the superimposition and transformation between these two tectonic domains.This study aims to address this issue through geochemical and zircon U–Pb dating analyses of the Yilan blueschist of Heilongjiang Complex exposed in the Ji–Hei HP Belt.In the geochemical analysis,it has been discovered that the protoliths of the blueschist in the Yilan area consist of subalkaline basalt,which displays geochemical characteristics of Ocean Island Basalt that indicated an oceanic island setting.The LA–ICP–MS zircon U–Pb analysis yields ages of 248±4 Ma and 259±2 Ma from the magma zircons of the blueschists,indicating that the basalt protolith was formed in Late Permian to Early Triassic(259–248 Ma).Based on the results of this study and the regional data,it is proposed that the Jilin–Heilongjiang Ocean opened during Late Permian to Early Triassic(259–248 Ma).This period marks a crucial stage from the closure of the Paleo-Asian Ocean to the initiation of Paleo-Pacific oceanic subduction.展开更多
The movement of global ocean circulation in the Earth’s main magnetic field generates a measurable induced magnetic field(about 2 nT at geomagnetic satellite altitudes).However,this ocean circulation-induced magnetic...The movement of global ocean circulation in the Earth’s main magnetic field generates a measurable induced magnetic field(about 2 nT at geomagnetic satellite altitudes).However,this ocean circulation-induced magnetic field has not been previously estimated or incorporated into geomagnetic field models,potentially causing leakage into the core field model.Here,we present a method to account for the circulation-induced magnetic field during geomagnetic field modeling.First,a forward model of the circulation-induced magnetic field is constructed by numerically solving electromagnetic induction equations based on a realistic ocean circulation model.Then,this forward model is subtracted from the observed data.Finally,the core and lithospheric fields,magnetospheric and Earth’s mantle-induced fields,and the ocean tide-induced magnetic field are co-estimated.Applying our method to over 20 years of MSS-1,Swarm,CryoSat-2,and CHAMP satellite magnetic data,we derive a new multisource geomagnetic field model(MGFM).We find that incorporating a forward model of the circulation-induced magnetic field marginally improves the fit to the data.Furthermore,we demonstrate that neglecting the circulation-induced magnetic field in geomagnetic field modeling results in leakage into the core field model.The highlights of the MGFM model include:(i)a good agreement with the widely used CHAOS model series;(ii)the incorporation of magnetic fields induced by both ocean tides and circulation;and(iii)the suppression of leakage of the circulation-induced magnetic field into the core field model.展开更多
Aims and scope Being an international journal,China Ocean Engineering(COE)takes its prime function as the integration of new research concepts,equipment,technology,materials and structures and other scientific advance...Aims and scope Being an international journal,China Ocean Engineering(COE)takes its prime function as the integration of new research concepts,equipment,technology,materials and structures and other scientific advances within the field of estuarial,coastal,offshore,and deepwater engineering with particular reference to developments.The Journal is concerned with all engineering aspects involved in the exploration and utilization of ocean resources.Topics regularly covered include research,design and construction of structures(including wharfs,dikes,breakwaters,platforms,mooring systems,etc.),instrumentation/testing(physical model and numerical model),wave dynamics,sedimentation,structural/stress analysis,soil mechanics,and material research.展开更多
Heating in the ocean has continued in 2024 in response to increased greenhouse gas concentrations in the atmosphere,despite the transition from an El Ni?o to neutral conditions. In 2024, both global sea surface temper...Heating in the ocean has continued in 2024 in response to increased greenhouse gas concentrations in the atmosphere,despite the transition from an El Ni?o to neutral conditions. In 2024, both global sea surface temperature(SST) and upper2000 m ocean heat content(OHC) reached unprecedented highs in the historical record. The 0–2000 m OHC in 2024exceeded that of 2023 by 16 ± 8 ZJ(1 Zetta Joules = 1021 Joules, with a 95% confidence interval)(IAP/CAS data), which is confirmed by two other data products: 18 ± 7 ZJ(CIGAR-RT reanalysis data) and 40 ± 31 ZJ(Copernicus Marine data,updated to November 2024). The Indian Ocean, tropical Atlantic, Mediterranean Sea, North Atlantic, North Pacific, and Southern Ocean also experienced record-high OHC values in 2024. The global SST continued its record-high values from2023 into the first half of 2024, and declined slightly in the second half of 2024, resulting in an annual mean of 0.61°C ±0.02°C(IAP/CAS data) above the 1981–2010 baseline, slightly higher than the 2023 annual-mean value(by 0.07°C ±0.02°C for IAP/CAS, 0.05°C ± 0.02°C for NOAA/NCEI, and 0.06°C ± 0.11°C for Copernicus Marine). The record-high values of 2024 SST and OHC continue to indicate unabated trends of global heating.展开更多
Dr Emily Thompson decided it was time to set sail on her first major maritime research expedition.She had always been fascinated by the mysteries of the ocean and wanted to uncover the secrets hidden beneath the waves...Dr Emily Thompson decided it was time to set sail on her first major maritime research expedition.She had always been fascinated by the mysteries of the ocean and wanted to uncover the secrets hidden beneath the waves.Her team boarded the research vessel early in the morning,excited at the adventure that awaited them.展开更多
A halocline in the Arctic Ocean significantly slows the upward heat flux from deep warm water,thereby inhibiting the melting of surface sea ice.The western Arctic Ocean exhibits a double-halocline(DH)structure due to ...A halocline in the Arctic Ocean significantly slows the upward heat flux from deep warm water,thereby inhibiting the melting of surface sea ice.The western Arctic Ocean exhibits a double-halocline(DH)structure due to the complexity of the water mass.Using in situ measurements,we analyzed the vertical structural characteristics of DH and its interannual variation.The results indicated that the DH primarily occurs at the Northwind Ridge and the southern Canada Basin,extending westward to the Chukchi Abyssal Plain and northward to the northern boundary of the Canada Basin.From 2002 to 2022,there were changes in water masses that determined the structure of the DH.The significant increase in Pacific Water has resulted in 42%and 65%increases in freshwater and the heat content of the DH,respectively,along with a 14%reduction in stratification.Pacific Winter Water characterized by salinity of 33 has exhibited a gradually decreasing trend,suggesting that the lower halocline may be difficult to ventilate.The combined effects of Ekman pumping,mesoscale eddies,and positive buoyancy forcing(heat and freshwater input)from Pacific Water have altered the thickness and stratification of the DH.This study has enhanced our understanding of the evolution of vertical heat flux in the upper western Arctic Ocean.展开更多
