Regional Storm Surge Forecast Method Based on a Neural Network and the Coupled ADCIRC-SWAN Model

Timely and accurate forecasting of storm surges can effectively prevent typhoon storm surges from causing large economic losses and casualties in coastal areas.At present,numerical model forecasting consumes too many resources and takes too long to compute,while neural network forecasting lacks regional data to train regional forecasting models.In this study,we used the DUAL wind model to build typhoon wind fields,and constructed a typhoon database of 75 processes in the northern South China Sea using the coupled Advanced Circulation-Simulating Waves Nearshore(ADCIRC-SWAN)model.Then,a neural network with a Res-U-Net structure was trained using the typhoon database to forecast the typhoon processes in the validation dataset,and an excellent storm surge forecasting effect was achieved in the Pearl River Estuary region.The storm surge forecasting effect of stronger typhoons was improved by adding a branch structure and transfer learning.

Future Changes in Various Cold Surges over China in CMIP6 Projections

Cold surges(CSs)often occur in the mid-latitude regions of the Northern Hemisphere and have enormous effects on socioeconomic development.We report that the occurrences of CSs and persistent CSs(PCSs)have rebounded since the 1990s,but the trends related to the frequencies of strong CSs(SCSs)and extreme CSs(ECSs)changed from increasing to decreasing after 2000.The highest-ranked model ensemble approach was used to project the occurrences of various CSs under the SSP1-2.6,SSP2-4.5,and SSP5-8.5 scenarios.The frequencies of the total CSs show overall decreasing trends.However,under the SSP1-2.6 scenario,slight increasing trends are noted for SCSs and ECSs in China.Atmospheric circulations that are characterized by an anomalous anticyclonic circulation with a significantly positive 500-hPa geopotential height(Z500)anomaly at high latitudes along with significant negative anomalies in China were favorable for cold air intrusions into China.In addition,the frequencies of all CS types under the SPP5-8.5 scenario greatly decreased in the long term(2071-2100),a finding which is thought to be related to negative SST anomalies in the central and western North Pacific,differences in sea level pressure(SLP)between high-and mid-latitude regions,and a weaker East Asian trough.In terms of ECSs,the decreasing trends observed during the historical period were maintained until 2024 under the SSP1-2.6 scenario.Compared to the SSP1-2.6 scenario,the Z500 pattern showed a trend of strengthened ridges over the Ural region and northern East Asia and weakened troughs over Siberia(60°-90°E)under the SSP2-4.5 and SSP5-8.5 scenarios,contributing to the shift to increasing trends of ECSs after 2014.

Trend of Storm Surge Induced by Typical Landfall Super Typhoons During 1975–2021 in the Eastern China Sea

Climate change affects the activity of global and regional tropical cyclones(TCs).Among all TCs,typical super typhoons(STYs)are particularly devastating because they maintain their intensity when landing on the coast and thus cause casualties,economic losses,and environmental damage.Using a 3D tidal model,we reconstructed the typhoon(TY)wind field to simulate the storm surge induced by typical STYs.The TY activity was then analyzed using historical data.Results showed a downtrend of varying degrees in the annual frequency of STYs and TCs in the Western North Pacific(WNP)Basin,with a significant trend change observed for TCs from 1949 to 2021.A large difference in the interannual change in frequency was found between STYs and TCs in the WNP and Eastern China Sea(ECS).Along the coast of EC,the frequency of landfall TCs showed a weak downtrend,and the typical STYs showed reverse micro growth with peak activity in August.Zhejiang,Fujian,and Taiwan were highly vulnerable to the frontal hits of typical STYs.Affected by climate change,the average lifetime maximum intensity(LMI)locations and landfall locations of typical STYs in the ECS basin showed a significant poleward migration trend.In addition,the annual average LMI and accumulated cyclone energy showed an uptrend,indicating the increasing severity of the disaster risk.Affected by the typical STY activity in the ECS,the maximum storm surge area also showed poleward migration,and the coast of North China faced potential growth in high storm surge risks.

