Effect of different cold air intensities and their lagged effects on outpatient visits for respiratory illnesses in Handan in different seasons

本文利用2016年到2019年邯郸市气象要素和呼吸系统疾病门诊数据,分析了不同季节不同强度的冷空气过程及其对呼吸系统疾病的影响,结果显示:尽管呼吸系统疾病在冬季高发,夏季最低,但冷空气对呼吸系统疾病的影响在夏,春季最大,就诊人数分别在冷空气日后两天和五天增加18.4%和13.3%,而冬季就诊人数在冷空气日后三天仅增加3.2%.冷空气对疾病影响的滞后时间在夏,秋和冬季随冷空气强度的增加而减少,而春季的滞后时间总是很长.这些发现可为科学应对气候异常导致的人群健康风险提供针对性依据.

The Forecast Skills and Predictability Sources of Marine Heatwaves in the NUIST-CFS1.0 Hindcasts

Using monthly observations and ensemble hindcasts of the Nanjing University of Information Science and Technology Climate Forecast System(NUIST-CFS1.0) for the period 1983–2020, this study investigates the forecast skill of marine heatwaves(MHWs) over the globe and the predictability sources of the MHWs over the tropical oceans. The MHW forecasts are demonstrated to be skillful on seasonal-annual time scales, particularly in tropical oceans. The forecast skill of the MHWs over the tropical Pacific Ocean(TPO) remains high at lead times of 1–24 months, indicating a forecast better than random chance for up to two years. The forecast skill is subject to the spring predictability barrier of El Nino-Southern Oscillation(ENSO). The forecast skills for the MHWs over the tropical Indian Ocean(TIO), tropical Atlantic Ocean(TAO), and tropical Northwest Pacific(NWP) are lower than that in the TPO. A reliable forecast at lead times of up to two years is shown over the TIO, while a shorter reliable forecast window(less than 17 months) occurs for the TAO and NWP.Additionally, the forecast skills for the TIO, TAO, and NWP are seasonally dependent. Higher skills for the TIO and TAO appear in boreal spring, while a greater skill for the NWP emerges in late summer-early autumn. Further analyses suggest that ENSO serves as a critical source of predictability for MHWs over the TIO and TAO in spring and MHWs over the NWP in summer.

Synergistic Interdecadal Evolution of Precipitation over Eastern China and the Pacific Decadal Oscillation during 1951-2015

By using the multi-taper method(MTM)of singular value decomposition(SVD),this study investigates the interdecadal evolution(10-to 30-year cycle)of precipitation over eastern China from 1951 to 2015 and its relationship with the North Pacific sea surface temperature(SST).Two significant interdecadal signals,one with an 11-year cycle and the other with a 23-year cycle,are identified in both the precipitation and SST fields.Results show that the North Pacific SST forcing modulates the precipitation distribution over China through the effects of the Pacific Decadal Oscillation(PDO)-related anomalous Aleutian low on the western Pacific subtropical high(WPSH)and Mongolia high(MH).During the development stage of the PDO cold phase associated with the 11-year cycle,a weakened WPSH and MH increased the precipitation over the Yangtze River Basin,whereas an intensified WPSH and MH caused the enhanced rain band to move northward to North China during the decay stage.During the development stage of the PDO cold phase associated with the 23-year cycle,a weakened WPSH and MH increased the precipitation over North China,whereas an intensified WPSH and the weakened MH increased the precipitation over South China during the decay stage.The 11-year and 23-year variabilities contribute differently to the precipitation variations in the different regions of China,as seen in the 1998flooding case.The 11-year cycle mainly accounts for precipitation increases over the Yangtze River Basin,while the 23-year cycle is responsible for the precipitation increase over Northeast China.These results have important implications for understanding how the PDO modulates the precipitation distribution over China,helping to improve interdecadal climate prediction.