The Middle to Late Jurassic,high-pressure metamorphic ophiolites of Inzecca Unit are well exposed in the Noceta-Vezzani area of Alpine Corsica.These metaophiolites were studied by using a multidisciplinary approach to...The Middle to Late Jurassic,high-pressure metamorphic ophiolites of Inzecca Unit are well exposed in the Noceta-Vezzani area of Alpine Corsica.These metaophiolites were studied by using a multidisciplinary approach to reconstruct the architecture of the oceanic sector from which they derived.The collected data indicate that this oceanic crust consists of a mantle metaperidotites and metaophicalcites,both covered by massive or pillow metabasalts with or without a layer of ophiolite-bearing metabreccias.展开更多
Marine heatwaves(MHWs)are extreme ocean events characterized by anomalously warm upper-ocean temperatures,posing significant threats to marine ecosystems.While various factors driving MHWs have been extensively studie...Marine heatwaves(MHWs)are extreme ocean events characterized by anomalously warm upper-ocean temperatures,posing significant threats to marine ecosystems.While various factors driving MHWs have been extensively studied,the role of ocean salinity remains poorly understood.This study investigates the influence of salinity on the major 2013-2014 MHW event in the Northeast Pacific using reanalysis data and climate model outputs.Our results show that salinity variabilities are crucial for the development of the MHW event.Notably,a significant negative correlation exists between sea surface temperature anomalies(SSTAs)and sea surface salinity anomalies(SSSAs)during the MHW,with the SSSAs emerging simultaneously with SSTAs in the same area.Negative salinity anomalies(SAs)result in a shallower mixed layer,which suppresses vertical mixing and thus sustains the upper-ocean warming.Moreover,salinity has a greater impact on mixed layer depth anomalies than temperature.Model sensitivity experiments further demonstrate that negative SAs during MHWs amplify positive SSTAs by enhancing upper-ocean stratification,intensifying the MHW.Additionally,our analysis indicates that the SAs are predominantly driven by local freshwater flux anomalies,which are mainly induced by positive precipitation anomalies during the MHW event.展开更多
High-Mg andesite/diorite(HMA)is useful for identifying subduction-related processes in orogenic belts,including the identification of ophiolites formed in suprasubduction zone(SSZ)environments.The E'rentaolegai hi...High-Mg andesite/diorite(HMA)is useful for identifying subduction-related processes in orogenic belts,including the identification of ophiolites formed in suprasubduction zone(SSZ)environments.The E'rentaolegai high-Mg diorite from the Diyanmiao ophiolite in central Inner Mongolia,North China,has been investigated revealing low-K tholeiitic-calc-alkaline characteristics and have SiO_(2)contents of 53.44-54.92 wt%,MgO contents of 8.44-9.54 wt%,and Mg~#of 54.35-57.60,with variable Fe_(2)O_(3)(7.51-8.61 wt%),Al_(2)O_(3)(11.95-15.09 wt%),and Na_(2)O(3.42-3.94 wt%)contents,low K_(2)O(0.34-0.97 wt%),TiO_(2)(0.35-0.67 wt%),and P2O5(0.12-0.15 wt%)contents,and high Ni(43-193 ppm)and Cr(189-556 ppm)contents.Samples collected have low total rare earth element(REE)contents(30.58-77.80 ppm),with flat or slightly right-dipping REE patterns(La_(N)/Yb_(N)=2.19-3.11)and a lack of pronounced Eu anomalies.The samples are also enriched in large-ion lithophile elements(LILEs,e.g.,K,Rb,Ba,U,and Sr)and depleted in high field strength elements(e.g.,Ta,Nb,Ti,and P).The E'rentaolegai high-Mg diorite has characteristics typical of HMA,and are similar to those of sanukites from the Setouchi Arc in SW Japan.They also display high positiveε_(Nd)(t)values(+6.32 to+7.80),comparable to the values of their host rocks.Petrogenetic analyses suggest that the E'rentaolegai HMA was probably formed by the interaction of partial melts and aqueous fluids from subducted sediments with mantle peridotite.Zircon U-Pb dating reveals that the high-Mg diorite crystallized at 313.6±2.4 Ma,i.e.,late Carboniferous.Combining our data with the temporal and spatial distribution of the Diyanmiao SSZ-type ophiolite,we propose that the eastern Paleo-Asian Ocean had not closed by the late Carboniferous,but intra-oceanic subduction was ongoing.A new model of the initiation of subduction in the eastern PAO during the late Paleozoic.展开更多
This review compiles studies on paleoceanographic and paleoenvironmental changes in the high-latitude Southern Ocean during the late Quaternary based on Chinese Antarctic Expeditions.Four major findings are summarized...This review compiles studies on paleoceanographic and paleoenvironmental changes in the high-latitude Southern Ocean during the late Quaternary based on Chinese Antarctic Expeditions.Four major findings are summarized as follows.(1)Diatom compositions in sediment record sea surface condition changes in the Bransfield Strait and Cosmonaut Sea,indicating an increase in sea ice cover since the Mid-Holocene for both areas,possibly linked to cold water mass injection from the Weddell Sea ice shelf.(2)Export productivity records from Antarctic marginal seas show a glacial-interglacial variation pattern,with higher and lower productivity during the interglacial and glacial periods,respectively,controlled by both the intensity of Circumpolar Deep Water upwelling and sea ice cover.An overall increase of export productivity from Marine Isotope Stage(MIS)12 to MIS 6 is noticed.(3)Ventilation state of the abyssal Southern Ocean is closely related to global climate change and atmospheric CO_(2) concentrations,with elevated ventilation efficiency during deglacial periods responsible for elevated atmospheric CO_(2) concentrations.(4)Antarctic marine-based ice sheets/glaciers wax and wane in line with global and regional ice volume changes,predominantly subject to oceanic forcing,while land-based ice sheets might only reorganize in specific glacial intervals.Despite significant progress in understanding the role of the Southern Ocean and the Antarctic Ice Sheet within the global climate system,challenges remain in sample collection and research methods.Future studies should aim to collect samples from a broader range of latitudes,ensure higher quality and longer temporal span,resolve dating issues,reconstruct seawater temperature,and focus on reconstructions of Southern Ocean carbon cycling and changes of intermediate to deep water masses.展开更多
As the Arctic undergoes rapid warming and sea ice continues to decline,Ocean-to-Ice Heat Flux(OIHF)plays a crucial role in regulating sea ice dynamics.This study investigates the seasonal variations in ocean-to-ice he...As the Arctic undergoes rapid warming and sea ice continues to decline,Ocean-to-Ice Heat Flux(OIHF)plays a crucial role in regulating sea ice dynamics.This study investigates the seasonal variations in ocean-to-ice heat flux in north of the Fram Strait using the regional Arctic Ocean/sea ice reanalysis product from 1991 to 2020.The analysis reveals that the OIHF exhibits significant seasonal variability,with a pronounced peak during winter in north of the Fram Strait,driven by inflows of Atlantic water.Warm Atlantic water intrusion begins in October,reaches its peak in January and February,and results in a delayed increase in OIHF,with maximum flux observed 2−3 months later.These results highlight the significant role of Atlantic water inflows in influencing Arctic sea ice dynamics and emphasize the need for further investigation into the coupled ocean-atmosphere processes that govern seasonal fluctuations in OIHF.展开更多
