In the satellite synthetic aperture radar（SAR） images of the Bohai Sea and Huanghai Sea,the authors observe sea surface imprints of wave-like patterns with an average wavelength of 3.8 km.Comparing SAR observations ...In the satellite synthetic aperture radar（SAR） images of the Bohai Sea and Huanghai Sea,the authors observe sea surface imprints of wave-like patterns with an average wavelength of 3.8 km.Comparing SAR observations with sea surface wind fields and surface weather maps,the authors find that the occurrence of the wave-like phenomena is associated with the passing of atmospheric front.The authors define the waves as atmospheric frontal gravity waves.The dynamical parameters of the wave packets are derived from statistics of 9 satellite SAR images obtained from 2002 to 2008.A two-dimensional linear physical wave model is used to analyze the generation mechanism of the waves.The atmospheric frontal wave induced wind variation across the frontal wave packet is compared with wind retrievals from the SAR images.The CMOD-5（C-band scatterometer ocean geophysical model function） is used for SAR wind retrievals VV（transmitted vertical and received vertical） for ENVISAT and HH（transmitted horizontally and received horizontally） for RADARSAT-1.A reasonable agreement between the analytical solution and the SAR observation is reached.This new SAR frontal wave observation adds to the school of SAR observations of sea surface imprints of AGWs including island lee waves,coastal lee waves,and upstream Atmospheric Gravity Waves（AGW）.展开更多
Observational analysis of the Earth’s stratospheric temperature structure and its dynamical behavior is of great significance for atmospheric dynamics research.In this paper,we present stratospheric temperatures in t...Observational analysis of the Earth’s stratospheric temperature structure and its dynamical behavior is of great significance for atmospheric dynamics research.In this paper,we present stratospheric temperatures in the range of 30–50 km above the Yinchuan observation site,retrieved from diurnal continuous Rayleigh scattering signal observation data collected by a 589 nm lidar throughout a single day.We also present observational studies of atmospheric tides and gravity wave cases.The diurnal temperature background field and perturbation field were obtained from the lidar data using the linear fitting method;these results exhibit good consistency with the temperature perturbation field extracted from ERA5.An obvious quasi-monochromatic inertial gravity wave was detected by application of a two-dimensional Fourier transform to the nighttime observation data with complete height coverage,which revealed these characteristic gravity wave parameters:a vertical wavelength of 8.53 km,a period of 8.46 h,and a downward-propagating vertical phase velocity.A nonlinear least-squares harmonic fitting method was used to extract amplitudes and phases of atmospheric diurnal and semi-diurnal tides in the 30−34 km range,where the diurnal data were relatively complete.The amplitudes increased with height,ranging from 0.6 to 2.5 K(diurnal tide)and 0.3 to 1.9 K(semi-diurnal tide),respectively.The phases showed a decreasing trend with height,indicating that the vertical phase velocity of the tides propagates downward while the energy propagates upward.These results indicate that diurnal 589 nm lidar observations data can provide important reference values for understanding the temperature structure of the stratosphere and the dynamical characteristics of atmospheric gravity waves and tides.展开更多
Accurate retrieval of atmospheric vertical profiles is critical for improving weather prediction and climate monitoring.However,the complexity of atmospheric processes in cloudy regions poses challenges compared to th...Accurate retrieval of atmospheric vertical profiles is critical for improving weather prediction and climate monitoring.However,the complexity of atmospheric processes in cloudy regions poses challenges compared to those of clear sky scenarios.This study presents a novel framework that integrates Bayesian optimization and machine learning approaches to retrieve atmospheric vertical profiles—including temperature,humidity,ozone concentration,cloud fraction,ice water content(IWC),and liquid water content(LWC)—from hyperspectral infrared observations.Specifically,a Bayesian method was used to refine ERA5 reanalysis data by minimizing brightness temperature(BT)discrepancies against FY-4B Geostationary Interferometric Infrared Sounder(GIIRS)observations,generating a high-quality profile database(~2.8 million profiles)across diverse weather systems.The optimized profiles improve radiative consistency,reducing BT biases from>40 K to<10 K in cloudy regions.To further overcome the limitations of the Bayesian method,we developed a Transformer-Resnet hybrid model(TERNet),which achieved superior performance with RMSE values of 1.61 K(temperature),5.77%(humidity),and 2.25×10^(–6)/6.09×10^(–6)kg kg^(–1)(IWC/LWC)across the entire vertical levels in all-sky conditions.The TERNet outperforms both ERA5 in cloud parameter retrieval and the GIIRS L2 product in thermodynamic profiling.Independent verification with radiosonde and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations(CALIPSO)datasets confirms the framework's reliability across various meteorological regimes.This work demonstrates the capability of combining physics-informed Bayesian methods with data-driven machine learning to fully exploit hyperspectral IR data.展开更多
Climate models are essential for understanding past,present,and future changes in atmospheric circulation,with circulation modes providing key sources of seasonal predictability and prediction uncertainties for both g...Climate models are essential for understanding past,present,and future changes in atmospheric circulation,with circulation modes providing key sources of seasonal predictability and prediction uncertainties for both global and regional climates.This study assesses the performance of models participating in phase 6 of the Coupled Model Intercomparison Project in simulating interannual variability modes of Northern Hemisphere 500-hPa geopotential height during winter and summer,distinguishing predictable(potentially predictable on seasonal or longer timescales)and unpredictable(intraseasonal and essentially unpredictable at long range)components,using reanalysis data and a variance decomposition method.Although most models effectively capture unpredictable modes in reanalysis,their ability to reproduce dominant predictable modes-specifically the Pacific-North American pattern,Arctic Oscillation,and Western Pacific Oscillation in winter,and the East Atlantic and North Atlantic Oscillations in summer-varies notably.An optimal ensemble is identified to distinguish(a)predictable-external modes,dominated by external forcing,and(b)predictable-internal modes,associated with slow internal variability,during the historical period(1950-2014)and the SSP5-8.5 scenario(2036-2100).Under increased radiative forcing,the leading winter/summer predictable-external mode exhibits a more uniform spatial distribution,remarkably larger trend and annual variance,and enhanced height-sea surface temperature(SST)covariance under SSP5-8.5 compared to historical conditions.The dominant winter/summer predictable-internal modes also exhibit increased variance and height-SST covariance under SSP5-8.5,along with localized changes in spatial configuration.Minimal changes are observed in spatial distribution or variance for dominant winter/summer unpredictable modes under SSP5-8.5.This study,from a predictive perspective,deepens our understanding of model uncertainties and projected changes in circulations.展开更多
This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlyin...This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlying physical mechanism. Specifically, for the simplified case of constant stratospheric N^(2), the refractive index square of planetary waves has a theoretical tendency to increase first and then decrease with an increased N^(2), whereas the group velocity weakens. Mechanistically, this behavior can be understood as an intensified suppression of vertical isentropic surface displacement caused by meridional heat transport of planetary waves under strong N^(2) conditions. Observational analysis corroborates this finding, demonstrating a reduction in the vertical-propagation velocity of waves with increased N^(2). A linear, quasi- geostrophic, mid-latitude beta-plane model with a constant background westerly wind and a prescribed N^(2) applicable to the stratosphere is used to obtain analytic solutions. In this model, the planetary waves are initiated by steady energy influx from the lower boundary. The analysis indicates that under strong N^(2) conditions, the amplitude of planetary waves can be sufficiently increased by the effective energy convergence due to the slowing vertical energy transfer, resulting in a streamfunction response in this model that contains more energy. For N^(2) with a quasi-linear vertical variation, the results bear a resemblance to the constant case, except that the wave amplitude and oscillating frequency show some vertical variations.展开更多
