Increasing nitrogen and phosphorus discharge and decreasing sediment input have made silicon(Si)a limiting element for diatoms in estuaries.Disturbances in nutrient structure and salinity fluctuation can greatly affec...Increasing nitrogen and phosphorus discharge and decreasing sediment input have made silicon(Si)a limiting element for diatoms in estuaries.Disturbances in nutrient structure and salinity fluctuation can greatly affect metal uptake by estuarine diatoms.However,the combined effects of Si and salinity on metal accumulation in these diatoms have not been evaluated.In this study,we aimed to investigate how salinity and Si availability combine to influence the adsorption of metals by a widely distributed diatom Phaeodactylum tricornutum.Our data indicate that replete Si and low salinity in seawater can enhance cadmium and copper adsorption onto the diatom surface.At the single-cell level,surface potential was a dominant factor determining metal adsorption,while surface roughness also contributed to the highermetal loading capacity at lower salinities.Using a combination of noninvasive micro-test technology,atomic force microscopy,X-ray photoelectron spectroscopy,and Fourier transform infrared spectroscopy,we demonstrate that the diversity and abundance of the functional groups embedded in diatom cell walls vary with salinity and Si supply.This results in a change in the cell surface potential and transient metal influx.Our study provides novel mechanisms to explain the highly variable metal adsorption capacity of a model estuarine diatom.展开更多
Flume experiments play a pivotal role in studying wave propagation,with wave elements typically assumed to remain constant in the perpendicular direction.However,evident cross wave phenomena were observed within flume...Flume experiments play a pivotal role in studying wave propagation,with wave elements typically assumed to remain constant in the perpendicular direction.However,evident cross wave phenomena were observed within flumes under certain conditions.This paper presents new analytical solutions for both primary and cross waves on double shoals in a flume via linear shallow-water equations,which may be used to idealize dynamic experimental configurations of coral reefs.The primary waves on double shoals are described by the associated Legendre functions,whereas the ultimate solutions are derived by considering the incident and reflected waves in front of a bathymetry and the transmitted waves positioned behind it.The effects of the angular frequency and topographic parameters on the primary waves are subsequently analyzed.Cross waves on double shoals constitute a type of topographically trapped wave whose solutions are formulated by combining the first and second types of the associated Legendre functions.The angular frequency is not only determined by the wavenumber but also influenced by the topographic parameters.Numerical experiments are conducted to investigate the generation mechanism of cross waves.The consistency between the numerical results and analytical solutions confirms the validity of the new analytical framework of cross waves on double shoals.展开更多
Biological contaminants(BCs),including but not limited to various pathogens and their endogenous pol-lutants such as intracellular pathogens and antimicrobial resistance genes(ARGs),are ubiquitously detected in efflue...Biological contaminants(BCs),including but not limited to various pathogens and their endogenous pol-lutants such as intracellular pathogens and antimicrobial resistance genes(ARGs),are ubiquitously detected in effluent of wastewater and drinking water treatment systems which were originally designed to remove common indicator bacteria,resulting in potential impacts on public health.Although there are many emerging technologies that showing promising antimicrobial effects,few have progressed to the actual water scenarios.It’s crucial to understand the main knowledge gaps and thereby design the future developments to better meet engineering requirements.In this review,we first summarize the perfor-mance of conventional water treatment towards BCs removal.Then we showcase the advances of proof-of-concept strategies,including nanotechnology,advanced oxidation process,biological control process and integrated techniques,for BCs control in light of antimicrobial mechanisms,characteristics,proper niches in water treatment,challenges and latest improvements.Further,we proposed a semi-quantitative framework coupling life cycle assessment(LCA)and analytic hierarchy process(AHP)to assess and compare the application potential of representative pilot technologies,in which the antimicro-bial effects,economic issues and sustainability are comprehensively considered.For wastewater treat-ment,non-thermal plasma weights highest among the emerging technologies and outperforms conventional disinfection in terms of efficacy indicators(overall inactivation rate,ARGs removal rate,and growth inhibition),but fall behind overall mainly due to more energy input.Bacteriophage-based treatment has the potential to synergistically inactive the persistent pathogens in combination with con-ventional disinfection,serving as a cost-effective and environmental-friendly supplement.For drinking water treatment,the integrated photocatalytic nanocomposite receives the highest application potential among the emerging technologies and appears to be supplementary or even alternative next-generation disinfectants.This review shares valuable insights to propel the proof-of-concept antimicrobial trials towards industrial procedures.展开更多
The crevice corrosion of the reinforcing steel in the carbonated simulated concrete pore solutions(SCPSs)containing 0.04 mol/L chloride was investigated.In comparison,the steel without crevice covered on its surface w...The crevice corrosion of the reinforcing steel in the carbonated simulated concrete pore solutions(SCPSs)containing 0.04 mol/L chloride was investigated.In comparison,the steel without crevice covered on its surface was also studied.Results showed that the crevice corrosion in the uncarbonated SCPS was not triggered and the steel remained passivity by suppressing the anodic dissolution in the crevice interior.As SCPS was carbonated to have pH values of 10.5 and 11.5,the crevice corrosion was easier to be activated than the widely reported pitting corrosion owing to the rapid oxygen depletion within the crevice,but the crevice corrosion damage might be alleviated to a certain extent due to the relative compact surface film formed inside the crevice.The further carbonation led to the activation dissolution of both the crevice interior and exterior,causing the more serious corrosion damage.Corrosion process of the crevice corrosion was systematically analyzed by combining the electrochemical measurement results and Evens polarization diagram.展开更多
The environmental magnetic proxies of stalagmites hold significant potential for reconstructing regional hydroclimate changes by revealing the content and grain size of magnetic particles within stalagmites.In this st...The environmental magnetic proxies of stalagmites hold significant potential for reconstructing regional hydroclimate changes by revealing the content and grain size of magnetic particles within stalagmites.In this study,we present the contents and grain sizes of magnetic particles within a stalagmite SZ-1,from Shizhu Cave in southwestern China from 70.4 to 22.3 thousand years ago(ka)during the last glacial period.Specifically,the parameters IRM_(soft),soil-derived magnetic minerals,and ARM/SIRM(anhysteretic remanent magnetization/saturation isothermal remanent magnetization),the ratio of fine magnetic particles to total ferrimagnetic particles preserved in stalagmite SZ-1,indicate the fluctuation of regional precipitation.Obvious half-precessional cycles are evident in these two proxies,indicating that hydroclimatic variations in southwestern China may predominantly arise from the heat and moisture transported from tropical oceans.These variations are likely influenced by shifts in the Intertropical Convergence Zone and fluctuations in the Asian Summer Monsoon.展开更多
