A STUDY OF THE INFLUENCE OF MICROPHYSICAL PROCESSES ON TYPHOON NIDA(2016) USING A NEW DOUBLE-MOMENT MICROPHYSICS SCHEME IN THE WEATHER RESEARCH AND FORECASTING MODEL

The basic structure and cloud features of Typhoon Nida(2016) are simulated using a new microphysics scheme(Liuma) within the Weather Research and Forecasting(WRF) model. Typhoon characteristics simulated with the Liuma microphysics scheme are compared with observations and those simulated with a commonly-used microphysics scheme(WSM6). Results show that using different microphysics schemes does not significantly alter the track of the typhoon but does significantly affect the intensity and the cloud structure of the typhoon. Results also show that the vertical distribution of cloud hydrometeors and the horizontal distribution of peripheral rainband are affected by the microphysics scheme. The mixing ratios of rain water and graupel correlate highly with the vertical velocity component and equivalent potential temperature at the typhoon eye-wall region. According to the simulation with WSM 6 scheme,it is likely that the very low typhoon central pressure results from the positive feedback between hydrometeors and typhoon intensity. As the ice-phase hydrometeors are mostly graupel in the Liuma microphysics scheme, further improvement in this aspect is required.

Analysis of Extreme Precipitation Weather Process in Henan during July 17-22, 2021

To learn more about the unusually heavy rainfall in central China, this research uses the monthly climatic data, weather map information and US NCEP re-analysis data to analyze the atmospheric circulation, precipitation and weather situation of this extreme precipitation weather process in Henan during July 17-22, 2021. The results show that the precipitation process is affected by the joint action of the subtropical high, the continental high, the low vortex, the low-level jet, the typhoon “In-fa” and other multi-scale systems in the middle and low latitudes. This precipitation process was also affected by the topographic uplift and blocking of Taihang Mountain and Funiu Mountain.

台风天气湛江钢铁煤气系统安全防御实践

以台风天气期间湛江钢铁的煤气系统如何安全保正压、停复役等为例,结合生产计划,有序安排煤气系统停复役及通过COG和氮气合成煤气、煤气柜储气等来保证台风天气期间的所需煤气,从而保证了台风等极端天气条件下的煤气系统安全稳定。

2023年河南麦收连阴雨的形成和环流异常分析

2023年5月25—30日河南遭遇了1961年以来同期持续时间最长、影响最大的连阴雨天气过程。连阴雨天气导致小麦大幅减产,品质下降,豫南、豫中和豫东部分种子田失去种用价值,被评为“烂场雨”。利用常规观测资料、NCEP再分析资料和EC数值预报产品,对这次连阴雨过程的大尺度环流形势和影响系统进行分析。结果表明:(1)该天气过程发生在异常大气环流背景下,西太平洋副热带高压显著偏强,脊线5天滑动平均位置偏北达8个纬度,越过25°N线;西伯利亚高压也显著偏强且频繁向南暴发。(2)乌拉尔山阻塞系统的形成导致我国新疆西北部长时间维持一深厚冷涡,从而在35°—40°N形成了稳定纬向环流,冷涡底部不断有冷空气分裂东移南下影响河南。远距离超强台风的逼近导致副热带高压迅速西伸北抬,在其外围形成了一条宽广、深厚的从南海伸向中纬度地区的暖湿气流输送带,最终在豫西北汇聚出低空急流。随着暖湿气流输送带向北扩展,在大风速区的前方,对流层中低部有明显的空气质量和水汽的辐合,从而引发上升运动的发生发展,导致多地暴雨、局部大暴雨的出现。(3)南北两个异常的天气系统的结合,促成了中纬度能量锋区的稳定维持,锋面抬升对暖区降水起到增幅和维持作用。(4)数值模式对中、短期环流趋势和影响系统均作出了较准确的预报,但对降水量级及其分布的预测还需要进一步推敲订正。