This paper presents the networking observation capabilities of Chinese ocean satellites and their diverse applications in ocean disaster prevention,ecological monitoring,and resource development.Since the inaugural la...This paper presents the networking observation capabilities of Chinese ocean satellites and their diverse applications in ocean disaster prevention,ecological monitoring,and resource development.Since the inaugural launch in 2002,China has achieved substantial advancements in ocean satellite technology,forming an observation system composed of the HY-1,HY-2,and HY-3 series satellites.These satellites are integral to global ocean environmental monitoring due to their high resolution,extensive coverage,and frequent observations.Looking forward,China aims to further enhance and expand its ocean satellite capabilities through ongoing projects to support global environmental protection and sustainable development.展开更多
The lithospheric magnetic field is an important component of the geomagnetic field,and the oceanic lithosphere exhibits distinct characteristics.Because of its formation mechanisms,evolutionary history,and geomagnetic...The lithospheric magnetic field is an important component of the geomagnetic field,and the oceanic lithosphere exhibits distinct characteristics.Because of its formation mechanisms,evolutionary history,and geomagnetic field polarity reversals,the oceanic lithosphere has significant remanent magnetization,which causes magnetic anomaly stripes parallel to the mid-ocean ridges.However,it is difficult to construct a high-resolution lithospheric magnetic field model in oceanic regions with relatively sparse data or no data.Using forward calculated lithospheric magnetic field data based on an oceanic remanent magnetization(ORM) model with physical and geological foundations as a supplement is a feasible approach.We first collect the latest available oceanic crust age grid,plate motion model,geomagnetic polarity timescale,and oceanic lithosphere thermal structure.Combining the assumptions that the paleo geomagnetic field is a geocentric axial dipole field and that the normal oceanic crust moves only in the horizontal direction,we construct a vertically integrated ORM model of the normal oceanic crust with a known age,including the intensity,inclination,and declination.Both the ORM model and the global induced magnetization(GIM) model are then scaled from two aspects between their forward calculated results and the lithospheric magnetic field model LCS-1.One aspect is the difference in their spherical harmonic power spectra,and the other is the misfit between the grid data over the oceans.We last compare the forward calculated lithospheric magnetic anomaly from the scaled ORM and GIM models with the Macao Science Satellite-1(MSS-1) observed data.The comparison results show that the magnetic anomalies over the normal oceanic crust regions at satellite altitude are mainly contributed by the high-intensity remanent magnetization corresponding to the Cretaceous magnetic quiet period.In these regions,the predicted and observed anomalies show good consistency in spatial distribution,whereas their amplitude differences vary across regions.This result suggests that regional ORM construction should be attempted in future work to address these amplitude discrepancies.展开更多
Mesoscale eddies play a central role in the poleward oceanic heat flux in the Southern Ocean.Previous studies have documented changes in the location of temperature fronts in the Southern Ocean,but little attention ha...Mesoscale eddies play a central role in the poleward oceanic heat flux in the Southern Ocean.Previous studies have documented changes in the location of temperature fronts in the Southern Ocean,but little attention has been paid to changes in the genesis locations of mesoscale eddies.Here,we provide evidence from three decades of satellite altimetry observations for the heterogeneity of the poleward shift of mesoscale activities,with the largest trend of~0.23°±0.05°(10 yr)^(-1) over the Atlantic sector and a moderate trend of~0.1°±0.03°(10 yr)^(-1) over the Indian sector,but no significant trend in the Pacific sector.The poleward shift of mesoscale eddies is associated with a southward shift of the local westerly winds while being constrained by the major topographies.As the poleward shift of westerly winds is projected to persist,the poleward oceanic heat flux from mesoscale eddies may influence future ice melt.展开更多
The Earth's crust,the outer shell of the Earth,consists of continental crust and oceanic crust.Oceanic crust is created at the mid-oceanic ridge,where it is magnetized in the ambient field of the Earth.As new mate...The Earth's crust,the outer shell of the Earth,consists of continental crust and oceanic crust.Oceanic crust is created at the mid-oceanic ridge,where it is magnetized in the ambient field of the Earth.As new material is extruded,the crust spreads outward,retaining its magnetization.The reversal of the polarity of the Earth's magnetic field over geologic time leads to a pattern of striped magnetic anomalies.In this study,we carry out a preliminary evaluation on how data from the Macao Science Satellite-1(MSS-1),which has a low orbital inclination,influences inversion models of the oceanic crustal magnetic field when combined with data from the Swarm mission.For our modeling we use an equivalent source method based on a cubed-sphere grid.Our model captures the broad magnetic structure over the North Atlantic Ocean and demonstrates that the trend of magnetic stripes is consistent with the age frame of the oceanic crust.The amplitude of the radial magnetic field at 450 km the North Atlantic Ocean ranges from–11 nT to+8 nT.The addition of MSS-1 observations to Swarm data generates results consistent with the overall magnetic stripe pattern.The lack of short-wavelength scale structure reveals the limitation of high-altitude satellites in portraying fine features and hence lower-altitude observations would be required to delineate a more detailed crustal signature.It is expected to obtain a finer structure of oceanic magnetic stripes by combining low-altitude CHAMP field data and east-west gradient data derived from MSS-1 in future work.展开更多
With respect to oceanic fluid dynamics,certain models have appeared,e.g.,an extended time-dependent(3+1)-dimensional shallow water wave equation in an ocean or a river,which we investigate in this paper.Using symbolic...With respect to oceanic fluid dynamics,certain models have appeared,e.g.,an extended time-dependent(3+1)-dimensional shallow water wave equation in an ocean or a river,which we investigate in this paper.Using symbolic computation,we find out,on one hand,a set of bilinear auto-Backlund transformations,which could connect certain solutions of that equation with other solutions of that equation itself,and on the other hand,a set of similarity reductions,which could go from that equation to a known ordinary differential equation.The results in this paper depend on all the oceanic variable coefficients in that equation.展开更多