Effect of Langmuir circulation （LC） on upper ocean mixing is investigated by a two-way wave-current coupled model. The model is coupled of the ocean circulation model ROMS （regional ocean modeling system） to the s...Effect of Langmuir circulation （LC） on upper ocean mixing is investigated by a two-way wave-current coupled model. The model is coupled of the ocean circulation model ROMS （regional ocean modeling system） to the surface wave model SWAN （simulating waves nearshore） via the model-coupling toolkit. The LC already certified its importance by many one-dimensional （1D） research and mechanism analysis work. This work focuses on inducing LC＇s effect in a three-dimensional （3-D） model and applying it to real field modeling. In ROMS, the Mellor-Yamada turbulence closure mixing scheme is modified by including LC＇s effect. The SWAN imports bathymetry, free surface and current information from the ROMS while exports signifi- cant wave parameters to the ROMS for Stokes wave computing every 6 s. This coupled model is applied to the South China Sea （SCS） during September 2008 cruise. The results show that LC increasing turbulence and deepening mixed layer depth （MLD） at order of O （10 m） in most of the areas, especially in the north part of SCS where most of our measurements operated. The coupled model further includes wave break- ing which will brings more energy into water. When LC works together with wave breaking, more energy is transferred into deep layer and accelerates the MLD deepening. In the north part of the SCS, their effects are more obvious. This is consistent with big wind event in the area of the Zhujiang River Delta. The shallow water depth as another reason makes them easy to influence the ocean mixing as well.展开更多
Yellowfin tuna (Thunnus albacares) is one of the most commercially important fish species for South Pacific island nations and territories and for effective conservation efforts it is important to understand the facto...Yellowfin tuna (Thunnus albacares) is one of the most commercially important fish species for South Pacific island nations and territories and for effective conservation efforts it is important to understand the factors which affect its time series pattern. Our research was aimed at elucidating the climatic factors which affected the trajectory of the yellowfin tuna stock in the Eastern and Western South Pacific Ocean. We utilized various climatic factors for the years t - n with n = 0, 1, ..., 8 and investigated their statistical relationship with the catch per unit effort (CPUE) of yellowfin tuna stock from 1957-2008 for three South Pacific zones ranging from the East to the West Pacific Ocean within the coverage area of the Western and Central Pacific Convention Area. Results showed that the climatic conditions of: (i) the global mean land and ocean temperature index (LOTI), (ii) the Pacific warm pool index (PWI) and (iii) Southern Oscillation Index (SOI) had significant relationship with the CPUE of yellowfin tuna in all three zones. LOTI, PWI and SOI were used as independent variables and fitted through modeling to replicate the CPUE trajectory of the yellowfin tuna in Zone 1, Zone 2 and Zone 3. Model selection was based on significant parameter estimates (p < 0.05), Akaikes Information Criterion (AIC) and R2 values. Models selected for all three zones had LOTI, PWI and SOI as the independent variables. This study shows that LOTI, PWI and SOI are climatic conditions which have significant impact on the fluctuation pattern of the yellowfin tuna CPUE in the Eastern and Western South Pacific Ocean. From the findings of this study it can be recommended that when management decisions are made for yellowfin tuna fishery conservation and sustainability in the Eastern and Western South Pacific, it is imperative to take the effect of climatic factors into account.展开更多
We quantified the systematic variations in global transform fault morphology,revealing a first-order dependence on the spreading rate.(1)The average age offset of both the full transform and transform sub-segments dec...We quantified the systematic variations in global transform fault morphology,revealing a first-order dependence on the spreading rate.(1)The average age offset of both the full transform and transform sub-segments decrease with increasing spreading rate.(2)The average depth of both the transform valley and adjacent ridges are smaller in the fast compared to the slow systems,reflecting possibly density anomalies associated with warmer mantle at the fast systems and rifting at the slow ridges.However,the average depth difference between the transform valley and adjacent ridges is relatively constant from the fast to slow systems.(3)The nodal basin at a ridge-transform intersection is deeper and dominant at the ultraslow and slow systems,possibly reflecting a lower magma supply and stronger viscous resistance to mantle upwelling near a colder transform wall.In contrast,the nodal high,is most prominent in the fast,intermediate,and hotspot-influenced systems,where robust axial volcanic ridges extend toward the ridge-transform intersection.(4)Statistically,the average transform valley is wider at a transform system of larger age offset,reflecting thicker deforming plates flanking the transform fault.(5)The maximum magnitude of the transform earthquakes increases with age offset owing to an increase in the seismogenic area.Individual transform faults also exhibit significant anomalies owing to the complex local tectonic and magmatic processes.展开更多
Over the years there has been growing interest regarding the effects of climatic variations on marine biodiversity. The exclusive economic zones of South Pacific Islands and territories are home to major international...Over the years there has been growing interest regarding the effects of climatic variations on marine biodiversity. The exclusive economic zones of South Pacific Islands and territories are home to major international exploitable stocks of albacore tuna (Thunnus alalunga);however the impact of climatic variations on these stocks is not fully understood. This study was aimed at determining the climatic variables which have impact on the time series stock fluctuation pattern of albacore tuna stock in the Eastern and Western South Pacific Ocean which was divided into three zones. The relationship of the climatic variables for the global mean land and ocean temperature index (LOTI), the Pacific warm pool index (PWI) and the Pacific decadal oscillation (PDO) was investigated against the albacore tuna catch per unit effort (CPUE) time series in Zone 1, Zone 2 and Zone 3 of the South Pacific Ocean from 1957 to 2008. From the results it was observed that LOTI, PWI and PDO at different lag periods exhibited significant correlation with albacore tuna CPUE for all three areas. LOTI, PWI and PDO were used as independent variables to develop suitable stock reproduction models for the trajectory of albacore tuna CPUE in Zone 1, Zone 2 and Zone 3. Model selection was based on Akaike Information Criterion (AIC), R2 values and significant parameter estimates at p < 0.05. The final models for albacore tuna CPUE in all three zones incorporated all three independent variables of LOTI, PWI and PDO. From the findings it can be said that the climatic conditions of LOTI, PWI and PDO play significant roles in structuring the stock dynamics of the albacore tuna in the Eastern and Western South Pacific Ocean. It is imperative to take these factors into account when making management decisions for albacore tuna in these areas.展开更多
Recent studies have demonstrated the ability of seismic oceanography to reveal finescale vertical structures of water column in the oceans based on multichannel seismic(MCS)reflection data.Such information can clarify...Recent studies have demonstrated the ability of seismic oceanography to reveal finescale vertical structures of water column in the oceans based on multichannel seismic(MCS)reflection data.Such information can clarify the dynamic processes of mixing,exchange,and translation of water mass and energy.In this study,we present four MCS lines and satellite data to show high-resolution seismic images of shallow waters over the Shatsky Rise in the Northwest Pacific Ocean,where the Kuroshio Exten-sion passes and bifurcates.One of our MCS transects crossed the center of an anticyclonic warm eddy on August 28,2010,confirmed by satellite data such as sea level anomaly(SLA),geostrophic current anomaly(GCA),and sea surface temperature anomaly(SSTa).The seismic image showed that the eddy vertical structure featured a bowl-like shape and onion-like internal layering.The slightly tilted(<0.5°)surface of the eddy was 400m below the sea surface,indicating a subsurface eddy.The eddy was inferred to have a radius of 50 km and a maximum thickness of 500m.Other MCS sections demonstrated the submesoscale structure of oceanfronts,characterized by the dipping reflectors(>2°-3°)at the boundaries between water masses with differing properties.In addition,the discrepancies in SLA,GCA,and SSTa between water masses resulted in different seismic reflectivities.The water masses with high SLA,anticyclonic GCA and positive SSTa featured high-amplitude,continuous,clear-layered,and non-linear reflections,whereas those with low SLA,cyclonic GCA,and negative SSTa were associated with weak,fragmented,less stratification,and more linear reflectors.展开更多