Exploration of standard dosage for GnRH antagonist protocol and dosage adjustments after premature luteinizing hormone surge

The gonadotropin-releasing hormone (GnRH) antagonist protocol has emerged as an efficacious alternative to the GnRH agonist protocol for controlled ovarian hyperstimulation (COH) during in vitro fertilization (IVF) cycles, and has been demonstrated applicability in infertile female patients with diverse ovarian responses. While the clinical implementation of the antagonist COH protocol has achieved widespread consensus, opportunities for refinement persist. Therefore, this review article focuses on the advantages and disadvantages of GnRH antagonist protocol, the selection of optimal standard doses, and the strategies for adjusting antagonist doses after the premature luteinizing hormone (LH) surge, aiming to provide more reasonable and scientific recommendations for the application of this scheme.

A typhoon-induced storm surge numerical model with GPU acceleration based on an unstructured spherical centroidal Voronoi tessellation grid

Storm surge is often the marine disaster that poses the greatest threat to life and property in coastal areas.Accurate and timely issuance of storm surge warnings to take appropriate countermeasures is an important means to reduce storm surge-related losses.Storm surge numerical models are important for storm surge forecasting.To further improve the performance of the storm surge forecast models,we developed a numerical storm surge forecast model based on an unstructured spherical centroidal Voronoi tessellation(SCVT)grid.The model is based on shallow water equations in vector-invariant form,and is discretized by Arakawa C grid.The SCVT grid can not only better describe the coastline information but also avoid rigid transitions,and it has a better global consistency by generating high-resolution grids in the key areas through transition refinement.In addition,the simulation speed of the model is accelerated by using the openACC-based GPU acceleration technology to meet the timeliness requirements of operational ensemble forecast.It only takes 37 s to simulate a day in the coastal waters of China.The newly developed storm surge model was applied to simulate typhoon-induced storm surges in the coastal waters of China.The hindcast experiments on the selected representative typhoon-induced storm surge processes indicate that the model can reasonably simulate the distribution characteristics of storm surges.The simulated maximum storm surges and their occurrence times are consistent with the observed data at the representative tide gauge stations,and the mean absolute errors are 3.5 cm and 0.6 h respectively,showing high accuracy and application prospects.

Metaverse Upsurge Drives Virtual Human Industry to Upgrade

The concept of a virtual human is rapidly fermenting with the boom of the metaverse in 2020.In March 2021,Roblox,a game company focusing on the socialization of teenagers’games and the free realization of UGC,went public.In its prospectus,Roblox is defined as the concept of the metaverse.Under this background,as the direct embodiment of“virtual identity”and“virtual reality coexisting”under the concept of the metaverse,the emerging definition of virtual human and its representative virtual image has gradually caught the attention of the public.

Risk assessment of coastal flooding disaster by storm surge based on Elevation-Area method and hydrodynamic models:Taking Bohai Bay as an example

The future inundation by storm surge on coastal areas are currently ill-defined.With increasing global sealevel due to climate change,the coastal flooding by storm surge is more and more frequently,especially in coastal lowland with land subsidence.Therefore,the risk assessment of such inundation for these areas is of great significance for the sustainable socio-economic development.In this paper,the authors use Elevation-Area method and Regional Ocean Model System(ROMS)model to assess the risk of the inundation of Bohai Bay by storm surge.The simulation results of Elevation-Area method show that either a 50-year or 100-year storm surge can inundate coastal areas exceeding 8000 km^(2);the numerical simulation results based on hydrodynamics,considering ground friction and duration of the storm surge high water,show that a 50-year or 100-year storm surge can only inundate an area of over 2000 km^(2),which is far less than 8000 km^(2);while,when taking into account the land subsidence and sea level rise,the very inundation range will rapidly increase by 2050 and 2100.The storm surge will greatly impact the coastal area within about 10-30 km of the Bohai Bay,in where almost all major coastal projects are located.The prompt response to flood disaster due to storm surge is urgently needed,for which five suggestions have been proposed based on the geological background of Bohai Bay.This study may offer insight into the development of the response and adaptive plans for flooding disasters caused by storm surge.

