Freshwater reservoirs are regarded as an important anthropogenic source of methane(CH_(4))emissions. The temporal and spatial variability of CH_(4) emissions from different reservoirs results in uncertainty in the est...Freshwater reservoirs are regarded as an important anthropogenic source of methane(CH_(4))emissions. The temporal and spatial variability of CH_(4) emissions from different reservoirs results in uncertainty in the estimation of the global CH_(4) budget. In this study, surface water CH_(4) concentrations were measured and diffusive CH_(4) fluxes were estimated via a thin boundary layer model in a temperate river–reservoir system in North China, using spatial(33 sites) and temporal(four seasons) monitoring;the system has experienced intensive aquaculture disturbance. Our results indicated that the dissolved CH_(4) concentration in the reservoir ranged from 0.07 to 0.58 μmol/L, with an annual average of 0.13 ± 0.10 μmol/L, and the diffusive CH_(4) flux across the water–air interface ranged from 0.66 to 3.61 μmol/(m^(2)·hr),with an annual average of 1.67 ± 0.75 μmol/(m^(2)·hr). During the study period, the dissolved CH_(4) concentration was supersaturated and was a net source of atmospheric CH_(4) . Notably,CH_(4) concentration and diffusive flux portrayed large temporal and spatial heterogeneity.The river inflow zone was determined to be a hotspot for CH_(4) emissions, and its flux was significantly higher than that of the tributary and main basin;the CH_(4) flux in autumn was greater than that in other seasons. We also deduced that the CH_(4) concentration/diffusive flux was co-regulated mainly by water temperature, water depth, and water productivity(Chla, trophic status). Our results highlight the importance of considering the spatiotemporal variability of diffusive CH_(4) flux from temperate reservoirs to estimate the CH_(4) budget at regional and global scales.展开更多
Understanding water chemistry in karst regions is crucial for improving global water resource management and deepening our knowledge of the biogeochemical cycles shaping these sensitive environments.Despite advance-me...Understanding water chemistry in karst regions is crucial for improving global water resource management and deepening our knowledge of the biogeochemical cycles shaping these sensitive environments.Despite advance-ments in karst hydrology,significant gaps remain in long-term trends,underlying processes,and quantitative effects of environmental changes.This is especially true in areas like the Wujiang River(WJ)in China,where human activities such as reservoir construction and land use/cover changes have accelerated hydrochemical changes.We combined recent and historical monitoring data to provide a detailed analysis of the spatial and temporal characteristics,evolution,and controlling factors of major ions in WJ.These findings are important for local water management and contribute to global efforts to manage similar karst systems facing human-induced pressures.Our research shows clear seasonal differences in solute concentrations,with higher levels during the dry season.WJ’s water is rich in calcium,with Ca-HCO_(3) ion pairs being the most common.Reservoir monitor-ing stations show much higher levels of NO_(3)^(−)and SO_(4)^(2−)compared to river-type stations,likely due to longer hydraulic retention time and increased acid deposition.The study confirms the significant role of pH and water temperature in rock weathering processes.Land use/cover changes were identified as the primary drivers of solute variations(46.37%),followed by lithology(13.92%)and temperature(8.35%).Over the past two decades,in-tense carbonate weathering has been observed,especially during wet seasons.Among karstic provinces,Guizhou Province stands out with the highest ion concentrations,indicative of its extensive karst coverage and heightened weathering processes.展开更多
Microbial communities play indispensable roles in the biogeochemical cycling of river ecosystems.However,the response patterns of microbial community diversity,niche breadth,and assembly to rainfall disturbances in co...Microbial communities play indispensable roles in the biogeochemical cycling of river ecosystems.However,the response patterns of microbial community diversity,niche breadth,and assembly to rainfall disturbances in complex mountainous riverine reservoirs remain inadequately understood.We employed high-throughput sequencing of 16S and 18S ribosomal RNA genes,along with multivariate statistical methods to systematically investigate prokaryotic and eukaryotic microorganisms in the riverine Zhaoshandu Reservoir,Wenzhou,Zhejiang,East China.Results show significant temporal heterogeneity in both prokaryotic and eukaryotic microbial communities,with eukaryotic microbes showing more pronounced temporal variation.Canonical correspondence analysis revealed that rainfall and water temperature were the key drivers shaping microbial communities.Additionally,eukaryotic microorganisms exhibited a more pronounced response to rainfall and water temperature compared to prokaryotes.Modified stochasticity ratio model indicated that deterministic processes predominantly governed microbial community assembly,with stronger deterministic processes in eukaryotic compared to prokaryotic microorganisms.Rainfall has significantly altered water quality,notably increasing phosphorus concentration in the water column.Total phosphorus and total nitrogen showed significant correlations with the niche breadth of prokaryotic and eukaryotic microorganisms,and phosphorus nutrients served as keystones and playing indispensable roles in their co-occurrence networks.A structural equation model confirmed the notable impacts of rainfall and water temperature on microbial community diversity,further revealing that rainfall indirectly influenced the niche breadth and co-occurrence relationships of microbial communities by altering phosphorus concentrations.The findings underscore the influence of rainfall and water temperature on microbial distribution,highlighting the sensitivity of riverine reservoir ecosystems to climate change.展开更多
The increased frequency and intensity of heavy rainfall events due to climate change could potentially influence the movement of nutrients from land-based regions into recipient rivers.However,little information is av...The increased frequency and intensity of heavy rainfall events due to climate change could potentially influence the movement of nutrients from land-based regions into recipient rivers.However,little information is available on how the rainfall affect nutrient dynamics in subtropicalmontane rivers with complex land use.This study conducted high-frequency monitoring to study the effects of rainfall on nutrients dynamics in an agricultural river draining to Lake Qiandaohu,a montane reservoir of southeast China.The results showed that riverine total nitrogen(TN)and total phosphorus(TP)concentrations increased continuously with increasing rainfall intensity,while TN:TP decreased.The heavy rainfall and rainstorm drove more than 30%of the annual N and P loading in only 5.20%of the total rainfall period,indicating that increased storm runoff is likely to exacerbate eutrophication in montane reservoirs.NO_(3)^(−)-N is the primary nitrogen form lost,while particulate phosphorus(PP)dominated phosphorus loss.Themain source of N is cropland,and themain source of P is residential area.Spatially,forestedwatersheds have better drainage quality,while it is still a potential source of nonpoint pollution during rainfall events.TN and TP concentrations were significantly higher at sites dominated by cropland and residential area,indicating their substantial contributions to deteriorating river water quality.Temporally,TN and TP concentrations reached high values in May-August when rainfall was most intense,while they were lower in autumn and winter than that in spring and summer under the same rainfall intensities.The results emphasize the influence of rainfall-runoff and land use on dynamics of riverine N and P loads,providing guidance for nutrient load reduction planning for Lake Qiandaohu.展开更多
Interaction between the Yangtze River and its tributaries in the Three Gorges Reservoir has an important influence on tributary algal blooms.Taking the Xiaojiang River as a typical tributary,a binary mixing model used...Interaction between the Yangtze River and its tributaries in the Three Gorges Reservoir has an important influence on tributary algal blooms.Taking the Xiaojiang River as a typical tributary,a binary mixing model used stable isotopes of hydrogen and oxygen to quantitatively analyze the water contribution and nutrient source structure of the tributary backwater area.Results showed that the isotope content(δD:−54.7‰,δ^(18)O−7.8‰)in the Yangtze River was higher than that in the tributaries(δD:−74.2‰,δ^(18)O−17.0‰)in the non-flood season and lower than that in the tributaries in the flood season.The Yangtze River contributed more than 50%water volume of the tributary backwater area in the non-flood season.The total nitrogen and total phosphorus concentrations in the backwater area were estimated based on water contribution ratio,and the results were in good agreement with the monitoring results.Load estimation showed that the nitrogen and phosphorus contribution ratio of the Yangtze River to the tributary backwater area was approximately 40%-80%in the non-flood season,and approximately 20%-40%in the flood season,on average.This study showed that the interaction between the Xiaojiang River and the Yangtze River is significant,and that Yangtze River recharge is an important source of nutrients in the Xiaojiang backwater area,which may play a driving role in Xiaojiang River algal blooms.展开更多
