The structure of the boundary layer affects the evolution of ozone(O3), and research into this structure will provide important insights for understanding photochemical pollution.In this study, we conducted a one-mont...The structure of the boundary layer affects the evolution of ozone(O3), and research into this structure will provide important insights for understanding photochemical pollution.In this study, we conducted a one-month observation(from June 15 to July 14, 2016) of the boundary layer meteorological factors as well as O3 and its precursors in Luancheng County,Shijiazhuang(37°53′N, 114°38′E). Our research showed that photochemical pollution in Shijiazhuang is serious, and the mean hourly maximum and mean 8-hr maximum O3 concentrations are 97.9 ± 26.1 and 84.4 ± 22.4 ppbV, respectively. Meteorological factors play a significant role in the formation of O3. High temperatures and southeasterly winds lead to elevated O3 values, and at moderate relative humidity(40%–50%) and medium boundary layer heights(1200–1500 m), O3 production sensitivity occurred in the transitional region between volatile organic compounds(VOC) and nitrogen oxides(NOx) limitations,and the O3 concentration was the highest. The vertical profiles of O3 were also measured by a tethered balloon. The results showed that a large amount of O3 was stored in the residual layer, and the concentration was positively correlated with the O3 concentration measured the previous day. During the daytime of the following day, the contribution of O3 stored in the residual layer to the boundary layer reached 27%± 7% on average.展开更多
Rainfall forecasts for the summer monsoon season in the Yangtze River basin(YRB) allow decision-makers to plan for possible flooding, which can affect the lives and livelihoods of millions of people. A trial climate s...Rainfall forecasts for the summer monsoon season in the Yangtze River basin(YRB) allow decision-makers to plan for possible flooding, which can affect the lives and livelihoods of millions of people. A trial climate service was developed in 2016, producing a prototype seasonal forecast product for use by stakeholders in the region, based on rainfall forecasts directly from a dynamical model. Here, we describe an improved service based on a simple statistical downscaling approach. Through using dynamical forecast of an East Asian summer monsoon(EASM) index, seasonal mean rainfall for the upper and middle/lower reaches of YRB can be forecast separately by use of the statistical downscaling, with significant skills for lead times of up to at least three months. The skill in different sub-basin regions of YRB varies with the target season. The rainfall forecast skill in the middle/lower reaches of YRB is significant in May–June–July(MJJ), and the forecast skill for rainfall in the upper reaches of YRB is significant in June–July–August(JJA). The mean rainfall for the basin as a whole can be skillfully forecast in both MJJ and JJA. The forecasts issued in 2019 gave good guidance for the enhanced rainfall in the MJJ period and the near-average conditions in JJA. Initial feedback from users in the basin suggests that the improved forecasts better meet their needs and will enable more robust decision-making.展开更多
Based on the concepts of cloud water resource(CWR)and related variables proposed in the first part of this study,this paper provides details of two methods to quantify the CWR.One is diagnostic quantification(CWR-DQ)b...Based on the concepts of cloud water resource(CWR)and related variables proposed in the first part of this study,this paper provides details of two methods to quantify the CWR.One is diagnostic quantification(CWR-DQ)based on satellite observations,precipitation products,and atmospheric reanalysis data;and the other is numerical quantification(CWR-NQ)based on a cloud resolving model developed at the Chinese Academy of Meteorological Sciences(CAMS).The two methods are applied to quantify the CWR in April and August 2017 over North China,and the results are evaluated against all available observations.Main results are as follows.(1)For the CWR-DQ approach,reference cloud profiles are firstly derived based on the Cloud Sat/CALIPSO joint satellite observations for 2007–2010.The NCEP/NCAR reanalysis data in 2000–2017 are then employed to produce three-dimensional cloud fields.The budget/balance equations of atmospheric water substance are lastly used,together with precipitation observations,to retrieve CWR and related variables.It is found that the distribution and vertical structure of clouds obtained by the diagnostic method are consistent with observations.(2)For the CWR-NQ approach,it assumes that the cloud resolving model is able to describe the cloud microphysical processes completely and precisely,from which four-dimensional distributions of atmospheric water vapor,hydrometeors,and wind fields can be obtained.The data are then employed to quantify the CWR and related terms/quantities.After one-month continuous integration,the mass of atmospheric water substance becomes conserved,and the tempospatial distributions of water vapor,hydrometeors/cloud water,and precipitation are consistent with observations.(3)Diagnostic values of the difference in the transition between hydrometeors and water vapor(Cvh-Chv)and the surface evaporation(Es)are well consistent with their numerical values.(4)Correlation and bias analyses show that the diagnostic CWR contributors are well correlated with observations,and match their n展开更多
Vertical distributions of aerosol optical properties based on aircraft measurements over the Loess Plateau were measured for the first time during a summertime aircraft campaign, 2013 in Shanxi, China. Data from four ...Vertical distributions of aerosol optical properties based on aircraft measurements over the Loess Plateau were measured for the first time during a summertime aircraft campaign, 2013 in Shanxi, China. Data from four flights were analyzed. The vertical distributions of aerosol optical properties including aerosol scattering coefficients（σsc）, absorption coefficients（σab）,Angstr？m exponent（α）, single scattering albedo（ω）, backscattering ratio（βsc）, aerosol mass scattering proficiency（Q sc） and aerosol surface scattering proficiency（Q sc′） were obtained. The mean statistical values of σsc were 77.45 Mm-1（at 450 nm）, 50.72 Mm-1（at 550 nm）, and32.02 Mm-1（at 700 nm）. The mean value of σab was 7.62 Mm-1（at 550 nm）. The mean values ofα, βsc and ω were 1.93, 0.15, and 0.91, respectively. Aerosol concentration decreased with altitude. Most effective diameters（ED） of aerosols were less than 0.8 μm. The vertical profiles of σsc,, α, βsc, Q sc and Q sc′ showed that the aerosol scattering properties at lower levels contributed the most to the total aerosol radiative forcing. Both α and βsc had relatively large values, suggesting that most aerosols in the observational region were small particles. The mean values of σsc, α, βsc, Q sc, Q sc′, σab and ω at different height ranges showed that most of the parameters decreased with altitude. The forty-eight hour backward trajectories of air masses during the observation days indicated that the majority of aerosols in the lower level contributed the most to the total aerosol loading, and most of these particles originated from local or regional pollution emissions.展开更多
For accurately identifying the distribution charac-teristic of Gaussian-like noises in unmanned aerial vehicle(UAV)state estimation,this paper proposes a non-parametric scheme based on curve similarity matching.In the...For accurately identifying the distribution charac-teristic of Gaussian-like noises in unmanned aerial vehicle(UAV)state estimation,this paper proposes a non-parametric scheme based on curve similarity matching.In the framework of the pro-posed scheme,a Parzen window(kernel density estimation,KDE)method on sliding window technology is applied for roughly esti-mating the sample probability density,a precise data probability density function(PDF)model is constructed with the least square method on K-fold cross validation,and the testing result based on evaluation method is obtained based on some data characteristic analyses of curve shape,abruptness and symmetry.Some com-parison simulations with classical methods and UAV flight exper-iment shows that the proposed scheme has higher recognition accuracy than classical methods for some kinds of Gaussian-like data,which provides better reference for the design of Kalman filter(KF)in complex water environment.展开更多
