Mean Flow–Storm Track Relationship and Rossby Wave Breaking in Two Types of El-Nino

The features of large-scale circulation, storm tracks and the dynamical relationship between them were examined by investigating Rossby wave breaking （RWB） processes associated with Eastern Pacific （EP） and Central Pacific （CP） E1-Nifio. During EP E1-Nino, the geopotential height anomaly at 500 hPa （Z500） exhibits a Pacific-North America （PNA） pattern. During CP EI-Nifio, the Z500 anomaly shows a north positive-south negative pattern over the North Pacific. The anomalous distributions of baroclinicity and storm track are consistent with those of upper-level zonal wind for both EP and CP EI-Nino, suggesting impacts of mean flow on storm track variability. Anticyclonic wave breaking （AWB） oczurs less frequently in EP EI-Nino years, while cyclonic wave breaking （CWB） occurs more frequently in CP EI-Nino years over the North Pacific sector. Outside the North Pacific, more CWB events occur over North America during EP Ei-NiNo. When AWB events occur less frequently over the North Pacific during EP EI-Nino, Z500 decreases locally and the zonal wind is strengthened （weakened） to the south （north）. This is because AWB events reflect a monopoie high anomaly at the centroid of breaking events. When CWB events occur more frequently over the North Pacific under CP EI-Nino conditions, and over North America under EP EI-Nino condition, Z500 increases （decreases） to the northeast （southwest）, since CWB events are related to a northeast-southwest dipole Z500 anomaly. The anomalous RWB events act to invigorate and reinforce the circulation anomalies over the North Pacific-North America region linked with the two types of EI-Nino.

Numerical Study of Storm Surge Inundation in the Southwestern Hangzhou Bay Region During Typhoon Chan-Hom in 2015

Storm surge inundation is a major concern in marine hazard risk assessment during extreme weather conditions.In this study,a high-resolution coupled model(the ADVanced CIRCulation model+the Simulating WAves Nearshore model)was used to investigate the storm surge inundation in the southwestern Hangzhou Bay region during Typhoon Chan-hom in 2015.The simulated hydrodynamic processes(sea surface wave and storm tide)were validated with measured data from wave buoys and tide gauges,indicating that the overall performance of the model was satisfactory.The storm surge inundation in the coastal area was simulated for several idealized control experiments,including different wave effects(wave-enhanced wind stress,wave-enhanced bottom stress,and wave radiation stress).Dike overflowing cases with different dike heights and dike breaking cases with different dike breach lengths were considered in the simulation.The results highlight the necessity of incorporating wave effects in the accurate simulation of storm surge inundation.Dike height significantly influences the magnitude and phase of the maximum inundation area in the dike overflowing cases,and dike breach length is an important factor impacting the magnitude of the maximum inundation area in the dike breaking cases.This study may serve as a useful reference for accurate coastal inundation simulation and risk assessment.

Morphodynamics of sandy beaches under the influence of storm sequences:Current research status and future needs

This paper reviews and discusses the current research status, trends, and future needs in the field of beach morphodynamics under the influence of storm sequences.The paper reviews how the three main research methods, field investigations, numerical modelling, and physical modelling, have been used to study beach morphodynamics during storm sequences.Available quantitative definitions of storm sequences at different sites are presented and discussed.It is shown that the definition of storm sequences is site-specific and requires knowledge of the storm climate, beach characteristics, and the temporal scale of beach recovery.Subsequently, the paper brings together currently available approaches aimed at describing the effect of storm sequences on beach erosion in a general way.The importance of storm chronology and the effects of an extreme storm within a sequence of storms are highlighted.Following that, the more poorly studied aspect of beach recovery in between storms within a sequence is discussed.Three indicators for defining beach recovery, namely the shoreline location, sediment volumes, and the beach state, are identified and compared.Finally, important research needs, including the need for detailed physical modelling, are identified.