How the strong segmentation of cascade reservoir dams and the spatiotemporal changes of sediment retention volume affect the river morphology adjustment in the reservoir area is a scientific issue worthy of exploratio...How the strong segmentation of cascade reservoir dams and the spatiotemporal changes of sediment retention volume affect the river morphology adjustment in the reservoir area is a scientific issue worthy of exploration.This study aims to reveal the adjustment mechanism of the thalweg longitudinal profile of cascade reservoirs.This study focuses on the Xiangjiaba and Xiluodu reservoirs located in the lower reaches of the Jinsha River.Utilizing multi-period observational data of thalweg elevation in reservoir reaches both before and after dam construction,the research employs statistical,geomorphological,and sedimentological methodologies to analyze variation characteristics in the measured curves,trend curves,and theoretical fitting curves of the thalweg longitudinal profile.The investigation ultimately reveals two distinct adjustment patterns in the longitudinal profiles of these cascade reservoirs:the concave curve type and the convex curve type.The former is characterized by weak riverbed scouring and silting changed to rapid aggradation in the upstream section of the reservoir area after dam closure,then changed to slow aggradation in the whole reservoir area,which is the common feature of reservoirs that were built earlier and are relatively located in the downstream(such as the Xiangjiaba Reservoir).The latter is characterized by a straight line or concave curve type with weak riverbed scouring and silting before the dam closure changed to a convex curve type with strong siltation after dam closure,which is the characteristic of reservoirs that were built later and are relatively located in the upstream(such as the Xiluodu Reservoir).The adjustment of the cascade reservoir longitudinal profile is controlled by the spatiotemporal changes of the sediment deposition volume and sedimentation rate in the reservoir area,and the alternating changes of the hydrodynamic gradient and regulation mode affect the spatial heterogeneity of the sedimentation rate.The research results are helpful for understanding the adjustment mechanism of the cascade reservoir longitudinal profile in similar areas and have a guiding role in predicting the adjustment trend of the cascade reservoir longitudinal profile without observation data.展开更多
Organic electrochemical transistor(OECT)devices demonstrate great promising potential for reservoir computing(RC)systems,but their lack of tunable dynamic characteristics limits their application in multi-temporal sca...Organic electrochemical transistor(OECT)devices demonstrate great promising potential for reservoir computing(RC)systems,but their lack of tunable dynamic characteristics limits their application in multi-temporal scale tasks.In this study,we report an OECT-based neuromorphic device with tunable relaxation time(τ)by introducing an additional vertical back-gate electrode into a planar structure.The dual-gate design enablesτreconfiguration from 93 to 541 ms.The tunable relaxation behaviors can be attributed to the combined effects of planar-gate induced electrochemical doping and back-gateinduced electrostatic coupling,as verified by electrochemical impedance spectroscopy analysis.Furthermore,we used theτ-tunable OECT devices as physical reservoirs in the RC system for intelligent driving trajectory prediction,achieving a significant improvement in prediction accuracy from below 69%to 99%.The results demonstrate that theτ-tunable OECT shows a promising candidate for multi-temporal scale neuromorphic computing applications.展开更多
Neuromorphic devices have garnered significant attention as potential building blocks for energy-efficient hardware systems owing to their capacity to emulate the computational efficiency of the brain.In this regard,r...Neuromorphic devices have garnered significant attention as potential building blocks for energy-efficient hardware systems owing to their capacity to emulate the computational efficiency of the brain.In this regard,reservoir computing(RC)framework,which leverages straightforward training methods and efficient temporal signal processing,has emerged as a promising scheme.While various physical reservoir devices,including ferroelectric,optoelectronic,and memristor-based systems,have been demonstrated,many still face challenges related to compatibility with mainstream complementary metal oxide semiconductor(CMOS)integration processes.This study introduced a silicon-based schottky barrier metal-oxide-semiconductor field effect transistor(SB-MOSFET),which was fabricated under low thermal budget and compatible with back-end-of-line(BEOL).The device demonstrated short-term memory characteristics,facilitated by the modulation of schottky barriers and charge trapping.Utilizing these characteristics,a RC system for temporal data processing was constructed,and its performance was validated in a 5×4 digital classification task,achieving an accuracy exceeding 98%after 50 training epochs.Furthermore,the system successfully processed temporal signal in waveform classification and prediction tasks using time-division multiplexing.Overall,the SB-MOSFET's high compatibility with CMOS technology provides substantial advantages for large-scale integration,enabling the development of energy-efficient reservoir computing hardware.展开更多
Effective conservation relies on robust assessments;however,the lack of waterbird data in the Yellow River Basin(YRB)has led to an underestimation of key habitat significance.This study addressed this gap by evaluatin...Effective conservation relies on robust assessments;however,the lack of waterbird data in the Yellow River Basin(YRB)has led to an underestimation of key habitat significance.This study addressed this gap by evaluating YRB wetland conservation importance using waterbirds as indicators and applying Ramsar,Important Bird Areas(IBA),and East Asian-Australasian Flyway(EAAF)criteria.We integrated coordinated surveys with citizen science data,creating a framework that tackles data deficiencies along the under-monitored Central Asian Flyway(CAF).Our analysis identified 75 priority wetlands,supporting 15 threatened species and 49 exceeding global/flyway 1%thresholds,highlighting the basin's biodiversity.We observed strong seasonal habitat use,with high-altitude wetlands vital for breeding and migration,and the Yellow River Delta providing year-round refuge.This research also provided data to refine Baer's Pochard population estimates.Alarmingly,one-third of the identified priority areas,primarily rivers and lakes,remain unprotected.To address this,we recommend systematic surveys,enhanced protected areas,OECMs,and targeted wetland restoration.This study underscores the YRB's role in regional conservation and provides essential data for adaptive management,particularly emphasizing the CAF's importance.展开更多
As a representative surviving example of residences associated with officials and merchants in the southwestern Shandong region of the lower Yellow River Basin,spanning the Ming and Qing Dynasties to the modern period...As a representative surviving example of residences associated with officials and merchants in the southwestern Shandong region of the lower Yellow River Basin,spanning the Ming and Qing Dynasties to the modern period,the Zhujia Courtyard in Shan County functions as a built medium through which commercial capital and clan culture were closely intertwined.Drawing on field investigation and a review of the literature,this study examines its architectural and cultural characteristics across five dimensions:an overview of the courtyard,spatial layout,structural system,decorative arts,and cultural meanings.The analysis points to four interrelated cores,including the spatial embodiment of Confucian ethics,the status aspirations of canal-based merchant groups,adaptive strategies shaped by Yellow River conditions,and the symbolic articulation of folk beliefs.展开更多
Rock damage significantly affects coupled thermo-hydro-mechanical(THM)behavior in deep geothermal exploitation through changing thermal and hydrological properties of rocks.For this,a thermo-hydro-mechanical-damage(TH...Rock damage significantly affects coupled thermo-hydro-mechanical(THM)behavior in deep geothermal exploitation through changing thermal and hydrological properties of rocks.For this,a thermo-hydro-mechanical-damage(THMD)coupled model was developed to describe the coupling between rock damage and mechanical,fluid flow and heat transfer fields.The model considers rock heterogeneity,and incorporates the Mohr-Coulomb failure criterion and the maximum tensile stress criterion to evaluate shear and tensile damage.This numerical modeling methodology was first verified against analytical solutions and experimental results,and was then used to simulate the THMD coupling behavior in deep geothermal exploitation.A coupled numerical model was set up to simulate the geothermal fluids extraction and re-injection process in a reservoir at 1 km depth over a 7-year period.Rock damage was found to accelerate the propagation of cold fronts away from the injection well,and have a distinct effect on the performance of geothermal exploitation.When the rock damage was considered,the field injectivity increases by 8.4 times,the range of cooled regions increases by 18.6 times,and the vertical deformation changes by 1.2 times after 7 years of geothermal operations,compared to the scenario where it was not considered.Parametric studies have suggested that thermal contraction dominates the rock damage evolution,and that thermal-induced rock damage only occurs at a sufficiently large temperature difference between fluids injected and the reservoir.This work underscores the importance of accurately accounting for the damage effect on reservoir response during fluid injection activities that cause significant cooling of reservoir rocks.展开更多