This study introduces an innovative dual-tunable absorption film with the capability to switch between ultra-wideband and narrowband absorption.By manipulating the temperature,the film can achieve multi-band absorptio...This study introduces an innovative dual-tunable absorption film with the capability to switch between ultra-wideband and narrowband absorption.By manipulating the temperature,the film can achieve multi-band absorption within the 30-45 THz range or ultra-wideband absorption spanning 30-130 THz,with an absorption rate exceeding 0.9.Furthermore,the structural parameters of the absorption film are optimized using the particle swarm optimization(PSO)algorithm to ensure the optimal absorption response.The absorption response of the film is primarily attributed to the coupling of guided-mode resonance and local surface plasmon resonance effects.The film's symmetric structure enables polarization incoherence and allows for tuning through various means such as doping/voltage,temperature and structural parameters.In the case of a multi-band absorption response,the film exhibits good sensitivity to refractive index changes in multiple absorption modes.Additionally,the absorption spectrum of the film remains effective even at large incidence angles,making it highly promising for applications in fields such as biosensing and infrared stealth.展开更多
The Internet of Things(IoT)is a network system that connects physical devices through the Internet,allowing them to interact.Nowadays,IoT has become an integral part of our lives,offering convenience and smart functio...The Internet of Things(IoT)is a network system that connects physical devices through the Internet,allowing them to interact.Nowadays,IoT has become an integral part of our lives,offering convenience and smart functionality.However,the growing number of IoT devices has brought about a corresponding increase in cybersecurity threats,such as device vulnerabilities,data privacy concerns,and network susceptibilities.Integrating blockchain technology with IoT has proven to be a promising approach to enhance IoT security.Nevertheless,the emergence of quantum computing poses a significant challenge to the security of traditional classical cryptography used in blockchain,potentially exposing it to quantum cyber-attacks.To support the growth of the IoT industry,mitigate quantum threats,and safeguard IoT data,this study proposes a robust blockchain solution for IoT that incorporates both classical and post-quantum security measures.Firstly,we present the Quantum-Enhanced Blockchain Architecture for IoT(QBIoT)to ensure secure data sharing and integrity protection.Secondly,we propose an improved Proof of Authority consensus algorithm called“Proof of Authority with Random Election”(PoARE),implemented within QBIoT for leader selection and new block creation.Thirdly,we develop a publickey quantum signature protocol for transaction verification in the blockchain.Finally,a comprehensive security analysis of QBIoT demonstrates its resilience against cyber threats from both classical and quantum adversaries.In summary,this research introduces an innovative quantum-enhanced blockchain solution to address quantum security concernswithin the realmof IoT.The proposedQBIoT framework contributes to the ongoing development of quantum blockchain technology and offers valuable insights for future research on IoT security.展开更多
The FAIR principles articulate the behaviors expected from digital artifacts that are Findable,Accessible,Interoperable and Reusable by machines and by people.Although by now widely accepted,the FAIR Principles by des...The FAIR principles articulate the behaviors expected from digital artifacts that are Findable,Accessible,Interoperable and Reusable by machines and by people.Although by now widely accepted,the FAIR Principles by design do not explicitly consider actual implementation choices enabling FAIR behaviors.As different communities have their own,often well-established implementation preferences and priorities for data reuse,coordinating a broadly accepted,widely used FAIR implementation approach remains a global challenge.In an effort to accelerate broad community convergence on FAIR implementation options,the GO FAIR community has launched the development of the FAIR Convergence Matrix.The Matrix is a platform that compiles for any community of practice,an inventory of their self-declared FAIR implementation choices and challenges.The Convergence Matrix is itself a FAIR resource,openly available,and encourages voluntary participation by any self-identified community of practice(not only the GO FAIR Implementation Networks).Based on patterns of use and reuse of existing resources,the Convergence Matrix supports the transparent derivation of strategies that optimally coordinate convergence on standards and technologies in the emerging Internet of FAIR Data and Services.展开更多
To quantitatively understand the dust aerosol effects on climate change, we calculated the global dis-tribution of direct radiative forcing due to dust aerosol under clear and cloudy skies in both winter and summer, b...To quantitatively understand the dust aerosol effects on climate change, we calculated the global dis-tribution of direct radiative forcing due to dust aerosol under clear and cloudy skies in both winter and summer, by using an improved radiative transfer model and the global distribution of dust mass concentra-tion given by GADS （Global Aerosol Data Set）. The results show that the global means of the solar forcing due to dust aerosol at the tropopause for winter and summer are -0.48 and -0.50 W m-2, respectively; the corresponding values for the longwave forcing due to dust are 0.11 and 0.09 W m-2, respectively. At the surface, the global means of the solar forcing clue to dust are -1.36 W m-2 for winter and -1.56 W m-2 for summer, whereas the corresponding values for the longwave forcing are 0.27 and 0.23 W m-2, respectively. This work points out that the absolute values of the solar forcing due to dust aerosol at both the tropopause and surface increase linearly with the cosine of solar zenith angle and surface albedo. The solar zenith angle influences both the strength and distribution of the solar forcing greatly. Clouds exert great effects on the direct radiative forcing of dust, depending on many factors including cloud cover, cloud height, cloud water path, surface albedo, solar zenith angle, etc. The effects of low clouds and middle clouds are larger than those of high clouds. The existence of clouds reduces the longwave radiative forcing at the tropopause, where the influences of low clouds are the most obvious. Therefore, the impacts of clouds should not be ignored when estimating the direct radiative forcing due to dust aerosol.展开更多
Forest volume, the major component of forest biomass, is an important issue in forest resource monitoring.It is estimated from tree volume tables or equations. Based on tree volume data of 1840 sample trees from Chine...Forest volume, the major component of forest biomass, is an important issue in forest resource monitoring.It is estimated from tree volume tables or equations. Based on tree volume data of 1840 sample trees from Chinese fir （Cunninghamia lanceolata） plantations in Guizhou Province in southwestern China, parallel one- and two-variable tree volume tables and tree height curves for central and other areas were constructed using an error-in-variable modeling method. The results show that, although the one-variable tree volume equations and height curves between the central and other areas were significantly different, the two-variable volume equations were sufficiently close, so that a generalized two-variable tree volume equation could be established for the entire province.展开更多
Quality education is one of the pillars in the United Nations 2030 Agenda for Sustainable Development,which aims to ensure inclusive and equitable quality education and promote lifelong learning opportunities for all....Quality education is one of the pillars in the United Nations 2030 Agenda for Sustainable Development,which aims to ensure inclusive and equitable quality education and promote lifelong learning opportunities for all.This overall goal can be connected to some general trends affecting education in the information age.We argue that education is key to the future quality of human life and the sustainability of the world.Generally,education is being transformed in both formal and informal learning contexts by new digital technologies.Overall,some of these major innovations and how they are changing education can be summarized into the following aspects:1)our educational aims and objectives;2)educational ecologies and contexts of learning;3)the processes of learning;4)the processes of teaching;and 5)educational governance and policy.Meanwhile,we note some of the potential risks and downsides of these technology trends.From the sustainable perspective,our review points to a great potential for educational reform,but it can only be achieved if we are willing to rethink and even abandon some of our traditional ways of doing things in education.展开更多