EXPERIMENTAL STUDY ON A DYNAMIC ASYMMETRICAL TYPHOON INITIALIZATION SCHEME BASED ON 4D-VAR

Axisymmetric bogus vortexes at sea level are usually used in the traditional bogus data assimilation (BDA) scheme. In the traditional scheme, the vortex could not accurately describe the specific characteristics of a typhoon, and the evolving real typhoon is forced to unreasonably adapt to this changeless vortex. For this reason, an asymmetrical typhoon bogus method with information blended from the analysis and the observation is put forward in this paper, in which the impact of the Subtropical High is also taken into consideration. With the fifth-generation Penn State/NCAR Mesoscale Model (MM5) and its adjoint model, a four-dimensional variational data assimilation (4D-Var) technique is employed to build a dynamic asymmetrical BDA scheme to assimilate different asymmetrical bogus vortexes at different time. The track and intensity of six summer typhoons much influenced by the Subtropical High are simulated and the results are compared. It is shown that the improvement in track simulation in the new scheme is more significant than that in the traditional scheme. Moreover, the periods for which the track cannot be simulated well by the traditional scheme can be improved with the new scheme. The results also reveal that although the simulated typhoon intensity in the new scheme is generally weaker than that in the traditional scheme, this trend enables the new scheme to simulate, in the later period, closer-to-observation intensity than the traditional scheme. However, despite the fact that the observed intensity has been largely weakened, the simulated intensity at later periods of the BDA schemes is still very intensive, resulting in overly development of the typhoon during the simulation. The limitation to the simulation effect of the BDA scheme due to this condition needs to be further studied.

AN IMPACT STUDY OF A NEW TYPE OF DATA OF ADAPTIVE OR TARGETING OBSERVATION ON TYPHOON FORECAST

There was a new concept of ‘adaptive or targeting observation’ in recent years, which is anadditional and targeting observation based on the existing and fixed observing network for the atmosphere on theimpacted region. Dropsonde is one of the important observing instruments in the adaptive or targetingobservation. In this paper, GRAPES, the next generation of numerical weather prediction system of China hasbeen used. The impacts on the typhoon Dujuan (No.200315) forecast in experiments with dropsonde have beenstudied and experiments on sensitivity have also been done. It was found that the forecasts of the elements havebeen improved obviously with the use of dropsonde, such as the path, the center location, and the intensity oftyphoon. It was also found in the sensitivity studies that the setting of deviation structure also has obviousimpacts on the forecast for typhoons. It is not true that the simulation is better when the proportion of the data ofdropsonde is larger in the course to modify the background.

A numerical simulation of latent heating within Typhoon Molave

The weather research and forecasting(WRF) model is a new generation mesoscale numerical model with a fine grid resolution(2 km), making it ideal to simulate the macro-and micro-physical processes and latent heating within Typhoon Molave(2009). Simulations based on a single-moment, six-class microphysical scheme are shown to be reasonable, following verification of results for the typhoon track, wind intensity, precipitation pattern, as well as inner-core thermodynamic and dynamic structures. After calculating latent heating rate, it is concluded that the total latent heat is mainly derived from condensation below the zero degree isotherm, and from deposition above this isotherm. It is revealed that cloud microphysical processes related to graupel are the most important contributors to the total latent heat. Other important latent heat contributors in the simulated Typhoon Molave are condensation of cloud water, deposition of cloud ice, deposition of snow, initiation of cloud ice crystals, deposition of graupel, accretion of cloud water by graupel, evaporation of cloud water and rainwater,sublimation of snow, sublimation of graupel, melting of graupel, and sublimation of cloud ice. In essence, the simulated latent heat profile is similar to ones recorded by the Tropical Rainfall Measuring Mission, although specific values differ slightly.

A SIMILARITY SCHEME FOR QUANTITATIVE FORECAST OF PRECIPITATION OF TYPHOONS

A quantitative scheme is put forward in our work of forecasting the storm rainfall of typhoons for specific sites.Using the initial parameters,weather situations and physical quantities as well as numerical weather prediction products,the scheme constructs multivariate,objective and similarity criteria for environmental factors for the time between the current and forthcoming moment within the domain of forecast.Through defining a non-linear similarity index,this work presents a comprehensive assessment of the similarity between historical samples of typhoons and those being forecast in terms of continuous dynamic states under the multivariate criteria in order to identify similar samples.The historical rainfall records of the similar samples are used to run weighted summarization of the similarity index to determine site-specific and quantitative forecasts of future typhoon rainfall.Samples resembling the typhoon being forecast are selected by defining a non-linear similarity index composed of multiple criteria.Trial tests have demonstrated that this scheme has positive prediction skill.