A Boost to Inbound Tourism China sees surge in foreign travellers following introduction of visa-free transit measures

One of the viral terms on Chinese social media these days-“city bu city”–was actually created by a foreign tourist.The tourist,a blogger,used the term,which literally means city or not city,in a short video he filmed while visiting the Great Wall,wondering whether the place is like a fashionable big city.

电源端口雷击和暂态过电压综合防护方案

介绍了电子通讯产品在易发生供电故障和易受雷击的供电环境下,电源端口雷击和暂态过电压的综合防护解决方案。该解决方案将雷击防护与暂态过电压防护有机结合,智能检测判断过电压是雷击还是暂态过电压,并及时启动防护功能,防止电源损坏等严重故障。该方案还可实现防护后自动恢复供电和远程控制供电,在复杂供电环境中保障供电安全和设备不被损坏,有很大的推广价值。

Research on Current Situation,Symptoms and Protection Technological Measures of Ancient Trees in Surging Waves Pavilion,China

The paper had studied growth situation and disease symptoms of ancient trees in Surging Waves Pavilion.There were 14 ancient trees belonging to 10 genera of 9 families,with tree age of 120-260 years.These trees had been well protected generally.There were 9 ancient trees growing well,occupying 64.29%,which were Ginkgo biloba,Cupressus funebris Endl.,Podocarpus macrophyllus,Zelkova schneideriana Hand.-Mazz,Cinnamomum camphora(L.)Presl,Buxus sinica,and Wisteria sinensis(Sims)Sweet.There were 5 ancient trees needing to be protected preferentially,occupying 35.71%,including Ligustrum lucidum,Osmanthus fragrans and Pterocarya stenoptera.The disease symptoms were trunk rot and hollow structure.Based on these symptoms,the paper had proposed protective measures for Ligustrum lucidum and Osmanthus fragrans:① enclosing eroding holes on the trunk;② clearing up eroded woodiness on the surface of trunk,disinfecting and applying anti-corrosion protectants;③ filling eroded holes of the trunk.Protective measures for Pterocarya stenoptera included:① clearing up the inner part and interior walls;② disinfecting the inside and interior walls of holes;③ applying anti-corrosion protectants.

Numerical Simulation of the Influence of Mean Sea Level Rise on Typhoon Storm Surge in the East China Sea

In this paper, ECOMSED （Estuarine Coastal Ocean Model with sediment transport） model is employed to simulate storm surge process caused by typhoon passing across East China Sea in nearly years. Capability of ECOMSED to simulate storm surge is validated by comparing model result with observed data. Sensitivity experiments are designed to study the influence of sea level rise on typhoon storm surge. Numerical experiment shows that influence of mean sea level rise on typhoon storm surge is non-uniform spatially and changes as typhoon process differs. Maybe fixed boundary method would weaken the influence of mean sea level rise on storm surge, and free boundary method is suggested for the succeeding study.

Numerical simulation of typhoon- induced storm surge on the coast of Jiangsu Province,China,based on coupled hydrodynamic and wave models

In order to facilitate engineering design and coastal flooding protection, the potential storm surge induced by a typhoon is studied.Using an unstructured mesh, a coupled model which combines the advanced circulation （ ADCIRC ） hydrodynamic model and simulating waves nearshore （ SWAN ） model is applied to analyze the storm surge and waves on the coast of Jiangsu Province.The verifications of wind velocity, tidal levels and wave height show that this coupling model performs well to reflect the characteristics of the water levels and waves in the studied region.Results show that the effect of radiation stress on storm surge is significant, especially in shallow areas such as the coast of Jiangsu Province and the Yangtze estuary.By running the coupled model, the simulated potential flooding results can be employed in coastal engineering applications in the Jiangsu coastal area, such as storm surge warnings and extreme water level predictions.