Earth observations and model simulations are generating big multidimensional array-based raster data.However,it is difficult to efficiently query these big raster data due to the inconsistency among the geospatial ras...Earth observations and model simulations are generating big multidimensional array-based raster data.However,it is difficult to efficiently query these big raster data due to the inconsistency among the geospatial raster data model,distributed physical data storage model,and the data pipeline in distributed computing frameworks.To efficiently process big geospatial data,this paper proposes a three-layer hierarchical indexing strategy to optimize Apache Spark with Hadoop Distributed File System(HDFS)from the following aspects:(1)improve I/O efficiency by adopting the chunking data structure;(2)keep the workload balance and high data locality by building the global index(k-d tree);(3)enable Spark and HDFS to natively support geospatial raster data formats(e.g.,HDF4,NetCDF4,GeoTiff)by building the local index(hash table);(4)index the in-memory data to further improve geospatial data queries;(5)develop a data repartition strategy to tune the query parallelism while keeping high data locality.The above strategies are implemented by developing the customized RDDs,and evaluated by comparing the performance with that of Spark SQL and SciSpark.The proposed indexing strategy can be applied to other distributed frameworks or cloud-based computing systems to natively support big geospatial data query with high efficiency.展开更多
The Qinghai-Tibet Plateau plays a very important role in studying severe weather in China and around the globe because of its unique characteristics. Moreover, the surface emissivities of the Qinghai-Tibet Plateau are...The Qinghai-Tibet Plateau plays a very important role in studying severe weather in China and around the globe because of its unique characteristics. Moreover, the surface emissivities of the Qinghai-Tibet Plateau are also important for retrieving surface and atmospheric parameters. In the current study, a retrieval algorithm was developed to retrieve the surface emissivities of the Qinghai-Tibet Plateau. The developed algorithm was derived from the radiative transfer model and was first validated using simulated data from a one-dimensional microwave simulator. The simulated results show good precision. Then, the surface emissivities of the Qinghai-Tibet Plateau were retrieved using brightness temperatures from the advanced microwave-scanning radiometer and atmospheric profile data from the moderate resolution imaging spectroradiometer. Finally, the features of the time and space distribution of the retrieved results were analyzed. In terms of spatial characteristics, a spatial distribution con- sistency was found between the retrieved results and surface coverage types of the Qinghai-Tibet Plateau. In terms of time characteristics, the changes in emissivity, which were within 0.01 for every day, were not evident within a one-month time scale. In addition, surface emissivities are sensitive to rainfall. The reasonability of the retrieved results indicates that the algorithm is feasible. A time-series surface emissivity database on the Qinghai-Tibet Plateau can be built using the developed algorithm, and then other surface or atmospheric parameters would have high retrieval precision to support related geological re- search on the Qinghai-Tibet Plateau.展开更多
The present study examines the impact of short-term public opinion sentiment on the secondary market,with a focus on the potential for such sentiment to cause dramatic stock price fluctuations and increase investment ...The present study examines the impact of short-term public opinion sentiment on the secondary market,with a focus on the potential for such sentiment to cause dramatic stock price fluctuations and increase investment risk.The quantification of investment sentiment indicators and the persistent analysis of their impact has been a complex and significant area of research.In this paper,a structured multi-head attention stock index prediction method based adaptive public opinion sentiment vector is proposed.The proposedmethod utilizes an innovative approach to transform numerous investor comments on social platforms over time into public opinion sentiment vectors expressing complex sentiments.It then analyzes the continuous impact of these vectors on the market through the use of aggregating techniques and public opinion data via a structured multi-head attention mechanism.The experimental results demonstrate that the public opinion sentiment vector can provide more comprehensive feedback on market sentiment than traditional sentiment polarity analysis.Furthermore,the multi-head attention mechanism is shown to improve prediction accuracy through attention convergence on each type of input information separately.Themean absolute percentage error(MAPE)of the proposedmethod is 0.463%,a reduction of 0.294% compared to the benchmark attention algorithm.Additionally,the market backtesting results indicate that the return was 24.560%,an improvement of 8.202% compared to the benchmark algorithm.These results suggest that themarket trading strategy based on thismethod has the potential to improve trading profits.展开更多
Wideband IMT-Advanced mobile communication systems tend to operate in the high frequency bands due to a relatively large capacity available. Thus, Measurement and modelling methods of radio propaga- tion eharaeteristi...Wideband IMT-Advanced mobile communication systems tend to operate in the high frequency bands due to a relatively large capacity available. Thus, Measurement and modelling methods of radio propaga- tion eharaeteristics are proposed for the field test of Chinese 4th generation （4G） trial system. The mea- surement system is established for 3.5GHz based on the sophistieated measurement instruments and the virtual instrument teehnology. The characteristic parameters of radio propagation sueh as path loss （PL） exponent and shadow fading standard deviation are extracted from measurement data, which result in the path loss model finally. The comparisons with other existing international models results validate our mea- surement in terms of path loss model. Based on the analysis of the existing extension model assumed for the microwave frequency at 3.5GHz, we find that the Stanford University Interim （SUI） model fits very well with the measurement result in the hotspot scenario, while the COST 231 model is closer to the mea- surement result in the suburban scenario. This result provides a measurement-based channel referenee for the development of the future IMT-Advanced systems in China.展开更多
Low temperature together with snow/freezing rain is disastrous in winter over southern China.Previous studies suggest that this is related to the sea surface temperature(SST)anomalies,especially La Nina conditions,ove...Low temperature together with snow/freezing rain is disastrous in winter over southern China.Previous studies suggest that this is related to the sea surface temperature(SST)anomalies,especially La Nina conditions,over the equatorial central–eastern Pacific Ocean(EP).In reality,however,La Nina episodes are not always accompanied by rainy/snowy/icy(CRSI)days in southern China,such as the case in winter 2020/2021.Is there any other factor that works jointly with the EP SST to affect the winter CRSI weather in southern China?To address this question,CRSI days are defined and calculated based on station observation data,and the related SST anomalies and atmospheric circulations are examined based on the Hadley Centre SST data and the NCEP/NCAR reanalysis data for winters of1978/1979–2017/2018.The results indicate that the CRSI weather with more CRSI days is featured with both decreased temperature and increased winter precipitation over southern China.The SSTs over both the EP and the southeastern Indian Ocean(SIO)are closely related to the CRSI days in southern China with correlation coefficients of-0.29 and 0.39,significant at the 90%and 95%confidence levels,respectively.The SST over EP affects significantly air temperature,as revealed by previous studies,with cooler EP closely related to the deepened East Asian trough,which benefits stronger East Asian winter monsoon(EAWM)and lower air temperature in southern China.Nevertheless,this paper discovers that the SST over SIO affects precipitation of southern China,with a correlation coefficient of 0.42,significant at the 99%confidence level,with warmer SIO correlated with deepened southern branch trough(SBT)and strengthened western North Pacific anomalous anticyclone(WNPAC),favoring more water vapor convergence and enhanced precipitation in southern China.Given presence of La Ni?a in both winters,compared to the winter of 2020/2021,the winter of 2021/2022 witnessed more CRSI days,perhaps due to the warmer SIO.展开更多