扩展水凝物控制变量的雷达资料同化对台风“天鸽”数值模拟的影响

利用WRF(Weather Research and Forecast)模式及WRFDA(WRF model data assimilation system)系统,针对2017年台风“天鸽”个例通过同化雷达径向速度(Vr)和反射率因子(RF),研究水凝物控制变量的雷达资料同化对台风分析预报的影响。研究表明:雷达径向速度的直接同化有效地改进了模式初始场中台风涡旋区的中小尺度信息,分析场中产生了气旋性的风场增量,对模式背景场中的台风有显著增强作用。通过在传统控制变量中扩展针对水凝物的控制变量可有效地同化雷达反射率因子资料,对初始场的水物质进行调整,并对随后确定性预报的台风路径和强度都有一定的正效果。此外,相比没有水凝物控制变量的雷达同化试验,加入了水凝物控制变量的雷达资料同化试验降水预报效果更好。这为将我国近海的地基多普勒天气雷达用于台风初始化分析和预报提供了一定的技术支撑和保障。

台风灾害下多阶段协同的受端电网弹性提升策略

近年来,台风成为影响沿海城市受端电网安全运行的主要自然灾害。文中综合考虑台风下负荷、区外来电、各类机组、储能、输电通道等在内的受端电网响应特性,提出一种计及预防阶段、抵抗-响应阶段、恢复阶段的多阶段协同弹性提升策略。通过实际运行曲线与理想运行曲线之差量化电网弹性,实现城市受端电网弹性评估。弹性提升模型以投资运行总成本最小和电网弹性最大为目标,包含输电通道加固、机组组合以及增加修复队伍3种措施,涵盖台风过境电网3个阶段状态变化。最后,选取中国某市实际受端电网结合中国气象局热带气旋中心台风数据验证了模型的有效性。

不同驱动场对东亚区域再分析系统中华南台风降水影响的对比研究

使用ERA-Interim和ERA5两套再分析资料分别驱动东亚区域再分析系统(East Asia Reanalysis System,EARS),并输出2015年一年期试验再分析资料,通过评估其中3次代表性的华南登陆台风降水过程,对比不同驱动场对该系统的影响,研究发现以ERA5驱动的EARS输出结果较ERA-Interim驱动的结果更准确,尤其在丘陵和山地等复杂地形下的降水模拟改进明显。进一步用ERA5驱动的EARS输出结果与欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)新一代陆面再分析资料ERA5-Land对比分析,发现ERA5-Land对于台风大尺度降水的把握更好,而EARS对中小尺度降水过程的再现更完整,特别是对沿海降水的模拟更准确。相较于ERA5-Land,EARS目前同化的观测资料有限,对物理过程参数化方案的选择仍欠准确,后续需要有针对性地改进。

计及台风场景运行效能的分布式储能规划方法

在配电网中合理规划分布式储能,不仅可以平滑新能源出力,提高风光利用率,还能够提高配电网在台风天气下的供电保障能力。鉴于此,提出了一种兼顾配电网在常规和台风场景下运行效能的分布式储能规划方法。首先,随机生成海量台风场景,并使用t-SNE算法进行了降维聚类;在此基础上,将规划问题建模为包含多类型场景的混合整数规划模型;随后,应用Benders分解法将该复杂模型分解为主问题与子问题并顺序迭代求解,解决了考虑海量场景后模型的维数灾难问题。最后,以IEEE 33节点系统为例进行数值仿真,验证了所提模型的有效性以及求解算法的快速性。

Analysis of Heavy Precipitation Process in North China from August 23 to 24, 2020

In order to better understand the formation mechanism of rainstorm in China and promote disaster prevention and reduction, based on the meteorological data of National Meteorological Information Center and Japan Meteorological Agency, this paper draws the isobaric surface map of 850 hPa and 500 hPa, relative humidity and precipitation distribution map. In this study, synoptic methods were used to analyze the heavy precipitation process in North China from August 23th to 24th, 2020. The results show that 1) The formation of short-term heavy precipitation requires sufficient water vapor and very strong upward movement;2) the heavy precipitation in August 23th to 24th 2020 in North China was influenced by the upper-level trough line, cold vortex and cold front, which made the warm and cold air strongly converge over North China, resulting in strong convective weather;3) the heavy rainfall over North China was also influenced by Typhoon Bawei, which caused maximum precipitation and air humidity.