A remarkable marine heatwave,known as the“Blob”,occurred in the Northeast Pacific Ocean from late 2013 to early 2016,which displayed strong warm anomalies extending from the surface to a depth of 300 m.This study em...A remarkable marine heatwave,known as the“Blob”,occurred in the Northeast Pacific Ocean from late 2013 to early 2016,which displayed strong warm anomalies extending from the surface to a depth of 300 m.This study employed two assimilation schemes based on the global Climate Forecast System of Nanjing University of Information Science(NUIST-CFS 1.0)to investigate the impact of ocean data assimilation on the seasonal prediction of this extreme marine heatwave.The sea surface temperature(SST)nudging scheme assimilates SST only,while the deterministic ensemble Kalman filter(EnKF)scheme assimilates observations from the surface to the deep ocean.The latter notably improves the forecasting skill for subsurface temperature anomalies,especially at the depth of 100-300 m(the lower layer),outperforming the SST nudging scheme.It excels in predicting both horizontal and vertical heat transport in the lower layer,contributing to improved forecasts of the lower-layer warming during the Blob.These improvements stem from the assimilation of subsurface observational data,which are important in predicting the upper-ocean conditions.The results suggest that assimilating ocean data with the EnKF scheme significantly enhances the accuracy in predicting subsurface temperature anomalies during the Blob and offers better understanding of its underlying mechanisms.展开更多
The mechanical influences involved in the interaction between the Antarctic sea ice and ocean surface current(OSC)on the subpolar Southern Ocean have been systematically investigated for the first time by conducting t...The mechanical influences involved in the interaction between the Antarctic sea ice and ocean surface current(OSC)on the subpolar Southern Ocean have been systematically investigated for the first time by conducting two simulations that include and exclude the OSC in the calculation of the ice-ocean stress(IOS), using an eddy-permitting coupled ocean-sea ice global model. By comparing the results of these two experiments, significant increases of 5%, 27%, and 24%, were found in the subpolar Southern Ocean when excluding the OSC in the IOS calculation for the ocean surface stress,upwelling, and downwelling, respectively. Excluding the OSC in the IOS calculation also visibly strengthens the total mechanical energy input to the OSC by about 16%, and increases the eddy kinetic energy and mean kinetic energy by about38% and 12%, respectively. Moreover, the response of the meridional overturning circulation in the Southern Ocean yields respective increases of about 16% and 15% for the upper and lower branches;and the subpolar gyres are also found to considerably intensify, by about 12%, 11%, and 11% in the Weddell Gyre, the Ross Gyre, and the Australian-Antarctic Gyre, respectively. The strengthened ocean circulations and Ekman pumping result in a warmer sea surface temperature(SST), and hence an incremental surface heat loss. The increased sea ice drift and warm SST lead to an expansion of the sea ice area and a reduction of sea ice volume. These results emphasize the importance of OSCs in the air-sea-ice interactions on the global ocean circulations and the mass balance of Antarctic ice shelves, and this component may become more significant as the rapid change of Antarctic sea ice.展开更多
The Heilongjiang Complex in northeast China(NE China)separates the Jiamusi and Songliao blocks and marks the suture zone of the former Mudanjiang Ocean,as evidenced by a variety of oceanic basalt-derived blueschists.U...The Heilongjiang Complex in northeast China(NE China)separates the Jiamusi and Songliao blocks and marks the suture zone of the former Mudanjiang Ocean,as evidenced by a variety of oceanic basalt-derived blueschists.Understanding the closure history of the Mudanjiang Ocean is crucial to unravelling the tectonic transition from the final amalgamation of the Central Asian Orogenic Belt(CAOB)to the onset of the Paleo-Pacific subduction.In this study,we investigate epidote-ferroglaucophane(Ep-Fgl)and garnet-ferrobarroisite(Grt-Fbrs)schists from the Yilan area of the Heilongjiang Complex through petrological,mineralogical,thermodynamic modelling,whole-rock geochemical,and geochronological analyses.The Ep-Fgl schists preserve a peak assemblage of ferroglaucophane+epidote+chlorite+clinopyroxene+phengite+titanite with peak P-T conditions of 13.5-15.8 kbar and 458-495℃.On the other hand,the Grt-Fbrs schists exhibit a peak assemblage of garnet+glaucophane/ferroglaucophane+lawsonite+chlorite+phengite+rutile±clinopyroxene±titanite,deriving peak P-T conditions of 16.4-18.3 kbar and 457-475℃.Both types of schist record similar clockwise P-T paths,with three metamorphic stages:a peak epidote-to-lawsonite blueschist-facies stage,a post-peak decompression stage in the epidote amphibolite-facies,and a late greenschist-facies overprint stage.The Ep-Fgl schists display alkaline OIB-like geochemical affinities,while the Grt-Fbrs schists show tholeiitic MORB-like characteristics,suggesting that the protoliths represent fragments of the Mudanjiang oceanic crust.Magmatic zircon grains from Ep-Fgl schists yield protolith ages of 276±1 Ma and 280±1 Ma,whereas zircon of Grt-Fbrs schists document protolith ages of 249±2 Ma and 248±2 Ma,indicating that the Mudanjiang Ocean existed since at least the early Permian.Reconstruction of the metamorphic P-T evolution,combined with previous magmatic and metamorphic age data from rocks of the Heilongjiang Complex and of adjacent tectonic units suggests that the subduction and eventual closure of the Mudanjiang Ocean occurred between the late Triassic and middle Jurassic,driven by a regional stress regime shift caused by the westward subduction of the Paleo-Pacific Plate beneath Eurasia.展开更多
基金supported the National Natural Science Foundation of China(Grant nos.4227624,42376239 and 42476253)。
文摘Because of their effect on climate,carbon dioxide(CO_(2)),methane(CH_(4)),nitrous oxide(N_(2)O),and dimethylsulfide(DMS)are collectively designated as climate-relevant gases(CRGs).CO_(2),CH_(4),and N_(2)O are greenhouse gases contributing to global warming(positive climate feedback).Conversely,DMS is involved in the generation of cloud condensation nuclei,thus in the formation of clouds that cool the boundary layer by reflecting incoming solar radiation(negative climate feedback).Despite their scarcity,field observations and model results have demonstrated the essential role of polar oceans in the budget of CRGs.For example,the Southern Ocean represents a substantial CO_(2)sink but a source of N_(2)O and DMS,thereby exerting variable feedback on climate change.Unfortunately,because of the severe environmental conditions at polar latitudes,substantial knowledge gaps remain,for example on the mechanisms underlying CRGs formation or on the strength and distribution of their sources and sinks in the Southern and Arctic Oceans.Here,we review the most recent research results on the distribution,production-loss processes,and abundance variations of CRGs in the polar oceans.We list the remaining knowledge gaps and propose future directions of research on CRGs in the polar oceans,as a useful reference for future studies.
基金Supported by projects of the National Natural Science Foundation of China(Nos.42430305,42430303 and 42302236).