Highly unusual amounts of rainfall were seen in the 2020 summer in many parts of China,Japan,and South Korea.At the intercontinental scale,case studies have attributed this exceptional event to a displacement of the c...Highly unusual amounts of rainfall were seen in the 2020 summer in many parts of China,Japan,and South Korea.At the intercontinental scale,case studies have attributed this exceptional event to a displacement of the climatological western North Pacific subtropical anticyclone,potentially associated Indian Ocean sea surface temperature patterns and a mid-latitude wave train emanating from the North Atlantic.Using clusters of spatial patterns of sea level pressure,we show that an unprecedented 80%of the 2020 summer days in East Asia were dominated by clusters of surface pressure greater than normal over the South China Sea.By examining the rainfall and water vapor fluxes in other years when these clusters were also prevalent,we find that the frequency of these types of clusters was likely to have been largely responsible for the unusual rainfall of 2020.From two ensembles of future climate projections,we show that summers like 2020 in East Asia may become more frequent and considerably wetter in a warmer world with an enhanced moisture supply.展开更多
The diversity of Samoa’s freshwater macroinvertebrates remains largely unexplored, with past studies focusing on specific species without comprehensive cataloguing. This research evaluated the health of Upolu Island...The diversity of Samoa’s freshwater macroinvertebrates remains largely unexplored, with past studies focusing on specific species without comprehensive cataloguing. This research evaluated the health of Upolu Island’s rural rivers through macroinvertebrate analysis, particularly in the Le Afe and Mulivaifagatoloa Rivers. Collaborating with Samoa’s Water Resources Division in the Ministry of Natural Resources and Environment (MNRE), three sites along each river were sampled, representing a gradient from pristine to anthropogenically impacted areas. A total of 2953 macroinvertebrates were collected and classified into five categories using established identification keys. The Macroinvertebrate Community Index (MCI) and Quantitative Macroinvertebrate Community Index (QMCI) were applied for analysis. The results showed no clear pattern of pollutant-sensitive species prevalence or decline in less disturbed rivers. High MCI scores with low QMCI values indicated numerous low-scoring species, while the opposite suggested a richness of high-scoring taxa. Although MCI and QMCI are tools for monitoring freshwater health, this study lays the groundwork for future research to categorize Samoan macroinvertebrates and assign tolerance scores based on their presence in varying river conditions. .展开更多
The layout design of satellite modules is considered to be NP-hard. It is not only a complex coupled system design problem but also a special multi-objective optimization problem. The greatest challenge in solving thi...The layout design of satellite modules is considered to be NP-hard. It is not only a complex coupled system design problem but also a special multi-objective optimization problem. The greatest challenge in solving this problem is that the function to be optimized is characterized by a multitude of local minima separated by high-energy barriers. The Wang-Landau(WL) sampling method, which is an improved Monte Carlo method, has been successfully applied to solve many optimization problems. In this paper we use the WL sampling method to optimize the layout of a satellite module. To accelerate the search for a global optimal layout, local search(LS) based on the gradient method is executed once the Monte-Carlo sweep produces a new layout. By combining the WL sampling algorithm, the LS method, and heuristic layout update strategies, a hybrid method called WL-LS is proposed to obtain a final layout scheme. Furthermore, to improve significantly the efficiency of the algorithm, we propose an accurate and fast computational method for the overlapping depth between two objects(such as two rectangular objects, two circular objects, or a rectangular object and a circular object) embedding each other. The rectangular objects are placed orthogonally. We test two instances using first 51 and then 53 objects. For both instances, the proposed WL-LS algorithm outperforms methods in the literature. Numerical results show that the WL-LS algorithm is an effective method for layout optimization of satellite modules.展开更多
The aim of this study is to calculate the low-level atmospheric motion vectors （AMVs） in clear areas with FY-2E IR2 window （11.59-12.79 μm） channel imagery,where the traditional cloud motion wind technique fails....The aim of this study is to calculate the low-level atmospheric motion vectors （AMVs） in clear areas with FY-2E IR2 window （11.59-12.79 μm） channel imagery,where the traditional cloud motion wind technique fails.A new tracer selection procedure,which we call the temporal difference technique,is demonstrated in this paper.This technique makes it possible to infer low-level wind by tracking features in the moisture pattern that appear as brightness temperature （TB） differences between consecutive sequences of 30-min-interval FY-2E IR2 images over cloud-free regions.The TB difference corresponding to a 10％ change in water vapor density is computed with the Moderate Resolution Atmospheric Transmission （MODTRAN4） radiative transfer model.The total contribution from each of the 10 layers is analyzed under four typical atmospheric conditions：tropical,midlatitude summer,U.S.standard,and midlatitude winter.The peak level of the water vapor weighting function for the four typical atmospheres is assigned as a specific height to the TB ＂wind＂.This technique is valid over cloudfree ocean areas.The proposed algorithm exhibits encouraging statistical results in terms of vector difference （VD）,speed bias （BIAS）,mean vector difference （MVD）,standard deviation （SD）,and root-mean-square error （RMSE）,when compared with the wind field of NCEP reanalysis data and rawinsonde observations.展开更多
基金supported by the National Key R&D Program of China(Nos.2017YFC0210000 and 2016YFC0203100)State Key Laboratory of Atmospheric Chemistry,Chinese Meteorological Administration(LAC/CMA)(No.2017A01)+4 种基金the Young Talent Project of the Center for Excellence in Regional Atmospheric Environment,Chinese Academy of Sciences(CAS)(No.CERAE201802)the National Natural Science Foundation of China(Nos.41705113,41877312 and 41675124)the National research program for key issues in air pollution control(No.DQGG0101)Beijing Major Science and Technology Project(No.Z181100005418014)Postgraduate Research and Practice Innovation Program of Jiangsu Province(No.SJCX18_0327)
文摘The structure of the boundary layer affects the evolution of ozone(O3), and research into this structure will provide important insights for understanding photochemical pollution.In this study, we conducted a one-month observation(from June 15 to July 14, 2016) of the boundary layer meteorological factors as well as O3 and its precursors in Luancheng County,Shijiazhuang(37°53′N, 114°38′E). Our research showed that photochemical pollution in Shijiazhuang is serious, and the mean hourly maximum and mean 8-hr maximum O3 concentrations are 97.9 ± 26.1 and 84.4 ± 22.4 ppbV, respectively. Meteorological factors play a significant role in the formation of O3. High temperatures and southeasterly winds lead to elevated O3 values, and at moderate relative humidity(40%–50%) and medium boundary layer heights(1200–1500 m), O3 production sensitivity occurred in the transitional region between volatile organic compounds(VOC) and nitrogen oxides(NOx) limitations,and the O3 concentration was the highest. The vertical profiles of O3 were also measured by a tethered balloon. The results showed that a large amount of O3 was stored in the residual layer, and the concentration was positively correlated with the O3 concentration measured the previous day. During the daytime of the following day, the contribution of O3 stored in the residual layer to the boundary layer reached 27%± 7% on average.