建筑外墙智能高压淋水机器人研究与应用

针对传统PVC布管淋水压力小、检测效果差的问题,研发了一种智能高压淋水机器人,用于模拟台风暴雨天气对外墙渗漏的影响。智能高压淋水机器人由智能高压淋水设备、智能柔性吊装设备、智能淋水在线操控平台、智能水泵组成,可通过智能提升、移动喷淋、远程控制、实时监测(压力、水量和时间等)等功能,实现高压、高效、智能化的淋水检测,真正解决建筑外墙渗漏的质量隐患。

远洋船舶避台航线设计方案--以台风“杜苏芮”(2305)为例

避台航线最优化问题是远洋气象导航中的关键问题之一,为解决该问题,文中提出了一种面向船舶避台航线规划的图搜索算法,通过船舶失速模型和台风影响下的船舶航行风险识别方法,引入船舶变速集,定义图搜索算法中每条边的权重,基于计划航线改进图搜索算法的搜索策略,提高算法的效率和避台航线的平滑性,以获得最小航时的避台航线。以2305号台风“杜苏芮”为例验证算法在避台航线设计中的有效性,实验结果表明,该算法能够有效地躲避台风“杜苏芮”的大风浪影响,并得到最优航时航线,对实现船舶智能避台、优化船舶航线设计具有重要意义。

一种极端天气条件下配电网预警系统设计与研究

为了提高配电网在极端天气事件下设备故障及电力失效预测准确率,设计了一种配电网极端天气预警系统。该系统包含三层结构,分别进行信息采集、信息处理和预警与评估。同时,提出了一种预测输电线路在台风灾害下受损概率的混合方法,采用极值Ⅰ型概率分布和蒙特卡罗方法模拟风场,采用随机森林预测输电线路的破坏概率,从而为防灾减灾提供决策支持。通过仿真分析,结果表明所提方法比传统RF方法性能更优。

考虑台风影响的大型风力机风致响应特性研究

与良态风场相比,台风场会显著影响风力机受力性能。为解决此问题,采用中尺度WRF和小尺度CFD对“鹦鹉”台风进行精细化数值模拟。并以某风电场5 MW大型风力机为分析对象,结合ANSYS软件重点对台风场和良态风场下风力机耦合体系风致响应、受力稳定性以及极限承载力等进行对比分析。研究结果表明:对比良态风场,台风作用使风力机表面三维气动力分布模式更加复杂,且明显增大了机舱-叶片-塔筒一体化耦合体系的结构响应,同时大幅降低了结构整体屈曲稳定和极限承载能力,主要结论可为此类风力机在台风环境下的受力预测提供参考。

台风“暹芭”造成商丘暴雨过程的成因分析

2022年7月5—6日,受台风“暹芭”影响,商丘地区出现暴雨、大暴雨天气,多处遭受洪涝灾害。利用常规观测资料、MICAPS资料、ERA5再分析资料和FY4A卫星云图等,对此次过程进行了成因分析。结果表明:前期大陆高压和西太平洋副热带高压不断加强,西南急流引导台风低压向北偏东方向移动,商丘处于低空急流出口区左侧,水汽条件充足。后期受西风槽和台风倒槽共同影响,商丘低空偏南偏东急流加强,处于低槽底部与台风倒槽顶部相结合区域,中西部水汽辐合加强,热力不稳定条件更加有利。“暹芭”台风从两广北上,急流长时间维持,后随低槽东移配合台风倒槽继续东北向移动,持续为商丘带来降水。

北上台风引发锦州连续性暴雨的成因分析

【目的】诊断分析锦州地区2019年8月10日至15日出现的连续性暴雨。【方法】利用Micaps实况数据资料、ECWMF再分析资料等进行分析。【结果】受西风带冷空气、副热带高压及减弱台风“利奇马”外围云系等连续影响,锦州地区此次暴雨过程持续时间长、累计雨量大、风力较强、致灾程度高,总降水量达暴雨到大暴雨量级,局部特大暴雨。【结论】此次暴雨持续时间长、累计雨量大主要是由于副热带高压和大陆高压两高对峙,移速较慢,以及源源不断的水汽和能量补充的影响,高层辐散、低层辐合的高低空配置有利于垂直上升运动发展。此外,冷空气从底层卷入使台风“利奇马”结构破坏,减弱填塞,斜压发展,虽然缩短了台风生命史,却是造成本次暴雨“长时效”特点的关键。

台风天气条件下的电网暂态稳定风险评估

基于风险的分析方法可以定量地评估灾害条件下电网的短期安全稳定水平,并为电网的安全预警提供支持。提出了一种台风天气条件下的电网暂态稳定风险评估方法。该方法考虑了台风天气条件对输电线路运行可靠性的影响,并根据故障概率建立电网风险评估的预想故障集。对于预想故障集中不满足暂态稳定或静态安全的故障,建立了该故障下的最优紧急控制模型,并以紧急控制代价来衡量各预想故障的后果。最后通过新英格兰测试系统初步验证了所提出方法的有效性。