文摘There have always been academic debates regarding the timing and geodynamics of the superimposition and transformation between the Paleo-Pacific Ocean and the Paleo-Asian Ocean.To resolve the relevant issues over this debate,the authors selected the Jilin–Heilongjiang high-pressure metamorphic belt(Ji–Hei HP Belt)between the Jiamusi–Khanka Block and the Songliao Block in NE China as the study area.This area preserves important records of the superimposition and transformation between these two tectonic domains.This study aims to address this issue through geochemical and zircon U–Pb dating analyses of the Yilan blueschist of Heilongjiang Complex exposed in the Ji–Hei HP Belt.In the geochemical analysis,it has been discovered that the protoliths of the blueschist in the Yilan area consist of subalkaline basalt,which displays geochemical characteristics of Ocean Island Basalt that indicated an oceanic island setting.The LA–ICP–MS zircon U–Pb analysis yields ages of 248±4 Ma and 259±2 Ma from the magma zircons of the blueschists,indicating that the basalt protolith was formed in Late Permian to Early Triassic(259–248 Ma).Based on the results of this study and the regional data,it is proposed that the Jilin–Heilongjiang Ocean opened during Late Permian to Early Triassic(259–248 Ma).This period marks a crucial stage from the closure of the Paleo-Asian Ocean to the initiation of Paleo-Pacific oceanic subduction.
基金supported by the National Natural Science Foundation of China(42250101,42250102)the Macao Foundation.
文摘The movement of global ocean circulation in the Earth’s main magnetic field generates a measurable induced magnetic field(about 2 nT at geomagnetic satellite altitudes).However,this ocean circulation-induced magnetic field has not been previously estimated or incorporated into geomagnetic field models,potentially causing leakage into the core field model.Here,we present a method to account for the circulation-induced magnetic field during geomagnetic field modeling.First,a forward model of the circulation-induced magnetic field is constructed by numerically solving electromagnetic induction equations based on a realistic ocean circulation model.Then,this forward model is subtracted from the observed data.Finally,the core and lithospheric fields,magnetospheric and Earth’s mantle-induced fields,and the ocean tide-induced magnetic field are co-estimated.Applying our method to over 20 years of MSS-1,Swarm,CryoSat-2,and CHAMP satellite magnetic data,we derive a new multisource geomagnetic field model(MGFM).We find that incorporating a forward model of the circulation-induced magnetic field marginally improves the fit to the data.Furthermore,we demonstrate that neglecting the circulation-induced magnetic field in geomagnetic field modeling results in leakage into the core field model.The highlights of the MGFM model include:(i)a good agreement with the widely used CHAOS model series;(ii)the incorporation of magnetic fields induced by both ocean tides and circulation;and(iii)the suppression of leakage of the circulation-induced magnetic field into the core field model.
文摘Aims and scope Being an international journal,China Ocean Engineering(COE)takes its prime function as the integration of new research concepts,equipment,technology,materials and structures and other scientific advances within the field of estuarial,coastal,offshore,and deepwater engineering with particular reference to developments.The Journal is concerned with all engineering aspects involved in the exploration and utilization of ocean resources.Topics regularly covered include research,design and construction of structures(including wharfs,dikes,breakwaters,platforms,mooring systems,etc.),instrumentation/testing(physical model and numerical model),wave dynamics,sedimentation,structural/stress analysis,soil mechanics,and material research.
基金supported by the National Key R&D Program of China (Grant No.2023YFF0806500)the International Partnership Program of the Chinese Academy of Sciences (Grant No.060GJHZ2024064MI)+10 种基金the Chinese Academy of Sciences and the National Research Council of Italy Scientific Cooperative Programmethe new Cornerstone Science Foundation through the XPLORER PRIZEthe National Key Scientific and Technological Infrastructure project “Earth System Science Numerical Simulator Facility” (Earth Lab), and Ocean Negative Carbon Emissions (ONCE)sponsored by the US National Science Foundationsupported by the Young Talent Support Project of Guangzhou Association for Science and Technologythe Open Research Cruise NORC2022-10+NORC2022-303 supported by NSFC shiptime Sharing Projects 42149910supported by NASA Awards 80NSSC17K0565, 80NSSC21K1191, and 80NSSC22K0046by the Regional and Global Model Analysis (RGMA) component of the Earth and Environmental System Modeling Program of the U.S.Department of Energy’s Office of Biological & Environmental Research (BER) via National Science Foundation IA 1947282supported by NOAA (Grant No.NA19NES4320002 to CISESS-MD at the University of Maryland)supported by the Austrian Science Fund (P33177)ESA (contract ref.4000145298/24/I-LR)。
文摘Heating in the ocean has continued in 2024 in response to increased greenhouse gas concentrations in the atmosphere,despite the transition from an El Ni?o to neutral conditions. In 2024, both global sea surface temperature(SST) and upper2000 m ocean heat content(OHC) reached unprecedented highs in the historical record. The 0–2000 m OHC in 2024exceeded that of 2023 by 16 ± 8 ZJ(1 Zetta Joules = 1021 Joules, with a 95% confidence interval)(IAP/CAS data), which is confirmed by two other data products: 18 ± 7 ZJ(CIGAR-RT reanalysis data) and 40 ± 31 ZJ(Copernicus Marine data,updated to November 2024). The Indian Ocean, tropical Atlantic, Mediterranean Sea, North Atlantic, North Pacific, and Southern Ocean also experienced record-high OHC values in 2024. The global SST continued its record-high values from2023 into the first half of 2024, and declined slightly in the second half of 2024, resulting in an annual mean of 0.61°C ±0.02°C(IAP/CAS data) above the 1981–2010 baseline, slightly higher than the 2023 annual-mean value(by 0.07°C ±0.02°C for IAP/CAS, 0.05°C ± 0.02°C for NOAA/NCEI, and 0.06°C ± 0.11°C for Copernicus Marine). The record-high values of 2024 SST and OHC continue to indicate unabated trends of global heating.
文摘Dr Emily Thompson decided it was time to set sail on her first major maritime research expedition.She had always been fascinated by the mysteries of the ocean and wanted to uncover the secrets hidden beneath the waves.Her team boarded the research vessel early in the morning,excited at the adventure that awaited them.
基金The National Key Research and Development Program of China under contract No.2023YFC2809101the National Natural Science Foundation of China under contract No.42276239.
文摘A halocline in the Arctic Ocean significantly slows the upward heat flux from deep warm water,thereby inhibiting the melting of surface sea ice.The western Arctic Ocean exhibits a double-halocline(DH)structure due to the complexity of the water mass.Using in situ measurements,we analyzed the vertical structural characteristics of DH and its interannual variation.The results indicated that the DH primarily occurs at the Northwind Ridge and the southern Canada Basin,extending westward to the Chukchi Abyssal Plain and northward to the northern boundary of the Canada Basin.From 2002 to 2022,there were changes in water masses that determined the structure of the DH.The significant increase in Pacific Water has resulted in 42%and 65%increases in freshwater and the heat content of the DH,respectively,along with a 14%reduction in stratification.Pacific Winter Water characterized by salinity of 33 has exhibited a gradually decreasing trend,suggesting that the lower halocline may be difficult to ventilate.The combined effects of Ekman pumping,mesoscale eddies,and positive buoyancy forcing(heat and freshwater input)from Pacific Water have altered the thickness and stratification of the DH.This study has enhanced our understanding of the evolution of vertical heat flux in the upper western Arctic Ocean.