A Storm Surge Intensity Classification Based on Extreme Water Level and Concomitant Wave Height

Storm surge is one of the predominant natural threats to coastal communities. Qingdao is located on the southern coast of the Shandong Peninsula in China. The storm surge disaster in Qingdao depends on various influencing factors such as the intensity, duration, and route of the passing typhoon, and thus a comprehensive understanding of natural coastal hazards is essential. In order to make up the defects of merely using the warning water level, this paper presents two statistical distribution models(Poisson Bi- variable Gumbel Logistic Distribution and Poisson Bi-variable Log-normal Distribution) to classify the intensity of storm surge. We emphasize the joint return period of typhoon-induced water levels and wave heights measured in the coastal area of Qingdao since 1949. The present study establishes a new criterion to classify the intensity grade of catastrophic storms using the typhoon surge estimated by the two models. A case study demonstrates that the new criterion is well defined in terms of probability concept, is easy to implement, and fits well the calculation of storm surge intensity. The procedures with the proposed statistical models would be useful for the disaster mitigation in other coastal areas influenced by typhoons.

A Transient but Protracted Geomagnetic Anomaly in the Sudbury Basin Following Two Near-Contiguous Intense Geomagnetic Storms

During the maintained quiescence between solar cycle 23 and 24, two unusually intense (K-indices = 7) global geomagnetic disturbances separated by 6 days occurred. They were followed by a protracted increase of between 150 and 200 nT in the vertical component of our local magnetic field (Sudbury, Ontario). The duration of the variation anomaly was unusually long, about 3 weeks, before returning to baseline following a one week period of below average intensity characterized by approximately 50 min periodicities. We suggest this anomaly supports previous research that specific temporal patterns of increased global geomagnetic activity when matched with local impedance/reluctance of ore bodies created the condition for remarkable transient changes in the surface static intensity of magnetic fields.

Doubly Periodic Propagating Wave for (2+1)-Dimensional Breaking Soliton Equation

Using the variable separation approach, we obtain a general exact solution with arbitrary variable separation functions for the （2＋1）-dimensional breaking soliton system. By introducing Jacobi elliptic functions in the seed solution, two families of doubly periodic propagating wave patterns are derived. We investigate these periodic wave solutions with different modulus m selections, many important and interesting properties are revealed. The interaction of Jabcobi elliptic function waves are graphically considered and found to be nonelastic.

THE GENERAL EFFECTS AND MODEL ANALYSIS OF MAJOR MAGNETIC STORM IN MARCH,1989

This paper has analysed the general solar-Terrestrial effect of major event in March, 1989 from 7 parameters using same time scale.The largest magnetic storm from AA index is compared on 8 stations of Changchun (43 ° 49 ′ 38 ″ N), Beijing (40 ° 02′ 22 ″ N), Wuhan(30 ° 31 ′ 39 ″ N) and Guangzhou (23 ° 05′ 34 ″ N) in China and Newport of Washington (48. 263 ° N), Boulder of Colorado (40. 138 ° N), Fredericksburg of VA (38. 205 ° N) and Norda of Mississippi in U. S. A.The ARMA (p, q) Autoregressive slide average model is used to simulate the geomagnetic storm data in 4 stations of China. The periodicity analysis, characteristic root and equation are used. The different models and characters are shown and explained.

Key indicators affecting maize stalk lodging resistance of different growth periods under different sowing dates

The accurate evaluation of maize stalk lodging resistance in different growth periods enables timely management of lodging risks and ensures stable and high maize yields.Here,we established five diferent sowing dates to create diferent conditions for maize growth.We evaluated the effects of the different growth conditions on lodging resistance by determining stalk morphology,moisture content,mechanical strength and dry matter,and the relationship between stalk breaking force and these indicators during the silking stage(R1),milk stage(R3),physiological maturity stage(R6),and 20 days after R6.Plant height at R1 positively affected stalk breaking force.At R3,the cofficient of ear height and the dry weight per unit length of basal internodes were key indicators of stalk lodging resistance.At R6,the key indicators were the coefficient of the center of gravity height and plant fresh weight.After R6,the key indicator was the coefficient of the center of gravity height.The crushing strength of the fourth internode correlated significanty and positively with the stalk breaking force from R1 to R6,which indicates that crushing strength is a reliable indicator of stalk mechanical strength.These results suggest that high stalk strength and low ear height beneft lodging resistance prior to R6.During and after R6,the cofficient of the center of gravity height and the mechanical strength of basal internodes can be used to evaluate plant lodging resistance and the appropriate time for harvesting in fields with a high lodging risk.