The Antarctic Bottom Water formation site Vincennes Bay,East Antarctica is experiencing a substantial intrusion of modified Circumpolar Deep Water(mCDW),which may inhibit the formation of Dense Shelf Water(DSW)and dri...The Antarctic Bottom Water formation site Vincennes Bay,East Antarctica is experiencing a substantial intrusion of modified Circumpolar Deep Water(mCDW),which may inhibit the formation of Dense Shelf Water(DSW)and drive basal melting of the ice shelves.Based on hydrographic data obtained from March to November in 2012,we evaluated the spatial spread of mCDW over the continental shelf region of Vincennes Bay and the associated temporal evolution of water properties,as well as the sea ice formation effect on water column in the coastal polynya.Results show that two branches of mCDW occupied the deep layers of the continental shelf,distinguished by the potential density(smaller than 27.8 kg/m^(3) or not)when potential temperatureθ=0.5°C in theθ-salinity space.The warmer and less dense branch observed on the east plateau,accessed the eastern ice shelves in the coastal polynya to drive basal melting of ice shelves.In contrast,the other colder and denser branch in the mid-depression reached the western Underwood Ice Shelf.DSW formation was detectable in the coastal polynya during September-November,proving the occurrence of deep convection.Surface heat loss and brine rejection during the intensive sea ice formation contributed to the destratification of the water column in the coastal polynya.It was estimated that at least 1.11±0.79 TW heat carried by mCDW into the inner part of the polynya.展开更多
The Jurassic oceanic crust is the oldest existing oceanic crust on earth,and although distributed sparsely,carries essential information about the earth's evolution.The area around the Pigafetta Basin in the west ...The Jurassic oceanic crust is the oldest existing oceanic crust on earth,and although distributed sparsely,carries essential information about the earth's evolution.The area around the Pigafetta Basin in the west Pacific Ocean(also known as the Jurassic Quiet Zone,JQZ)is one of a few areas where the Jurassic oceanic crust is present.This study takes full advantage of high-resolution multichannel seismic reflection profiles in combination with bathymetry,magnetic,and gravity data from the JQZ to examine the structure,deformation,and morphology of the Jurassic oceanic crust.Our results show the following insights:1)The Moho lies at 2–3 s in two-way travel time beneath the seafloor with the segmented feature.The gaps between the Moho segments well correspond to the seamounts on the seafloor,suggesting the upward migration of magma from the mantle has interrupted the pre-existing Moho.2)The oceanic crust is predominantly deformed by crustal-scale thrust faults,normal faults cutting through the top of basement,and vertical seismic disturbance zones in association with migration of thermal fluids.The thrust faults are locally found and interpreted as the results of tectonic inversion.3)Seafloor morphology in the JQZ is characterized by fault scarps,fold scarps,seamounts,and small hills,indicating the occurrence of active faults.4)The oceanic crust in the JQZ and East Pacific Rise has many structural and geometrical variations,such as the thickness of sediments,seafloor topography,basement morphology,fault size and type.展开更多
The fields of structural geology and tectonics have witnessed great progress over the last decade and are poised for further expansion in the future. One of the significant breakthroughs is the establishment of the &#...The fields of structural geology and tectonics have witnessed great progress over the last decade and are poised for further expansion in the future. One of the significant breakthroughs is the establishment of the 'Beyond Plate Tectonics Theory' where a combination of conceptual models and numerical modeling on plume tectonics and plate tectonics has enabled new insights into the structural and tectonic architecture and processes in the deep interior and deep sea. This paper synthesizes developments of structural geology and tectonics from a macroscopic perspective in deep interior and deep sea. Four key techniques are also reviewed: satellite altimetry for surface structures in deep-sea multi-beam sea-floor mapping; tomography for tectonics of the deep interior; diverse modeling approaches and software for unfolding dynamic evolution; and techniques for HT/HP experiments on material rheology and in situ component measurements.展开更多
A 3.8-kin Coupled Ice-Ocean Model （C1OM） was implemented to successfully reproduce many observed phenomena in the Beaufort and Chukchi seas, including the Bering-inflow-originated coastal current that splits into th...A 3.8-kin Coupled Ice-Ocean Model （C1OM） was implemented to successfully reproduce many observed phenomena in the Beaufort and Chukchi seas, including the Bering-inflow-originated coastal current that splits into three branches： Alaska Coastal Water （ACW） , Central Channel, and Herald Valley branches. Other modeled phenomena include the Beaufort Slope Current （BSC） , the Beaufort Gyre, the East Siberian Current （ ESC）, mesoscale eddies, seasonal landfast ice, sea ice ridging, shear, and deformation. Many of these downscaling processes can only be captured by using a high-resolution CIOM, nested in a global climate model. The seasonal cycles for sea ice concentration, thickness, velocity, and other variables are well reproduced with Solid validation by satellite measurements. The seasonal cycles for upper ocean dynamics and thermodynamics are also well reproduced, which include the formation of the cold saline layer due to the injection of salt during sea ice formation, the BSC, and the subsurface upwelling in winter that brings up warm, even more saline Atlantic Water along the shelfbreak and shelf along the Beaufort coast.展开更多
Debris flows pose serious risks to communities in mountainous areas,often resulting in large losses of human life and property.The impeding presence of urban buildings often affects the runout behavior and deposition ...Debris flows pose serious risks to communities in mountainous areas,often resulting in large losses of human life and property.The impeding presence of urban buildings often affects the runout behavior and deposition of debris flows.But the impact of different building densities and sizes on debris flow dynamics has yet to be quantified to guide urban planning in debris flow risk zones.This study focused on a debris flow that occurred in Zhouqu County,Gansu Province,China on August 7th,2010,which was catastrophic and destroyed many buildings.The FLO-2D software was used to simulate this debris flow in two scenarios,i.e.the presence and the absence of buildings,to obtain debris-flow intensity parameters.The developed model was then used to further analyze the influence of large buildings and narrow channels within the urban environment.The simulation results show that considering the presence of buildings in the simulation is essential for accurate assessment of debris flow intensity and deposition distribution.The layout of buildings in the upstream urban area,such as large buildings or parallel buildings which form narrow channels,can affect the flow velocity and depth of debris flow heading towards downstream buildings.To mitigate damage to downstream buildings,the relative spacing(d/a)between upstream and downstream buildings should not exceed a value of two and should ideally be even lower.These findings provide valuable insights for improving the resistance of mountainous cities to urban debris flows.展开更多
The vacuum-assisted prefabricated horizontal drain offers a promising method for strengthening soil slurry,allowing simultaneous filling and vacuum-dewatering via staged construction.However,there is limited research ...The vacuum-assisted prefabricated horizontal drain offers a promising method for strengthening soil slurry,allowing simultaneous filling and vacuum-dewatering via staged construction.However,there is limited research on the unique characteristics of staged filling.This study aims to investigate the vacuum consolidation process of staged-filled soil slurry through laboratory model tests and numerical simulations,also assessing the impact of anionic polyacrylamide.Comparative analyses are conducted between vacuum consolidation with and without anionic polyacrylamide,as well as self-weight consolidation without anionic polyacrylamide.Results reveal contour lines of excess pore pressure,water content,and soil strength forming an ellipse around the prefabricated horizontal drain board.During the consolidation process,a higher degree of consolidation,lower water content,and higher soil strength were observed closer to the prefabricated horizontal drain board.After treatment,the uppermost filling layer exhibits an average water content that was approximately 40%higher than the lower filling layer,and its average strength was about 60%lower.This discrepancy is primarily due to the absence of sealing on the top surface and the relatively short vacuum consolidation time caused by staged filling.The introduction of anionic polyacrylamide-induced flocculation significantly improves the initial consolidation rate but minimally affects the dewatering capacity of vacuum preloading.Using flocculant can enhance both the staged filling rate and soil strength(by 1e2 times).Additionally,employing a staggered arrangement between different prefabricated horizontal drain layers is advisable to prevent top-down penetration in areas with low soil strength.展开更多