Characteristics and Mechanisms of Persistent Wet–Cold Events with Different Cold-air Paths in South China

We investigate the characteristics and mechanisms of persistent wet–cold events(PWCEs)with different types of coldair paths.Results show that the cumulative single-station frequency of the PWCEs in the western part of South China is higher than that in the eastern part.The pattern of single-station frequency of the PWCEs are“Yangtze River(YR)uniform”and“east–west inverse”.The YR uniform pattern is the dominant mode,so we focus on this pattern.The cold-air paths for PWCEs of the YR uniform pattern are divided into three types—namely,the west,northwest and north types—among which the west type accounts for the largest proportion.The differences in atmospheric circulation of the PWCEs under the three types of paths are obvious.The thermal inversion layer in the lower troposphere is favorable for precipitation during the PWCEs.The positive water vapor budget for the three types of PWCEs mainly appears at the southern boundary.

Distinct Interannual Variability and Physical Mechanisms of Snowfall Frequency over the Eurasian Continent during Autumn and Winter

This study investigates the dominant modes of interannual variability of snowfall frequency over the Eurasian continent during autumn and winter,and explores the underlying physical mechanisms.The first EOF mode(EOF1)of snowfall frequency during autumn is mainly characterized by positive anomalies over the Central Siberian Plateau(CSP)and Europe,with opposite anomalies over Central Asia(CA).EOF1 during winter is characterized by positive anomalies in Siberia and negative anomalies in Europe and East Asia(EA).During autumn,EOF1 is associated with the anomalous sea ice in the Kara–Laptev seas(KLS)and sea surface temperature(SST)over the North Atlantic.Increased sea ice in the KLS may cause an increase in the meridional air temperature gradient,resulting in increased synoptic-scale wave activity,thereby inducing increased snowfall frequency over Europe and the CSP.Anomalous increases of both sea ice in the KLS and SST in the North Atlantic may stimulate downstream propagation of Rossby waves and induce an anomalous high in CA corresponding to decreased snowfall frequency.In contrast,EOF1 is mainly affected by the anomalous atmospheric circulation during winter.In the positive phase of the North Atlantic Oscillation(NAO),an anomalous deep cold low(warm high)occurs over Siberia(Europe)leading to increased(decreased)snowfall frequency over Siberia(Europe).The synoptic-scale wave activity excited by the positive NAO can induce downstream Rossby wave propagation and contribute to an anomalous high and descending motion over EA,which may inhibit snowfall.The NAO in winter may be modulated by the Indian Ocean dipole and sea ice in the Barents-Kara-Laptev Seas in autumn.

Synergistic Impacts of Indian Ocean SST and Indo-China Peninsula Soil Moisture on the 2020 Record-breaking Mei-yu

The Yangtze River basin(YRB)experienced a record-breaking mei-yu season in June‒July 2020.This unique long-lasting extreme event and its origin have attracted considerable attention.Previous studies have suggested that the Indian Ocean(IO)SST forcing and soil moisture anomaly over the Indochina Peninsula(ICP)were responsible for this unexpected event.However,the relative contributions of IO SST and ICP soil moisture to the 2020 mei-yu rainfall event,especially their linkage with atmospheric circulation changes,remain unclear.By using observations and numerical simulations,this study examines the synergistic impacts of IO SST and ICP soil moisture on the extreme mei-yu in 2020.Results show that the prolonged dry soil moisture led to a warmer surface over the ICP in May under strong IO SST backgrounds.The intensification of the warm condition further magnified the land thermal effects,which in turn facilitated the westward extension of the western North Pacific subtropical high(WNPSH)in June‒July.The intensified WNPSH amplified the water vapor convergence and ascending motion over the YRB,thereby contributing to the 2020 mei-yu.In contrast,the land thermal anomalies diminish during normal IO SST backgrounds due to the limited persistence of soil moisture.The roles of IO SST and ICP soil moisture are verified and quantified using the Community Earth System Model.Their synergistic impacts yield a notable 32%increase in YRB precipitation.Our findings provide evidence for the combined influences of IO SST forcing and ICP soil moisture variability on the occurrence of the 2020 super mei-yu.

Interdecadal change and projection of the relationship between spring Arctic Oscillation and summer precipitation in the Yangtze River valley in CMIP6 models

评估了20个CMIP6模式对春季北极涛动(AO)与长江流域夏季降水(YRP)关系的模拟能力.结果表明, 4个模式(ACCESS-ESM1-5, CMC-CM2-SR5, MRI-ESM2-0, NorESM2-LM))能合理模拟出1990年代后期AO-YRP关系的减弱. 1980-1998年,当春季AO位于正位相时,夏季东亚急流北移,长江流域为异常下沉运动,同时西太平洋副热带高压减弱,减少向长江流域的水汽输送,结果导致降水减少. 1999-2014年,上述大气环流与春季AO的联系不显著,从而减弱AO-YRP的关系.利用这四个模式进一步预估了RCP4.5情景下2015-2100年期间AO-YRP的关系.两者在2015-2040年为显著负相关关系,随后再次减弱.