Reservoir-induced landslides in China's Three Gorges Reservoir area are prone to tensile cracks due to the influenceof their own weight and fluctuationsin water levels.The presence of cracks indicates that the ten...Reservoir-induced landslides in China's Three Gorges Reservoir area are prone to tensile cracks due to the influenceof their own weight and fluctuationsin water levels.The presence of cracks indicates that the tensile stress in the area has exceeded the tensile strength of the soil,leading to local instability.To explore the impact of tensile failure behavior on the stability and failure modes of reservoir landslides,the Huangtupo Riverside Slump#1 is taken as a case study.By considering local tensile failure,potential tensile cracks are incorporated into the analysis via the limit equilibrium method and reliability theory.The reliability of landslides under different tensile failure scenarios is quantified.Strain-softening characteristics of the soil are combined to further analyze the failure transmission path of the landslide.Finally,these potential failure modes were validated through physical model tests.The results show that cracks developing at rear positions reduce the stability of the slope and increase the probability of instability.During the destruction process,retrogressive failures with multiple sliding surfaces are likely to occur.However,tensile failure at the forefront reduces the likelihood of an individual slide mass descending.Progressive failure results in both regular and skip transmission patterns.Additionally,cracks and water level changes can also lead to shifts in the positions of the most dangerous blocks.Therefore,in practical landslide analysis and prevention,it is necessary to consider local tensile damage and identify potential tensile crack locations in advance to optimize prevention measures and accurately evaluate landslide risk.展开更多
With the efficient and intelligent development of computer-based big data processing,applying machine learning methods to the processing and interpretation of logging data in the field of geophysical well logging has ...With the efficient and intelligent development of computer-based big data processing,applying machine learning methods to the processing and interpretation of logging data in the field of geophysical well logging has broad potential for improving production efficiency.Currently,the Jiyuan Oilfield in the Ordos Basin relies mainly on manual reprocessing and interpretation of old well logging data to identify different fluid types in low-contrast reservoirs,guiding subsequent production work.This study uses well logging data from the Chang 1 reservoir,partitioning the dataset based on individual wells for model training and testing.A deep learning model for intelligent reservoir fluid identification was constructed by incorporating the focal loss function.Comparative validations with five other models,including logistic regression(LR),naive Bayes(NB),gradient boosting decision trees(GBDT),random forest(RF),and support vector machine(SVM),show that this model demonstrates superior identification performance and significantly improves the accuracy of identifying oil-bearing fluids.Mutual information analysis reveals the model's differential dependency on various logging parameters for reservoir fluid identification.This model provides important references and a basis for conducting regional studies and revisiting old wells,demonstrating practical value that can be widely applied.展开更多
In this study,based on MERRA-2 reanalysis data and a multi-algorithm integrated atmospheric river(AR)iden-tification method,the authors reveal the cross-seasonal regulation mechanism of El Niño-Southern Oscillati...In this study,based on MERRA-2 reanalysis data and a multi-algorithm integrated atmospheric river(AR)iden-tification method,the authors reveal the cross-seasonal regulation mechanism of El Niño-Southern Oscillation(ENSO)on winter-spring AR activities in East Asia.The results show that ENSO asymmetrically modulates AR ac-tivity through teleconnection and hysteresis effects,and has significant enhancement/inhibition effects on ARs in different regions.At the onset of El Niño,enhanced southwesterly flow at the western edge of the western Pacific subtropical high(WPSH)leads to enhanced AR activity in the western Pacific,and anomalous southerly winds in the Indian Ocean promote northward transport of water vapor in the Arabian Sea and Bay of Bengal.With a three-month lag,the weakening and eastward retreat of the WPSH weakens the low-latitude AR activity,but persistent southerly winds in the Bay of Bengal maintain the AR activity over Southwest China.The mid-to high-latitude AR response exhibits delayed dynamics,initially dominated by the synergistic effect of the southward deviation of the upper-air rapids and the low-level convergence(double-rapid-flow effect)and later modulated by the Pacific-North American teleconnection(PNA)-triggered East Asian ridge,which enhances the precipitation efficiency through prolonged frontal activity and enhanced cold-warm airmass convergence.Overall,El Niño promotes the development of low-and midlatitude AR activity in East Asia,while La Niña promotes(maritime continental)AR activity in the tropics.This study establishes the“ENSO teleconnection→circulation adjust-ment→East Asian AR response”chain,revealing a cross-seasonal lagged response mechanisms of East Asian AR activity,and provides a theoretical basis for winter and spring climate prediction and extreme precipitation forecasting.展开更多
We conducted a field campaign to investigate the chemical composition,sources,and light absorption of submicron aerosols(PM_(1))from early 2022 in Nanjing,China.The average concentration of PM_(1) was 31μg m^(−3),org...We conducted a field campaign to investigate the chemical composition,sources,and light absorption of submicron aerosols(PM_(1))from early 2022 in Nanjing,China.The average concentration of PM_(1) was 31μg m^(−3),organics(33%)constituted the largest fraction,followed by nitrate(30%),sulfate(18%),ammonium(15%),chloride(3%),and rBC(2%).Four organic aerosol(OA)subcomponents were identified,including two primary OA(POA)and two secondary OA(SOA).The less-oxidized SOA(LO-OOA)contributes the most to the total OA mass(59%).LO-OOA is tightly correlated with the tracer ion C_(2)H_(4)O_(2)^(+)from levoglucosan,and another aged biomass-burning derived species,K_(3)SO_(4)^(+),suggesting it was likely influenced by aged biomass-burning OA.Our study also revealed that fireworks during the Spring Festival have a detrimental impact on air quality,contributing to secondary formation and accumulation under static winter meteorological conditions,prolonging the pollution duration.Also,LO-OOA was found to have the strongest light-absorbing ability.Our results highlight that the light absorption of LO-OOA can mainly be attributed to the C_(x)H_(y)N^(+) family,increased with the double-bond equivalent value.The more-oxidized SOA(MO-OOA)exhibited a negligible light absorption and was strongly correlated with daytime photochemical processes,implying a light-bleaching effect.This study enhances our understanding of the regional contribution of biomass combustion and fireworks to PM_(1) pollution in Nanjing,a typical megacity in the Yangtze River Delta region,during winter,aiding in the development of strategies for long-term air quality improvement in the region.展开更多
Human activities have significantly impacted the land surface temperature(LST),endangering human health;however,the relationship between these two factors has not been adequately quantified.This study comprehensively ...Human activities have significantly impacted the land surface temperature(LST),endangering human health;however,the relationship between these two factors has not been adequately quantified.This study comprehensively constructs a Human Activity Intensity(HAI)index and employs the Maximal Information Coefficient,four-quadrant model,and XGBoostSHAP model to investigate the spatiotemporal relationship and influencing factors of HAI-LST in the Yellow River Basin(YRB)from 2000 to 2020.The results indicated that from 2000 to 2020,as HAI and LST increased,the static HAI-LST relationship in the YRB showed a positive correlation that continued to strengthen.This dynamic relationship exhibited conflicting development,with the proportion of coordinated to conflicting regions shifting from 1:4 to 1:2,indicating a reduction in conflict intensity.Notably,only the degree of conflict in the source area decreased significantly,whereas it intensified in the upper and lower reaches.The key factors influencing the HAI-LST relationship include fractional vegetation cover,slope,precipitation,and evapotranspiration,along with region-specific factors such as PM_(2.5),biodiversity,and elevation.Based on these findings,region-specific ecological management strategies have been proposed to mitigate conflict-prone areas and alleviate thermal stress,thereby providing important guidance for promoting harmonious development between humans and nature.展开更多