基金Supported by the UK–China Research and Innovation Partnership Fund through the Met Office Climate Science for Service Partnership(CSSP)China as part of the Newton Fund。
文摘Rainfall forecasts for the summer monsoon season in the Yangtze River basin(YRB) allow decision-makers to plan for possible flooding, which can affect the lives and livelihoods of millions of people. A trial climate service was developed in 2016, producing a prototype seasonal forecast product for use by stakeholders in the region, based on rainfall forecasts directly from a dynamical model. Here, we describe an improved service based on a simple statistical downscaling approach. Through using dynamical forecast of an East Asian summer monsoon(EASM) index, seasonal mean rainfall for the upper and middle/lower reaches of YRB can be forecast separately by use of the statistical downscaling, with significant skills for lead times of up to at least three months. The skill in different sub-basin regions of YRB varies with the target season. The rainfall forecast skill in the middle/lower reaches of YRB is significant in May–June–July(MJJ), and the forecast skill for rainfall in the upper reaches of YRB is significant in June–July–August(JJA). The mean rainfall for the basin as a whole can be skillfully forecast in both MJJ and JJA. The forecasts issued in 2019 gave good guidance for the enhanced rainfall in the MJJ period and the near-average conditions in JJA. Initial feedback from users in the basin suggests that the improved forecasts better meet their needs and will enable more robust decision-making.
基金Supported by the National Key Research and Development Program of China(2016YFA0601701)National High Technology Research and Development Program of China(2012AA120902)。
文摘Based on the concepts of cloud water resource(CWR)and related variables proposed in the first part of this study,this paper provides details of two methods to quantify the CWR.One is diagnostic quantification(CWR-DQ)based on satellite observations,precipitation products,and atmospheric reanalysis data;and the other is numerical quantification(CWR-NQ)based on a cloud resolving model developed at the Chinese Academy of Meteorological Sciences(CAMS).The two methods are applied to quantify the CWR in April and August 2017 over North China,and the results are evaluated against all available observations.Main results are as follows.(1)For the CWR-DQ approach,reference cloud profiles are firstly derived based on the Cloud Sat/CALIPSO joint satellite observations for 2007–2010.The NCEP/NCAR reanalysis data in 2000–2017 are then employed to produce three-dimensional cloud fields.The budget/balance equations of atmospheric water substance are lastly used,together with precipitation observations,to retrieve CWR and related variables.It is found that the distribution and vertical structure of clouds obtained by the diagnostic method are consistent with observations.(2)For the CWR-NQ approach,it assumes that the cloud resolving model is able to describe the cloud microphysical processes completely and precisely,from which four-dimensional distributions of atmospheric water vapor,hydrometeors,and wind fields can be obtained.The data are then employed to quantify the CWR and related terms/quantities.After one-month continuous integration,the mass of atmospheric water substance becomes conserved,and the tempospatial distributions of water vapor,hydrometeors/cloud water,and precipitation are consistent with observations.(3)Diagnostic values of the difference in the transition between hydrometeors and water vapor(Cvh-Chv)and the surface evaporation(Es)are well consistent with their numerical values.(4)Correlation and bias analyses show that the diagnostic CWR contributors are well correlated with observations,and match their n
基金supported partially by the Ministry of Science and Technology of China under its national key project on global change studies (No.2013CB955804)the Special Fund for doctorate programs in Chinese Universities (No.20113228110002)+1 种基金the Public Meteorology Special Foundation of MOST (No.GYHY201306065)the Shanxi Meteorological Bureau Key Research Projects (No.SXKZDTC20140605)
文摘Vertical distributions of aerosol optical properties based on aircraft measurements over the Loess Plateau were measured for the first time during a summertime aircraft campaign, 2013 in Shanxi, China. Data from four flights were analyzed. The vertical distributions of aerosol optical properties including aerosol scattering coefficients（σsc）, absorption coefficients（σab）,Angstr？m exponent（α）, single scattering albedo（ω）, backscattering ratio（βsc）, aerosol mass scattering proficiency（Q sc） and aerosol surface scattering proficiency（Q sc′） were obtained. The mean statistical values of σsc were 77.45 Mm-1（at 450 nm）, 50.72 Mm-1（at 550 nm）, and32.02 Mm-1（at 700 nm）. The mean value of σab was 7.62 Mm-1（at 550 nm）. The mean values ofα, βsc and ω were 1.93, 0.15, and 0.91, respectively. Aerosol concentration decreased with altitude. Most effective diameters（ED） of aerosols were less than 0.8 μm. The vertical profiles of σsc,, α, βsc, Q sc and Q sc′ showed that the aerosol scattering properties at lower levels contributed the most to the total aerosol radiative forcing. Both α and βsc had relatively large values, suggesting that most aerosols in the observational region were small particles. The mean values of σsc, α, βsc, Q sc, Q sc′, σab and ω at different height ranges showed that most of the parameters decreased with altitude. The forty-eight hour backward trajectories of air masses during the observation days indicated that the majority of aerosols in the lower level contributed the most to the total aerosol loading, and most of these particles originated from local or regional pollution emissions.
基金supported by the National Natural Science Foundation of China(62033010)Qing Lan Project of Jiangsu Province(R2023Q07)。
文摘For accurately identifying the distribution charac-teristic of Gaussian-like noises in unmanned aerial vehicle(UAV)state estimation,this paper proposes a non-parametric scheme based on curve similarity matching.In the framework of the pro-posed scheme,a Parzen window(kernel density estimation,KDE)method on sliding window technology is applied for roughly esti-mating the sample probability density,a precise data probability density function(PDF)model is constructed with the least square method on K-fold cross validation,and the testing result based on evaluation method is obtained based on some data characteristic analyses of curve shape,abruptness and symmetry.Some com-parison simulations with classical methods and UAV flight exper-iment shows that the proposed scheme has higher recognition accuracy than classical methods for some kinds of Gaussian-like data,which provides better reference for the design of Kalman filter(KF)in complex water environment.