Freshwater scarcity is exacerbated by uneven distribution of limited freshwater resources and high energy costs of desalination technologies.Atmospheric water vapor,a vast and geographically unrestricted reservoir,cou...Freshwater scarcity is exacerbated by uneven distribution of limited freshwater resources and high energy costs of desalination technologies.Atmospheric water vapor,a vast and geographically unrestricted reservoir,could become a sustainable alternative.Sorption-based atmospheric water harvesting(SAWH)has emerged as an available solution,yet conventional desorption methods relying on energy-intensive electrical heating hinder its scalability.Herein,a photothermal hygroscopic sponge has been developed for solar-driven atmospheric water harvesting.The composites combine a malleable melamine sponge skeleton,lithium chloride as a hygroscopic agent,and hydrangea-like molybdenum disulfide as a photothermal component,forming a multiscale“pore-film”cross-linked structure by an eco-friendly immersion-freeze-drying method.The optimized sample achieves exceptional hygroscopic capacity(3.92 g/g at 90%RH)and freshwater production efficiency(87.77%),which is attributed to synergistic effects of porous skeleton based crosslinked structures and“pore-film”structures,and outstanding photothermal conversion efficiency of MoS2.The unique structure could stabilize LiCl to prevent leakage,increase mass transfer effectiveness of whole SWAH process,and enable flexibility for diverse applications.We carried out outdoor experiments to demonstrate a solar-driven water production rate of 4.22 L m^(-2) d^(-1) without external energy input.This work provides insights into sustainable freshwater generation and promotes green energy utilization in addressing global water scarcity.展开更多
Software-defined,data-intensive cyber-physical systems and software-defined networks of atmospheric observers are evolving rapidly due to the rapid expansion of sensing diversity,the volume of streaming data,and the d...Software-defined,data-intensive cyber-physical systems and software-defined networks of atmospheric observers are evolving rapidly due to the rapid expansion of sensing diversity,the volume of streaming data,and the demand for low-latency,decision-relevant products.Simultaneously,artificial intelligence(AI)and the continuously evolving state of computing are making it possible to create end-to-end architecture fostering the migrations of the presumably single algorithm to combined intelligent ingestion,quality control,and multi-modal fusion,uncertainty-related retrieval,and scalable service delivery at the edge-to-cloud-high-performance computing(HPC)environment.This overview summarizes AI-based models of future atmospheric observation networks within a single,consolidated taxonomy based on deployment topology,learning and update modes,connectivity to physical models and data assimilation,level of autonomy(passive to adaptive sensing),and model of governance.Next,we consider recurring architectural themes,such as edge intelligence and streaming provenance and machine learning operations(MLOps)/model operations(ModelOps)to continue evaluation and safely update,and we scrutinize integration gateways with physical models,like data-assimilation-oriented outputs,hybrid/physics-informed designs,and simulation of observing systems using digital twins.Lastly,we address evaluation and readiness aspects that are not limited to predictive skill,but also involve calibrated uncertainty,nonstationary and extreme robustness,system latency and reliability,interoperability,security,and demonstrated downstream influence on analyses and forecasts.Through bringing together the cross-cutting issues and prospects,this review provides a road map with respect to trustworthy,interoperable,and sustainable observation infrastructures in which code and climate science will co-evolve.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
The rapid decay of the surface wettability of plasma-treated polymers remains a critical limitation for their practical application in advanced materials.This study introduces a continuous atmospheric pressure plasma(...The rapid decay of the surface wettability of plasma-treated polymers remains a critical limitation for their practical application in advanced materials.This study introduces a continuous atmospheric pressure plasma(APP)technique for fabricating polyethylene(PE)separators with durable wettability,and elucidates the underlying mechanism.A systematic comparison of APP treatments with non-deposition and deposition gases,including Ar,Ar/O_(2),Ar/tetramethylcyclotetrasiloxane(TMCTS),and Ar/O_(2)/TMCTS,revealed the key impact factors in achieving durable wettability.Owing to the synergistic interactions of SiO_(x)C_(y)H_(z)nanoparticulate deposition,physical etching,and oxidative functionalization,the PE separator treated by Ar/O_(2)/TMCTS exhibited a 17.5-fold electrolyte wetting area compared to the original one.The improved surface energy and roughness of the SiO_(x)C_(y)H_(z)nanoparticle coating enhanced its electrochemical performance.The ionic conductivity increased by 1.9 times,while the charge transfer resistance decreased by 73.7%.Remarkably,owing to further oxidation of the SiO_(x)C_(y)H_(z)nanoparticle coating and the increase in its silica-like structure,the wetting area of the Ar/O_(2)/TMCTS-treated separator was still over 14-fold larger than that of the original separator after aging for 90 days.This study demonstrates an eco-friendly and scalable approach for fabricating high-performance battery separators and provides mechanistic insights into durable wettability by APP.展开更多
The atmospheric corrosion behavior of 510L low alloy steel subjected to acid-cleaned surface(ACS)and eco-pickled surface(EPS)treatments is systematically examined.After 1 year of atmospheric exposure,both ACS-and EPS-...The atmospheric corrosion behavior of 510L low alloy steel subjected to acid-cleaned surface(ACS)and eco-pickled surface(EPS)treatments is systematically examined.After 1 year of atmospheric exposure,both ACS-and EPS-treated samples demonstrate protective ability index values exceeding 2,indicating robust protective properties of the developed rust layers.The corrosion rates of ACS-and EPS-treated samples are similar.During the initial corrosion stage,γ-FeOOH emerges as the dominant corrosion product.With the prolonged atmospheric exposure,γ-FeOOH content progressively decreases through phase transformation into thermodynamically stableα-FeOOH and densely structured Fe_(3)O_(4),which markedly suppresses the corrosion of the steel.Notably,the corrosion rate of the coated EPS sample is obviously lower than that of the coated ACS counterpart,which is ascribed to the distinctive micro-roughness of EPS-treated surfaces that promote mechanical interlocking with protective coatings.展开更多
Atmospheric oxidation capacity(AOC)refers to the oxidation capacity of atmospheric chemical processes for major pollutants.A comprehensive observation campaign was conducted on a typical PM_(2.5)pollution event in Uru...Atmospheric oxidation capacity(AOC)refers to the oxidation capacity of atmospheric chemical processes for major pollutants.A comprehensive observation campaign was conducted on a typical PM_(2.5)pollution event in Urumqi,Northwest China,from January 15 to February 15,2024.Four typical cases representing PM_(2.5)levels from non-polluted to heavily polluted periods were selected to estimate AOC,OH reactivity,their relationship with secondary components,and the HO_(x)budget in PM_(2.5)using the Framework for 0-D Atmospheric Modeling model.Aromatics and alkanes contributed 54%-79%and 18%-46%of secondary organic aerosols(SOA)formation,respectively.The sulfur oxidation ratio(SOR)and nitrogen oxidation ratio(NOR)increased with rising PM_(2.5)levels.As AOC increased,SOR showed the same trend,while NOR and SOA decreased slightly,and ammonia oxidation ratio values remained almost unchanged.OH radicals were the primary oxidants during the daytime,whereas NO_(3)played a dominant role at nighttime.CO(24%-51%),NO2(27%-34%),and alkenes(7%-12%)were the dominant contributors to OH reactivity.The HO_(2)+NO reaction pathway contributes 67%-84%to the production of OH,while Others(including carbonyl compounds photolysis,the permutation reactions of RO2,etc.),RO_(2)+NO and OH+CO reaction pathways were the main pathways for HO2 production.A comprehensive understanding of the interactions among AOC,SOA,and radical cycling is crucial for formulating effective air quality management strategies aimed at mitigating secondary pollution under diverse atmospheric conditions.展开更多