The Selenge River Basin(SRB)in Mongolia has faced ecosystem degradation because of climate change and overloading.The dynamics of the pastoral system and the extent of overload under future scenarios have not been doc...The Selenge River Basin(SRB)in Mongolia has faced ecosystem degradation because of climate change and overloading.The dynamics of the pastoral system and the extent of overload under future scenarios have not been documented.This study aims to answer the following questions:Will the typical soums in the SRB become more overgrazed in the future?What optimal strategy should be implemented?Multisource data were integrated and utilized to model the pastoral system of typical soums using a system dynamics approach.Future scenarios under three SSP-RCPs were projected using the model.The conclusions are as follows:(1)From upstream to downstream,rational scenarios for pastoral system transferred from SSP1-RCP2.6 to SSP2-RCP4.5,which reflect improved productivity at the expense of ecosystem stability.(2)Compared with that during the historical period of 2000-2020,the projected carrying capacity of the soums decreases by 15.2%-37.3%,whereas the number of livestock continues to increase.Consequently,the stocking rate is expected to increase from 0.32-1.16 during 2000-2020 to 1.26-2.02 during 2021-2050,indicating that rangeland will become more overloaded.(3)A livestock reduction strategy based on future livestock stock and grassland carrying capacity scenarios was proposed to maintain a dynamic forage-livestock equilibrium.It is suggested that reducing livestock is a practical option for harmonizing grassland conservation with livestock husbandry development.展开更多
Guided by the significant theoretical principle of the“Two Integrations”and grounded in Marxist cultural theory as its methodological basis,this paper constructs a bidirectional interpretative model linking“Yellow ...Guided by the significant theoretical principle of the“Two Integrations”and grounded in Marxist cultural theory as its methodological basis,this paper constructs a bidirectional interpretative model linking“Yellow River Culture”with“Cultural Confidence”.It proposes an integrated“Objective-Content-Path-Support”framework.Through the synergy of three-dimensional objectives,adaptation of stratified content,innovation in four-dimensional pathways,and support from a three-dimensional guarantee system,this framework establishes a closed-loop operational mechanism of“Curriculum-Practice-Evaluation-Feedback”.The study focuses on core issues in integrating Yellow River culture into university education practices,such as content construction,methodological pathways,and institutional guarantees.It aims to provide a systematic reference for universities to fulfill their fundamental task of“fostering virtue and cultivating talent”and to serve the national strategies for ecological protection and high-quality development in the Yellow River Basin.展开更多
The widely distributed loess deposits in the Yellow River Basin exhibit unique engineering geological characteristics.The variations in their thickness and stratigraphic structure significantly amplify ground motion p...The widely distributed loess deposits in the Yellow River Basin exhibit unique engineering geological characteristics.The variations in their thickness and stratigraphic structure significantly amplify ground motion parameters,directly influencing the regional seismic hazard risk level.This study methodically conducted on-site studies and observations of building collapses and damages resulting from seismic amplification effects,using the Wenchuan M_(S)8.0 earthquake as a case study.Comprehensive experimental and numerical simulation studies were carried out.A large-scale shaking table test was performed,and numerical models for 14 different loess sites types were established.Various types of seismic waves were incorporated into these models for systematic numerical simulation calculations.The research reveals the mechanisms by which loess deposit thickness and stratigraphic structure in the Yellow River Basin affect seismic ground motion amplification.The results indicate that as the epicentral distance increases,the peak ground motion shows a marked attenuation trend,with the horizontal component attenuating substantially faster than the vertical component.As the overlying loess layer thickness increases from 50 to 100 m,the seismic intensity may escalate by 3−4 degrees,and the peak acceleration may amplify by 1.5−2.2 times.With the augmentation of loess deposit thickness and the proliferation of soil layers,both the peak acceleration response spectrum and the characteristic period demonstrate an upward tendency,exhibiting slight fluctuations contingent upon the seismic wave type.展开更多
Landslide susceptibility mapping(LSM)is an essential tool for mitigating the escalating global risk of landslides.However,challenges such as the heterogeneity of different landslide triggers,extensive engineering acti...Landslide susceptibility mapping(LSM)is an essential tool for mitigating the escalating global risk of landslides.However,challenges such as the heterogeneity of different landslide triggers,extensive engineering activities exacerbated reactivation,and the interpretability of data-driven models have hindered the practical application of LSM.This work proposes a novel framework for enhancing LSM considering different triggers for accumulation and rock landslides,leveraging interpretable machine learning and Multi-temporal Interferometric Synthetic Aperture Radar(MT-InSAR)technology.Initially,a refined fieldinvestigation was conducted to delineate the accumulation and rock area according to landslide types,leading to the identificationof relevant contributing factors.Deformation along the slope was then combined with time-series analysis to derive a landslide activity level(AL)index to recognize the likelihood of reactivation or dormancy.The SHapley Additive exPlanation(SHAP)technique facilitated the interpretation of factors and the identificationof determinants in high susceptibility areas.The results indicate that random forest(RF)outperformed other models in both accumulation and rock areas.Key factors including thickness and weak intercalation were identifiedfor accumulation and rock landslides.The introduction of AL substantially enhanced the predictive capability of the LSM and outperformed models that neglect movement trends or deformation rates with an average ratio of 81.23%in high susceptibility zones.Besides,the fieldvalidation confirmedthat 83.8%of newly identifiedlandslides were correctly upgraded.Given its efficiencyand operational simplicity,the proposed hybrid model opens new avenues for the feasibility of enhancement in LSM at urban settlements worldwide.展开更多
基金supported by the National Nature Science Foundation of China(Nos.41771516,41771122)the Bureau of Luanhe Diversion Project of the Haihe River Water Conservancy Commission,Ministry of Water Resources of China and Tianjin Water Affairs Bureau project(Nos.HYGP-2019-C-130,TJGC-2019-C-060)。
文摘Freshwater reservoirs are regarded as an important anthropogenic source of methane(CH_(4))emissions. The temporal and spatial variability of CH_(4) emissions from different reservoirs results in uncertainty in the estimation of the global CH_(4) budget. In this study, surface water CH_(4) concentrations were measured and diffusive CH_(4) fluxes were estimated via a thin boundary layer model in a temperate river–reservoir system in North China, using spatial(33 sites) and temporal(four seasons) monitoring;the system has experienced intensive aquaculture disturbance. Our results indicated that the dissolved CH_(4) concentration in the reservoir ranged from 0.07 to 0.58 μmol/L, with an annual average of 0.13 ± 0.10 μmol/L, and the diffusive CH_(4) flux across the water–air interface ranged from 0.66 to 3.61 μmol/(m^(2)·hr),with an annual average of 1.67 ± 0.75 μmol/(m^(2)·hr). During the study period, the dissolved CH_(4) concentration was supersaturated and was a net source of atmospheric CH_(4) . Notably,CH_(4) concentration and diffusive flux portrayed large temporal and spatial heterogeneity.The river inflow zone was determined to be a hotspot for CH_(4) emissions, and its flux was significantly higher than that of the tributary and main basin;the CH_(4) flux in autumn was greater than that in other seasons. We also deduced that the CH_(4) concentration/diffusive flux was co-regulated mainly by water temperature, water depth, and water productivity(Chla, trophic status). Our results highlight the importance of considering the spatiotemporal variability of diffusive CH_(4) flux from temperate reservoirs to estimate the CH_(4) budget at regional and global scales.