基金support by the National Natural Science Foundation of China(Nos.51606158,11604311,12074151)funding from the Sichuan Science and Technology Program(No.2021JDRC0022)+3 种基金funding from the Natural Science Foundation of Fujian Province(No.2021J05202)funding from the Research Project of Fashu Foundation(No.MFK23006)funding from the Open Fund of the Key Laboratory for Metallurgical Equipment and Control Technology of Ministry of Education in Wuhan University of Science and Technology,China(No.MECOF2022B01)funding by the project supported by Guangxi Key Laboratory of Precision Navigation Technology and Application,Guilin University of Electronic Technology(No.DH202321).
文摘This study introduces an innovative dual-tunable absorption film with the capability to switch between ultra-wideband and narrowband absorption.By manipulating the temperature,the film can achieve multi-band absorption within the 30-45 THz range or ultra-wideband absorption spanning 30-130 THz,with an absorption rate exceeding 0.9.Furthermore,the structural parameters of the absorption film are optimized using the particle swarm optimization(PSO)algorithm to ensure the optimal absorption response.The absorption response of the film is primarily attributed to the coupling of guided-mode resonance and local surface plasmon resonance effects.The film's symmetric structure enables polarization incoherence and allows for tuning through various means such as doping/voltage,temperature and structural parameters.In the case of a multi-band absorption response,the film exhibits good sensitivity to refractive index changes in multiple absorption modes.Additionally,the absorption spectrum of the film remains effective even at large incidence angles,making it highly promising for applications in fields such as biosensing and infrared stealth.
基金supported by National Key RD Program of China(Grant No.2022YFB3104402,the Research on Digital Identity Trust System for Massive Heterogeneous Terminals in Road Traffic System)the Fundamental Research Funds for the Central Universities(Grant Nos.3282023015,3282023035,3282023051)National First-Class Discipline Construction Project of Beijing Electronic Science and Technology Institute(No.3201012).
文摘The Internet of Things(IoT)is a network system that connects physical devices through the Internet,allowing them to interact.Nowadays,IoT has become an integral part of our lives,offering convenience and smart functionality.However,the growing number of IoT devices has brought about a corresponding increase in cybersecurity threats,such as device vulnerabilities,data privacy concerns,and network susceptibilities.Integrating blockchain technology with IoT has proven to be a promising approach to enhance IoT security.Nevertheless,the emergence of quantum computing poses a significant challenge to the security of traditional classical cryptography used in blockchain,potentially exposing it to quantum cyber-attacks.To support the growth of the IoT industry,mitigate quantum threats,and safeguard IoT data,this study proposes a robust blockchain solution for IoT that incorporates both classical and post-quantum security measures.Firstly,we present the Quantum-Enhanced Blockchain Architecture for IoT(QBIoT)to ensure secure data sharing and integrity protection.Secondly,we propose an improved Proof of Authority consensus algorithm called“Proof of Authority with Random Election”(PoARE),implemented within QBIoT for leader selection and new block creation.Thirdly,we develop a publickey quantum signature protocol for transaction verification in the blockchain.Finally,a comprehensive security analysis of QBIoT demonstrates its resilience against cyber threats from both classical and quantum adversaries.In summary,this research introduces an innovative quantum-enhanced blockchain solution to address quantum security concernswithin the realmof IoT.The proposedQBIoT framework contributes to the ongoing development of quantum blockchain technology and offers valuable insights for future research on IoT security.
基金FAIRsharing is funded by grants awarded to SAS that include elements of this workspecifically,grants from the UK BBSRC and Research Councils(BB/L024101/1,BB/L005069/1)+1 种基金European Union(H2020-EU.3.1,634107,H2020-EU.1.4.1.3,654241,H2020-EU.1.4.1.1,676559),IMI(116060)and NIH(U54 AI117925,1U24AI117966-01,1OT3OD025459-01,1OT3OD025467-01,1OT3OD025462-01)the new FAIRsharing award from the Wellcome Trust(212930/Z/18/Z),as well as a related award(208381/A/17/Z).
文摘The FAIR principles articulate the behaviors expected from digital artifacts that are Findable,Accessible,Interoperable and Reusable by machines and by people.Although by now widely accepted,the FAIR Principles by design do not explicitly consider actual implementation choices enabling FAIR behaviors.As different communities have their own,often well-established implementation preferences and priorities for data reuse,coordinating a broadly accepted,widely used FAIR implementation approach remains a global challenge.In an effort to accelerate broad community convergence on FAIR implementation options,the GO FAIR community has launched the development of the FAIR Convergence Matrix.The Matrix is a platform that compiles for any community of practice,an inventory of their self-declared FAIR implementation choices and challenges.The Convergence Matrix is itself a FAIR resource,openly available,and encourages voluntary participation by any self-identified community of practice(not only the GO FAIR Implementation Networks).Based on patterns of use and reuse of existing resources,the Convergence Matrix supports the transparent derivation of strategies that optimally coordinate convergence on standards and technologies in the emerging Internet of FAIR Data and Services.
基金Supported by the National Key Technology R&D Program under Grant No.2008BAC40B02the National Basic Research Program of China under Grant No.2011CB403405the Special Fund for Public Welfare (meteorology) by the Ministry of Science and Technology under Grant No.GYHY200706036
文摘To quantitatively understand the dust aerosol effects on climate change, we calculated the global dis-tribution of direct radiative forcing due to dust aerosol under clear and cloudy skies in both winter and summer, by using an improved radiative transfer model and the global distribution of dust mass concentra-tion given by GADS （Global Aerosol Data Set）. The results show that the global means of the solar forcing due to dust aerosol at the tropopause for winter and summer are -0.48 and -0.50 W m-2, respectively; the corresponding values for the longwave forcing due to dust are 0.11 and 0.09 W m-2, respectively. At the surface, the global means of the solar forcing clue to dust are -1.36 W m-2 for winter and -1.56 W m-2 for summer, whereas the corresponding values for the longwave forcing are 0.27 and 0.23 W m-2, respectively. This work points out that the absolute values of the solar forcing due to dust aerosol at both the tropopause and surface increase linearly with the cosine of solar zenith angle and surface albedo. The solar zenith angle influences both the strength and distribution of the solar forcing greatly. Clouds exert great effects on the direct radiative forcing of dust, depending on many factors including cloud cover, cloud height, cloud water path, surface albedo, solar zenith angle, etc. The effects of low clouds and middle clouds are larger than those of high clouds. The existence of clouds reduces the longwave radiative forcing at the tropopause, where the influences of low clouds are the most obvious. Therefore, the impacts of clouds should not be ignored when estimating the direct radiative forcing due to dust aerosol.