The atmospheric surface layer of the tropical coastal ocean is commonly very unstable and experiences weakwind conditions.How the latent(LE)and sensible(H)heat fluxes behave under such conditions are unclear because o...The atmospheric surface layer of the tropical coastal ocean is commonly very unstable and experiences weakwind conditions.How the latent(LE)and sensible(H)heat fluxes behave under such conditions are unclear because of the lack of observation stations in the tropics.Thus,this study aims to analyze LE and H and the microclimate parameters influencing them.The authors deployed an eddy covariance system in a tropical coastal region for seven months.The microclimate parameters investigated were wind speed(U),vapor pressure deficit(Δe),temperature difference(ΔT),wind-vapor pressure deficit(UΔe),wind-temperature difference(UΔT),and atmospheric stability(z/L),where z is height and L is the Monin–Obukhov length.On the daily time scale,the results show that LE was more associated with U thanΔe,while H was more related toΔT than U.Cross-wavelet analysis revealed the strong coherence in the LE-U relationship for periods between one and two days,and for H–ΔT,0.5 to 1 day.Correlation and regression analyses confirmed the time series analyses results,where strong positive correlation coefficients(r)were obtained between LE and U(r=0.494)and H andΔT(r=0.365).Compared to other water bodies,the transfer coefficient of moisture(CE N)was found to be small(=0.40×10^(-3))and independent of stability;conversely,the transfer coefficient of heat(CH N)was closer to literature values(=1.00×10^(-3))and a function of stability.展开更多
Using a recognition model of atmospheric gravity waves(AGWs),we identified 519 AGW events from the OH airglow images observed at the Dandong and Lhasa stations from 2015 to 2017.The 317 AGW events detected at the Dand...Using a recognition model of atmospheric gravity waves(AGWs),we identified 519 AGW events from the OH airglow images observed at the Dandong and Lhasa stations from 2015 to 2017.The 317 AGW events detected at the Dandong station have wavelengths ranging from 30 to 60 km,periods from 14 to 20 min,horizontal speeds from 30 to 60 m/s,and relative intensities from 0.4%to 0.6%,respectively.The parameters of 202 events recorded at the Lhasa station mainly vary within 15-35 km in horizontal wavelength,4-6 min in period,40-100 m/s in horizontal velocity,and 0.1%-0.3%in relative intensity.The occurrence rate peaks in winter and summer at Dandong and the peak in summer are absent at Lhasa because of the lack of convective weather.The seasonal propagation directions of the waves are influenced by both the wind field-filtering effect and the distribution of wave sources.In spring,because of the southeastward background wind field,fewer southeastward events are observed at the Dandong station.The situation at the Lhasa station is similar.In summer,both the Lhasa and Dandong stations are dominated by northeastward AGWs,which can be attributed to the southwestward wind.In autumn,ray-tracing results show that the events at Dandong mainly originate from wind shear,whereas the events at the Lhasa station are triggered by convective weather.The location of the wave sources determines the trend of the propagation directions at the Dandong and Lhasa stations in autumn.In winter,because of the eastward wind,more events are propagating to the southwest at the Dandong station.展开更多
Ground water is a crucial ecological resource and source of drinking water to a great percentage of theworld population.The quality of groundwater in an area with industrial emission and air pollution is an especially...Ground water is a crucial ecological resource and source of drinking water to a great percentage of theworld population.The quality of groundwater in an area with industrial emission and air pollution is an especiallyimportant issue that requires proper evaluation.This paper introduces a spatiotemporal deep learning model thatincorporates the use of metaheuristic optimization in predicting groundwater quality in various pollution contexts.Thegiven method is a combination of the Spatial-Temporal-Assisted Deep Belief Network(StaDBN)and a hybrid WhaleOptimization Algorithm and Tiki-Taka Algorithms(WOA-TTA)that would model intricate patterns of contamination.Historical ground water data sets with the hydrochemical data and time are preprocessed and pertinent and nonredundant features are determined with the Addax Optimization Algorithm(AOA).Spatial and temporal dependenciesare explicitly integrated in StaDBN architecture to facilitate representation learning,and network hyperparametersare optimized by the WOA-TTA module to increase the training efficiency and predictive performance.The modelwas coded in Python and tested based on common statistical measures,such as root mean square error(RMSE),Nash Sutcliffe efficiency(NSE),mean absolute error(MAE),and the correlation coefficient(R).The proposedGWQP-StaDBN-WOA-TTA framework demonstrates superior predictive performance and interpretability comparedto conventional machine learning and deep learning models,achieving higher correlation(R=0.963),improvedNash-Sutcliffe efficiency(NSE=0.84),and substantially lower prediction errors(MAE=0.29,RMSE=0.48),therebyvalidating its effectiveness for groundwater quality assessment under industrial and atmospheric pollution scenarios.展开更多
In Global Navigation Satellite System(GNSS)meteo rology,the atmospheric weighted mean temperatu re(T_(m))is a critical intermediate parameter for converting zenith wet delay(ZWD)to precipitable water vapor(PWV),essent...In Global Navigation Satellite System(GNSS)meteo rology,the atmospheric weighted mean temperatu re(T_(m))is a critical intermediate parameter for converting zenith wet delay(ZWD)to precipitable water vapor(PWV),essential for accurate atmospheric water content estimation.However,global models often overlook regional climatic variability,leading to reduced accuracy in localized applications.This study introduces an improved T_(m)model developed using radiosonde observations across Iran and GNSS radio occultation(RO)profiles from CHAMP,GRACE,MetOp-A/B/C,COSMIC,TerraSAR-X,and TanDEM-X missions collected between 2007 and 2022.A novel integral formulation was proposed to estimate T_(m)more accurately by incorporating vertical water vapor distribution and temperature linearity.Based on this formulation,three regional T_(m)models were constructed using annual,semiannual,and diurnal periodicities,along with surface temperature(T_(s)),each varying in structure and complexity.Validation against independent radiosonde observations from 2022 showed that Models Two and Three outperformed the Bevis model,reducing RMSE by 30.7%.When evaluated against GNSS RO profiles,Model One—excluding T_(s)due to its inaccessibility in RO data—yielded the highest accuracy,with a 42.6%improvement in RMSE over the Bevis model.To evaluate the practical effectiveness of the proposed T_(m)model,PWV was derived from GNSS data at the tehn and tabz stations during the second half of 2022and compared with PWV values obtained from co-located radiosonde observations in Tehran and Tabriz.Using T_(m)from Model One improved PWV estimation compared to the Bevis model,reducing RMSE and MAE by up to 54%and 53.8%in Tabriz and 50.6%and 52.9%in Tehran,respectively.These results demonstrate that regionalized T_(m)modeling,particularly approaches that avoid dependence on T_(s),can significantly enhance GNSS-based PWV estimation in areas with limited surface data.展开更多
Various satellite data,JRA-25(Japan reanalysis of 25 years) reanalyzed data and WRF(Weather Research Forecast) model are used to investigate the in situ effect of the ESKF(East China Sea Kuroshio Front) on the MABL(ma...Various satellite data,JRA-25(Japan reanalysis of 25 years) reanalyzed data and WRF(Weather Research Forecast) model are used to investigate the in situ effect of the ESKF(East China Sea Kuroshio Front) on the MABL(marine atmospheric boundary layer).The intensity of the ESKF is most robust from January to April in its annual cycle.The local strong surface northerly/northeasterly winds are observed right over the ESKF in January and in April and the wind speeds decrease upward in the MABL.The thermal wind effect that is derived from the baroclinic MABL forced by the strong SST gradient contributes to the strong surface winds to a large degree.The convergence zone existing along the warm flank of the ESKF is stronger in April than in January corresponding to the steeper SST(sea surface temperature) gradient.The collocations of the cloud cover maximum and precipitation maximum are basically consistent with the convergence zone of the wind field.The clouds develop higher(lower) in the warm(cold) flank of the ESKF due to the less(more) stable stratification in the MABL.The lowest clouds are observed in April on the cold flank of the ESKF and over the Yellow Sea due to the existence of the pronounced temperature inversion.The numerical experiments with smoothed SST are consistent with the results from the ovservations.展开更多
