Influence of Fast Global Variations of Solar Magnetic Fields on Space Weather in Cycle 23

It is established that the large-scale and global magnetic fields in the Sun's atmosphere do not change smoothly, and long-lasting periods of gradual variations are superseded by fast structural changes of the global magnetic field. Periods of fast global changes on the Sun are accompanied by anomalous manifestations in the interplanetary space and in the geomagnetic field. There is a regular recurrence of these periods in each cycle of solar activity, and the periods are characterized by enhanced flaring activity that reflects fast changes in magnetic structures. Is demonstrated, that the fast changes have essential influencing on a condition of space weather, as most strong geophysical disturbances are connected to sporadic phenomena on the Sun. An explanation has been offered for the origin of anomalous geomagnetic disturbances that are unidentifiable in traditionally used solar activity indices. Is shown, main physical mechanism that leads to fast variations of the magnetic fields in the Sun's atmosphere is the reconnection process.

Numerical Simulation of the Influence of Tunnel Construction by Mining Method on the Seepage Field in Weathered Granite Stratum

In actual space, considering the heterogeneity and anisotropy of rock and soil, the difference of hydrogeological conditions and the influence of tunnel excavation, tunnel seepage problem is a very complex three-dimensional seepage problem, which is very difficult to solve. The equivalent continuum model is one of the most commonly simplified models used in solving tunnel seepage problems. In this paper, the finite element software ABAQUS and the research results are used to establish a seepage numerical calculation model, study the influence of mining method construction on the seepage field in weathered granite, and clarify the influence of each stage of mining method construction on the groundwater environment. On this basis, the sensitivity of the seepage field to various factors such as natural environment, engineering geology and hydrogeology, tunnel construction and so on is analyzed, which provides a basis to establish the evaluation system of groundwater environment negative effect in weathered granite stratum by mining method tunnel construction.

利用无人机有源标定仪开展天气雷达远场标定试验

文章针对天气雷达缺乏远场标定能力的现状,提出利用无人机有源标定仪开展天气雷达远场标定的方案。通过给出无人机有源标定仪开展天气雷达远场标定试验的测试项目与条件,完成了对雷达天线、发射通道和接收通道的标定测试,试验结果符合相关技术要求。后期将对标定仪做进一步改进和完善,以期更好地满足雷达标定业务需要。

黄渤海海区风速推算方法及效果评估

为了弥补海上风场监测数据不足,提高对黄渤海海上风场监测能力,针对不同大气环流形势,基于较为稳定的74个沿海和海岛站等陆基站2017—2020年风场观测资料,以及同时段具有一定连续性的21个浮标站和船舶站等海基站观测数据,采用多元线性回归方法,建立由陆基站推算海区风速的模型。利用2021年实况资料对推算结果进行检验评估。结果表明:分别针对全部风力等级和6级及以上大风建立的风速推算模型(以下分别简称CM模型和HM模型)均具有较高的可靠性,其中HM模型对大风推算的准确率更高;8种天气类型中共5种类型发生大风的概率高于60%,其中对西北高东南低类型的推算效果最好,对西高东低型、西南高东北低型和西北低东南高型的6~7级大风推算效果较好,对8级及以上大风的推算效果略差;不同海区大风的推算结果中,对黄渤海大部分海区推算的风速略偏小,仅对渤海西南部海区的部分站点推算的风速略偏大;对黄海北部海区风速推算的平均绝对误差最小(0.95 m·s^(-1)),对其他海区风速推算的平均绝对误差在1.32~1.70 m·s^(-1);在海区观测不连续、不稳定的情况下,推算的风速能够对海上风场资料进行有效的补充。该推算方法易于业务化应用,可随不同海区观测资料的增加而进一步优化,对海洋观测布局设计也有一定的参考作用。

Contrast Analysis of Two Low Vortices Weather Processes

Two cold vortex weather processes in Liaoning Province in June of 2006 were analyzed.In the process of low vortex of June 3,strong convection weather,such lightning storm and hailstone,came forth in most areas of Liaoning Province.White and bright cloud was shown in satellite nephogram.Bow echo and cyclonic circumfluence were shown in weather radar production.In the process of low vortex of June 14,strong precipitation weather came forth in most area of Liaoning Province.Based on the velocity field production of weather radar,the relative place of front and radar station can be judged.The weather situation and forecast were the main basis of short-term prediction.And satellite nephogram,weather radar,automatic weather station play important roles in the monitoring and short-term prediction of disaster weathers.