Application of Linear Mean-Square Estimation in Ocean Engineering

The attempt to obtain long-term observed data around some sea areas we concern is usually very hard or even impossible in practical offshore and ocean engineering situations. In this paper, by means of linear mean-square estimation method, a new way to extend short-term data to long-term ones is developed. The long-term data about concerning sea areas can be constructed via a series of long-term data obtained from neighbor oceanographic stations, through relevance analysis of different data series. It is effective to cover the insufficiency of time series prediction method＇s overdependence upon the length of data series, as well as the limitation of variable numbers adopted in multiple linear regression model. The storm surge data collected from three oceanographic stations located in Shandong Peninsula are taken as examples to analyze the number-selection effect of reference oceanographic stations（adjacent to the concerning sea area） and the correlation coefficients between sea sites which are selected for reference and for engineering projects construction respectively. By comparing the N-year return-period values which are calculated from observed raw data and processed data which are extended from finite data series by means of the linear mean-square estimation method, one can draw a conclusion that this method can give considerably good estimation in practical ocean engineering, in spite of different extreme value distributions about raw and processed data.

极端气象水文条件下滨海地区小流域溃坝洪水模拟及风险评估

极端气象水文条件下的小流域水库溃坝,往往造成更为严重的洪水风险。为分析滨海小流域溃坝洪水风险,以粤港澳大湾区滨海小流域为例,基于二维溃坝洪水演进模型和洪水风险分级方法,探究小流域洪水淹没过程和风险分区,及极端降水和风暴潮影响下的变化响应。结果表明,溃坝洪水快涨慢退,主要敏感点约在17.5~22.0min之间达到最大淹没水深,退水时间约为6h,淹没范围占48.9%,以中、高风险区为主。极端降水和风暴潮对洪水涨退水规律影响较小,但对主要敏感点的最大流速和最大淹没水深影响较大。百年一遇极端降水叠加风暴潮,主要敏感点的最大流速、最大淹没水深分别增加了23.8%~39.9%、10.7%~31.4%,其中风暴潮贡献分别为8.3%~14.9%、4.7%~14.4%。极端降水使得洪水淹没范围扩大且风险等级上升,而风暴潮对风险区范围和等级影响较小,仅使临近海岸局部地区的风险等级有所上升。研究结果可为滨海地区中小型水库洪水溃坝风险管理提供参考。

渤、黄海天文潮—风暴潮相互作用及其对极值水位的贡献

基于Delft3D模型建立了中国渤、黄海风暴潮数值模型,选取1979—2020年影响该海域的93场风暴过程(包括台风、寒潮和温带气旋),模拟了所产生的风暴增水和风暴潮总水位。采用泊松—皮尔逊复合极值分布理论,推算了渤、黄海对应不同重现期的极值水位;通过数值试验,对天文潮—风暴潮非线性相互作用对极值水位的贡献进行了量化分析。研究结果表明,渤海的莱州湾、渤海湾,以及黄海的江华湾、西朝鲜湾风暴增水最大,其中江华湾北侧和渤海湾西南侧的百年一遇风暴增水可达4 m;天文潮—风暴潮非线性相互作用在潮差较大、水深较浅的河口、湾顶区域更为显著,与耦合模型结果相比,非线性作用使极值水位值偏小,天文潮、风暴潮增水的线性叠加可显著高估极值水位,高估的幅值可达0.5~0.8 m。考虑重现期极值水位是海岸灾害防护工程的关键设计参数之一,对海岸构筑物的安全和建造成本影响极大,应重视天文潮—风暴潮非线性相互作用对重现期水位的影响。