This paper reviews the progress in our understanding of the atmospheric response to midlatitude oceanic fronts and eddies,emphasizing the Kuroshio-Oyashio Extension(KOE)region.Oceanic perturbations of interest consist...This paper reviews the progress in our understanding of the atmospheric response to midlatitude oceanic fronts and eddies,emphasizing the Kuroshio-Oyashio Extension(KOE)region.Oceanic perturbations of interest consist of sharp oceanic fronts,temperature anomalies associated with mesoscale eddies,and to some extent even higher-frequency submesoscale variability.The focus is on the free atmosphere above the boundary layer.As the midlatitude atmosphere is dominated by vigorous transient eddy activity in the storm track,the response of both the time-mean flow and the storm track is assessed.The storm track response arguably overwhelms the mean-flow response and makes the latter hard to detect from observations.Oceanic frontal impacts on the mesoscale structures of individual synoptic storms are discussed,followed by the role of oceanic fronts in maintaining the storm track as a whole.KOE fronts exhibit significant decadal variability and can therefore presumably modulate the storm track.Relevant studies are summarized and intercompared.Current understanding has advanced greatly but is still subject to large uncertainties arising from inadequate data resolution and other factors.Recent modeling studies highlighted the importance of mesoscale eddies and probably even submesoscale processes in maintaining the storm track but confirmation and validation are still needed.Moreover,the atmospheric response can potentially provide a feedback mechanism for the North Pacific climate.By reviewing the above aspects,we envision that future research shall focus more upon the interaction between smaller-scale oceanic processes(fronts,eddies,submesoscale features)and atmospheric processes(fronts,extratropical cyclones etc.),in an integrated way,within the context of different climate background states.展开更多
In order to improve the correction effect of the adaptive optical system in coherent optical communication, we investigate the relative distortion between the wavefronts of different wavelengths of the beams transmitt...In order to improve the correction effect of the adaptive optical system in coherent optical communication, we investigate the relative distortion between the wavefronts of different wavelengths of the beams transmitted on the near-ground horizontal atmospheric turbulent links emitted by coherent optical communication system. And the situation is analyzed when the wavelength corresponding to the wavefront detected by the wavefront detector and the wavelength corrected by the deformed mirror are different, the influence of the wavelength factor on the adaptive optical system correction. We use a series of trigonometric functions and the Hankel transformation to derive the corrected residual variance and the Strehl ratio between the wavefront distortions of the wavelengths of the dual-wavelength combined beam in atmospheric turbulence. In relation to the parameters of the turbulent environment, the ensemble average of the wavefront difference corresponding to different wavelengths the derived is proposed as the coefficient to correct the dual-wavelength adaptive optical system. The results show that the statistic of the turbulence internal scale has a major influence on the difference between the wavefronts. By adding the correction coefficient, the signal light’s wavefront of the coherent optical communication system can be corrected more effectively by the dual-wavelength adaptive optical closure.展开更多
Developing a cost-effective and environmentally friendly process for the production of valuable chemicals from abundant herbal biomass receives great attentions in recent years.Herein,taking advantage of the“lignin f...Developing a cost-effective and environmentally friendly process for the production of valuable chemicals from abundant herbal biomass receives great attentions in recent years.Herein,taking advantage of the“lignin first”strategy,corn straw is converted to valuable chemicals including lignin monomers,furfural and 5-methoxymethylfurfural via a two steps process.The key of this research lies in the development of a green and low-cost catalytic process utilizing magnetic Raney Ni catalyst and high boiling point ethylene glycol.The utilization of neat ethylene glycol as the sole slovent under atmospheric conditions obviates the need for additional additives,thereby facilitating the entire process to be conducted in glass flasks and rendering it highly convenient for scaling up.In the initial step,depolymerization of corn straw lignin resulted in a monomer yield of 18.1 wt%.Subsequently,in a dimethyl carbonate system,the carbohydrate component underwent complete conversion in a one-pot process,yielding furfural and 5-methoxymethylfurfural as the primary products with an impressive yield of 47.7%.展开更多
The atmospheric corrosion monitoring(ACM)technique has been widely employed to track the real-time corrosion behavior of metal materials.However,limited studies have applied ACM to the corrosion protection properties ...The atmospheric corrosion monitoring(ACM)technique has been widely employed to track the real-time corrosion behavior of metal materials.However,limited studies have applied ACM to the corrosion protection properties of organic coatings.This study compared a bare epoxy coating with one containing zinc phosphate corrosion inhibitors,both applied on ACM sensors,to observe their corrosion protection properties over time.Coatings with artificial damage via scratches were exposed to immersion and alternating dry and wet environments,which allowed for monitoring galvanic corrosion currents in real-time.Throughout the corrosion tests,the ACM currents of the zinc phosphate/epoxy coating were considerably lower than those of the blank epoxy coating.The trend in ACM current variations closely matched the results obtained from regular electrochemical tests and surface analysis.This alignment highlights the potential of the ACM technique in evaluating the corrosion protection capabilities of organic coatings.Compared with the blank epoxy coating,the zinc phosphate/epoxy coating showed much-decreased ACM current values that confirmed the effective inhibition of zinc phosphate against steel corrosion beneath the damaged coating.展开更多
基金RADARSAT-1 data were obtained under the NASA RADARSAT ADRO-2 Program (Project RADARSAT-0011-0071) and processed by the Alaska Satellite FacilityThe ASAR images were provided by the European Space Agency under ENVISAT Projects 141 and 6133
文摘In the satellite synthetic aperture radar（SAR） images of the Bohai Sea and Huanghai Sea,the authors observe sea surface imprints of wave-like patterns with an average wavelength of 3.8 km.Comparing SAR observations with sea surface wind fields and surface weather maps,the authors find that the occurrence of the wave-like phenomena is associated with the passing of atmospheric front.The authors define the waves as atmospheric frontal gravity waves.The dynamical parameters of the wave packets are derived from statistics of 9 satellite SAR images obtained from 2002 to 2008.A two-dimensional linear physical wave model is used to analyze the generation mechanism of the waves.The atmospheric frontal wave induced wind variation across the frontal wave packet is compared with wind retrievals from the SAR images.The CMOD-5（C-band scatterometer ocean geophysical model function） is used for SAR wind retrievals VV（transmitted vertical and received vertical） for ENVISAT and HH（transmitted horizontally and received horizontally） for RADARSAT-1.A reasonable agreement between the analytical solution and the SAR observation is reached.This new SAR frontal wave observation adds to the school of SAR observations of sea surface imprints of AGWs including island lee waves,coastal lee waves,and upstream Atmospheric Gravity Waves（AGW）.