海底风化槽地铁盾构隧道结构受力监测与计算

[目的]为探明海底风化槽盾构隧道结构荷载分布特征,特开展隧道管片结构内力响应规律研究。[方法]依托某跨海地铁盾构隧道项目,针对其海底风化槽段,实施了管片水土荷载及结构内力的系统性监测。通过数据分析,揭示了该区域隧道结构荷载与内力的分布特征,并进一步验算了潮汐荷载作用下管片的疲劳特性。[结果及结论]①监测结果显示,水土压力与钢筋内力经历了初期的显著波动后趋于稳定。稳定阶段的水土压力维持在0.1~0.4 MPa范围内。内侧钢筋应力范围为-2.19~-38.60 MPa,外侧的则为-6.95~-34.59 MPa。对比钢筋应力的计算值与实测值,二者比值为0.6~1.8,显示出良好的一致性。②管片所受水土荷载随潮汐水位的周期性变化(周期为12 h)而呈现相应的波动。管片接缝处的最大主应力水平为-2.45~-2.60 MPa,应力幅值在0.31~0.34 MPa之间,应力比则介于0.87~0.96之间。③在不同潮汐荷载幅值条件下,管片的应力水平保持相对稳定,而应力幅值则随潮汐荷载幅值的增加而线性增长,同时应力比呈线性下降趋势。当潮汐荷载幅值达到实测值的5倍时,管片的主应力幅值增大至1.70 MPa,应力比降至0.84,此时混凝土主应力的最大值范围为-1.6~-3.6 MPa。

2021年宁夏两次持续沙尘重污染天气对比分析

为探究气象条件变化对宁夏沙尘重污染天气过程的影响特征,利用常规气象观测数据、NCEP再分析资料及环境空气质量数据,选取2021年1月11-14日和2021年3月14-19日两次沙尘重污染天气(分别简称“0113”过程和“0315”过程)为研究对象,基于天气形势、后向轨迹模拟及物理量场诊断等方法,对比两次过程影响系统及传输轨迹,探讨形成和维持机制.结果表明:①“0113”过程主要影响宁夏北部四市,“0315”过程影响整个宁夏,两次沙尘过程中重度及以上污染平均持续时间分别为35.0和105.2h,沙尘污染暴发阶段PM_(10)浓度平均值分别为1735和5265μg/m3.②“0113”过程为一次强度一般的锋面过境引起的沙尘重污染天气,稳定少动的青藏高压与其北侧蒙古热低压之间形成显著的气压梯度带,高空脊前多股强西北气流引起动量下传,使宁夏及上游地区大风将沙尘输送至宁夏造成重污染;“0315”过程为一次较强的典型锋面过境及蒙古气旋造成的持续沙尘重污染天气,蒙古冷高压受强盛蒙古气旋和青藏高原热低压夹击稳定少动,其西南、东南及东部与两个热低压形成气压梯度带,加之受地面冷锋过境影响,宁夏及周边地区多方向大风将沙尘向宁夏上空输送造成“0315”过程较“0113”过程污染更严重.③两次过程中沙尘均为境外和境内同时输送,“0113”过程为西北和偏西路径,传输距离长且高度较低;“0315”过程为西北、偏北和偏东路径,传输距离短且高度较高.④“0315”过程中蒙古国及我国新疆-甘肃一带负水平螺旋度中心值为“0113”过程的1.75倍,较强的辐合上升运动和西风气流将沙尘持续向宁夏上空输送并与本地沙尘叠加,上升和下沉运动交替使沙尘长时间悬浮于空中,而“0113”过程受多股强下沉气流造成沙尘迅速沉降至地面,污染快速减弱.研究显示:冷锋和蒙古气旋是宁夏沙尘重污染天气的主要影响系统,当有只冷锋过境时,上游沙尘传输高度低,到达宁夏上空沙尘粒子相对少,使宁夏沙尘重污染天气持续时间短且强度相对较弱;当伴有蒙古气旋活动时,沙尘传输高度高,到达宁夏上空沙尘粒子多,使宁夏沙尘重污染天气持续时间长、影响范围广且强度较强.