Typhoons in the western Pacific have a significant impact on the transport of heat,salt and particles through the Luzon Strait.However,there are very limited field observations of this impact because of extreme diffic...Typhoons in the western Pacific have a significant impact on the transport of heat,salt and particles through the Luzon Strait.However,there are very limited field observations of this impact because of extreme difficulties and even dangers for ship-based measurements during the rough weather.Here,we present the preliminary results from analyzing a dataset collected by a glider deployed west of the Luzon Strait a few days prior to the arrival of typhoon MITAG.The gilder data revealed an abnormally salinity(>34.8)subsurface water apparently sourced from Kuroshio intrusion during the typhoon.When typhoon MITAG traveled on the east of the Luzon Strait,the positive wind stress curl strengthened the cyclonic eddy and weakened the anti-cyclonic eddy.This led to a slowdown of Kuroshio and made its intrusion easier.The main axis of the Kuroshio at the northern part of the strait shifted westward after the typhoon and did not return to its original position until a week later.The Ekman transport from persistent northerly wind of typhoon MITAG was significant,but its importance in enhancing the Kuroshio intrusion is only secondary relative to the eddies variations.展开更多
Haptophytes(Eukaryota,Hacrobia)play a crucial role in the energy budget and element cycling of diverse aquatic ecosystems due to their ability to engage in both phototrophic and mixotrophic nutritional modes.Neverthel...Haptophytes(Eukaryota,Hacrobia)play a crucial role in the energy budget and element cycling of diverse aquatic ecosystems due to their ability to engage in both phototrophic and mixotrophic nutritional modes.Nevertheless,there is a significant lack of knowledge regarding the short-term variations,such as diel dynamics,of their ecological features.During a short time frame in the summer of 2018,samples were collected from three distinct water layers in the South China Sea,including surface water,the deep chlorophyll maximum(DCM)layer,and 200 m depth.Fluorescence in situ hybridization coupled with tyramide signal amplification was used to quantify haptophyte cell abundance.Most haptophyte communities in all three water layers were composed of cells 2-5μm in size,while the proportion of cells<2μm increased with water depth.High-throughput sequencing of the V4 hypervariable regions of the SSU rRNA revealed that Chrysochromulina and Phaeocystis predominated the community,and the former was more abundant in the surface water and 200 m depth and the latter was more abundant in the DCM layer.Higher abundance of small cells(<2μm and 2-5μm)during the night was found compared to the day time,whereas large cells(5-10μm and 10-20μm)were more prevalent during the day time.The results of correlation analyses showed that haptophyte abundance was possibly impacted by both environmental biotic(heterotrophic nanoflagellates,heterotrophic bacteria,and viruses)and abiotic(temperature,salinity,and nutrients)factors.展开更多
In order to quantify the influence of external forcings on the predictability limit using observational data,the author introduced an algorithm of the conditional nonlinear local Lyapunov exponent(CNLLE)method.The eff...In order to quantify the influence of external forcings on the predictability limit using observational data,the author introduced an algorithm of the conditional nonlinear local Lyapunov exponent(CNLLE)method.The effectiveness of this algorithm is validated and compared with the nonlinear local Lyapunov exponent(NLLE)and signal-to-noise ratio methods using a coupled Lorenz model.The results show that the CNLLE method is able to capture the slow error growth constrained by external forcings,therefore,it can quantify the predictability limit induced by the external forcings.On this basis,a preliminary attempt was made to apply this method to measure the influence of ENSO on the predictability limit for both atmospheric and oceanic variable fields.The spatial distribution of the predictability limit induced by ENSO is similar to that arising from the initial conditions calculated by the NLLE method.This similarity supports ENSO as the major predictable signal for weather and climate prediction.In addition,a ratio of predictability limit(RPL)calculated by the CNLLE method to that calculated by the NLLE method was proposed.The RPL larger than 1 indicates that the external forcings can significantly benefit the long-term predictability limit.For instance,ENSO can effectively extend the predictability limit arising from the initial conditions of sea surface temperature over the tropical Indian Ocean by approximately four months,as well as the predictability limit of sea level pressure over the eastern and western Pacific Ocean.Moreover,the impact of ENSO on the geopotential height predictability limit is primarily confined to the troposphere.展开更多
Challenges in stratigraphic modeling arise from underground uncertainty.While borehole exploration is reliable,it remains sparse due to economic and site constraints.Electrical resistivity tomography(ERT)as a cost-eff...Challenges in stratigraphic modeling arise from underground uncertainty.While borehole exploration is reliable,it remains sparse due to economic and site constraints.Electrical resistivity tomography(ERT)as a cost-effective geophysical technique can acquire high-density data;however,uncertainty and nonuniqueness inherent in ERT impede its usage for stratigraphy identification.This paper integrates ERT and onsite observations for the first time to propose a novel method for characterizing stratigraphic profiles.The method consists of two steps:(1)ERT for prior knowledge:ERT data are processed by soft clustering using the Gaussian mixture model,followed by probability smoothing to quantify its depthdependent uncertainty;and(2)Observations for calibration:a spatial sequential Bayesian updating(SSBU)algorithm is developed to update the prior knowledge based on likelihoods derived from onsite observations,namely topsoil and boreholes.The effectiveness of the proposed method is validated through its application to a real slope site in Foshan,China.Comparative analysis with advanced borehole-driven methods highlights the superiority of incorporating ERT data in stratigraphic modeling,in terms of prediction accuracy at borehole locations and sensitivity to borehole data.Informed by ERT,reduced sensitivity to boreholes provides a fundamental solution to the longstanding challenge of sparse measurements.The paper further discusses the impact of ERT uncertainty on the proposed model using time-lapse measurements,the impact of model resolution,and applicability in engineering projects.This study,as a breakthrough in stratigraphic modeling,bridges gaps in combining geophysical and geotechnical data to address measurement sparsity and paves the way for more economical geotechnical exploration.展开更多
基金supported by the National Natural Science Foundation of China (Nos.U23A2048,42376152,41976140,and 42076148)the Special Program of Key Sectors in Guangdong Universities (Nos.2022ZDZX4040 and 2023KCXTD028).
文摘Increasing nitrogen and phosphorus discharge and decreasing sediment input have made silicon(Si)a limiting element for diatoms in estuaries.Disturbances in nutrient structure and salinity fluctuation can greatly affect metal uptake by estuarine diatoms.However,the combined effects of Si and salinity on metal accumulation in these diatoms have not been evaluated.In this study,we aimed to investigate how salinity and Si availability combine to influence the adsorption of metals by a widely distributed diatom Phaeodactylum tricornutum.Our data indicate that replete Si and low salinity in seawater can enhance cadmium and copper adsorption onto the diatom surface.At the single-cell level,surface potential was a dominant factor determining metal adsorption,while surface roughness also contributed to the highermetal loading capacity at lower salinities.Using a combination of noninvasive micro-test technology,atomic force microscopy,X-ray photoelectron spectroscopy,and Fourier transform infrared spectroscopy,we demonstrate that the diversity and abundance of the functional groups embedded in diatom cell walls vary with salinity and Si supply.This results in a change in the cell surface potential and transient metal influx.Our study provides novel mechanisms to explain the highly variable metal adsorption capacity of a model estuarine diatom.