基金supported by Guangdong Basic and Applied Basic Research Foundation(Nos.2023A1515110824 and 2025A1515011839)Shenzhen Science and Technology Program(No.RCBS20231211090638066).
文摘Understanding water chemistry in karst regions is crucial for improving global water resource management and deepening our knowledge of the biogeochemical cycles shaping these sensitive environments.Despite advance-ments in karst hydrology,significant gaps remain in long-term trends,underlying processes,and quantitative effects of environmental changes.This is especially true in areas like the Wujiang River(WJ)in China,where human activities such as reservoir construction and land use/cover changes have accelerated hydrochemical changes.We combined recent and historical monitoring data to provide a detailed analysis of the spatial and temporal characteristics,evolution,and controlling factors of major ions in WJ.These findings are important for local water management and contribute to global efforts to manage similar karst systems facing human-induced pressures.Our research shows clear seasonal differences in solute concentrations,with higher levels during the dry season.WJ’s water is rich in calcium,with Ca-HCO_(3) ion pairs being the most common.Reservoir monitor-ing stations show much higher levels of NO_(3)^(−)and SO_(4)^(2−)compared to river-type stations,likely due to longer hydraulic retention time and increased acid deposition.The study confirms the significant role of pH and water temperature in rock weathering processes.Land use/cover changes were identified as the primary drivers of solute variations(46.37%),followed by lithology(13.92%)and temperature(8.35%).Over the past two decades,in-tense carbonate weathering has been observed,especially during wet seasons.Among karstic provinces,Guizhou Province stands out with the highest ion concentrations,indicative of its extensive karst coverage and heightened weathering processes.
基金Supported by the Zhejiang Provincial Natural Science Foundation of China(No.LD21C030001)the Key Research and Development Program of National Natural Science Foundation of China(No.2021YFE0112000)+1 种基金the National Natural Science Foundation of China(Nos.32371634,31970219)the Scientific Research Project of the Shanghai Municipal Bureau of Ecology and Environment(No.202409)。
文摘Microbial communities play indispensable roles in the biogeochemical cycling of river ecosystems.However,the response patterns of microbial community diversity,niche breadth,and assembly to rainfall disturbances in complex mountainous riverine reservoirs remain inadequately understood.We employed high-throughput sequencing of 16S and 18S ribosomal RNA genes,along with multivariate statistical methods to systematically investigate prokaryotic and eukaryotic microorganisms in the riverine Zhaoshandu Reservoir,Wenzhou,Zhejiang,East China.Results show significant temporal heterogeneity in both prokaryotic and eukaryotic microbial communities,with eukaryotic microbes showing more pronounced temporal variation.Canonical correspondence analysis revealed that rainfall and water temperature were the key drivers shaping microbial communities.Additionally,eukaryotic microorganisms exhibited a more pronounced response to rainfall and water temperature compared to prokaryotes.Modified stochasticity ratio model indicated that deterministic processes predominantly governed microbial community assembly,with stronger deterministic processes in eukaryotic compared to prokaryotic microorganisms.Rainfall has significantly altered water quality,notably increasing phosphorus concentration in the water column.Total phosphorus and total nitrogen showed significant correlations with the niche breadth of prokaryotic and eukaryotic microorganisms,and phosphorus nutrients served as keystones and playing indispensable roles in their co-occurrence networks.A structural equation model confirmed the notable impacts of rainfall and water temperature on microbial community diversity,further revealing that rainfall indirectly influenced the niche breadth and co-occurrence relationships of microbial communities by altering phosphorus concentrations.The findings underscore the influence of rainfall and water temperature on microbial distribution,highlighting the sensitivity of riverine reservoir ecosystems to climate change.
基金supported by the National Natural Science Foundation of China(Nos.U2340209,and 42271126)the NIGLAS Foundation(No.NIGLAS2022GS03)+1 种基金the Natural Science Foundation of Jiangsu Province(No.BK20220041)the US National Science Foundation Projects(Nos.1831096,1803697,and 2108917).
文摘The increased frequency and intensity of heavy rainfall events due to climate change could potentially influence the movement of nutrients from land-based regions into recipient rivers.However,little information is available on how the rainfall affect nutrient dynamics in subtropicalmontane rivers with complex land use.This study conducted high-frequency monitoring to study the effects of rainfall on nutrients dynamics in an agricultural river draining to Lake Qiandaohu,a montane reservoir of southeast China.The results showed that riverine total nitrogen(TN)and total phosphorus(TP)concentrations increased continuously with increasing rainfall intensity,while TN:TP decreased.The heavy rainfall and rainstorm drove more than 30%of the annual N and P loading in only 5.20%of the total rainfall period,indicating that increased storm runoff is likely to exacerbate eutrophication in montane reservoirs.NO_(3)^(−)-N is the primary nitrogen form lost,while particulate phosphorus(PP)dominated phosphorus loss.Themain source of N is cropland,and themain source of P is residential area.Spatially,forestedwatersheds have better drainage quality,while it is still a potential source of nonpoint pollution during rainfall events.TN and TP concentrations were significantly higher at sites dominated by cropland and residential area,indicating their substantial contributions to deteriorating river water quality.Temporally,TN and TP concentrations reached high values in May-August when rainfall was most intense,while they were lower in autumn and winter than that in spring and summer under the same rainfall intensities.The results emphasize the influence of rainfall-runoff and land use on dynamics of riverine N and P loads,providing guidance for nutrient load reduction planning for Lake Qiandaohu.
基金supported by the National Natural Science Foundation of China(No.U2040210).
文摘Interaction between the Yangtze River and its tributaries in the Three Gorges Reservoir has an important influence on tributary algal blooms.Taking the Xiaojiang River as a typical tributary,a binary mixing model used stable isotopes of hydrogen and oxygen to quantitatively analyze the water contribution and nutrient source structure of the tributary backwater area.Results showed that the isotope content(δD:−54.7‰,δ^(18)O−7.8‰)in the Yangtze River was higher than that in the tributaries(δD:−74.2‰,δ^(18)O−17.0‰)in the non-flood season and lower than that in the tributaries in the flood season.The Yangtze River contributed more than 50%water volume of the tributary backwater area in the non-flood season.The total nitrogen and total phosphorus concentrations in the backwater area were estimated based on water contribution ratio,and the results were in good agreement with the monitoring results.Load estimation showed that the nitrogen and phosphorus contribution ratio of the Yangtze River to the tributary backwater area was approximately 40%-80%in the non-flood season,and approximately 20%-40%in the flood season,on average.This study showed that the interaction between the Xiaojiang River and the Yangtze River is significant,and that Yangtze River recharge is an important source of nutrients in the Xiaojiang backwater area,which may play a driving role in Xiaojiang River algal blooms.
