不同类型台风气象场对深圳近海海域风暴潮模拟的比较研究——以台风“山竹”为例

台风引起的风暴增水严重影响沿海地区的生产生活,是造成经济损失最严重的海洋灾害之一。深圳市位于中国南海北部沿岸,是易受风暴潮灾害影响的区域,对深圳近海海域风暴潮开展研究不仅能够提升对风暴潮物理机制的认识,同时对沿海城市有效防灾减灾预警有重要意义。在风暴潮模拟研究过程中,台风气象场是风暴潮模拟准确与否的关键因素。本文针对深圳近海区域海洋环境,以海流模型FVCOM(finite volume community ocean model)和海浪模型SWAN(simulation wave nearshore)为基础,建立了区域风暴潮–波浪耦合模型,分别用再分析气象数据(European center for medium weather forecasting,ECMWF)、理想台风模型(Holland)及大气模型台风模拟结果(weather research and forecast,WRF)作为驱动场条件,对台风“山竹”期间的风暴潮过程进行模拟。结果表明:分辨率较低的ECMWF再分析气象数据难以准确体现台风水平结构,从而导致模拟误差;Holland气象场在整体上能够对台风“山竹”进行准确模拟,但无法再现台风在近岸区域的结构形变,从而导致在蛇口及附近(深圳湾,珠江口内侧)区域的风暴潮模拟水位偏高;WRF对风速、气压、水位、波浪都有较好的模拟效果,且WRF很好的改善了Holland在靠近台风登陆点的区域风暴潮水位偏高的问题,对珠江口、深圳湾区域定量改进约20%~30%。在未来的风暴潮预报中,如果采用类似于Holland这样的理想台风场,需注意上述区域的模拟结果。此外,Holland理想台风场和WRF模型结果驱动下的波浪场模拟效果都较好。

林木台风气象灾害事件本体模型构建初析

林木在台风气象灾害事件中是较特殊的生物类承灾载体。林木因风灾损毁,不仅自身遭到灾损,还带来其他领域的灾损事件和公共安全隐患。本研究应用斯坦福大学本体模型构建“七步法”,通过分析广东省和海南省台风气象灾害在林业生产领域、城市管理领域、及森林生态安全领域的林木个体事件,抽提出林木台风气象灾害事件的类、个体及属性概念,进行元语言转化。应用Protégé4.3本体构建软件进行林木气象灾害事件本体框架模型构建,重点分析了承灾载体的致灾属性——抗风性,及决定抗风性属性的自身因素。

天长市应对“温比亚”台风气象服务的总结与思考

以天长市应对"温比亚"台风的气象服务为例,总结了"温比亚"台风对天长市风雨影响,并从监测预警及短临预报情况、决策气象服务情况、公众气象服务情况、部门联动开展情况4个方面对天长市"温比亚"台风气象服务情况进行了总结,并就台风路径预报和监测、台风服务的针对性、台风服务的发布渠道3个方面提出了台风气象服务存在的问题和改进措施,以期为今后的台风气象服务提供参考和指导。

对于台风气象的一点研究

随着经济全球化席卷世界的趋势的加剧,经济文化一体化的同时,中国作为负责任的大国也与各国共同承担风险。其中,台风作为一种危险性的气象在很大程度上影响了民众的生活,引起了全球气象学家的广泛关注。本文主要从台风气象产生条件的研究和台风灾害的影响因素以及台风灾害带来的危机等方面展开论述。

新型台风海洋网络气象信息系统的设计与实现

该文将时空数据模型的概念引入台风海洋网络气象信息系统,旨在构建一个多源、异构气象服务产品与数据按照统一的时空数据模型进行组织、集成和融合,并在互联网上实时展现的信息系统平台。介绍了该系统的设计思路和技术框架,同时分析了该系统中引入时空数据模型的技术难点和关键技术,重点展示了系统构建成型后能实现的主要功能,包括台风路径信息与卫星云图、天气形势场等多种气象信息的叠加显示;多功能历史台风路径信息查询;台风实况路径信息与城市风雨监测实况、卫星云图、雷达图的同步动画显示;气象灾害预警信息、气象资讯、城市天气实况及预报等内容的集成发布等。该研究成果已在中国天气台风网(typhoon.weather.com.cn)得到实际应用。

台风对大跨度钢桁拱桥抗风性能的影响

采用Monte-Carlo台风随机模拟算法的结果和风荷载规范良态气象风环境参数建议取值,在大气边界层风洞中利用被动紊流发生装置再现了良态和台风2类气象条件下的风环境特征.以地处珠江流域台风多发区的广州新光大桥为例,采用全桥气弹模型风洞试验和基于主梁及肋拱测力试验的3维静风稳定性数值计算等手段,详细分析了中承式大跨度连续刚桁拱桥在2类风环境中平均风位移、风致抖振响应和3维稳定性的差异,分析过程比较了2类气象条件下重现期设计风速、平均风和紊流度剖面等因素对于拱桥抗风性能的影响.