基金supported by the Agricultural Science and Technique Foundation of Guizhou Province, China (No. 2008-3059)the Research Funds of Forestry Administration of Guizhou Province, China (Nos. 2010-01-08, 2010-01, 200625)
文摘Forest volume, the major component of forest biomass, is an important issue in forest resource monitoring.It is estimated from tree volume tables or equations. Based on tree volume data of 1840 sample trees from Chinese fir （Cunninghamia lanceolata） plantations in Guizhou Province in southwestern China, parallel one- and two-variable tree volume tables and tree height curves for central and other areas were constructed using an error-in-variable modeling method. The results show that, although the one-variable tree volume equations and height curves between the central and other areas were significantly different, the two-variable volume equations were sufficiently close, so that a generalized two-variable tree volume equation could be established for the entire province.
文摘Quality education is one of the pillars in the United Nations 2030 Agenda for Sustainable Development,which aims to ensure inclusive and equitable quality education and promote lifelong learning opportunities for all.This overall goal can be connected to some general trends affecting education in the information age.We argue that education is key to the future quality of human life and the sustainability of the world.Generally,education is being transformed in both formal and informal learning contexts by new digital technologies.Overall,some of these major innovations and how they are changing education can be summarized into the following aspects:1)our educational aims and objectives;2)educational ecologies and contexts of learning;3)the processes of learning;4)the processes of teaching;and 5)educational governance and policy.Meanwhile,we note some of the potential risks and downsides of these technology trends.From the sustainable perspective,our review points to a great potential for educational reform,but it can only be achieved if we are willing to rethink and even abandon some of our traditional ways of doing things in education.
基金This research is funded by NASA(National Aeronautics and Space Administration)NCCS and AIST(NNX15AM85G)NSF I/UCRC,CSSI,and EarthCube Programs(1338925 and 1835507).
文摘Earth observations and model simulations are generating big multidimensional array-based raster data.However,it is difficult to efficiently query these big raster data due to the inconsistency among the geospatial raster data model,distributed physical data storage model,and the data pipeline in distributed computing frameworks.To efficiently process big geospatial data,this paper proposes a three-layer hierarchical indexing strategy to optimize Apache Spark with Hadoop Distributed File System(HDFS)from the following aspects:(1)improve I/O efficiency by adopting the chunking data structure;(2)keep the workload balance and high data locality by building the global index(k-d tree);(3)enable Spark and HDFS to natively support geospatial raster data formats(e.g.,HDF4,NetCDF4,GeoTiff)by building the local index(hash table);(4)index the in-memory data to further improve geospatial data queries;(5)develop a data repartition strategy to tune the query parallelism while keeping high data locality.The above strategies are implemented by developing the customized RDDs,and evaluated by comparing the performance with that of Spark SQL and SciSpark.The proposed indexing strategy can be applied to other distributed frameworks or cloud-based computing systems to natively support big geospatial data query with high efficiency.
基金supported by National Natural Science Foundation of China(Grant Nos. 41101314 and 40930530)State Key Laboratory of Remote Sensing Open Fund (Grant No. OFSLRSS201104)+2 种基金Institute of Plateau Meteorology Open Fund (Grant No. LPM2011018)Digital Earth Key Laboratory of CAS Open Fund (Grant No. 2010LDE008)Chinese Academy of Meteorological Science Special Fund (Grant No. 2008Z003)
文摘The Qinghai-Tibet Plateau plays a very important role in studying severe weather in China and around the globe because of its unique characteristics. Moreover, the surface emissivities of the Qinghai-Tibet Plateau are also important for retrieving surface and atmospheric parameters. In the current study, a retrieval algorithm was developed to retrieve the surface emissivities of the Qinghai-Tibet Plateau. The developed algorithm was derived from the radiative transfer model and was first validated using simulated data from a one-dimensional microwave simulator. The simulated results show good precision. Then, the surface emissivities of the Qinghai-Tibet Plateau were retrieved using brightness temperatures from the advanced microwave-scanning radiometer and atmospheric profile data from the moderate resolution imaging spectroradiometer. Finally, the features of the time and space distribution of the retrieved results were analyzed. In terms of spatial characteristics, a spatial distribution con- sistency was found between the retrieved results and surface coverage types of the Qinghai-Tibet Plateau. In terms of time characteristics, the changes in emissivity, which were within 0.01 for every day, were not evident within a one-month time scale. In addition, surface emissivities are sensitive to rainfall. The reasonability of the retrieved results indicates that the algorithm is feasible. A time-series surface emissivity database on the Qinghai-Tibet Plateau can be built using the developed algorithm, and then other surface or atmospheric parameters would have high retrieval precision to support related geological re- search on the Qinghai-Tibet Plateau.
基金funded by the Major Humanities and Social Sciences Research Projects in Zhejiang higher education institutions,grant number 2023QN082,awarded to Cheng ZhaoThe National Natural Science Foundation of China also provided funding,grant number 61902349,awarded to Cheng Zhao.
文摘The present study examines the impact of short-term public opinion sentiment on the secondary market,with a focus on the potential for such sentiment to cause dramatic stock price fluctuations and increase investment risk.The quantification of investment sentiment indicators and the persistent analysis of their impact has been a complex and significant area of research.In this paper,a structured multi-head attention stock index prediction method based adaptive public opinion sentiment vector is proposed.The proposedmethod utilizes an innovative approach to transform numerous investor comments on social platforms over time into public opinion sentiment vectors expressing complex sentiments.It then analyzes the continuous impact of these vectors on the market through the use of aggregating techniques and public opinion data via a structured multi-head attention mechanism.The experimental results demonstrate that the public opinion sentiment vector can provide more comprehensive feedback on market sentiment than traditional sentiment polarity analysis.Furthermore,the multi-head attention mechanism is shown to improve prediction accuracy through attention convergence on each type of input information separately.Themean absolute percentage error(MAPE)of the proposedmethod is 0.463%,a reduction of 0.294% compared to the benchmark attention algorithm.Additionally,the market backtesting results indicate that the return was 24.560%,an improvement of 8.202% compared to the benchmark algorithm.These results suggest that themarket trading strategy based on thismethod has the potential to improve trading profits.
基金supported by the High Technology Research and Development Programme of China(2007AA01Z278)
文摘Wideband IMT-Advanced mobile communication systems tend to operate in the high frequency bands due to a relatively large capacity available. Thus, Measurement and modelling methods of radio propaga- tion eharaeteristics are proposed for the field test of Chinese 4th generation （4G） trial system. The mea- surement system is established for 3.5GHz based on the sophistieated measurement instruments and the virtual instrument teehnology. The characteristic parameters of radio propagation sueh as path loss （PL） exponent and shadow fading standard deviation are extracted from measurement data, which result in the path loss model finally. The comparisons with other existing international models results validate our mea- surement in terms of path loss model. Based on the analysis of the existing extension model assumed for the microwave frequency at 3.5GHz, we find that the Stanford University Interim （SUI） model fits very well with the measurement result in the hotspot scenario, while the COST 231 model is closer to the mea- surement result in the suburban scenario. This result provides a measurement-based channel referenee for the development of the future IMT-Advanced systems in China.