Study on the interannual variability of the Kerama Gap transport and its relation to the Kuroshio/Ryukyu Current system

An analysis of a 68-year monthly hindcast output from an eddy-resolving ocean general circulation model reveals the relationship between the interannual variability of the Kerama Gap transport(KGT)and the Kuroshio/Ryukyu Current system.The study found a significant difference in the interannual variability of the upstream and downstream transports of the East China Sea-(ECS-)Kuroshio and the Ryukyu Current.The interannual variability of the KGT was found to be of paramount importance in causing the differences between the upstream and downstream ECS-Kuroshio.Additionally,it contributed approximately 37%to the variability of the Ryukyu Current.The interannual variability of the KGT was well described by a two-layer rotating hydraulic theory.It was dominated by its subsurface-intensified flow core,and the upper layer transport made a weaker negative contribution to the total KGT.The subsurface flow core was found to be mainly driven by the subsurface pressure head across the Kerama Gap,and the pressure head was further dominated by the subsurface density anomalies on the Pacific side.These density anomalies could be traced back to the eastern open ocean,and their propagation speed was estimated to be about 7.4 km/d,which is consistent with the speed of the local first-order baroclinic Rossby wave.When the negative(positive)density anomaly signal reached the southern region of the Kerama Gap,it triggered the increase(decrease)of the KGT towards the Pacific side and the formation of an anticyclonic(cyclonic)vortex by baroclinic adjustment.Meanwhile,there is an increase(decrease)in the upstream transport of the entire Kuroshio/Ryukyu Current system and an offshore flow that decreases(increases)the downstream Ryukyu Current.

Joint computation offloading and parallel scheduling to maximize delay-guarantee in cooperative MEC systems

The growing development of the Internet of Things(IoT)is accelerating the emergence and growth of new IoT services and applications,which will result in massive amounts of data being generated,transmitted and pro-cessed in wireless communication networks.Mobile Edge Computing(MEC)is a desired paradigm to timely process the data from IoT for value maximization.In MEC,a number of computing-capable devices are deployed at the network edge near data sources to support edge computing,such that the long network transmission delay in cloud computing paradigm could be avoided.Since an edge device might not always have sufficient resources to process the massive amount of data,computation offloading is significantly important considering the coop-eration among edge devices.However,the dynamic traffic characteristics and heterogeneous computing capa-bilities of edge devices challenge the offloading.In addition,different scheduling schemes might provide different computation delays to the offloaded tasks.Thus,offloading in mobile nodes and scheduling in the MEC server are coupled to determine service delay.This paper seeks to guarantee low delay for computation intensive applica-tions by jointly optimizing the offloading and scheduling in such an MEC system.We propose a Delay-Greedy Computation Offloading(DGCO)algorithm to make offloading decisions for new tasks in distributed computing-enabled mobile devices.A Reinforcement Learning-based Parallel Scheduling(RLPS)algorithm is further designed to schedule offloaded tasks in the multi-core MEC server.With an offloading delay broadcast mechanism,the DGCO and RLPS cooperate to achieve the goal of delay-guarantee-ratio maximization.Finally,the simulation results show that our proposal can bound the end-to-end delay of various tasks.Even under slightly heavy task load,the delay-guarantee-ratio given by DGCO-RLPS can still approximate 95%,while that given by benchmarked algorithms is reduced to intolerable value.The simulation results are demonstrated the effective-ness of DGCO-RLPS for delay guarantee in MEC.