基金financially supported by the National Natural Science Foundation of China (Grant No. 52071128)the Natural Science Foundation of Jiangsu Basic Research Program (Grant No. BK20220082)
文摘Flume experiments play a pivotal role in studying wave propagation,with wave elements typically assumed to remain constant in the perpendicular direction.However,evident cross wave phenomena were observed within flumes under certain conditions.This paper presents new analytical solutions for both primary and cross waves on double shoals in a flume via linear shallow-water equations,which may be used to idealize dynamic experimental configurations of coral reefs.The primary waves on double shoals are described by the associated Legendre functions,whereas the ultimate solutions are derived by considering the incident and reflected waves in front of a bathymetry and the transmitted waves positioned behind it.The effects of the angular frequency and topographic parameters on the primary waves are subsequently analyzed.Cross waves on double shoals constitute a type of topographically trapped wave whose solutions are formulated by combining the first and second types of the associated Legendre functions.The angular frequency is not only determined by the wavenumber but also influenced by the topographic parameters.Numerical experiments are conducted to investigate the generation mechanism of cross waves.The consistency between the numerical results and analytical solutions confirms the validity of the new analytical framework of cross waves on double shoals.
基金supported by the National Natural Science Foundation of China(52293443,52321005,52230004)the Natural Science Foundation of Guangdong Basic and Applied Basic Research Foundation(2024A1515010085)+1 种基金Shenzhen Science and Technology Program(GXWD20231127195344001 and JCYJ20241202123735045)Shenzhen Overseas High-level Talents Research Startup Program(20200518750C).
文摘Biological contaminants(BCs),including but not limited to various pathogens and their endogenous pol-lutants such as intracellular pathogens and antimicrobial resistance genes(ARGs),are ubiquitously detected in effluent of wastewater and drinking water treatment systems which were originally designed to remove common indicator bacteria,resulting in potential impacts on public health.Although there are many emerging technologies that showing promising antimicrobial effects,few have progressed to the actual water scenarios.It’s crucial to understand the main knowledge gaps and thereby design the future developments to better meet engineering requirements.In this review,we first summarize the perfor-mance of conventional water treatment towards BCs removal.Then we showcase the advances of proof-of-concept strategies,including nanotechnology,advanced oxidation process,biological control process and integrated techniques,for BCs control in light of antimicrobial mechanisms,characteristics,proper niches in water treatment,challenges and latest improvements.Further,we proposed a semi-quantitative framework coupling life cycle assessment(LCA)and analytic hierarchy process(AHP)to assess and compare the application potential of representative pilot technologies,in which the antimicro-bial effects,economic issues and sustainability are comprehensively considered.For wastewater treat-ment,non-thermal plasma weights highest among the emerging technologies and outperforms conventional disinfection in terms of efficacy indicators(overall inactivation rate,ARGs removal rate,and growth inhibition),but fall behind overall mainly due to more energy input.Bacteriophage-based treatment has the potential to synergistically inactive the persistent pathogens in combination with con-ventional disinfection,serving as a cost-effective and environmental-friendly supplement.For drinking water treatment,the integrated photocatalytic nanocomposite receives the highest application potential among the emerging technologies and appears to be supplementary or even alternative next-generation disinfectants.This review shares valuable insights to propel the proof-of-concept antimicrobial trials towards industrial procedures.
基金supported by the Fundamental Research Program of Shanxi Province(Grant Nos.202203021222188 and 202303021211166)Scientific Research Fund of Taiyuan University of Science and Technology(Grant No.20222073)+1 种基金Award Fund for Outstanding Doctors in Shanxi Province(Grant No.20232047)Scientific and Technological Innovation Programs of Higher Education Institutions in Shanxi(Grant No.2022L280).
文摘The crevice corrosion of the reinforcing steel in the carbonated simulated concrete pore solutions(SCPSs)containing 0.04 mol/L chloride was investigated.In comparison,the steel without crevice covered on its surface was also studied.Results showed that the crevice corrosion in the uncarbonated SCPS was not triggered and the steel remained passivity by suppressing the anodic dissolution in the crevice interior.As SCPS was carbonated to have pH values of 10.5 and 11.5,the crevice corrosion was easier to be activated than the widely reported pitting corrosion owing to the rapid oxygen depletion within the crevice,but the crevice corrosion damage might be alleviated to a certain extent due to the relative compact surface film formed inside the crevice.The further carbonation led to the activation dissolution of both the crevice interior and exterior,causing the more serious corrosion damage.Corrosion process of the crevice corrosion was systematically analyzed by combining the electrochemical measurement results and Evens polarization diagram.
基金supported by the National Natural Science Foundation of China(Nos.42074071,42274094,42261144739)the Shenzhen Science and Technology Program(No.KQTD20170810111725321)+2 种基金supported by the Taiwan University Core Consortiums Project(No.112L894202)the Higher Education Sprout Project of the Ministry of Education(No.112L901001)the National Science and Technology Council(No.111-2116-M-002-022-MY3)。
文摘The environmental magnetic proxies of stalagmites hold significant potential for reconstructing regional hydroclimate changes by revealing the content and grain size of magnetic particles within stalagmites.In this study,we present the contents and grain sizes of magnetic particles within a stalagmite SZ-1,from Shizhu Cave in southwestern China from 70.4 to 22.3 thousand years ago(ka)during the last glacial period.Specifically,the parameters IRM_(soft),soil-derived magnetic minerals,and ARM/SIRM(anhysteretic remanent magnetization/saturation isothermal remanent magnetization),the ratio of fine magnetic particles to total ferrimagnetic particles preserved in stalagmite SZ-1,indicate the fluctuation of regional precipitation.Obvious half-precessional cycles are evident in these two proxies,indicating that hydroclimatic variations in southwestern China may predominantly arise from the heat and moisture transported from tropical oceans.These variations are likely influenced by shifts in the Intertropical Convergence Zone and fluctuations in the Asian Summer Monsoon.
基金the National Basic Research Program of China under contract Nos 2011CB403501 and 2012CB417402the Open Research Foundation for the State Key Laboratory of Satellite Ocean Environment Dynamics,Second Institute of Oceanography,State Oceanic Administration under contract No. SOED1210the Fund for Creative Research Groups by NSFC under contract No. 41121064
文摘Effect of Langmuir circulation （LC） on upper ocean mixing is investigated by a two-way wave-current coupled model. The model is coupled of the ocean circulation model ROMS （regional ocean modeling system） to the surface wave model SWAN （simulating waves nearshore） via the model-coupling toolkit. The LC already certified its importance by many one-dimensional （1D） research and mechanism analysis work. This work focuses on inducing LC＇s effect in a three-dimensional （3-D） model and applying it to real field modeling. In ROMS, the Mellor-Yamada turbulence closure mixing scheme is modified by including LC＇s effect. The SWAN imports bathymetry, free surface and current information from the ROMS while exports signifi- cant wave parameters to the ROMS for Stokes wave computing every 6 s. This coupled model is applied to the South China Sea （SCS） during September 2008 cruise. The results show that LC increasing turbulence and deepening mixed layer depth （MLD） at order of O （10 m） in most of the areas, especially in the north part of SCS where most of our measurements operated. The coupled model further includes wave break- ing which will brings more energy into water. When LC works together with wave breaking, more energy is transferred into deep layer and accelerates the MLD deepening. In the north part of the SCS, their effects are more obvious. This is consistent with big wind event in the area of the Zhujiang River Delta. The shallow water depth as another reason makes them easy to influence the ocean mixing as well.