基于物理模型试验的库岸散粒体滑坡涌浪特性

滑坡涌浪灾害具有历时短、地形条件复杂、规模大的特点,是国内外研究的重要地质和工程问题之一。本文以库岸滑坡失稳入水涌浪过程为研究对象,考虑水上滑坡与淹没滑坡两种情景,设计并开展散粒体滑坡涌浪3维物理模型试验,量测滑坡入水运动堆积过程及涌浪产生、传播过程特征,并进一步分析沿滑坡运动方向传播的离岸波与沿河道上下游传播的侧向波波幅、传播规律特性等。结果表明:当滑坡从淹没工况到水上工况时,涌浪波幅最大值特征逐渐从波峰小于波谷转向波峰大于波谷;沿滑坡运动方向产生的涌浪波幅大于沿库岸传播的涌浪波幅,侧向波传播过程中波幅高度衰减程度小于离岸波;进一步分析发现,涌浪沿河道上下游传播时,侧向波最大浪高为其首浪高度的2.5倍;散粒体滑坡涌浪最大高度与散粒体质量成正相关,与散粒体初始淹没率成负相关;受滑坡体入水时相对厚度的影响,涌浪最大高度与入水高差成负相关;在此基础上,利用无量纲分析方法与多元非线性回归方法,推导出散粒体滑坡涌浪最大高度经验公式,并采用提出的经验公式对三峡库区巫山红岩子滑坡与加拿大切哈利斯湖滑坡涌浪案例最大浪高进行计算分析,验证该公式具有较好的适用性和准确性。

铁水包脱硫吹气赶渣工艺多相流数值模拟研究

近年来吹气加机械扒渣的涌动式扒渣工艺在生产中以除渣效率高、铁损少、成本低等优点得到应用。但对于该工艺的研究大都停留在基于实验室的简单研究和企业的经验积累,缺少理论上的支撑。以125 t铁水包为研究对象,采用数值模拟的方法对扒渣过程进行了研究,建立了铁水-渣-空气流动的三维数学模型,探究了喷枪吹气流量、插入深度、插入位置、渣层厚度等工艺参数对无渣层区域面积、长度、宽度和液面波动高度的影响,结果表明:喷枪吹气流量为300 m^(3)/h左右时,能达到较好的驱渣效果;喷枪插入深度在800~1000 mm时满足涌而不喷溅的条件,此时最有利于扒渣;喷枪插入位置为0.4P左右时,驱渣效果最好,最有利于扒渣。经过修正换算后,确定工业生产中最佳的喷吹气体流量约为100 m^(3)/h,最佳的喷枪插入深度范围为800~1000 mm,喷枪插入位置在距离后包壁600~700 mm处时能达到最佳的驱渣效果,提高扒渣效率,为铁水扒渣的实际工业生产提供理论依据,保证钢铁公司低硫钢的稳定生产。

浮式风力机纵荡过程气动稳定性分析

气动稳定性对于浮式风力机的运行安全具有重要影响,该文采用升力线自由尾迹模型,通过气动功对浮式风力机纵荡过程中翼型及风轮的气动稳定性进行分析。结果表明,浮台的纵荡运动会造成翼型及风轮所受气动力的周期性波动,由此导致的气动阻尼会对风力机的气动稳定性产生影响。此外,来流风速也会对风力机的气动阻尼产生影响,当风速较大时叶片中段的翼型会进入深度失速状态,使翼型在一个纵荡周期内的气动功为负。在较宽的纵荡工况和来流风速范围内风轮均受到正气动阻尼作用,但随着纵荡频率和幅值的增加,风轮的气动阻比尼降低;当纵荡工况较为剧烈时,风力机会进入螺旋桨状态,其所受推力的方向会发生改变,增加风轮的气动功;此外在开启控制后,系统的变转速及变桨控制会改变叶片及风轮载荷的绝对值及波动幅值,从而影响风力机的气动功。