Morphological and Sulfur-Isotopic Characteristics of Pyrites in the Deep Sediments from Xisha Trough,South China Sea

Pyrite is one of the common authigenic minerals in marine sediments.Previous studies have shown that the morphological and isotopic characteristics of pyrite are closely related to the geochemical environment where it is formed.To better understand the for-mation mechanism of authigenic pyrite,we analyzed the isotopic composition,morphology,and distribution of pyrite in the sediment at 500m below the seafloor from Xisha Trough,South China Sea.Mineral morphologies were observed by scanning electron micros-copy and Raman spectrography.X-Ray computed tomography was applied to measure the particle size of pyrite.The size of pyrite crystals in the matrix sediment mainly ranged between 25 and 65µm(av.ca.40µm),although crystals were larger(av.ca.50μm)in the veins.The pyrites had a fine-grained truncated octahedral shape with occasionally well-developed growth steps,which implies the low growth rate and weak anaerobic oxidation of methane-sulfate reduction when pyrite was formed.Theδ^(34)S values of pyrites ranged from+20.8‰Vienna-defined Canyon Diablo Troilite(V-CDT)to+33.2‰V-CDT and from+44.8‰V-CDT to+48.9‰,which suggest two growth stages.In the first stage,with the continuous low methane flux,the pyrite possibly formed in an environment with good access to seawater.In the second stage,the pyrites mainly developed in sediment fractures and appeared in veins,probably due to the limited availability of sulfate.The less exposure of pyrite to the environment in the second stage was probably caused by sediment accumulation or perturbation.In this study,an episodic pyritization process was identified,and the paleoenvironment was reconstructed for the sediment investigated.

Effects of Mg-doping temperature on the structural and electrical properties of nonpolar a-plane p-type GaN films

Nonpolar(11–20) a-plane p-type GaN films were successfully grown on r-plane sapphire substrate with the metal–organic chemical vapor deposition(MOCVD) system. The effects of Mg-doping temperature on the structural and electrical properties of nonpolar p-type GaN films were investigated in detail. It is found that all the surface morphology, crystalline quality, strains, and electrical properties of nonpolar a-plane p-type GaN films are interconnected, and are closely related to the Mg-doping temperature. This means that a proper performance of nonpolar p-type GaN can be expected by optimizing the Mg-doping temperature. In fact, a hole concentration of 1.3×10^(18)cm^(-3), a high Mg activation efficiency of 6.5%,an activation energy of 114 me V for Mg acceptor, and a low anisotropy of 8.3% in crystalline quality were achieved with a growth temperature of 990℃. This approach to optimizing the Mg-doping temperature of the nonpolar a-plane p-type GaN film provides an effective way to fabricate high-efficiency optoelectronic devices in the future.

Consistency of Tropospheric Water Vapor between Reanalyses and Himawari-8/AHI Measurements over East Asia

High spatiotemporal resolution radiances from the advanced imagers onboard the new generation of geostationary weather satellites provide a unique opportunity to evaluate the abilities of various reanalysis datasets to depict multilayer tropospheric water vapor(WV),thereby enhancing our understanding of the deficiencies of WV in reanalysis datasets.Based on daily measurements from the Advanced Himawari Imager(AHI)onboard the Himawari-8 satellite in 2016,the bias features of multilayer WV from six reanalysis datasets over East Asia are thoroughly evaluated.The assessments show that wet biases exist in the upper troposphere in all six reanalysis datasets;in particular,these biases are much larger in summer.Overall,we find better depictions of WV in the middle troposphere than in the upper troposphere.The accuracy of WV in the ERA5 dataset is the highest,in terms of the bias magnitude,dispersion,and pattern similarity.The characteristics of the WV bias over the Tibetan Plateau are significantly different from those over other parts of East Asia.In addition,the reanalysis datasets all capture the shift of the subtropical high very well,with ERA5 performing better overall.

Prediction of the Pore-Pressure Built-Up and Temperature of Fire-Loaded Concrete with Pix2Pix

Concrete subjected to fire loads is susceptible to explosive spalling, which can lead to the exposure of reinforcingsteel bars to the fire, substantially jeopardizing the structural safety and stability. The spalling of fire-loaded concreteis closely related to the evolution of pore pressure and temperature. Conventional analytical methods involve theresolution of complex, strongly coupled multifield equations, necessitating significant computational efforts. Torapidly and accurately obtain the distributions of pore-pressure and temperature, the Pix2Pix model is adoptedin this work, which is celebrated for its capabilities in image generation. The open-source dataset used hereinfeatures RGB images we generated using a sophisticated coupled model, while the grayscale images encapsulate the15 principal variables influencing spalling. After conducting a series of tests with different layers configurations,activation functions and loss functions, the Pix2Pix model suitable for assessing the spalling risk of fire-loadedconcrete has been meticulously designed and trained. The applicability and reliability of the Pix2Pix model inconcrete parameter prediction are verified by comparing its outcomes with those derived fromthe strong couplingTHC model. Notably, for the practical engineering applications, our findings indicate that utilizing monochromeimages as the initial target for analysis yields more dependable results. This work not only offers valuable insightsfor civil engineers specializing in concrete structures but also establishes a robust methodological approach forresearchers seeking to create similar predictive models.