大型浅水湖泊高时空分辨率风场特征数值模拟研究:以巢湖为例

【目的】大型浅水湖泊的风场是影响湖泊流场、水体富营养化和藻华运移聚集规律的关键因素之一,仅依托气象站点的观测数据难以有效捕捉湖面风场在空间和时间上的快速变化。为精细刻画湖泊高频变化风场,辨识其时空变化特征,【方法】以巢湖为研究对象,综合利用气象观测数据、全球再分析数据集和地理静态数据,通过中尺度天气预报模式和地理空间分析技术,模拟分析巢湖地区2019年高时空分辨率的风场变化过程。【结果】结果显示:巢湖区域风速由东向西、由南向北、由湖面向陆面逐渐减弱;湖面主导风向为东风和偏东风,主导风速为二级至四级,湖面平均风速在11月最大,12月次之,5月最小,不同季节湖面平均风速由大到小依次为冬季、秋季、夏季和春季。【结论】结果表明:巢湖在白天(夜晚)出现冷(暖)湖效应,其风场在早上6时和夜晚23时出现陆风和湖风转换;西半湖受湖陆风和城市热岛影响显著,在夏季会出现明显的环湖湖风锋,其湖风锋穿透内陆距离约4.7~9 km;东半湖受山谷风影响显著,在东南部山脉以东湖区易形成低风速区,在湖口附近受狭管效应易形成高风速区。通过研究成果可进一步认知巢湖区域风场特征,为巢湖水生态环境治理提供技术支撑。

昭通CINRAD/CC天气雷达磁场电源故障诊断与调试

2021-05-02昭通天气雷达发射部分磁场电源2故障,在上级相关部门的支持和省内雷达站的支援下,经雷达维护保障人员及时处理,锁定故障位置,排除了故障,雷达恢复正常运行。文章对磁场电源工作原理、故障发生过程、故障排除过程、故障排除后调试等进行了介绍,以期为今后雷达类似故障情况积累经验、提供参考,为气象防灾减灾提供可靠的雷达保障服务。

全风化花岗岩地层隧道施工降水优化分析

以福州某滨海全风化花岗岩地层隧道施工降水为依托,为确保周边建筑物的安全,提出了止水帷幕、地表旋喷桩和挡墙加固的综合加固方案。监测表明,周边建筑物在第二次降水条件下的平均沉降量仅为3.3 mm,占总平均沉降量的25.3%;平均倾斜率仅为0.0274,占总平均倾斜率的28.8%。该综合加固手段有效控制了建筑物的倾斜及沉降,为隧道施工提供了安全保障,可为临海区域强风化花岗岩地层隧道降水施工提供参考。

滇南一次暖区暴雨过程的雷达反演风场分析

利用自动气象站资料、ERA5再分析资料、探空资料和CINRAD/CC普洱天气雷达数据等多源资料,对2020年8月7日滇南大暴雨过程进行天气尺度和中小尺度系统综合分析.结果表明:①此次强降水是典型的暖区暴雨过程;②500 hPa东风波和700 hPa低涡系统是主要的影响系统,200 hPa高空辐散特征加强了低层系统的发展;③本次过程发生在高湿、高能、强垂直运动的大气环境背景下,孟加拉湾低压为滇南局地强降水提供充足的水汽,水汽通量散度强度达-4.6×10^(-6) g·cm^(-2)·hPa^(-1)·s^(-1);副高在滇南地区向北凹陷有利于不稳定能量积累,∑θ_(se)≥260℃的区域与地面6 h强降水落区对应一致;特大暴雨发生期间伴随有能量和强暖平流输送;④中尺度对流系统生命史完整且漫长,回波原地生消,中心稳定少动,“列车效应”明显,低质心暖云回波贡献了短时高效的降水,导致地面降水持续时间长、强度大、落区局地性强;对流发展旺盛阶段存在明显小尺度次级环流和水平气旋式辐合,二者投影位置一致,呈现出对流系统三维立体运动特征;地面投影附近集中出现20 mm·h^(-1)以上短时强降水,最大78.6 mm·h^(-1);⑤滇南地形对东(抬升)、西(降低)两股气流截然不同的影响加剧了辐合区垂直运动发展,在“喇叭口”地形隔挡下两股气流长时间交汇对峙,为特大暴雨的形成提供了有利的地形条件.