文摘Yellowfin tuna (Thunnus albacares) is one of the most commercially important fish species for South Pacific island nations and territories and for effective conservation efforts it is important to understand the factors which affect its time series pattern. Our research was aimed at elucidating the climatic factors which affected the trajectory of the yellowfin tuna stock in the Eastern and Western South Pacific Ocean. We utilized various climatic factors for the years t - n with n = 0, 1, ..., 8 and investigated their statistical relationship with the catch per unit effort (CPUE) of yellowfin tuna stock from 1957-2008 for three South Pacific zones ranging from the East to the West Pacific Ocean within the coverage area of the Western and Central Pacific Convention Area. Results showed that the climatic conditions of: (i) the global mean land and ocean temperature index (LOTI), (ii) the Pacific warm pool index (PWI) and (iii) Southern Oscillation Index (SOI) had significant relationship with the CPUE of yellowfin tuna in all three zones. LOTI, PWI and SOI were used as independent variables and fitted through modeling to replicate the CPUE trajectory of the yellowfin tuna in Zone 1, Zone 2 and Zone 3. Model selection was based on significant parameter estimates (p < 0.05), Akaikes Information Criterion (AIC) and R2 values. Models selected for all three zones had LOTI, PWI and SOI as the independent variables. This study shows that LOTI, PWI and SOI are climatic conditions which have significant impact on the fluctuation pattern of the yellowfin tuna CPUE in the Eastern and Western South Pacific Ocean. From the findings of this study it can be recommended that when management decisions are made for yellowfin tuna fishery conservation and sustainability in the Eastern and Western South Pacific, it is imperative to take the effect of climatic factors into account.
基金The foundation of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)under contract No.GML2019ZD0205the National Natural Science Foundation of China under contract Nos 41976064,41890813,41976066,91958211,and 41706056+4 种基金the scholarship of China Scholarship Councilthe foundations of the Chinese Academy of Sciences under contract Nos Y4SL021001,QYZDY-SSW-DQC005,133244KYSB20180029,and 131551KYSB20200021the National Key Research and Development Program of China under contract Nos 2018YFC0309800 and 2018YFC0310105the Foundation of the China Ocean Mineral Resources Research and Development Association under contract No.DY135-S2-1-04the Guangdong Basic and Applied Basic Research Foundation under contract No.2021A1515012227。
文摘We quantified the systematic variations in global transform fault morphology,revealing a first-order dependence on the spreading rate.(1)The average age offset of both the full transform and transform sub-segments decrease with increasing spreading rate.(2)The average depth of both the transform valley and adjacent ridges are smaller in the fast compared to the slow systems,reflecting possibly density anomalies associated with warmer mantle at the fast systems and rifting at the slow ridges.However,the average depth difference between the transform valley and adjacent ridges is relatively constant from the fast to slow systems.(3)The nodal basin at a ridge-transform intersection is deeper and dominant at the ultraslow and slow systems,possibly reflecting a lower magma supply and stronger viscous resistance to mantle upwelling near a colder transform wall.In contrast,the nodal high,is most prominent in the fast,intermediate,and hotspot-influenced systems,where robust axial volcanic ridges extend toward the ridge-transform intersection.(4)Statistically,the average transform valley is wider at a transform system of larger age offset,reflecting thicker deforming plates flanking the transform fault.(5)The maximum magnitude of the transform earthquakes increases with age offset owing to an increase in the seismogenic area.Individual transform faults also exhibit significant anomalies owing to the complex local tectonic and magmatic processes.
文摘Over the years there has been growing interest regarding the effects of climatic variations on marine biodiversity. The exclusive economic zones of South Pacific Islands and territories are home to major international exploitable stocks of albacore tuna (Thunnus alalunga);however the impact of climatic variations on these stocks is not fully understood. This study was aimed at determining the climatic variables which have impact on the time series stock fluctuation pattern of albacore tuna stock in the Eastern and Western South Pacific Ocean which was divided into three zones. The relationship of the climatic variables for the global mean land and ocean temperature index (LOTI), the Pacific warm pool index (PWI) and the Pacific decadal oscillation (PDO) was investigated against the albacore tuna catch per unit effort (CPUE) time series in Zone 1, Zone 2 and Zone 3 of the South Pacific Ocean from 1957 to 2008. From the results it was observed that LOTI, PWI and PDO at different lag periods exhibited significant correlation with albacore tuna CPUE for all three areas. LOTI, PWI and PDO were used as independent variables to develop suitable stock reproduction models for the trajectory of albacore tuna CPUE in Zone 1, Zone 2 and Zone 3. Model selection was based on Akaike Information Criterion (AIC), R2 values and significant parameter estimates at p < 0.05. The final models for albacore tuna CPUE in all three zones incorporated all three independent variables of LOTI, PWI and PDO. From the findings it can be said that the climatic conditions of LOTI, PWI and PDO play significant roles in structuring the stock dynamics of the albacore tuna in the Eastern and Western South Pacific Ocean. It is imperative to take these factors into account when making management decisions for albacore tuna in these areas.
基金This research was supported by the National Key R&D Program of China(No.2018YFC0309800)the Guangdong Basic and Applied Basic Research Foundation(No.2021B1515020098)+3 种基金the Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0205)the National Natural Science Foundation of China(Nos.41776058 and 41890813)the Chinese Academy of Sciences(Nos.133244KYSB20180029,131551KYSB20200021,Y4SL021001,QYZDY-SSW-DQC005 and ISEE 2019ZR01)the Laboratory for Marine Mineral Re-sources,Qingdao National Laboratory for Marine Sci-ence and Technology(No.MMRZZ201801).
文摘Recent studies have demonstrated the ability of seismic oceanography to reveal finescale vertical structures of water column in the oceans based on multichannel seismic(MCS)reflection data.Such information can clarify the dynamic processes of mixing,exchange,and translation of water mass and energy.In this study,we present four MCS lines and satellite data to show high-resolution seismic images of shallow waters over the Shatsky Rise in the Northwest Pacific Ocean,where the Kuroshio Exten-sion passes and bifurcates.One of our MCS transects crossed the center of an anticyclonic warm eddy on August 28,2010,confirmed by satellite data such as sea level anomaly(SLA),geostrophic current anomaly(GCA),and sea surface temperature anomaly(SSTa).The seismic image showed that the eddy vertical structure featured a bowl-like shape and onion-like internal layering.The slightly tilted(<0.5°)surface of the eddy was 400m below the sea surface,indicating a subsurface eddy.The eddy was inferred to have a radius of 50 km and a maximum thickness of 500m.Other MCS sections demonstrated the submesoscale structure of oceanfronts,characterized by the dipping reflectors(>2°-3°)at the boundaries between water masses with differing properties.In addition,the discrepancies in SLA,GCA,and SSTa between water masses resulted in different seismic reflectivities.The water masses with high SLA,anticyclonic GCA and positive SSTa featured high-amplitude,continuous,clear-layered,and non-linear reflections,whereas those with low SLA,cyclonic GCA,and negative SSTa were associated with weak,fragmented,less stratification,and more linear reflectors.