Frontogenesis and Frontolysis of a Cold Filament Driven by the Cross-Filament Wind and Wave Fields Simulated by a Large Eddy Simulation

The variations of the frontogenetic trend of a cold filament induced by the cross-filament wind and wave fields are studied by a non-hydrostatic large eddy simulation. Five cases with different strengths of wind and wave fields are studied.The results show that the intense wind and wave fields further break the symmetries of submesoscale flow fields and suppress the levels of filament frontogenesis. The changes of secondary circulation directions—that is, the conversion between the convergence and divergence of the surface cross-filament currents with the downwelling and upwelling jets in the filament center—are associated with the inertial oscillation. The filament frontogenesis and frontolysis caused by the changes of secondary circulation directions may periodically sharpen and smooth the gradient of submesoscale flow fields.The lifecycle of the cold filament may include multiple stages of filament frontogenesis and frontolysis.

Characteristics and Preliminary Causes of Tropical Cyclone Remote Precipitation over China

In this study,the characteristics and preliminary causes of tropical cyclone remote precipitation(TRP)over China during the period from 1979 to 2020 are investigated.Results indicated that approximately 72.42%of tropical cyclones(TCs)in the Western Pacific produce TRP over China.The peak months for TRP are July and August.The four key regions of TRP are the adjacent areas between the Sichuan and Shaanxi Provinces,the northern coast of the Bohai Sea,the coast of the Yellow Sea,and the southern coast area.The typical distance between the station with TRP and the TC center ranges from 1500 to 2500 km.Most of these stations are situated north to 60°west of north of the TC.The south–west water vapor transportation on the west side of the TC is crucial to TRP.TRP has a decreasing trend because of the decrease in the number of TCs that generate TRP.From the perspective of large-scale environmental conditions,a decrease in the integrated horizontal water vapor transport in China' Mainland,the weakening of upward motion at approximately 25°–35°N,which is inconducive to convection,and an increase in low-level vertical wind shear,which is unfavorable for the development of TC in areas with high frequencies of TRP-related TCs,are the factors that result in the decreasing trend of TRP.

Comparison of Adaptive Simulation Observation Experiments of the Heavy Rainfall in South China and Sichuan Basin

This study examines the effectiveness of adaptive observation experiments using the ensemble transformation sensitivity(ETS) method to improve precipitation forecasts during heavy rainfall events in South China and the Sichuan Basin. High-resolution numerical models are employed to simulate adaptive observations. By identifying the sensitive areas of key weather system positions 42 hours before heavy rainfall events, the adaptive observations improve the prediction of jet streams, strong winds, and shear lines, which are essential for accurate heavy rainfall forecasting. This improvement is reflected in both the precipitation structure and location accuracy within the verification region. In South China, targeted observations enhance rainfall predictions by improving water vapor transport. In the Sichuan Basin, adaptive observations refine water vapor transport and adjust vortex dynamics. This research highlights the importance of accurately predicting shear lines and jet streams for forecasting heavy rainfall in these areas. Overall, this study found that adaptive observation enhances the precipitation forecast skills of the structure and location for heavy rainfall in South China and the Sichuan Basin, emphasizing their potential utility in operational numerical weather prediction.

Evaluation of CMIP6 model performance in simulating the PDO and its future change

本文基于40个CMIP6模式输出结果,系统评估了模式对历史时期太平洋年代际振荡(PDO)的模拟性能,并利用其中17个模式的4种共享社会经济路径情景数据预估了PDO未来可能变化趋势.结果表明,CMIP6模式能够合理再现PDO相关海表温度异常的空间模态,但模式模拟PDO位相演变的能力普遍较弱.多模式集合能够合理再现PDO的50年左右周期,但无法模拟出其20年左右周期,并且低估了PDO的变化幅度.在未来变暖情景下,PDO可能在2050左右出现由负位相向正位相的转变,同时其50年左右周期也将明显缩短.