不同破断距下开采覆岩裂隙网络分形特征研究

为研究神东矿区不同破断距下开采覆岩裂隙网络分形特征,分析了基本顶周期破断距影响因素,选取大柳塔煤矿52505和上湾煤矿12401工作面进行物理相似模拟实验,探究了不同破断距影响下覆岩裂隙网络分布特征,借助Matlab软件获取不同覆岩裂隙网络分布分形维数,定量描述了覆岩裂隙发育特征,进一步探讨了覆岩裂隙传播影响下不同岩层沉降规律。研究结果表明:影响基本顶周期破断距主要因素包括基本顶厚度、抗拉强度以及承载载荷;大柳塔52505工作面、上湾12401工作面模拟开采平均破断距分别为20和30.4 m;不同破断距下覆岩裂隙网络的分形维数随煤层工作面推进呈现阶梯形增长态势,分形维数可较好地表征覆岩裂隙分布。两工作面最高离层裂隙发育高度与分形维数变化趋势均近似呈非线性正相关;不同破断距对覆岩整体裂隙发育扩展趋势影响显著,工作面回采前期大柳塔52505工作面分形维数相对较低,回采中后期则相反,破断距小,覆岩整体裂隙发育程度相对较高;两工作面覆岩沉降曲线呈“凸”型,近似以采空区中部对称。

A STUDY ON THE ONSET AND ITS ACTIVE AND BREAK PERIODS OF SUMMER MONSOON OVER THE SOUTH CHINA SEA

Based on ECMWF reanalysis data of 1979-1993 and TBB data of GMS,an analysis on the onset and its activities of the summer monsoon over the South China Sea (SCS) is made.It is found that the mean onset date is around 16 May,the latest onset is at beginning of June.There is a marked interannual variation of the onset date.There occurs marked southwesterly wind over the SCS in the last dekad of April in some years,but it only persists for a short period,and then,the easterly flow appears again.In the beginning of June,the true onset occurs.From the end of April to the middle of May prior to the onset,strong southwesterly wind appears to the north of 15°N over the SCS,which could not be treated as the onset of the SCS summer monsoon.These strong westerlies are due to the southward propagation of cold front or the strengthening of the subtropical high in the SCS.After the onset,there are active and break periods of the southwesterly summer monsoon,the average break period is about 15 days in one year (from onset of summer monsoon to 20 August).

Evolution characteristics and quantization of wave period variation for breaking waves

The wave parameters(the wave height and period)are important environmental factors in the ocean engineering design.General numerical wave models,such as SWAN and WAVEWATCH,are widely employed to simulate the wave conditions.However,significant differences were observed between the measurement and the simulation for both the wave height and period,which asks for wave model improvements.The differences are mainly due to the uncertainty of parameterizing various physical processes,including the wave breaking.The energy transfer and loss during the wave breaking involves an important physical mechanism,and the energy dissipation and the period changes are not well studied.This paper studies the deep and shallow water wave breaking using the wave focusing and the slope platform random wave experiments.The characteristics of the wave periods under different conditions are studied in detail,including the period variation.The results show that the periods change during the wave propagation and breaking processes.The energy transfer caused by the strongly nonlinear interaction between the wave components,as well as the energy loss caused by the wave breaking,are the primary causes.The corresponding relationships are established by fitting the data.For the deep water breaking waves induced by the wave focusing,the spectrally averaged period(SAP)increases,and a positive correlation between the rate of change and the wave steepness is found.In the shallow water,the nonlinear interactions are stronger than in the deep water,the wave periods are significantly reduced,and a negative correlation between the rate of change and a nonlinear parameter is found.The inherent mechanism of the period variation is analyzed based on the energy spectrum distribution variations.The contributions of the nonlinear interactions and the wave breaking to the SAP evolution are discussed.