基金supported by the Key Research Program of the Chinese Academy of Sciences(Grant NO.KGFZD-145-23-17)the Specialized Research Fund for State Key Laboratories.
文摘Observational analysis of the Earth’s stratospheric temperature structure and its dynamical behavior is of great significance for atmospheric dynamics research.In this paper,we present stratospheric temperatures in the range of 30–50 km above the Yinchuan observation site,retrieved from diurnal continuous Rayleigh scattering signal observation data collected by a 589 nm lidar throughout a single day.We also present observational studies of atmospheric tides and gravity wave cases.The diurnal temperature background field and perturbation field were obtained from the lidar data using the linear fitting method;these results exhibit good consistency with the temperature perturbation field extracted from ERA5.An obvious quasi-monochromatic inertial gravity wave was detected by application of a two-dimensional Fourier transform to the nighttime observation data with complete height coverage,which revealed these characteristic gravity wave parameters:a vertical wavelength of 8.53 km,a period of 8.46 h,and a downward-propagating vertical phase velocity.A nonlinear least-squares harmonic fitting method was used to extract amplitudes and phases of atmospheric diurnal and semi-diurnal tides in the 30−34 km range,where the diurnal data were relatively complete.The amplitudes increased with height,ranging from 0.6 to 2.5 K(diurnal tide)and 0.3 to 1.9 K(semi-diurnal tide),respectively.The phases showed a decreasing trend with height,indicating that the vertical phase velocity of the tides propagates downward while the energy propagates upward.These results indicate that diurnal 589 nm lidar observations data can provide important reference values for understanding the temperature structure of the stratosphere and the dynamical characteristics of atmospheric gravity waves and tides.
基金supported by the National Natural Science Foundation of China under Grant U2442219Fengyun Satellite Application Pioneer Program(2023)Special Initiative on Numerical Weather Prediction(NWP)Applications,the Civil Aerospace Technology Pre-Research Project(D040405)the Joint Funds of the Zhejiang Provincial Natural Science Foundation of China under Grant No.LZJMZ23D050003。
文摘Accurate retrieval of atmospheric vertical profiles is critical for improving weather prediction and climate monitoring.However,the complexity of atmospheric processes in cloudy regions poses challenges compared to those of clear sky scenarios.This study presents a novel framework that integrates Bayesian optimization and machine learning approaches to retrieve atmospheric vertical profiles—including temperature,humidity,ozone concentration,cloud fraction,ice water content(IWC),and liquid water content(LWC)—from hyperspectral infrared observations.Specifically,a Bayesian method was used to refine ERA5 reanalysis data by minimizing brightness temperature(BT)discrepancies against FY-4B Geostationary Interferometric Infrared Sounder(GIIRS)observations,generating a high-quality profile database(~2.8 million profiles)across diverse weather systems.The optimized profiles improve radiative consistency,reducing BT biases from>40 K to<10 K in cloudy regions.To further overcome the limitations of the Bayesian method,we developed a Transformer-Resnet hybrid model(TERNet),which achieved superior performance with RMSE values of 1.61 K(temperature),5.77%(humidity),and 2.25×10^(–6)/6.09×10^(–6)kg kg^(–1)(IWC/LWC)across the entire vertical levels in all-sky conditions.The TERNet outperforms both ERA5 in cloud parameter retrieval and the GIIRS L2 product in thermodynamic profiling.Independent verification with radiosonde and Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations(CALIPSO)datasets confirms the framework's reliability across various meteorological regimes.This work demonstrates the capability of combining physics-informed Bayesian methods with data-driven machine learning to fully exploit hyperspectral IR data.
基金supported by the National Natural Science Foundation of China(Grant Nos.U2342210 and 42275043)the National Institute of Natural Hazards,Ministry of Emergency Management of China(Grant Nos.J2223806,ZDJ2024-25 and ZDJ2025-34)。
文摘Climate models are essential for understanding past,present,and future changes in atmospheric circulation,with circulation modes providing key sources of seasonal predictability and prediction uncertainties for both global and regional climates.This study assesses the performance of models participating in phase 6 of the Coupled Model Intercomparison Project in simulating interannual variability modes of Northern Hemisphere 500-hPa geopotential height during winter and summer,distinguishing predictable(potentially predictable on seasonal or longer timescales)and unpredictable(intraseasonal and essentially unpredictable at long range)components,using reanalysis data and a variance decomposition method.Although most models effectively capture unpredictable modes in reanalysis,their ability to reproduce dominant predictable modes-specifically the Pacific-North American pattern,Arctic Oscillation,and Western Pacific Oscillation in winter,and the East Atlantic and North Atlantic Oscillations in summer-varies notably.An optimal ensemble is identified to distinguish(a)predictable-external modes,dominated by external forcing,and(b)predictable-internal modes,associated with slow internal variability,during the historical period(1950-2014)and the SSP5-8.5 scenario(2036-2100).Under increased radiative forcing,the leading winter/summer predictable-external mode exhibits a more uniform spatial distribution,remarkably larger trend and annual variance,and enhanced height-sea surface temperature(SST)covariance under SSP5-8.5 compared to historical conditions.The dominant winter/summer predictable-internal modes also exhibit increased variance and height-SST covariance under SSP5-8.5,along with localized changes in spatial configuration.Minimal changes are observed in spatial distribution or variance for dominant winter/summer unpredictable modes under SSP5-8.5.This study,from a predictive perspective,deepens our understanding of model uncertainties and projected changes in circulations.