A Model Study of Three-Dimensional Wind Field Analysis from Dual-Doppler Radar Data

A three-dimensional wind field analysis sollware based on the Beigng-Gucheng dual-Doppler weather radar system has been built, and evaluated by using the numerical cloud model producing storm flow and hydrometeor fields. The effects of observation noise and the spatial distribution of wind field analysis error are also investigated.

一种针对模式预报场的精细化插值新方法

随着智能网格预报业务的深入发展,为了不断提高网格预报产品的时空精度和准度,同时让网格和站点预报产品保持一致性,通过研究提出一种既考虑了静态真实地形又考虑了大气动态垂直变率的快速插值方法(Fast Refinement Interpolation,简称FRI),并选择2022年1月1日到2022年3月31日的ECMWF和CMAGFS、CMA-MESO三个模式的3~36 h预报产品作为试验数据,开展了个例天气过程试验、FRI参数选取试验和长期插值检验对比。从长期插值检验和个例试验来看,FRI方法相对双线性插值方法具有明显优势,空间上,FRI方法能提高近地面2 m气温的空间插值精度,插值结果更加符合地形变化情况,时间上,FRI方法较双线性插值方法的2 m气温插值结果准确率明显提高,特别是在具有复杂下垫面的中西部地区。方法中的修正参数还能被作为检验模式三维预报场垂直变率的一种指标。FRI方法插值快速高效,具有明确的物理解释意义,它的提出为更精准的预报近地面气象要素提供了重要理论支撑。

Real-Time Mesoscale Forecast Support During the CLAMS Field Campaign

This paper reports the use of a specialized, mesoscale, numerical weather prediction （NWP） system and a satellite imaging and prediction system that were set up to support the CLAMS （Chesapeake Lighthouse and Aircraft Measurements for Satellites） field campaign during the summer of 2001. The primary objective of CLAMS was to validate satellite-based retrievals of aerosol properties and vertical profiles of the radiative flux, temperature and water vapor. Six research aircraft were deployed to make detailed coincident measurements of the atmosphere and ocean surface with the research satellites that orbited overhead. The mesoscale weather modeling system runs in real-time to provide high spatial and temporal resolution for forecasts that are delivered via the World Wide Web along with a variety of satellite imagery and satellite location predictions. This system is a multi-purpose modeling system capable of both data analysis/assimilation and multi-scale NWP ranging from cloud-scale to larger than regional scale. This is a three-dimensional, non-hydrostatic compressible model in a terrain-following coordinate. The model employs advanced numerical techniques and contains detailed interactive physical processes. The utility of the forecasting system is illustrated throughout the discussion on the impact of the surface-wind forecast on BRDF （Bidirectional Reflectance Distribution Function） and the description of the cloud/moisture forecast versus the aircraft measurement.

WIND SHEAR IDENTIFICATION WITH THE RETRIEVED WIND OF DOPPLER WEATHER RADAR

Wind shear reflects that the wind field is not uniform, which is one of the primary factors which make the retrieval of the wind field difficult. Based on volume velocity process(VVP) wind field retrieval technique, the intensity of wind shear is identified in this paper. After analyzing the traditional techniques that rely on the difference of radial velocity to identify wind shear, a fixed difference among radial velocities that may cause false identification in a uniform wind field was found. Because of the non-uniformity in wind shear areas, the difference of retrieved results between surrounding analysis volumes can be used as a measurement to show how strong the wind shear is. According to the analysis of a severe convective weather process that occurred in Guangzhou, it can be found that the areas of wind shear appeared with the strength significantly larger than in other regions and the magnitude generally larger than4.5 m/(s·km). Besides, by comparing the variation of wind shear strength during the convection, it can be found that new cells will be more likely to generate when the strength is above 3.0 m/(s·km). Therefore, the analysis of strong wind shear's movement and development is helpful to forecasting severe convections.