基于海绵城市理念的市政道路排水设计方案

为提升城市整体排水能力,防止城市内涝问题的发生,文中以某市政道路工程为例,结合海绵城市理念,提出了市政道路排水设计方案,同时对路面雨水径流量峰值、暴雨重现期影响进行了分析。结果表明,海绵城市道路路面径流量变化和未开发前情况大体接近,该设计方案可较好地控制路面雨水径流。

宋辽金墓葬中顶心悬镜现象再探

宋辽金时期,墓室顶心多悬挂铜镜。本文以这一时期发现的28例悬镜为研究基础,将墓顶悬镜、与铜镜组合的墓顶意象、墓室内的结构和装饰视为统一的整体进行考察,认为悬镜的表现形式可分为三类;并且结合《营造法式》,探讨了“悬镜”语汇在屋宇、佛塔地宫建筑空间中的共享;而其表现意涵,是“取光明破暗”和“驱邪压胜”之意。

坚硬顶板周期来压覆岩破断力学机理研究

坚硬顶板破断运移规律一直是采矿领域研究的热点,针对覆岩内部破断裂隙分布不明晰的问题,以砌体梁理论中的关键块体为研究对象,建立了线性增压荷载下悬臂梁模型,根据弹性力学应力逆解法,在艾里应力函数满足双调和方程的基础上,采用叠加原理推导并验证了满足模型应力边界条件的内应力分量解析解。在此基础上,以Mohr-Coulomb屈服准则作为破断判据,推导了破断迹线隐函数方程式。采用Matlab软件计算和绘图得到了破断迹线,通过算例校验分析了岩石黏聚力、内摩擦角对破断迹线的影响规律,验证了破裂迹线求解的正确性。这对于进一步认识覆岩破断力学机理具有一定的意义。

中洲河“22.6”暴雨洪水分析

受超强“龙舟水”影响,2022年6月20日至21日,中洲河大象(二)水文站出现建站以来最大洪水过程,洪峰水位为7.57 m(冻结基面,下同),洪峰流量为1410 m^(3)/s。该文对中洲河“22.6”大洪水的暴雨成因、暴雨过程及特点、洪水过程、洪水重现期以及洪水特点等方面进行了分析,研究成果可为今后中洲河防洪减灾、水资源合理利用与开发提供可靠的水文数据及技术支撑。

围术期患者发生心室电风暴的急救处理及疗效分析

目的总结6例手术患者在围术期发生心室电风暴(VES)的抢救治疗经验。方法根据患者术前、术中的基本情况,回顾性分析2019年2月~2023年6月6例患者在术中或术后发生VES的原因、救治方法及患者的转归。结果6例患者经过心肺复苏术(CPR)、电除颤以及应用胺碘酮、艾司洛尔、肾上腺素、去甲肾上腺素、利多卡因等多种血管活性药物,均抢救成功,无神经并发症,均治愈出院。结论6例手术患者在围术期发生VES可能与手术、麻醉、内环境严重紊乱或感染等多因素引起心脏交感风暴有关,通过去除病因、CPR、电除颤和合理使用上述血管活性药物等处理,有利于恢复心脏的供血、供氧,保证心肌氧气供需平衡,达到抢救成功的目的。

大地电场变化的频谱特征

处理了中国大陆地区嘉峪关、昌黎、崇明、蒙城、兴济、宝坻和阳原等7个台的地电场观测数据，应用最大熵谱方法研究了大地电场日变化、地电暴等谱成分的特征．结果表明，大地电场日变化主要是12h的半日波成分最强，24-25h的全日波和8h周期成分次之；地电暴是在大尺度空间同步发生的，其谱值高于日变化谱值约2～3个数量级，主要以较长周期成分为主．这一结果初步解释了大地电场变化的主要谱成分的生成机制．