基金supported by the National Natural Science Foundation of China(Grant No.42261134532,42405059,and U2342212)。
文摘This study investigates the relationship between atmospheric stratification (i.e., static stability given by N^(2)) and the vertical energy transfer of stationary planetary waves, and further illustrates the underlying physical mechanism. Specifically, for the simplified case of constant stratospheric N^(2), the refractive index square of planetary waves has a theoretical tendency to increase first and then decrease with an increased N^(2), whereas the group velocity weakens. Mechanistically, this behavior can be understood as an intensified suppression of vertical isentropic surface displacement caused by meridional heat transport of planetary waves under strong N^(2) conditions. Observational analysis corroborates this finding, demonstrating a reduction in the vertical-propagation velocity of waves with increased N^(2). A linear, quasi- geostrophic, mid-latitude beta-plane model with a constant background westerly wind and a prescribed N^(2) applicable to the stratosphere is used to obtain analytic solutions. In this model, the planetary waves are initiated by steady energy influx from the lower boundary. The analysis indicates that under strong N^(2) conditions, the amplitude of planetary waves can be sufficiently increased by the effective energy convergence due to the slowing vertical energy transfer, resulting in a streamfunction response in this model that contains more energy. For N^(2) with a quasi-linear vertical variation, the results bear a resemblance to the constant case, except that the wave amplitude and oscillating frequency show some vertical variations.
基金supported by the National Key Research and Development Program of China(No.2022YFC3702800)the National Natural Science Foundation of China(Nos.22366008,22406032)the Guizhou Provincial Basic Research Program(Natural Science)(No.ZK(2023)045).
文摘Freshwater scarcity is exacerbated by uneven distribution of limited freshwater resources and high energy costs of desalination technologies.Atmospheric water vapor,a vast and geographically unrestricted reservoir,could become a sustainable alternative.Sorption-based atmospheric water harvesting(SAWH)has emerged as an available solution,yet conventional desorption methods relying on energy-intensive electrical heating hinder its scalability.Herein,a photothermal hygroscopic sponge has been developed for solar-driven atmospheric water harvesting.The composites combine a malleable melamine sponge skeleton,lithium chloride as a hygroscopic agent,and hydrangea-like molybdenum disulfide as a photothermal component,forming a multiscale“pore-film”cross-linked structure by an eco-friendly immersion-freeze-drying method.The optimized sample achieves exceptional hygroscopic capacity(3.92 g/g at 90%RH)and freshwater production efficiency(87.77%),which is attributed to synergistic effects of porous skeleton based crosslinked structures and“pore-film”structures,and outstanding photothermal conversion efficiency of MoS2.The unique structure could stabilize LiCl to prevent leakage,increase mass transfer effectiveness of whole SWAH process,and enable flexibility for diverse applications.We carried out outdoor experiments to demonstrate a solar-driven water production rate of 4.22 L m^(-2) d^(-1) without external energy input.This work provides insights into sustainable freshwater generation and promotes green energy utilization in addressing global water scarcity.
文摘Software-defined,data-intensive cyber-physical systems and software-defined networks of atmospheric observers are evolving rapidly due to the rapid expansion of sensing diversity,the volume of streaming data,and the demand for low-latency,decision-relevant products.Simultaneously,artificial intelligence(AI)and the continuously evolving state of computing are making it possible to create end-to-end architecture fostering the migrations of the presumably single algorithm to combined intelligent ingestion,quality control,and multi-modal fusion,uncertainty-related retrieval,and scalable service delivery at the edge-to-cloud-high-performance computing(HPC)environment.This overview summarizes AI-based models of future atmospheric observation networks within a single,consolidated taxonomy based on deployment topology,learning and update modes,connectivity to physical models and data assimilation,level of autonomy(passive to adaptive sensing),and model of governance.Next,we consider recurring architectural themes,such as edge intelligence and streaming provenance and machine learning operations(MLOps)/model operations(ModelOps)to continue evaluation and safely update,and we scrutinize integration gateways with physical models,like data-assimilation-oriented outputs,hybrid/physics-informed designs,and simulation of observing systems using digital twins.Lastly,we address evaluation and readiness aspects that are not limited to predictive skill,but also involve calibrated uncertainty,nonstationary and extreme robustness,system latency and reliability,interoperability,security,and demonstrated downstream influence on analyses and forecasts.Through bringing together the cross-cutting issues and prospects,this review provides a road map with respect to trustworthy,interoperable,and sustainable observation infrastructures in which code and climate science will co-evolve.
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supported by the National Natural Science Foundation of China(No.12075054)the Fundamental Research Funds for the Central Universities(No.CUSF-DH-T-2024069)。
文摘The rapid decay of the surface wettability of plasma-treated polymers remains a critical limitation for their practical application in advanced materials.This study introduces a continuous atmospheric pressure plasma(APP)technique for fabricating polyethylene(PE)separators with durable wettability,and elucidates the underlying mechanism.A systematic comparison of APP treatments with non-deposition and deposition gases,including Ar,Ar/O_(2),Ar/tetramethylcyclotetrasiloxane(TMCTS),and Ar/O_(2)/TMCTS,revealed the key impact factors in achieving durable wettability.Owing to the synergistic interactions of SiO_(x)C_(y)H_(z)nanoparticulate deposition,physical etching,and oxidative functionalization,the PE separator treated by Ar/O_(2)/TMCTS exhibited a 17.5-fold electrolyte wetting area compared to the original one.The improved surface energy and roughness of the SiO_(x)C_(y)H_(z)nanoparticle coating enhanced its electrochemical performance.The ionic conductivity increased by 1.9 times,while the charge transfer resistance decreased by 73.7%.Remarkably,owing to further oxidation of the SiO_(x)C_(y)H_(z)nanoparticle coating and the increase in its silica-like structure,the wetting area of the Ar/O_(2)/TMCTS-treated separator was still over 14-fold larger than that of the original separator after aging for 90 days.This study demonstrates an eco-friendly and scalable approach for fabricating high-performance battery separators and provides mechanistic insights into durable wettability by APP.
基金support by National Natural Science Foundation of China(Grant No.52401103)Key Scientific Research Project in Shanxi Province(Grant No.202302050201015)+3 种基金Central Guiding Science and Technology Development of Local Fund(Grant No.YDZJSK20231A046)the Special Fund for Science and Technology Innovation Teams of Shanxi Province(202204051001004)Science and Technology Cooperation and Exchange Special Project of Shanxi Province(202404041101038)Postgraduate Education Innovation Project of Shanxi Province(Grant No.2024SJ304).
文摘The atmospheric corrosion behavior of 510L low alloy steel subjected to acid-cleaned surface(ACS)and eco-pickled surface(EPS)treatments is systematically examined.After 1 year of atmospheric exposure,both ACS-and EPS-treated samples demonstrate protective ability index values exceeding 2,indicating robust protective properties of the developed rust layers.The corrosion rates of ACS-and EPS-treated samples are similar.During the initial corrosion stage,γ-FeOOH emerges as the dominant corrosion product.With the prolonged atmospheric exposure,γ-FeOOH content progressively decreases through phase transformation into thermodynamically stableα-FeOOH and densely structured Fe_(3)O_(4),which markedly suppresses the corrosion of the steel.Notably,the corrosion rate of the coated EPS sample is obviously lower than that of the coated ACS counterpart,which is ascribed to the distinctive micro-roughness of EPS-treated surfaces that promote mechanical interlocking with protective coatings.
基金supported by the Chinese Research Academy of Envi-ronmental Sciences(No.2024YSKY-57)the National Key Research and Development Program of China(No.2017YFC0212501)Xinjiang Uygur Autonomous Region Environmental Monitoring Central Station(No.HYZB-2022-0320).