基金Supported by the National Natural Science Foundation of China(42088101)Joint Open Project of KLME&CIC-FEMD,NUIST(KLME202212)。
文摘Low temperature together with snow/freezing rain is disastrous in winter over southern China.Previous studies suggest that this is related to the sea surface temperature(SST)anomalies,especially La Nina conditions,over the equatorial central–eastern Pacific Ocean(EP).In reality,however,La Nina episodes are not always accompanied by rainy/snowy/icy(CRSI)days in southern China,such as the case in winter 2020/2021.Is there any other factor that works jointly with the EP SST to affect the winter CRSI weather in southern China?To address this question,CRSI days are defined and calculated based on station observation data,and the related SST anomalies and atmospheric circulations are examined based on the Hadley Centre SST data and the NCEP/NCAR reanalysis data for winters of1978/1979–2017/2018.The results indicate that the CRSI weather with more CRSI days is featured with both decreased temperature and increased winter precipitation over southern China.The SSTs over both the EP and the southeastern Indian Ocean(SIO)are closely related to the CRSI days in southern China with correlation coefficients of-0.29 and 0.39,significant at the 90%and 95%confidence levels,respectively.The SST over EP affects significantly air temperature,as revealed by previous studies,with cooler EP closely related to the deepened East Asian trough,which benefits stronger East Asian winter monsoon(EAWM)and lower air temperature in southern China.Nevertheless,this paper discovers that the SST over SIO affects precipitation of southern China,with a correlation coefficient of 0.42,significant at the 99%confidence level,with warmer SIO correlated with deepened southern branch trough(SBT)and strengthened western North Pacific anomalous anticyclone(WNPAC),favoring more water vapor convergence and enhanced precipitation in southern China.Given presence of La Ni?a in both winters,compared to the winter of 2020/2021,the winter of 2021/2022 witnessed more CRSI days,perhaps due to the warmer SIO.
基金Lixia ZHANG was supported by the National Natural Science Foundation of China under Grant No.42075037the Innovative Team Project of Lanzhou Institute of Arid Meteorology(GHSCXTD-2020-2)Chaofan LI was supported by the National Key Research and Development Program of China(2018YFC1506005).
文摘Highly unusual amounts of rainfall were seen in the 2020 summer in many parts of China,Japan,and South Korea.At the intercontinental scale,case studies have attributed this exceptional event to a displacement of the climatological western North Pacific subtropical anticyclone,potentially associated Indian Ocean sea surface temperature patterns and a mid-latitude wave train emanating from the North Atlantic.Using clusters of spatial patterns of sea level pressure,we show that an unprecedented 80%of the 2020 summer days in East Asia were dominated by clusters of surface pressure greater than normal over the South China Sea.By examining the rainfall and water vapor fluxes in other years when these clusters were also prevalent,we find that the frequency of these types of clusters was likely to have been largely responsible for the unusual rainfall of 2020.From two ensembles of future climate projections,we show that summers like 2020 in East Asia may become more frequent and considerably wetter in a warmer world with an enhanced moisture supply.
文摘The diversity of Samoa’s freshwater macroinvertebrates remains largely unexplored, with past studies focusing on specific species without comprehensive cataloguing. This research evaluated the health of Upolu Island’s rural rivers through macroinvertebrate analysis, particularly in the Le Afe and Mulivaifagatoloa Rivers. Collaborating with Samoa’s Water Resources Division in the Ministry of Natural Resources and Environment (MNRE), three sites along each river were sampled, representing a gradient from pristine to anthropogenically impacted areas. A total of 2953 macroinvertebrates were collected and classified into five categories using established identification keys. The Macroinvertebrate Community Index (MCI) and Quantitative Macroinvertebrate Community Index (QMCI) were applied for analysis. The results showed no clear pattern of pollutant-sensitive species prevalence or decline in less disturbed rivers. High MCI scores with low QMCI values indicated numerous low-scoring species, while the opposite suggested a richness of high-scoring taxa. Although MCI and QMCI are tools for monitoring freshwater health, this study lays the groundwork for future research to categorize Samoan macroinvertebrates and assign tolerance scores based on their presence in varying river conditions. .
基金supported by the National Natural Science Foundation of China(Nos.61373016 and 61403206)the Six Talent Peaks Project of Jiangsu Province,China(No.DZXX-041)+1 种基金Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutionsthe Natural Science Foundation of Jiangsu Province,China(No.BK20141005)
文摘The layout design of satellite modules is considered to be NP-hard. It is not only a complex coupled system design problem but also a special multi-objective optimization problem. The greatest challenge in solving this problem is that the function to be optimized is characterized by a multitude of local minima separated by high-energy barriers. The Wang-Landau(WL) sampling method, which is an improved Monte Carlo method, has been successfully applied to solve many optimization problems. In this paper we use the WL sampling method to optimize the layout of a satellite module. To accelerate the search for a global optimal layout, local search(LS) based on the gradient method is executed once the Monte-Carlo sweep produces a new layout. By combining the WL sampling algorithm, the LS method, and heuristic layout update strategies, a hybrid method called WL-LS is proposed to obtain a final layout scheme. Furthermore, to improve significantly the efficiency of the algorithm, we propose an accurate and fast computational method for the overlapping depth between two objects(such as two rectangular objects, two circular objects, or a rectangular object and a circular object) embedding each other. The rectangular objects are placed orthogonally. We test two instances using first 51 and then 53 objects. For both instances, the proposed WL-LS algorithm outperforms methods in the literature. Numerical results show that the WL-LS algorithm is an effective method for layout optimization of satellite modules.
基金supported by the National Natural Science Foundation of China (Grant Nos.41175035 and 41005005)the National Basic Research Program of China (Grant No.2009CB421502)a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions(PAPD)
文摘The aim of this study is to calculate the low-level atmospheric motion vectors （AMVs） in clear areas with FY-2E IR2 window （11.59-12.79 μm） channel imagery,where the traditional cloud motion wind technique fails.A new tracer selection procedure,which we call the temporal difference technique,is demonstrated in this paper.This technique makes it possible to infer low-level wind by tracking features in the moisture pattern that appear as brightness temperature （TB） differences between consecutive sequences of 30-min-interval FY-2E IR2 images over cloud-free regions.The TB difference corresponding to a 10％ change in water vapor density is computed with the Moderate Resolution Atmospheric Transmission （MODTRAN4） radiative transfer model.The total contribution from each of the 10 layers is analyzed under four typical atmospheric conditions：tropical,midlatitude summer,U.S.standard,and midlatitude winter.The peak level of the water vapor weighting function for the four typical atmospheres is assigned as a specific height to the TB ＂wind＂.This technique is valid over cloudfree ocean areas.The proposed algorithm exhibits encouraging statistical results in terms of vector difference （VD）,speed bias （BIAS）,mean vector difference （MVD）,standard deviation （SD）,and root-mean-square error （RMSE）,when compared with the wind field of NCEP reanalysis data and rawinsonde observations.