基金supported by PRIN 2020 project(Resp.Michele Marroni)Claudia D’Oriano(INGV)Matteo Masotta and Danis Filimon(Earth Science Dept)are also thanked for analytical support in the laboratoriesThis work benefited from the PRA 2022 project handled by Francesca Meneghini.
文摘The Middle to Late Jurassic,high-pressure metamorphic ophiolites of Inzecca Unit are well exposed in the Noceta-Vezzani area of Alpine Corsica.These metaophiolites were studied by using a multidisciplinary approach to reconstruct the architecture of the oceanic sector from which they derived.The collected data indicate that this oceanic crust consists of a mantle metaperidotites and metaophicalcites,both covered by massive or pillow metabasalts with or without a layer of ophiolite-bearing metabreccias.
基金The Laoshan Laboratory under contract Nos LSKJ202202403 and LSKJ202202402the National Natural Science Foundation of China under contract Nos 42030410 and 42406202+3 种基金the Natural Science Foundation of Jiangsu Province under contract No.BK20240718the Startup Foundation for Introducing Talent of Nanjing University of Information Science and Technologythe Jiangsu Innovation Research Group under contract No.JSSCTD202346the Jiangsu Funding Program for Excellent Postdoctoral Talent under contract No.2023ZB690.
文摘Marine heatwaves(MHWs)are extreme ocean events characterized by anomalously warm upper-ocean temperatures,posing significant threats to marine ecosystems.While various factors driving MHWs have been extensively studied,the role of ocean salinity remains poorly understood.This study investigates the influence of salinity on the major 2013-2014 MHW event in the Northeast Pacific using reanalysis data and climate model outputs.Our results show that salinity variabilities are crucial for the development of the MHW event.Notably,a significant negative correlation exists between sea surface temperature anomalies(SSTAs)and sea surface salinity anomalies(SSSAs)during the MHW,with the SSSAs emerging simultaneously with SSTAs in the same area.Negative salinity anomalies(SAs)result in a shallower mixed layer,which suppresses vertical mixing and thus sustains the upper-ocean warming.Moreover,salinity has a greater impact on mixed layer depth anomalies than temperature.Model sensitivity experiments further demonstrate that negative SAs during MHWs amplify positive SSTAs by enhancing upper-ocean stratification,intensifying the MHW.Additionally,our analysis indicates that the SAs are predominantly driven by local freshwater flux anomalies,which are mainly induced by positive precipitation anomalies during the MHW event.
基金supported by the Ministry of Science and Technology of the People’s Republic of China(Grant No.2022FY101704)the National Natural Science Foundation of China(Grant No.41972061)+1 种基金Science and Technology Innovation Team of Hebei GEO University(30801071)the China Geological Survey(Grant Nos.1212011120701 and 1212011120711)。
文摘High-Mg andesite/diorite(HMA)is useful for identifying subduction-related processes in orogenic belts,including the identification of ophiolites formed in suprasubduction zone(SSZ)environments.The E'rentaolegai high-Mg diorite from the Diyanmiao ophiolite in central Inner Mongolia,North China,has been investigated revealing low-K tholeiitic-calc-alkaline characteristics and have SiO_(2)contents of 53.44-54.92 wt%,MgO contents of 8.44-9.54 wt%,and Mg~#of 54.35-57.60,with variable Fe_(2)O_(3)(7.51-8.61 wt%),Al_(2)O_(3)(11.95-15.09 wt%),and Na_(2)O(3.42-3.94 wt%)contents,low K_(2)O(0.34-0.97 wt%),TiO_(2)(0.35-0.67 wt%),and P2O5(0.12-0.15 wt%)contents,and high Ni(43-193 ppm)and Cr(189-556 ppm)contents.Samples collected have low total rare earth element(REE)contents(30.58-77.80 ppm),with flat or slightly right-dipping REE patterns(La_(N)/Yb_(N)=2.19-3.11)and a lack of pronounced Eu anomalies.The samples are also enriched in large-ion lithophile elements(LILEs,e.g.,K,Rb,Ba,U,and Sr)and depleted in high field strength elements(e.g.,Ta,Nb,Ti,and P).The E'rentaolegai high-Mg diorite has characteristics typical of HMA,and are similar to those of sanukites from the Setouchi Arc in SW Japan.They also display high positiveε_(Nd)(t)values(+6.32 to+7.80),comparable to the values of their host rocks.Petrogenetic analyses suggest that the E'rentaolegai HMA was probably formed by the interaction of partial melts and aqueous fluids from subducted sediments with mantle peridotite.Zircon U-Pb dating reveals that the high-Mg diorite crystallized at 313.6±2.4 Ma,i.e.,late Carboniferous.Combining our data with the temporal and spatial distribution of the Diyanmiao SSZ-type ophiolite,we propose that the eastern Paleo-Asian Ocean had not closed by the late Carboniferous,but intra-oceanic subduction was ongoing.A new model of the initiation of subduction in the eastern PAO during the late Paleozoic.
基金The National Natural Science Foundation of China under contract Nos 42030401 and 42276077the Open Foundation of State Key Laboratory of Marine Geology,Tongji University under contract No.MGK202207+1 种基金the Open Foundation Project of the Key Laboratory of Polar Geology and Marine Mineral Resources of Ministry of Education,China University of Geosciences (Beijing),under contract Nos PGMR-2024-102 and PGMR-2023-304the Start-up Foundation of Guangdong Ocean University under contract No.060302032110
文摘This review compiles studies on paleoceanographic and paleoenvironmental changes in the high-latitude Southern Ocean during the late Quaternary based on Chinese Antarctic Expeditions.Four major findings are summarized as follows.(1)Diatom compositions in sediment record sea surface condition changes in the Bransfield Strait and Cosmonaut Sea,indicating an increase in sea ice cover since the Mid-Holocene for both areas,possibly linked to cold water mass injection from the Weddell Sea ice shelf.(2)Export productivity records from Antarctic marginal seas show a glacial-interglacial variation pattern,with higher and lower productivity during the interglacial and glacial periods,respectively,controlled by both the intensity of Circumpolar Deep Water upwelling and sea ice cover.An overall increase of export productivity from Marine Isotope Stage(MIS)12 to MIS 6 is noticed.(3)Ventilation state of the abyssal Southern Ocean is closely related to global climate change and atmospheric CO_(2) concentrations,with elevated ventilation efficiency during deglacial periods responsible for elevated atmospheric CO_(2) concentrations.(4)Antarctic marine-based ice sheets/glaciers wax and wane in line with global and regional ice volume changes,predominantly subject to oceanic forcing,while land-based ice sheets might only reorganize in specific glacial intervals.Despite significant progress in understanding the role of the Southern Ocean and the Antarctic Ice Sheet within the global climate system,challenges remain in sample collection and research methods.Future studies should aim to collect samples from a broader range of latitudes,ensure higher quality and longer temporal span,resolve dating issues,reconstruct seawater temperature,and focus on reconstructions of Southern Ocean carbon cycling and changes of intermediate to deep water masses.