Survey on digital twins for Internet of Vehicles:Fundamentals,challenges,and opportunities

As autonomous vehicles and the other supporting infrastructures(e.g.,smart cities and intelligent transportation systems)become more commonplace,the Internet of Vehicles(IoV)is getting increasingly prevalent.There have been attempts to utilize Digital Twins(DTs)to facilitate the design,evaluation,and deployment of IoV-based systems,for example by supporting high-fidelity modeling,real-time monitoring,and advanced predictive capabilities.However,the literature review undertaken in this paper suggests that integrating DTs into IoV-based system design and deployment remains an understudied topic.In addition,this paper explains how DTs can benefit IoV system designers and implementers,as well as describes several challenges and opportunities for future researchers.

Distribution and Formation Causes of PM_(2.5) and O_(3) Double High Pollution Events in China during 2013–20

Fine particulate matter(PM_(2.5))and ozone(O_(3))double high pollution(DHP)events have occurred frequently over China in recent years,but their causes are not completely clear.In this study,the spatiotemporal distribution of DHP events in China during 2013–20 is analyzed.The synoptic types affecting DHP events are identified with the Lamb–Jenkinson circulation classification method.The meteorological and chemical causes of DHP events controlled by the main synoptic types are further investigated.Results show that DHP events(1655 in total for China during 2013–20)mainly occur over the North China Plain,Yangtze River Delta,Pearl River Delta,Sichuan Basin,and Central China.The occurrence frequency increases by 5.1%during 2013–15,and then decreases by 56.1%during 2015–20.The main circulation types of DHP events are“cyclone”and“anticyclone”,accounting for over 40%of all DHP events over five main polluted regions in China,followed by southerly or easterly flat airflow types,like“southeast”,“southwest”,and“east”.Compared with non-DHP events,DHP events are characterized by static or weak wind,high temperature(20.9℃ versus 23.1℃)and low humidity(70.0%versus 64.9%).The diurnal cycles of meteorological conditions cause PM_(2.5)(0300–1200 LST,Local Standard Time=UTC+8 hours)and O_(3)(1500–2100 LST)to exceed the national standards at different periods of the DHP day.Three pollutant conversion indices further indicate the rapid secondary conversions during DHP events,and thus the concentrations of NO_(2),SO_(2) and volatile organic compounds decrease by 13.1%,4.7%and 4.4%,respectively.The results of this study can be informative for future decisions on the management of DHP events.

Analysis of Summer Cold Vortex Activity Anomalies in Northeastern China and Their Relationship with Regional Precipitation and Temperature

The Northeastern China cold vortex(NCCV)is one type of strong cyclonic vortex that occurs near Northeastern China(NEC),and NCCV activities are typically accompanied by a series of hazardous weather.This paper employed an automatic algorithm to identify the NCCVs from 1979 to 2018 and analyzed their circulation patterns and climatic impacts by using the defined NCCV intensity index(NCCVI).The analysis revealed that the NCCV activities in summer exhibited a strong inter-annual variability,with an obvious periodicity of 3-4 years and 6-7 years,but without significant trends.In years when the NCCVI was high,NEC experienced negative geopotential height anomalies,cyclonic circulation,and cooler temperature anomalies,which were conducive to the maintenance and development of NCCV activities.Furthermore,large amounts of water vapor converged in NEC through two transportation routes as the NCCVs intensified,leading to a significant positive(negative)correlation with the summer precipitation(surface temperature)in NEC.The Atlantic sea surface temperature(SST)anomalies were closely related to summer NCCV activities.As the Atlantic SST rose,large amounts of surface sensible and latent heat flux were transported into the lower troposphere,inducing a positive geopotential height anomaly that occurred on the east side of the heat source.As a result,an eastward diverging flow was formed in the upper troposphere and propagated downstream,i.e.,the eastward propagating Rossby wave train,which eventually led to a coupled circulation in the Ural Mountains and NEC,as well as more intensive NCCV activities in summer.