Statistical and causes analysis of storm surges along Tianjin coast during the past 20 years

Based on tidal data statistical analysis for 20 years of Tanggu Marine Environmental Monitoring Station from 1991 to 2010, we concluded that an average of nearly 10 days of 100 cm above water increase took place at Tianjin coast every year. The maximum high tide and average tide of Tianjin coast occurred in summer and autumn, and the maximum water increase also occurred in summer and autumn. Days with water increase more than 100 cm mostly occurred in spring, autumn and winter. Then we summarized the causes of coastal storm surge disaster in Tianjin based on astronomical tide factors, meteorological factors, sea level rise, land subsidence, and geographic factors, et al. Finally, we proposed storm surge disaster prevention measures.

新兴经济体跨境资本流入激增与企业金融化

本文基于2000-2021年23个新兴经济体非金融企业的数据,考察跨境资本流入激增对企业金融化的影响。研究结果表明,新兴经济体跨境资本流入的激增提高了企业金融化水平,且股权、债权资本流入激增均有此作用。机制分析表明,资本流入激增通过资产价格、信贷以及风险承担渠道产生影响。异质性分析表明,在金融市场发展程度高、经济政策不确定性小、外汇市场压力小的国家,该提升作用更为明显。

促进绿色经济的城市绿色基础设施生态系统服务——欧盟GREEN SURGE研究项目解析

从整体到分项,对基于欧盟城市可持续与绿色发展的GREEN SURGE项目进行深入分析与总结。GREEN SURGE是第7个欧盟研究与技术发展框架计划中的一个研究项目。研究从整体、理念到实践的创新对GREEN SURGE项目进行了解读。其目的主要是促进绿色基础设施和城市生物多样性对城市可持续发展和绿色经济建设的积极作用。理念上,创新性地提出城市生物文化多样性的概念,并对城市绿色基础设施生态系统服务进行评估,对绿色经济提出新的认识与理解;实践上,通过对欧洲城市地区的研究调查,凝练出5大绿色基础设施战略规划方法以及6大绿色基础设施创新治理安排。这些经验对于我国绿色空间研究、规划及治理均具有较为重要的启示作用。

Aerodynamic instability evolution of a multi-stage combined compressor

Unstable operating conditions such as surge could cause damage to both aerodynamic performance and structural integrity of a compression system.This paper addresses the critical issue of aerodynamic instability in compressor design,particularly focusing on an axial-centrifugal combined compressor,a widely used yet underexplored configuration.An experimental investigation was conducted on a three-stage axial and one-stage centrifugal compressor(3A1C),using two pipe systems and employing fast-responding transducers to capture the dynamic instability process from choke condition to deep surge.Results reveal that at the design speed,3A1C enters deep surge directly,whereas at off-design speeds,it experiences rotating stall and mild surge across a wide mass flow range.Some special instability features in the combined compressor can be found in the steady state map and dynamic process.The characteristic curve of the first axial stage keeps a positive slope during the whole mass flow range at an off-design speed.The first stage could work stably on the stall characteristic curve because the centrifugal stage has stronger pressurization and plays a dominant role in global aerodynamic instability.Besides,rotating instability occurs at the first rotor tip and disappears as the back pressure increases,which is also rarely seen in a single-axial compressor.This is also related to the strong pressurization of the centrifugal stage.The findings of this paper will contribute to the understanding of aerodynamic instabilities in combined compressors.

煤层定向钻孔技术在煤矿瓦斯突出控制和温室气体减排中的应用

随着煤矿开采深度的不断增加,瓦斯突出灾害日益严重,严重影响了煤矿的生产安全。结合台头煤业煤层地质条件和煤层定向钻孔技术,开展了长壁工作面和巷道定向钻孔工作,实施后钻孔瓦斯抽放率均大于70%,残余瓦斯含量均小于8 m^(3)/t,实现了瓦斯突出的有效控制,提高了煤矿的安全生产水平和经济效益。