基金National Key R&D Program of China,No.2022YFC3203903National Natural Science Foundation of China,No.42371010,No.41971004。
文摘How the strong segmentation of cascade reservoir dams and the spatiotemporal changes of sediment retention volume affect the river morphology adjustment in the reservoir area is a scientific issue worthy of exploration.This study aims to reveal the adjustment mechanism of the thalweg longitudinal profile of cascade reservoirs.This study focuses on the Xiangjiaba and Xiluodu reservoirs located in the lower reaches of the Jinsha River.Utilizing multi-period observational data of thalweg elevation in reservoir reaches both before and after dam construction,the research employs statistical,geomorphological,and sedimentological methodologies to analyze variation characteristics in the measured curves,trend curves,and theoretical fitting curves of the thalweg longitudinal profile.The investigation ultimately reveals two distinct adjustment patterns in the longitudinal profiles of these cascade reservoirs:the concave curve type and the convex curve type.The former is characterized by weak riverbed scouring and silting changed to rapid aggradation in the upstream section of the reservoir area after dam closure,then changed to slow aggradation in the whole reservoir area,which is the common feature of reservoirs that were built earlier and are relatively located in the downstream(such as the Xiangjiaba Reservoir).The latter is characterized by a straight line or concave curve type with weak riverbed scouring and silting before the dam closure changed to a convex curve type with strong siltation after dam closure,which is the characteristic of reservoirs that were built later and are relatively located in the upstream(such as the Xiluodu Reservoir).The adjustment of the cascade reservoir longitudinal profile is controlled by the spatiotemporal changes of the sediment deposition volume and sedimentation rate in the reservoir area,and the alternating changes of the hydrodynamic gradient and regulation mode affect the spatial heterogeneity of the sedimentation rate.The research results are helpful for understanding the adjustment mechanism of the cascade reservoir longitudinal profile in similar areas and have a guiding role in predicting the adjustment trend of the cascade reservoir longitudinal profile without observation data.
基金supported by the National Key Research and Development Program of China under Grant 2022YFB3608300in part by the National Nature Science Foundation of China(NSFC)under Grants 62404050,U2341218,62574056,62204052。
文摘Organic electrochemical transistor(OECT)devices demonstrate great promising potential for reservoir computing(RC)systems,but their lack of tunable dynamic characteristics limits their application in multi-temporal scale tasks.In this study,we report an OECT-based neuromorphic device with tunable relaxation time(τ)by introducing an additional vertical back-gate electrode into a planar structure.The dual-gate design enablesτreconfiguration from 93 to 541 ms.The tunable relaxation behaviors can be attributed to the combined effects of planar-gate induced electrochemical doping and back-gateinduced electrostatic coupling,as verified by electrochemical impedance spectroscopy analysis.Furthermore,we used theτ-tunable OECT devices as physical reservoirs in the RC system for intelligent driving trajectory prediction,achieving a significant improvement in prediction accuracy from below 69%to 99%.The results demonstrate that theτ-tunable OECT shows a promising candidate for multi-temporal scale neuromorphic computing applications.
基金supported in part by the Chinese Academy of Sciences(No.XDA0330302)NSFC program(No.22127901)。
文摘Neuromorphic devices have garnered significant attention as potential building blocks for energy-efficient hardware systems owing to their capacity to emulate the computational efficiency of the brain.In this regard,reservoir computing(RC)framework,which leverages straightforward training methods and efficient temporal signal processing,has emerged as a promising scheme.While various physical reservoir devices,including ferroelectric,optoelectronic,and memristor-based systems,have been demonstrated,many still face challenges related to compatibility with mainstream complementary metal oxide semiconductor(CMOS)integration processes.This study introduced a silicon-based schottky barrier metal-oxide-semiconductor field effect transistor(SB-MOSFET),which was fabricated under low thermal budget and compatible with back-end-of-line(BEOL).The device demonstrated short-term memory characteristics,facilitated by the modulation of schottky barriers and charge trapping.Utilizing these characteristics,a RC system for temporal data processing was constructed,and its performance was validated in a 5×4 digital classification task,achieving an accuracy exceeding 98%after 50 training epochs.Furthermore,the system successfully processed temporal signal in waveform classification and prediction tasks using time-division multiplexing.Overall,the SB-MOSFET's high compatibility with CMOS technology provides substantial advantages for large-scale integration,enabling the development of energy-efficient reservoir computing hardware.
基金The Science and Technology Basic Resources Survey Project,No.2021FY101002Wetland Protection and Restoration in China Funded by the Palson Institute and Laoniu Foundation,UNDP-GEF Flyway Project,No.PIMS ID:6110。
文摘Effective conservation relies on robust assessments;however,the lack of waterbird data in the Yellow River Basin(YRB)has led to an underestimation of key habitat significance.This study addressed this gap by evaluating YRB wetland conservation importance using waterbirds as indicators and applying Ramsar,Important Bird Areas(IBA),and East Asian-Australasian Flyway(EAAF)criteria.We integrated coordinated surveys with citizen science data,creating a framework that tackles data deficiencies along the under-monitored Central Asian Flyway(CAF).Our analysis identified 75 priority wetlands,supporting 15 threatened species and 49 exceeding global/flyway 1%thresholds,highlighting the basin's biodiversity.We observed strong seasonal habitat use,with high-altitude wetlands vital for breeding and migration,and the Yellow River Delta providing year-round refuge.This research also provided data to refine Baer's Pochard population estimates.Alarmingly,one-third of the identified priority areas,primarily rivers and lakes,remain unprotected.To address this,we recommend systematic surveys,enhanced protected areas,OECMs,and targeted wetland restoration.This study underscores the YRB's role in regional conservation and provides essential data for adaptive management,particularly emphasizing the CAF's importance.
基金Major Project of the National Social Science Foundation of China“Historical Collation and Research of Cultural Exchanges Between Chinese and Foreign Craftsmen Along the Silk Road”(Approval No.22&ZD227)the Planning Project of Shaanxi Art Institute“Research on National Cultural Park Design”(Project No.YG2025001).
文摘As a representative surviving example of residences associated with officials and merchants in the southwestern Shandong region of the lower Yellow River Basin,spanning the Ming and Qing Dynasties to the modern period,the Zhujia Courtyard in Shan County functions as a built medium through which commercial capital and clan culture were closely intertwined.Drawing on field investigation and a review of the literature,this study examines its architectural and cultural characteristics across five dimensions:an overview of the courtyard,spatial layout,structural system,decorative arts,and cultural meanings.The analysis points to four interrelated cores,including the spatial embodiment of Confucian ethics,the status aspirations of canal-based merchant groups,adaptive strategies shaped by Yellow River conditions,and the symbolic articulation of folk beliefs.
基金funded by the Major National Science and Technology Project for Deep Earth of China(Grant No.2024ZD1003805)the National Natural Science Foundation of China(Grant Nos.52311530070 and 52004015).