文摘Atmospheric oxidation capacity(AOC)refers to the oxidation capacity of atmospheric chemical processes for major pollutants.A comprehensive observation campaign was conducted on a typical PM_(2.5)pollution event in Urumqi,Northwest China,from January 15 to February 15,2024.Four typical cases representing PM_(2.5)levels from non-polluted to heavily polluted periods were selected to estimate AOC,OH reactivity,their relationship with secondary components,and the HO_(x)budget in PM_(2.5)using the Framework for 0-D Atmospheric Modeling model.Aromatics and alkanes contributed 54%-79%and 18%-46%of secondary organic aerosols(SOA)formation,respectively.The sulfur oxidation ratio(SOR)and nitrogen oxidation ratio(NOR)increased with rising PM_(2.5)levels.As AOC increased,SOR showed the same trend,while NOR and SOA decreased slightly,and ammonia oxidation ratio values remained almost unchanged.OH radicals were the primary oxidants during the daytime,whereas NO_(3)played a dominant role at nighttime.CO(24%-51%),NO2(27%-34%),and alkenes(7%-12%)were the dominant contributors to OH reactivity.The HO_(2)+NO reaction pathway contributes 67%-84%to the production of OH,while Others(including carbonyl compounds photolysis,the permutation reactions of RO2,etc.),RO_(2)+NO and OH+CO reaction pathways were the main pathways for HO2 production.A comprehensive understanding of the interactions among AOC,SOA,and radical cycling is crucial for formulating effective air quality management strategies aimed at mitigating secondary pollution under diverse atmospheric conditions.
基金supported by a PETRONAS-Academia Collabora-tion Dialogue 2022 Grant[Grant number PACD 2022]from PETRONAS Research Sdn.Bhd。
文摘The atmospheric surface layer of the tropical coastal ocean is commonly very unstable and experiences weakwind conditions.How the latent(LE)and sensible(H)heat fluxes behave under such conditions are unclear because of the lack of observation stations in the tropics.Thus,this study aims to analyze LE and H and the microclimate parameters influencing them.The authors deployed an eddy covariance system in a tropical coastal region for seven months.The microclimate parameters investigated were wind speed(U),vapor pressure deficit(Δe),temperature difference(ΔT),wind-vapor pressure deficit(UΔe),wind-temperature difference(UΔT),and atmospheric stability(z/L),where z is height and L is the Monin–Obukhov length.On the daily time scale,the results show that LE was more associated with U thanΔe,while H was more related toΔT than U.Cross-wavelet analysis revealed the strong coherence in the LE-U relationship for periods between one and two days,and for H–ΔT,0.5 to 1 day.Correlation and regression analyses confirmed the time series analyses results,where strong positive correlation coefficients(r)were obtained between LE and U(r=0.494)and H andΔT(r=0.365).Compared to other water bodies,the transfer coefficient of moisture(CE N)was found to be small(=0.40×10^(-3))and independent of stability;conversely,the transfer coefficient of heat(CH N)was closer to literature values(=1.00×10^(-3))and a function of stability.
基金supported by the National Key Research and Development Program of China(Grant No.2022YFF0711402)the Specialized Research Fund for State Key Laboratories。
文摘Using a recognition model of atmospheric gravity waves(AGWs),we identified 519 AGW events from the OH airglow images observed at the Dandong and Lhasa stations from 2015 to 2017.The 317 AGW events detected at the Dandong station have wavelengths ranging from 30 to 60 km,periods from 14 to 20 min,horizontal speeds from 30 to 60 m/s,and relative intensities from 0.4%to 0.6%,respectively.The parameters of 202 events recorded at the Lhasa station mainly vary within 15-35 km in horizontal wavelength,4-6 min in period,40-100 m/s in horizontal velocity,and 0.1%-0.3%in relative intensity.The occurrence rate peaks in winter and summer at Dandong and the peak in summer are absent at Lhasa because of the lack of convective weather.The seasonal propagation directions of the waves are influenced by both the wind field-filtering effect and the distribution of wave sources.In spring,because of the southeastward background wind field,fewer southeastward events are observed at the Dandong station.The situation at the Lhasa station is similar.In summer,both the Lhasa and Dandong stations are dominated by northeastward AGWs,which can be attributed to the southwestward wind.In autumn,ray-tracing results show that the events at Dandong mainly originate from wind shear,whereas the events at the Lhasa station are triggered by convective weather.The location of the wave sources determines the trend of the propagation directions at the Dandong and Lhasa stations in autumn.In winter,because of the eastward wind,more events are propagating to the southwest at the Dandong station.
基金Fund for funding this research work under Research Support Program for Central labs at King Khalid University through the project number CL/CO/B/6.
文摘Ground water is a crucial ecological resource and source of drinking water to a great percentage of theworld population.The quality of groundwater in an area with industrial emission and air pollution is an especiallyimportant issue that requires proper evaluation.This paper introduces a spatiotemporal deep learning model thatincorporates the use of metaheuristic optimization in predicting groundwater quality in various pollution contexts.Thegiven method is a combination of the Spatial-Temporal-Assisted Deep Belief Network(StaDBN)and a hybrid WhaleOptimization Algorithm and Tiki-Taka Algorithms(WOA-TTA)that would model intricate patterns of contamination.Historical ground water data sets with the hydrochemical data and time are preprocessed and pertinent and nonredundant features are determined with the Addax Optimization Algorithm(AOA).Spatial and temporal dependenciesare explicitly integrated in StaDBN architecture to facilitate representation learning,and network hyperparametersare optimized by the WOA-TTA module to increase the training efficiency and predictive performance.The modelwas coded in Python and tested based on common statistical measures,such as root mean square error(RMSE),Nash Sutcliffe efficiency(NSE),mean absolute error(MAE),and the correlation coefficient(R).The proposedGWQP-StaDBN-WOA-TTA framework demonstrates superior predictive performance and interpretability comparedto conventional machine learning and deep learning models,achieving higher correlation(R=0.963),improvedNash-Sutcliffe efficiency(NSE=0.84),and substantially lower prediction errors(MAE=0.29,RMSE=0.48),therebyvalidating its effectiveness for groundwater quality assessment under industrial and atmospheric pollution scenarios.
文摘In Global Navigation Satellite System(GNSS)meteo rology,the atmospheric weighted mean temperatu re(T_(m))is a critical intermediate parameter for converting zenith wet delay(ZWD)to precipitable water vapor(PWV),essential for accurate atmospheric water content estimation.However,global models often overlook regional climatic variability,leading to reduced accuracy in localized applications.This study introduces an improved T_(m)model developed using radiosonde observations across Iran and GNSS radio occultation(RO)profiles from CHAMP,GRACE,MetOp-A/B/C,COSMIC,TerraSAR-X,and TanDEM-X missions collected between 2007 and 2022.A novel integral formulation was proposed to estimate T_(m)more accurately by incorporating vertical water vapor distribution and temperature linearity.Based on this formulation,three regional T_(m)models were constructed using annual,semiannual,and diurnal periodicities,along with surface temperature(T_(s)),each varying in structure and complexity.Validation against independent radiosonde observations from 2022 showed that Models Two and Three outperformed the Bevis model,reducing RMSE by 30.7%.When evaluated against GNSS RO profiles,Model One—excluding T_(s)due to its inaccessibility in RO data—yielded the highest accuracy,with a 42.6%improvement in RMSE over the Bevis model.To evaluate the practical effectiveness of the proposed T_(m)model,PWV was derived from GNSS data at the tehn and tabz stations during the second half of 2022and compared with PWV values obtained from co-located radiosonde observations in Tehran and Tabriz.Using T_(m)from Model One improved PWV estimation compared to the Bevis model,reducing RMSE and MAE by up to 54%and 53.8%in Tabriz and 50.6%and 52.9%in Tehran,respectively.These results demonstrate that regionalized T_(m)modeling,particularly approaches that avoid dependence on T_(s),can significantly enhance GNSS-based PWV estimation in areas with limited surface data.