基金The National Natural Science Foundation of China under contract Nos 42406259,42175172,and 41975134the Science Foundation for Youths of Hunan Province(Category C)under contract No.2025JJ60240.
文摘As the Arctic undergoes rapid warming and sea ice continues to decline,Ocean-to-Ice Heat Flux(OIHF)plays a crucial role in regulating sea ice dynamics.This study investigates the seasonal variations in ocean-to-ice heat flux in north of the Fram Strait using the regional Arctic Ocean/sea ice reanalysis product from 1991 to 2020.The analysis reveals that the OIHF exhibits significant seasonal variability,with a pronounced peak during winter in north of the Fram Strait,driven by inflows of Atlantic water.Warm Atlantic water intrusion begins in October,reaches its peak in January and February,and results in a delayed increase in OIHF,with maximum flux observed 2−3 months later.These results highlight the significant role of Atlantic water inflows in influencing Arctic sea ice dynamics and emphasize the need for further investigation into the coupled ocean-atmosphere processes that govern seasonal fluctuations in OIHF.
基金Supported by Remote Sensing Support for Offshore Ocean Environment and Polar Sea Ice Early Warning Services(102121201550000009004)。
文摘This paper presents the networking observation capabilities of Chinese ocean satellites and their diverse applications in ocean disaster prevention,ecological monitoring,and resource development.Since the inaugural launch in 2002,China has achieved substantial advancements in ocean satellite technology,forming an observation system composed of the HY-1,HY-2,and HY-3 series satellites.These satellites are integral to global ocean environmental monitoring due to their high resolution,extensive coverage,and frequent observations.Looking forward,China aims to further enhance and expand its ocean satellite capabilities through ongoing projects to support global environmental protection and sustainable development.
基金supported by the National Natural Science Foundation of China (41804067, 42174090, 42250101, and 42250103)the Science Research Project of the Hebei Education Department (BJK2024107)+3 种基金the Hebei Natural Science Foundation (D2022403044)the Opening Fund of the Key Laboratory of Geological Survey and Evaluation of the Ministry of Education (GLAB2023ZR02)the MOST Special Fund from the State Key Laboratory of Geological Processes and Mineral Resources (MSFGPMR2022-4)the Excellent Young Scientist Fund of Hebei GEO University (YQ202403)。
文摘The lithospheric magnetic field is an important component of the geomagnetic field,and the oceanic lithosphere exhibits distinct characteristics.Because of its formation mechanisms,evolutionary history,and geomagnetic field polarity reversals,the oceanic lithosphere has significant remanent magnetization,which causes magnetic anomaly stripes parallel to the mid-ocean ridges.However,it is difficult to construct a high-resolution lithospheric magnetic field model in oceanic regions with relatively sparse data or no data.Using forward calculated lithospheric magnetic field data based on an oceanic remanent magnetization(ORM) model with physical and geological foundations as a supplement is a feasible approach.We first collect the latest available oceanic crust age grid,plate motion model,geomagnetic polarity timescale,and oceanic lithosphere thermal structure.Combining the assumptions that the paleo geomagnetic field is a geocentric axial dipole field and that the normal oceanic crust moves only in the horizontal direction,we construct a vertically integrated ORM model of the normal oceanic crust with a known age,including the intensity,inclination,and declination.Both the ORM model and the global induced magnetization(GIM) model are then scaled from two aspects between their forward calculated results and the lithospheric magnetic field model LCS-1.One aspect is the difference in their spherical harmonic power spectra,and the other is the misfit between the grid data over the oceans.We last compare the forward calculated lithospheric magnetic anomaly from the scaled ORM and GIM models with the Macao Science Satellite-1(MSS-1) observed data.The comparison results show that the magnetic anomalies over the normal oceanic crust regions at satellite altitude are mainly contributed by the high-intensity remanent magnetization corresponding to the Cretaceous magnetic quiet period.In these regions,the predicted and observed anomalies show good consistency in spatial distribution,whereas their amplitude differences vary across regions.This result suggests that regional ORM construction should be attempted in future work to address these amplitude discrepancies.
基金supported by the National Natural Science Foundation of China(Grant Nos.42230405,42006029)Science and Technology Plan of Liaoning Province(2024JH2/102400061)+1 种基金Dalian Science and Technology Innovation Fund(2024JJ11PT007)Dalian Science and Technology Pro-gram for Innovation Talents of Dalian(2022RJ06).
文摘Mesoscale eddies play a central role in the poleward oceanic heat flux in the Southern Ocean.Previous studies have documented changes in the location of temperature fronts in the Southern Ocean,but little attention has been paid to changes in the genesis locations of mesoscale eddies.Here,we provide evidence from three decades of satellite altimetry observations for the heterogeneity of the poleward shift of mesoscale activities,with the largest trend of~0.23°±0.05°(10 yr)^(-1) over the Atlantic sector and a moderate trend of~0.1°±0.03°(10 yr)^(-1) over the Indian sector,but no significant trend in the Pacific sector.The poleward shift of mesoscale eddies is associated with a southward shift of the local westerly winds while being constrained by the major topographies.As the poleward shift of westerly winds is projected to persist,the poleward oceanic heat flux from mesoscale eddies may influence future ice melt.
基金supported by the National Natural Science Foundation of China(42250101,42250102,42250103)the Macao Foundation,and the Science and Technology Development Fund,Macao SAR(File No.0002/2019/APD)。
文摘The Earth's crust,the outer shell of the Earth,consists of continental crust and oceanic crust.Oceanic crust is created at the mid-oceanic ridge,where it is magnetized in the ambient field of the Earth.As new material is extruded,the crust spreads outward,retaining its magnetization.The reversal of the polarity of the Earth's magnetic field over geologic time leads to a pattern of striped magnetic anomalies.In this study,we carry out a preliminary evaluation on how data from the Macao Science Satellite-1(MSS-1),which has a low orbital inclination,influences inversion models of the oceanic crustal magnetic field when combined with data from the Swarm mission.For our modeling we use an equivalent source method based on a cubed-sphere grid.Our model captures the broad magnetic structure over the North Atlantic Ocean and demonstrates that the trend of magnetic stripes is consistent with the age frame of the oceanic crust.The amplitude of the radial magnetic field at 450 km the North Atlantic Ocean ranges from–11 nT to+8 nT.The addition of MSS-1 observations to Swarm data generates results consistent with the overall magnetic stripe pattern.The lack of short-wavelength scale structure reveals the limitation of high-altitude satellites in portraying fine features and hence lower-altitude observations would be required to delineate a more detailed crustal signature.It is expected to obtain a finer structure of oceanic magnetic stripes by combining low-altitude CHAMP field data and east-west gradient data derived from MSS-1 in future work.