文摘Rock damage significantly affects coupled thermo-hydro-mechanical(THM)behavior in deep geothermal exploitation through changing thermal and hydrological properties of rocks.For this,a thermo-hydro-mechanical-damage(THMD)coupled model was developed to describe the coupling between rock damage and mechanical,fluid flow and heat transfer fields.The model considers rock heterogeneity,and incorporates the Mohr-Coulomb failure criterion and the maximum tensile stress criterion to evaluate shear and tensile damage.This numerical modeling methodology was first verified against analytical solutions and experimental results,and was then used to simulate the THMD coupling behavior in deep geothermal exploitation.A coupled numerical model was set up to simulate the geothermal fluids extraction and re-injection process in a reservoir at 1 km depth over a 7-year period.Rock damage was found to accelerate the propagation of cold fronts away from the injection well,and have a distinct effect on the performance of geothermal exploitation.When the rock damage was considered,the field injectivity increases by 8.4 times,the range of cooled regions increases by 18.6 times,and the vertical deformation changes by 1.2 times after 7 years of geothermal operations,compared to the scenario where it was not considered.Parametric studies have suggested that thermal contraction dominates the rock damage evolution,and that thermal-induced rock damage only occurs at a sufficiently large temperature difference between fluids injected and the reservoir.This work underscores the importance of accurately accounting for the damage effect on reservoir response during fluid injection activities that cause significant cooling of reservoir rocks.
基金supported by the Major Program of National Natural Science Foundation of China(Grant No.42090055)the National Key ScientificInstruments and Equipment Development Projects of China(Grant No.41827808)the National Nature Science Foundation of China(Grant No.42207216).
文摘Reservoir-induced landslides in China's Three Gorges Reservoir area are prone to tensile cracks due to the influenceof their own weight and fluctuationsin water levels.The presence of cracks indicates that the tensile stress in the area has exceeded the tensile strength of the soil,leading to local instability.To explore the impact of tensile failure behavior on the stability and failure modes of reservoir landslides,the Huangtupo Riverside Slump#1 is taken as a case study.By considering local tensile failure,potential tensile cracks are incorporated into the analysis via the limit equilibrium method and reliability theory.The reliability of landslides under different tensile failure scenarios is quantified.Strain-softening characteristics of the soil are combined to further analyze the failure transmission path of the landslide.Finally,these potential failure modes were validated through physical model tests.The results show that cracks developing at rear positions reduce the stability of the slope and increase the probability of instability.During the destruction process,retrogressive failures with multiple sliding surfaces are likely to occur.However,tensile failure at the forefront reduces the likelihood of an individual slide mass descending.Progressive failure results in both regular and skip transmission patterns.Additionally,cracks and water level changes can also lead to shifts in the positions of the most dangerous blocks.Therefore,in practical landslide analysis and prevention,it is necessary to consider local tensile damage and identify potential tensile crack locations in advance to optimize prevention measures and accurately evaluate landslide risk.
基金supported by a project of the Shaanxi Youth Science and Technology Star(2021KJXX-87)public welfare geological survey projects of Shaanxi Institute of Geologic Survey(20180301,201918 and 202103)。
文摘With the efficient and intelligent development of computer-based big data processing,applying machine learning methods to the processing and interpretation of logging data in the field of geophysical well logging has broad potential for improving production efficiency.Currently,the Jiyuan Oilfield in the Ordos Basin relies mainly on manual reprocessing and interpretation of old well logging data to identify different fluid types in low-contrast reservoirs,guiding subsequent production work.This study uses well logging data from the Chang 1 reservoir,partitioning the dataset based on individual wells for model training and testing.A deep learning model for intelligent reservoir fluid identification was constructed by incorporating the focal loss function.Comparative validations with five other models,including logistic regression(LR),naive Bayes(NB),gradient boosting decision trees(GBDT),random forest(RF),and support vector machine(SVM),show that this model demonstrates superior identification performance and significantly improves the accuracy of identifying oil-bearing fluids.Mutual information analysis reveals the model's differential dependency on various logging parameters for reservoir fluid identification.This model provides important references and a basis for conducting regional studies and revisiting old wells,demonstrating practical value that can be widely applied.
基金supported by the National Natural Science Foundation of China[grant number 41830964]the Natural Science Foundation of Hunan Province[grant number 2023JJ40666]。
文摘In this study,based on MERRA-2 reanalysis data and a multi-algorithm integrated atmospheric river(AR)iden-tification method,the authors reveal the cross-seasonal regulation mechanism of El Niño-Southern Oscillation(ENSO)on winter-spring AR activities in East Asia.The results show that ENSO asymmetrically modulates AR ac-tivity through teleconnection and hysteresis effects,and has significant enhancement/inhibition effects on ARs in different regions.At the onset of El Niño,enhanced southwesterly flow at the western edge of the western Pacific subtropical high(WPSH)leads to enhanced AR activity in the western Pacific,and anomalous southerly winds in the Indian Ocean promote northward transport of water vapor in the Arabian Sea and Bay of Bengal.With a three-month lag,the weakening and eastward retreat of the WPSH weakens the low-latitude AR activity,but persistent southerly winds in the Bay of Bengal maintain the AR activity over Southwest China.The mid-to high-latitude AR response exhibits delayed dynamics,initially dominated by the synergistic effect of the southward deviation of the upper-air rapids and the low-level convergence(double-rapid-flow effect)and later modulated by the Pacific-North American teleconnection(PNA)-triggered East Asian ridge,which enhances the precipitation efficiency through prolonged frontal activity and enhanced cold-warm airmass convergence.Overall,El Niño promotes the development of low-and midlatitude AR activity in East Asia,while La Niña promotes(maritime continental)AR activity in the tropics.This study establishes the“ENSO teleconnection→circulation adjust-ment→East Asian AR response”chain,revealing a cross-seasonal lagged response mechanisms of East Asian AR activity,and provides a theoretical basis for winter and spring climate prediction and extreme precipitation forecasting.
基金support from the Natural Science Foundation of Jiangsu Province(Grant No.BK20240036)the National Natural Science Foundation of China(Grant Nos.U24A20515,22276099,and 22361162668)Guangxi Key Research and Development Program,China(Grant No.Guike AB24010074)。
文摘We conducted a field campaign to investigate the chemical composition,sources,and light absorption of submicron aerosols(PM_(1))from early 2022 in Nanjing,China.The average concentration of PM_(1) was 31μg m^(−3),organics(33%)constituted the largest fraction,followed by nitrate(30%),sulfate(18%),ammonium(15%),chloride(3%),and rBC(2%).Four organic aerosol(OA)subcomponents were identified,including two primary OA(POA)and two secondary OA(SOA).The less-oxidized SOA(LO-OOA)contributes the most to the total OA mass(59%).LO-OOA is tightly correlated with the tracer ion C_(2)H_(4)O_(2)^(+)from levoglucosan,and another aged biomass-burning derived species,K_(3)SO_(4)^(+),suggesting it was likely influenced by aged biomass-burning OA.Our study also revealed that fireworks during the Spring Festival have a detrimental impact on air quality,contributing to secondary formation and accumulation under static winter meteorological conditions,prolonging the pollution duration.Also,LO-OOA was found to have the strongest light-absorbing ability.Our results highlight that the light absorption of LO-OOA can mainly be attributed to the C_(x)H_(y)N^(+) family,increased with the double-bond equivalent value.The more-oxidized SOA(MO-OOA)exhibited a negligible light absorption and was strongly correlated with daytime photochemical processes,implying a light-bleaching effect.This study enhances our understanding of the regional contribution of biomass combustion and fireworks to PM_(1) pollution in Nanjing,a typical megacity in the Yangtze River Delta region,during winter,aiding in the development of strategies for long-term air quality improvement in the region.