基金Supported by the National Natural Science Foundation of China(No.42130402)the International Science and Technology Cooperation Key Special Project of the National Key Research and Development Program of China(No.2023YFE0104500)。
文摘The Antarctic Bottom Water formation site Vincennes Bay,East Antarctica is experiencing a substantial intrusion of modified Circumpolar Deep Water(mCDW),which may inhibit the formation of Dense Shelf Water(DSW)and drive basal melting of the ice shelves.Based on hydrographic data obtained from March to November in 2012,we evaluated the spatial spread of mCDW over the continental shelf region of Vincennes Bay and the associated temporal evolution of water properties,as well as the sea ice formation effect on water column in the coastal polynya.Results show that two branches of mCDW occupied the deep layers of the continental shelf,distinguished by the potential density(smaller than 27.8 kg/m^(3) or not)when potential temperatureθ=0.5°C in theθ-salinity space.The warmer and less dense branch observed on the east plateau,accessed the eastern ice shelves in the coastal polynya to drive basal melting of ice shelves.In contrast,the other colder and denser branch in the mid-depression reached the western Underwood Ice Shelf.DSW formation was detectable in the coastal polynya during September-November,proving the occurrence of deep convection.Surface heat loss and brine rejection during the intensive sea ice formation contributed to the destratification of the water column in the coastal polynya.It was estimated that at least 1.11±0.79 TW heat carried by mCDW into the inner part of the polynya.
基金the Guangdong Basic and Applied Basic Research Foundation(No.2021B1515020098)the Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD 0205)+6 种基金the National Natural Science Foundation of China(Nos.41776058,41890813,42006056,42276222)the Chinese Academy of Sciences Project(Nos.133244KYSB20180029,131551KYSB20200021,Y4SL021001,QYZDYSSW-DQC005,ISEE2021PY03,E1SL3C02)the Development Fund of South China Sea Institute of Oceanology of the Chinese Academy of Sciences(No.SCSIO202207)Guangdong Provincial Research and Development Program in Key Areas(No.2020B1111520001)the Hainan Provincial Natural Science Foundation of China(No.421QN381)the Science and Technology Program of Guangzhou(No.202201010221)the China Postdoctoral Science Foundation(No.2022M711480)。
文摘The Jurassic oceanic crust is the oldest existing oceanic crust on earth,and although distributed sparsely,carries essential information about the earth's evolution.The area around the Pigafetta Basin in the west Pacific Ocean(also known as the Jurassic Quiet Zone,JQZ)is one of a few areas where the Jurassic oceanic crust is present.This study takes full advantage of high-resolution multichannel seismic reflection profiles in combination with bathymetry,magnetic,and gravity data from the JQZ to examine the structure,deformation,and morphology of the Jurassic oceanic crust.Our results show the following insights:1)The Moho lies at 2–3 s in two-way travel time beneath the seafloor with the segmented feature.The gaps between the Moho segments well correspond to the seamounts on the seafloor,suggesting the upward migration of magma from the mantle has interrupted the pre-existing Moho.2)The oceanic crust is predominantly deformed by crustal-scale thrust faults,normal faults cutting through the top of basement,and vertical seismic disturbance zones in association with migration of thermal fluids.The thrust faults are locally found and interpreted as the results of tectonic inversion.3)Seafloor morphology in the JQZ is characterized by fault scarps,fold scarps,seamounts,and small hills,indicating the occurrence of active faults.4)The oceanic crust in the JQZ and East Pacific Rise has many structural and geometrical variations,such as the thickness of sediments,seafloor topography,basement morphology,fault size and type.
基金Funding Sources:Marine 863 Project (No.2009AA093401)Projects of the National Natural Science Foundation of China (Nos.41072152,90814011 and 41190072)
文摘The fields of structural geology and tectonics have witnessed great progress over the last decade and are poised for further expansion in the future. One of the significant breakthroughs is the establishment of the 'Beyond Plate Tectonics Theory' where a combination of conceptual models and numerical modeling on plume tectonics and plate tectonics has enabled new insights into the structural and tectonic architecture and processes in the deep interior and deep sea. This paper synthesizes developments of structural geology and tectonics from a macroscopic perspective in deep interior and deep sea. Four key techniques are also reviewed: satellite altimetry for surface structures in deep-sea multi-beam sea-floor mapping; tomography for tectonics of the deep interior; diverse modeling approaches and software for unfolding dynamic evolution; and techniques for HT/HP experiments on material rheology and in situ component measurements.
基金supports from the University of Alaska Costal Marine Institute(CMI) and Minerals Management Service(MMS) and IARC/JAMSTEC Cooperative Agreementsupported by NSF OPP Project ARC-0712673 awarded to Yanling Yu and Hajo Eicken (PIs) and Jia Wang(co-PI).This is GLERL Contribution No.1497
文摘A 3.8-kin Coupled Ice-Ocean Model （C1OM） was implemented to successfully reproduce many observed phenomena in the Beaufort and Chukchi seas, including the Bering-inflow-originated coastal current that splits into three branches： Alaska Coastal Water （ACW） , Central Channel, and Herald Valley branches. Other modeled phenomena include the Beaufort Slope Current （BSC） , the Beaufort Gyre, the East Siberian Current （ ESC）, mesoscale eddies, seasonal landfast ice, sea ice ridging, shear, and deformation. Many of these downscaling processes can only be captured by using a high-resolution CIOM, nested in a global climate model. The seasonal cycles for sea ice concentration, thickness, velocity, and other variables are well reproduced with Solid validation by satellite measurements. The seasonal cycles for upper ocean dynamics and thermodynamics are also well reproduced, which include the formation of the cold saline layer due to the injection of salt during sea ice formation, the BSC, and the subsurface upwelling in winter that brings up warm, even more saline Atlantic Water along the shelfbreak and shelf along the Beaufort coast.
基金This study was funded by the National Key Research and Development Program of China(Grant No.2019YFC1806001)the National Natural Science Foundation of China(Grant No.51988101,Grant No.52278376,Grant No.42007245)the Science and Technology Development Fund,Macao SAR(File nos.0083/2020/A2 and 001/2024/SKL).
文摘Debris flows pose serious risks to communities in mountainous areas,often resulting in large losses of human life and property.The impeding presence of urban buildings often affects the runout behavior and deposition of debris flows.But the impact of different building densities and sizes on debris flow dynamics has yet to be quantified to guide urban planning in debris flow risk zones.This study focused on a debris flow that occurred in Zhouqu County,Gansu Province,China on August 7th,2010,which was catastrophic and destroyed many buildings.The FLO-2D software was used to simulate this debris flow in two scenarios,i.e.the presence and the absence of buildings,to obtain debris-flow intensity parameters.The developed model was then used to further analyze the influence of large buildings and narrow channels within the urban environment.The simulation results show that considering the presence of buildings in the simulation is essential for accurate assessment of debris flow intensity and deposition distribution.The layout of buildings in the upstream urban area,such as large buildings or parallel buildings which form narrow channels,can affect the flow velocity and depth of debris flow heading towards downstream buildings.To mitigate damage to downstream buildings,the relative spacing(d/a)between upstream and downstream buildings should not exceed a value of two and should ideally be even lower.These findings provide valuable insights for improving the resistance of mountainous cities to urban debris flows.
基金supported by the Research Grants Council of Hong Kong Special Administrative Region Government of China(Grant Nos.15210322 and R5037-18)the financial support(Grant No.86902-00000240)from Shenzhen University.