基金supported by the National Natural Science Foundation of China (No.40975003)the Ph.D.Programs Foundation of Ministry of Education of China (No.20090132110008)GYHY(QX)2007-6-31
文摘Various satellite data,JRA-25(Japan reanalysis of 25 years) reanalyzed data and WRF(Weather Research Forecast) model are used to investigate the in situ effect of the ESKF(East China Sea Kuroshio Front) on the MABL(marine atmospheric boundary layer).The intensity of the ESKF is most robust from January to April in its annual cycle.The local strong surface northerly/northeasterly winds are observed right over the ESKF in January and in April and the wind speeds decrease upward in the MABL.The thermal wind effect that is derived from the baroclinic MABL forced by the strong SST gradient contributes to the strong surface winds to a large degree.The convergence zone existing along the warm flank of the ESKF is stronger in April than in January corresponding to the steeper SST(sea surface temperature) gradient.The collocations of the cloud cover maximum and precipitation maximum are basically consistent with the convergence zone of the wind field.The clouds develop higher(lower) in the warm(cold) flank of the ESKF due to the less(more) stable stratification in the MABL.The lowest clouds are observed in April on the cold flank of the ESKF and over the Yellow Sea due to the existence of the pronounced temperature inversion.The numerical experiments with smoothed SST are consistent with the results from the ovservations.
基金supported by the National Natural Science Foundation of China(Grant No.41906001)the Natural Science Foundation of Jiangsu Province(Grant No.BK20190501)the Fundamental Research Funds for the Central Universities(Grant No.B210202137)。
文摘This paper reviews the progress in our understanding of the atmospheric response to midlatitude oceanic fronts and eddies,emphasizing the Kuroshio-Oyashio Extension(KOE)region.Oceanic perturbations of interest consist of sharp oceanic fronts,temperature anomalies associated with mesoscale eddies,and to some extent even higher-frequency submesoscale variability.The focus is on the free atmosphere above the boundary layer.As the midlatitude atmosphere is dominated by vigorous transient eddy activity in the storm track,the response of both the time-mean flow and the storm track is assessed.The storm track response arguably overwhelms the mean-flow response and makes the latter hard to detect from observations.Oceanic frontal impacts on the mesoscale structures of individual synoptic storms are discussed,followed by the role of oceanic fronts in maintaining the storm track as a whole.KOE fronts exhibit significant decadal variability and can therefore presumably modulate the storm track.Relevant studies are summarized and intercompared.Current understanding has advanced greatly but is still subject to large uncertainties arising from inadequate data resolution and other factors.Recent modeling studies highlighted the importance of mesoscale eddies and probably even submesoscale processes in maintaining the storm track but confirmation and validation are still needed.Moreover,the atmospheric response can potentially provide a feedback mechanism for the North Pacific climate.By reviewing the above aspects,we envision that future research shall focus more upon the interaction between smaller-scale oceanic processes(fronts,eddies,submesoscale features)and atmospheric processes(fronts,extratropical cyclones etc.),in an integrated way,within the context of different climate background states.
文摘In order to improve the correction effect of the adaptive optical system in coherent optical communication, we investigate the relative distortion between the wavefronts of different wavelengths of the beams transmitted on the near-ground horizontal atmospheric turbulent links emitted by coherent optical communication system. And the situation is analyzed when the wavelength corresponding to the wavefront detected by the wavefront detector and the wavelength corrected by the deformed mirror are different, the influence of the wavelength factor on the adaptive optical system correction. We use a series of trigonometric functions and the Hankel transformation to derive the corrected residual variance and the Strehl ratio between the wavefront distortions of the wavelengths of the dual-wavelength combined beam in atmospheric turbulence. In relation to the parameters of the turbulent environment, the ensemble average of the wavefront difference corresponding to different wavelengths the derived is proposed as the coefficient to correct the dual-wavelength adaptive optical system. The results show that the statistic of the turbulence internal scale has a major influence on the difference between the wavefronts. By adding the correction coefficient, the signal light’s wavefront of the coherent optical communication system can be corrected more effectively by the dual-wavelength adaptive optical closure.
基金supported by the Fundamental Research Funds for the Central Universities(QNTD202302)National Natural Science Foundation of China(22378024)the Foreign expert program(G2022109001L).
文摘Developing a cost-effective and environmentally friendly process for the production of valuable chemicals from abundant herbal biomass receives great attentions in recent years.Herein,taking advantage of the“lignin first”strategy,corn straw is converted to valuable chemicals including lignin monomers,furfural and 5-methoxymethylfurfural via a two steps process.The key of this research lies in the development of a green and low-cost catalytic process utilizing magnetic Raney Ni catalyst and high boiling point ethylene glycol.The utilization of neat ethylene glycol as the sole slovent under atmospheric conditions obviates the need for additional additives,thereby facilitating the entire process to be conducted in glass flasks and rendering it highly convenient for scaling up.In the initial step,depolymerization of corn straw lignin resulted in a monomer yield of 18.1 wt%.Subsequently,in a dimethyl carbonate system,the carbohydrate component underwent complete conversion in a one-pot process,yielding furfural and 5-methoxymethylfurfural as the primary products with an impressive yield of 47.7%.
基金financially supported by the National Natural Science Foundation of China(No.52371049)the Young Elite Scientists Sponsorship Program by the China Association for Science and Technology(YESS,No.2020QNRC001)the National Science and Technology Resources Investigation Program of China(Nos.2021FY100603 and 2019FY101404)。
文摘The atmospheric corrosion monitoring(ACM)technique has been widely employed to track the real-time corrosion behavior of metal materials.However,limited studies have applied ACM to the corrosion protection properties of organic coatings.This study compared a bare epoxy coating with one containing zinc phosphate corrosion inhibitors,both applied on ACM sensors,to observe their corrosion protection properties over time.Coatings with artificial damage via scratches were exposed to immersion and alternating dry and wet environments,which allowed for monitoring galvanic corrosion currents in real-time.Throughout the corrosion tests,the ACM currents of the zinc phosphate/epoxy coating were considerably lower than those of the blank epoxy coating.The trend in ACM current variations closely matched the results obtained from regular electrochemical tests and surface analysis.This alignment highlights the potential of the ACM technique in evaluating the corrosion protection capabilities of organic coatings.Compared with the blank epoxy coating,the zinc phosphate/epoxy coating showed much-decreased ACM current values that confirmed the effective inhibition of zinc phosphate against steel corrosion beneath the damaged coating.