基金Shanxi Province Graduate Research Practice Innovation Project,No.2023KY465Project on the Reform of Graduate Education and Teaching in Shanxi Province,No.2021YJJG146+1 种基金Research Project of Shanxi Provincial Cultural Relics Bureau,No.22-8-14-1400-119National Key R&D Program of China,No.2021YFB3901300。
文摘Human activities have significantly impacted the land surface temperature(LST),endangering human health;however,the relationship between these two factors has not been adequately quantified.This study comprehensively constructs a Human Activity Intensity(HAI)index and employs the Maximal Information Coefficient,four-quadrant model,and XGBoostSHAP model to investigate the spatiotemporal relationship and influencing factors of HAI-LST in the Yellow River Basin(YRB)from 2000 to 2020.The results indicated that from 2000 to 2020,as HAI and LST increased,the static HAI-LST relationship in the YRB showed a positive correlation that continued to strengthen.This dynamic relationship exhibited conflicting development,with the proportion of coordinated to conflicting regions shifting from 1:4 to 1:2,indicating a reduction in conflict intensity.Notably,only the degree of conflict in the source area decreased significantly,whereas it intensified in the upper and lower reaches.The key factors influencing the HAI-LST relationship include fractional vegetation cover,slope,precipitation,and evapotranspiration,along with region-specific factors such as PM_(2.5),biodiversity,and elevation.Based on these findings,region-specific ecological management strategies have been proposed to mitigate conflict-prone areas and alleviate thermal stress,thereby providing important guidance for promoting harmonious development between humans and nature.
基金National Natural Science Foundation of China,No.32161143025,No.42371283,No.W2412155National Key R&D Program of China,No.2022YFE0119200。
文摘The Selenge River Basin(SRB)in Mongolia has faced ecosystem degradation because of climate change and overloading.The dynamics of the pastoral system and the extent of overload under future scenarios have not been documented.This study aims to answer the following questions:Will the typical soums in the SRB become more overgrazed in the future?What optimal strategy should be implemented?Multisource data were integrated and utilized to model the pastoral system of typical soums using a system dynamics approach.Future scenarios under three SSP-RCPs were projected using the model.The conclusions are as follows:(1)From upstream to downstream,rational scenarios for pastoral system transferred from SSP1-RCP2.6 to SSP2-RCP4.5,which reflect improved productivity at the expense of ecosystem stability.(2)Compared with that during the historical period of 2000-2020,the projected carrying capacity of the soums decreases by 15.2%-37.3%,whereas the number of livestock continues to increase.Consequently,the stocking rate is expected to increase from 0.32-1.16 during 2000-2020 to 1.26-2.02 during 2021-2050,indicating that rangeland will become more overloaded.(3)A livestock reduction strategy based on future livestock stock and grassland carrying capacity scenarios was proposed to maintain a dynamic forage-livestock equilibrium.It is suggested that reducing livestock is a practical option for harmonizing grassland conservation with livestock husbandry development.
基金Philosophy and Social Sciences Research Project of Shandong Higher Education Institutions:“Research on the Double Helix Mechanism of Yellow River Culture Empowering Ideological and Political Education in Universities from the Perspective of Cultural Confidence Cultivation”(2025ZSYB077)Youth Key Project of Shandong Humanities and Social Sciences Research Project,“Research on Integrating Yellow River Culture into the Cultivation of University Students’Cultural Confidence”Shandong Higher Education Institutions Young Innovation Team Program:“Yellow River Delta Ecological Protection and Governance Innovation Team”(2023RW036).
文摘Guided by the significant theoretical principle of the“Two Integrations”and grounded in Marxist cultural theory as its methodological basis,this paper constructs a bidirectional interpretative model linking“Yellow River Culture”with“Cultural Confidence”.It proposes an integrated“Objective-Content-Path-Support”framework.Through the synergy of three-dimensional objectives,adaptation of stratified content,innovation in four-dimensional pathways,and support from a three-dimensional guarantee system,this framework establishes a closed-loop operational mechanism of“Curriculum-Practice-Evaluation-Feedback”.The study focuses on core issues in integrating Yellow River culture into university education practices,such as content construction,methodological pathways,and institutional guarantees.It aims to provide a systematic reference for universities to fulfill their fundamental task of“fostering virtue and cultivating talent”and to serve the national strategies for ecological protection and high-quality development in the Yellow River Basin.
基金supported by the Earthquake Science and Technology Spark Plan Project(No.XH23041C)The Natural Science Foundation of Gansu Province(No.22JR11RA090)Gansu Lanzhou Geophysics National Observation and Research Station(No.2021Y14).
文摘The widely distributed loess deposits in the Yellow River Basin exhibit unique engineering geological characteristics.The variations in their thickness and stratigraphic structure significantly amplify ground motion parameters,directly influencing the regional seismic hazard risk level.This study methodically conducted on-site studies and observations of building collapses and damages resulting from seismic amplification effects,using the Wenchuan M_(S)8.0 earthquake as a case study.Comprehensive experimental and numerical simulation studies were carried out.A large-scale shaking table test was performed,and numerical models for 14 different loess sites types were established.Various types of seismic waves were incorporated into these models for systematic numerical simulation calculations.The research reveals the mechanisms by which loess deposit thickness and stratigraphic structure in the Yellow River Basin affect seismic ground motion amplification.The results indicate that as the epicentral distance increases,the peak ground motion shows a marked attenuation trend,with the horizontal component attenuating substantially faster than the vertical component.As the overlying loess layer thickness increases from 50 to 100 m,the seismic intensity may escalate by 3−4 degrees,and the peak acceleration may amplify by 1.5−2.2 times.With the augmentation of loess deposit thickness and the proliferation of soil layers,both the peak acceleration response spectrum and the characteristic period demonstrate an upward tendency,exhibiting slight fluctuations contingent upon the seismic wave type.
基金supported by the National Key R&D Program of China(Grant No.2023YFC3007201)the National Natural Science Foundation of China(Grant No.42377161)the Opening Fund of Key Laboratory of Geological Survey and Evaluation of Ministry of Education(Grant No.GLAB 2024ZR03).
文摘Landslide susceptibility mapping(LSM)is an essential tool for mitigating the escalating global risk of landslides.However,challenges such as the heterogeneity of different landslide triggers,extensive engineering activities exacerbated reactivation,and the interpretability of data-driven models have hindered the practical application of LSM.This work proposes a novel framework for enhancing LSM considering different triggers for accumulation and rock landslides,leveraging interpretable machine learning and Multi-temporal Interferometric Synthetic Aperture Radar(MT-InSAR)technology.Initially,a refined fieldinvestigation was conducted to delineate the accumulation and rock area according to landslide types,leading to the identificationof relevant contributing factors.Deformation along the slope was then combined with time-series analysis to derive a landslide activity level(AL)index to recognize the likelihood of reactivation or dormancy.The SHapley Additive exPlanation(SHAP)technique facilitated the interpretation of factors and the identificationof determinants in high susceptibility areas.The results indicate that random forest(RF)outperformed other models in both accumulation and rock areas.Key factors including thickness and weak intercalation were identifiedfor accumulation and rock landslides.The introduction of AL substantially enhanced the predictive capability of the LSM and outperformed models that neglect movement trends or deformation rates with an average ratio of 81.23%in high susceptibility zones.Besides,the fieldvalidation confirmedthat 83.8%of newly identifiedlandslides were correctly upgraded.Given its efficiencyand operational simplicity,the proposed hybrid model opens new avenues for the feasibility of enhancement in LSM at urban settlements worldwide.