文摘The vacuum-assisted prefabricated horizontal drain offers a promising method for strengthening soil slurry,allowing simultaneous filling and vacuum-dewatering via staged construction.However,there is limited research on the unique characteristics of staged filling.This study aims to investigate the vacuum consolidation process of staged-filled soil slurry through laboratory model tests and numerical simulations,also assessing the impact of anionic polyacrylamide.Comparative analyses are conducted between vacuum consolidation with and without anionic polyacrylamide,as well as self-weight consolidation without anionic polyacrylamide.Results reveal contour lines of excess pore pressure,water content,and soil strength forming an ellipse around the prefabricated horizontal drain board.During the consolidation process,a higher degree of consolidation,lower water content,and higher soil strength were observed closer to the prefabricated horizontal drain board.After treatment,the uppermost filling layer exhibits an average water content that was approximately 40%higher than the lower filling layer,and its average strength was about 60%lower.This discrepancy is primarily due to the absence of sealing on the top surface and the relatively short vacuum consolidation time caused by staged filling.The introduction of anionic polyacrylamide-induced flocculation significantly improves the initial consolidation rate but minimally affects the dewatering capacity of vacuum preloading.Using flocculant can enhance both the staged filling rate and soil strength(by 1e2 times).Additionally,employing a staggered arrangement between different prefabricated horizontal drain layers is advisable to prevent top-down penetration in areas with low soil strength.
基金The fund from Science,Technology and Innovation Commission of Shenzhen Municipality under contract No.JCYJ20210324105211031the National Natural Science Foundation of China under contract No.41720104001.
文摘Typhoons in the western Pacific have a significant impact on the transport of heat,salt and particles through the Luzon Strait.However,there are very limited field observations of this impact because of extreme difficulties and even dangers for ship-based measurements during the rough weather.Here,we present the preliminary results from analyzing a dataset collected by a glider deployed west of the Luzon Strait a few days prior to the arrival of typhoon MITAG.The gilder data revealed an abnormally salinity(>34.8)subsurface water apparently sourced from Kuroshio intrusion during the typhoon.When typhoon MITAG traveled on the east of the Luzon Strait,the positive wind stress curl strengthened the cyclonic eddy and weakened the anti-cyclonic eddy.This led to a slowdown of Kuroshio and made its intrusion easier.The main axis of the Kuroshio at the northern part of the strait shifted westward after the typhoon and did not return to its original position until a week later.The Ekman transport from persistent northerly wind of typhoon MITAG was significant,but its importance in enhancing the Kuroshio intrusion is only secondary relative to the eddies variations.
基金supported by the National Natural Science Foundation of China(Nos.42276095,42188102,42141003,and U20A20103)the Open Innovation Fund for Undergraduate Students of Xiamen University,and Ocean Negative Carbon Emissions(ONCE)program。
文摘Haptophytes(Eukaryota,Hacrobia)play a crucial role in the energy budget and element cycling of diverse aquatic ecosystems due to their ability to engage in both phototrophic and mixotrophic nutritional modes.Nevertheless,there is a significant lack of knowledge regarding the short-term variations,such as diel dynamics,of their ecological features.During a short time frame in the summer of 2018,samples were collected from three distinct water layers in the South China Sea,including surface water,the deep chlorophyll maximum(DCM)layer,and 200 m depth.Fluorescence in situ hybridization coupled with tyramide signal amplification was used to quantify haptophyte cell abundance.Most haptophyte communities in all three water layers were composed of cells 2-5μm in size,while the proportion of cells<2μm increased with water depth.High-throughput sequencing of the V4 hypervariable regions of the SSU rRNA revealed that Chrysochromulina and Phaeocystis predominated the community,and the former was more abundant in the surface water and 200 m depth and the latter was more abundant in the DCM layer.Higher abundance of small cells(<2μm and 2-5μm)during the night was found compared to the day time,whereas large cells(5-10μm and 10-20μm)were more prevalent during the day time.The results of correlation analyses showed that haptophyte abundance was possibly impacted by both environmental biotic(heterotrophic nanoflagellates,heterotrophic bacteria,and viruses)and abiotic(temperature,salinity,and nutrients)factors.
基金supported by the National Natural Science Foundation of China(Grant Nos.42225501 and 42105059)the National Key Scientific and Tech-nological Infrastructure project“Earth System Numerical Simula-tion Facility”(EarthLab).
文摘In order to quantify the influence of external forcings on the predictability limit using observational data,the author introduced an algorithm of the conditional nonlinear local Lyapunov exponent(CNLLE)method.The effectiveness of this algorithm is validated and compared with the nonlinear local Lyapunov exponent(NLLE)and signal-to-noise ratio methods using a coupled Lorenz model.The results show that the CNLLE method is able to capture the slow error growth constrained by external forcings,therefore,it can quantify the predictability limit induced by the external forcings.On this basis,a preliminary attempt was made to apply this method to measure the influence of ENSO on the predictability limit for both atmospheric and oceanic variable fields.The spatial distribution of the predictability limit induced by ENSO is similar to that arising from the initial conditions calculated by the NLLE method.This similarity supports ENSO as the major predictable signal for weather and climate prediction.In addition,a ratio of predictability limit(RPL)calculated by the CNLLE method to that calculated by the NLLE method was proposed.The RPL larger than 1 indicates that the external forcings can significantly benefit the long-term predictability limit.For instance,ENSO can effectively extend the predictability limit arising from the initial conditions of sea surface temperature over the tropical Indian Ocean by approximately four months,as well as the predictability limit of sea level pressure over the eastern and western Pacific Ocean.Moreover,the impact of ENSO on the geopotential height predictability limit is primarily confined to the troposphere.
基金the financial support from the National Key R&D Program of China(Grant No.2021YFC3001003)Science and Technology Development Fund,Macao SAR(File No.0056/2023/RIB2)Guangdong Provincial Department of Science and Technology(Grant No.2022A0505030019).
文摘Challenges in stratigraphic modeling arise from underground uncertainty.While borehole exploration is reliable,it remains sparse due to economic and site constraints.Electrical resistivity tomography(ERT)as a cost-effective geophysical technique can acquire high-density data;however,uncertainty and nonuniqueness inherent in ERT impede its usage for stratigraphy identification.This paper integrates ERT and onsite observations for the first time to propose a novel method for characterizing stratigraphic profiles.The method consists of two steps:(1)ERT for prior knowledge:ERT data are processed by soft clustering using the Gaussian mixture model,followed by probability smoothing to quantify its depthdependent uncertainty;and(2)Observations for calibration:a spatial sequential Bayesian updating(SSBU)algorithm is developed to update the prior knowledge based on likelihoods derived from onsite observations,namely topsoil and boreholes.The effectiveness of the proposed method is validated through its application to a real slope site in Foshan,China.Comparative analysis with advanced borehole-driven methods highlights the superiority of incorporating ERT data in stratigraphic modeling,in terms of prediction accuracy at borehole locations and sensitivity to borehole data.Informed by ERT,reduced sensitivity to boreholes provides a fundamental solution to the longstanding challenge of sparse measurements.The paper further discusses the impact of ERT uncertainty on the proposed model using time-lapse measurements,the impact of model resolution,and applicability in engineering projects.This study,as a breakthrough in stratigraphic modeling,bridges gaps in combining geophysical and geotechnical data to address measurement sparsity and paves the way for more economical geotechnical exploration.