基金financially supported by the Scientific Research Foundation of North China University of Technology(Grant Nos.11005136024XN147-87 and 110051360024XN151-86).
文摘With respect to oceanic fluid dynamics,certain models have appeared,e.g.,an extended time-dependent(3+1)-dimensional shallow water wave equation in an ocean or a river,which we investigate in this paper.Using symbolic computation,we find out,on one hand,a set of bilinear auto-Backlund transformations,which could connect certain solutions of that equation with other solutions of that equation itself,and on the other hand,a set of similarity reductions,which could go from that equation to a known ordinary differential equation.The results in this paper depend on all the oceanic variable coefficients in that equation.
基金supported by the National Natural Science Foundation of China [grant number 42030605]the National Key R&D Program of China [grant number 2020YFA0608004]。
文摘A remarkable marine heatwave,known as the“Blob”,occurred in the Northeast Pacific Ocean from late 2013 to early 2016,which displayed strong warm anomalies extending from the surface to a depth of 300 m.This study employed two assimilation schemes based on the global Climate Forecast System of Nanjing University of Information Science(NUIST-CFS 1.0)to investigate the impact of ocean data assimilation on the seasonal prediction of this extreme marine heatwave.The sea surface temperature(SST)nudging scheme assimilates SST only,while the deterministic ensemble Kalman filter(EnKF)scheme assimilates observations from the surface to the deep ocean.The latter notably improves the forecasting skill for subsurface temperature anomalies,especially at the depth of 100-300 m(the lower layer),outperforming the SST nudging scheme.It excels in predicting both horizontal and vertical heat transport in the lower layer,contributing to improved forecasts of the lower-layer warming during the Blob.These improvements stem from the assimilation of subsurface observational data,which are important in predicting the upper-ocean conditions.The results suggest that assimilating ocean data with the EnKF scheme significantly enhances the accuracy in predicting subsurface temperature anomalies during the Blob and offers better understanding of its underlying mechanisms.
基金supported by the Independent Research Foundation of Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai) (Grant No. SML2021SP306)National Natural Science Foundation of China (Grant Nos. 41941007, 41806216, 41876220, and 62177028)+2 种基金Natural Science Foundation of Jiangsu Province (Grant No. BK20211015)China Postdoctoral Science Foundation (Grant Nos. 2019T120379 and 2018M630499)the Talent start-up fund of Nanjing Xiaozhuang University (Grant No. 4172111)。
文摘The mechanical influences involved in the interaction between the Antarctic sea ice and ocean surface current(OSC)on the subpolar Southern Ocean have been systematically investigated for the first time by conducting two simulations that include and exclude the OSC in the calculation of the ice-ocean stress(IOS), using an eddy-permitting coupled ocean-sea ice global model. By comparing the results of these two experiments, significant increases of 5%, 27%, and 24%, were found in the subpolar Southern Ocean when excluding the OSC in the IOS calculation for the ocean surface stress,upwelling, and downwelling, respectively. Excluding the OSC in the IOS calculation also visibly strengthens the total mechanical energy input to the OSC by about 16%, and increases the eddy kinetic energy and mean kinetic energy by about38% and 12%, respectively. Moreover, the response of the meridional overturning circulation in the Southern Ocean yields respective increases of about 16% and 15% for the upper and lower branches;and the subpolar gyres are also found to considerably intensify, by about 12%, 11%, and 11% in the Weddell Gyre, the Ross Gyre, and the Australian-Antarctic Gyre, respectively. The strengthened ocean circulations and Ekman pumping result in a warmer sea surface temperature(SST), and hence an incremental surface heat loss. The increased sea ice drift and warm SST lead to an expansion of the sea ice area and a reduction of sea ice volume. These results emphasize the importance of OSCs in the air-sea-ice interactions on the global ocean circulations and the mass balance of Antarctic ice shelves, and this component may become more significant as the rapid change of Antarctic sea ice.
基金the support of Yajing Mao and Lingquan Zhao during the preparation of the manuscript.This research was financially supported by the National Natural Science Foundation of China(No.U2244206).
文摘The Heilongjiang Complex in northeast China(NE China)separates the Jiamusi and Songliao blocks and marks the suture zone of the former Mudanjiang Ocean,as evidenced by a variety of oceanic basalt-derived blueschists.Understanding the closure history of the Mudanjiang Ocean is crucial to unravelling the tectonic transition from the final amalgamation of the Central Asian Orogenic Belt(CAOB)to the onset of the Paleo-Pacific subduction.In this study,we investigate epidote-ferroglaucophane(Ep-Fgl)and garnet-ferrobarroisite(Grt-Fbrs)schists from the Yilan area of the Heilongjiang Complex through petrological,mineralogical,thermodynamic modelling,whole-rock geochemical,and geochronological analyses.The Ep-Fgl schists preserve a peak assemblage of ferroglaucophane+epidote+chlorite+clinopyroxene+phengite+titanite with peak P-T conditions of 13.5-15.8 kbar and 458-495℃.On the other hand,the Grt-Fbrs schists exhibit a peak assemblage of garnet+glaucophane/ferroglaucophane+lawsonite+chlorite+phengite+rutile±clinopyroxene±titanite,deriving peak P-T conditions of 16.4-18.3 kbar and 457-475℃.Both types of schist record similar clockwise P-T paths,with three metamorphic stages:a peak epidote-to-lawsonite blueschist-facies stage,a post-peak decompression stage in the epidote amphibolite-facies,and a late greenschist-facies overprint stage.The Ep-Fgl schists display alkaline OIB-like geochemical affinities,while the Grt-Fbrs schists show tholeiitic MORB-like characteristics,suggesting that the protoliths represent fragments of the Mudanjiang oceanic crust.Magmatic zircon grains from Ep-Fgl schists yield protolith ages of 276±1 Ma and 280±1 Ma,whereas zircon of Grt-Fbrs schists document protolith ages of 249±2 Ma and 248±2 Ma,indicating that the Mudanjiang Ocean existed since at least the early Permian.Reconstruction of the metamorphic P-T evolution,combined with previous magmatic and metamorphic age data from rocks of the Heilongjiang Complex and of adjacent tectonic units suggests that the subduction and eventual closure of the Mudanjiang Ocean occurred between the late Triassic and middle Jurassic,driven by a regional stress regime shift caused by the westward subduction of the Paleo-Pacific Plate beneath Eurasia.