基于改进人工势场法的危险天气下路径改航

航空器在飞行过程中易受危险天气的影响,造成财产损失,威胁人员生命安全。为保障飞行安全,需对航空器实施改航,以避开航路中的危险天气。本文首先对航空器飞行过程中改航问题进行研究,以最短改航路径为目标,综合考虑多种航空器性能及飞行安全约束构建改航路径规划模型,提出基于改进人工势场法的改航路径规划算法。其次,为解决传统人工势场法中目标点不可达问题,将传统斥力势场函数进行改进,同时融合模拟退火算法,解决局部极小值问题。最后,对该算法进行仿真分析,实验结果表明,相比传统人工势场法改航路径减少了18.52%。该算法可为空管部门对危险天气下的航空器改航提供理论参考。

特高压直流输电线路合成电场的天气影响因素及预测模型

特高压直流输电线路电离周围空气产生的离子和线路电场叠加形成合成电场,并在环境因素的作用下使得地面的合成场强发生变化。研究了天气因素对地面合成场强的影响,并提出了基于天气因素的电场预测模型。利用高压直流电场测量装置测量地面合成电场值及环境监测系统所测的天气参数,分析了风速、湿度、气压、温度、PM_(10)、PM_(2.5)、PM_(1.0)与场强的相关性。利用基于树形结构Parzen估计器(tree-structured Parzen estimator,TPE)优化的CatBoost建立地面场强在天气因素下的预测模型,并基于所测数据进行模型的训练和预测。结果表明:天气因素对场强的影响权重由高到低为湿度、风速、气压、温度、PM_(1.0)、PM_(2.5)、PM_(10)。通过特征排序选取前5个特征和所有特征预测所得到的均方根误差分别为0.83 kV/m和0.85 kV/m,实现了相对准确的预测。研究结果可为特高压直流输电工程环境评估提供有用的合成电场分析方法。

极端天气下桥塔温致效应及抗裂性能优化

为深入研究我国西部横断山脉地区极端天气下桥塔的温致效应,以某大跨悬索桥为工程背景,分析极端天气下该桥混凝土桥塔的温度场以及温度应力分布特征,并提出相应的抗裂优化措施.首先,基于桥址区实测数据,提出桥址区极端天气的识别与模拟方法;然后,采用ANSYS有限元软件分析了桥塔的温度分布以及温度应力分布特征;最后,针对桥塔外表面存在开裂风险的问题,提出了2种提高桥塔外表面抗裂性能的优化方案,包括桥塔外表面涂装有机涂料方案和外包超高性能混凝土UHPC(ultra high performance concrete)方案.结果表明:在强降温天气下,桥塔表面拉应力极值为2.19 MPa,存在较大开裂风险;当采用抗裂优化措施后,两种优化方案均能有效降低混凝土桥塔表面的拉应力极值;对于桥塔外表面涂装有机涂料方案,白色有机涂料优化效果最佳;对于桥塔外包UHPC方案,当UHPC厚度为0.08 m时优化效果最佳.通过对比2种抗裂优化方案的经济性和施工难易程度,推荐采用白色有机涂料优化方案.

微型智能气象站降雨观测对比试验

为了增强对微型(一体式)智能气象站(简称微智站)测雨性能的认识,2021年6—11月河北雄安新区气象局开展了不同测雨原理微智站的对比试验。分析表明:过程雨量不低于10 mm时,翻斗式微智站相对于标准站能够满足观测误差的控制要求,雷达式微智站测值偏大,光电式和压电式微智站测值偏小;过程雨量小于10 mm时,翻斗式微智站和压电式微智站相对于标准站能够满足观测误差的控制要求,雷达式微智站测值偏大,光电式微智站测值偏小。在雨强方面,双翻斗式微智站适合降雨极大值观测,光电式微智站和压电式微智站降雨极大值测值偏小;微智站雨强累积占比大于95%的雨强为[0.3 mm·min^(-1),0.6 mm·min^(-1)],雨量累积占比大于50%的雨强为[0.1 mm·min^(-1),0.4 mm·min^(-1)]。雷达式微智站对降雨响应比较快。微智站雨量传感器的分辨力越精细,对细微降雨观测越有效,有效降雨率也越大。

全风化花岗岩路基填料改良试验研究

海南地区全风化花岗岩广泛分布,却无法直接用作路基填料。针对这一问题,对全风化花岗岩采用水泥进行改良,同时开展界限含水率、重型击实、加州承载比(California Bearing Ratio,CBR)、无侧限抗压强度、回弹模量、动三轴试验研究素土及改良土工程特性。结果表明:随着水泥掺量增加,塑性指数递减,最优含水率和最大干密度均呈线性递增趋势;随着水泥掺量的增大,CBR值、无侧限抗压强度、回弹模量和动应力大幅增长,改良土工程性质显著提升。根据试验成果,建议基床表层采用水泥掺量6%的全风化花岗岩改良土,基床底层及基床以下路基采用水泥掺量4%的改良土。