基于移动互联网的浙江台风信息发布系统研发与应用

随着移动信息技术的发展和智能手机的普及,公众对移动互联网气象信息服务的需求与日俱增,同时以微信为代表的社交软件的使用大大提高了信息传播的效率,另外由于社会经济活动的日趋活跃,公众特别是沿海用户对获取台风信息的权威性、便捷性、及时性、全面性要求也越来越高。本文利用移动互联网技术进行快速迭代开发,研究设计既适合微信传播,又能通过手机APP应用市场下载使用的浙江台风信息发布系统,打造了一个浙江台风信息发布的权威平台满足新形势下公众的需求。

利用互联网收集台风信息

介绍了如何利用互联网收集台风气象信息 ,主要介绍利用香港天文台的收集过程。

沿海地区低压架空线路防风加固技术措施探讨

近年广东沿海台风频发,严重冲击了沿线地区的低压电网,造成较大的经济损失和社会影响。但未引起各地管理部门的高度重视,对抗风措施一直没有相关的研究,造成低压架空线路的抗风技术能力不高,成为抗风的短板。

THE EFFECTS OF BOGUS TYPHOON AND OBSERVED OCEANIC DATA ON THE ABILITY OF T_(213)L_(31) TO PREDICT TC TRACK

The abilities of typhoon (TC) track prediction by a medium-range forecast model T213L31 at National Meteorological Center are analyzed and its ability to improve its TC forecasts is discussed. The results show that about 57% of the TCs could be predicted by T213L31 but the initial position errors are large. The 43% area without the prediction of TC tracks is concentrated between 13°N and 20°N and east of 120°E and lack of conventional observation data is the main reason for the absence of TC prediction in this area. The adding of bogus TC could improve the ability of TC track prediction when there is no TC vortex in the analysis field, but could only have positive effects on the short-range TC track prediction when there is TC vortex in the T213L31 analysis field.

An Observational Study of Typhoon Imbudo in 2003

Typhoon Imbudo was a super-typhoon over the northwestern Pacific in 2003. It caused tremendous damage when it made landfalls in the Philippines and China. This paper documents observational analyses of Typhoon Imbudo during its landfall in China. All available observations are used to study its motion, intensity changes, convection, structure and precipitation. Best-track data indicate that Imbudo moved west-northwestward until 1800 UTC 23 July and then turned northwestward. FNL (final) analysis data show that the motion of Imbudo is dominated by changes of the subtropical high. At Imbudo's mature stage, the minimum sea level pressure dropped to 910 hPa and the maximum sustained winds were as high as 67 m s 1, which is the intensity of a super-typhoon. The surface wind field exhibited asymmetric characteristics. Polar-orbiting satellite imagery also manifested convective asymmetry before Imbudo made landfall in China. Analyzed the vertical wind shear, it is shown that the convection has a downshear-left pattern. All kinds of precipitation data were used to identify the asymmetric characteristic of the rainfall associated with the Imbudo. The maximum rainfalls were located in the southern boundary area between Guangxi and Guangdong. However, the lack of in situ observations limited further analyses of this typhoon.

CLIMATOLOGICAL VARIATION FEATURES OF TYPHOON PRECIPITATION INFLUENCING FUJIAN FOR THE PAST 46 YEARS

The results of an analysis of the temporal and spatial distribution of typhoon precipitation influencing Fujian from 1960 to 2005 show that typhoon precipitation in Fujian province occurs from May to November, with the most in August. There has been a decreasing trend since 1960. Typhoon precipitation gradually decreases from the coastal region to the northwestern mainland of Fujian and the maximum typhoon precipitation occurs in the northeast and the south of Fujian. Typhoon torrential rain is one of the extreme rainfall events in Fujian. High frequencies of typhoon torrential rain occur in the coastal and southwest regions of the province. With the impact of Fujian＇s terrain, typhoon precipitation occurs more easily to the east of the mountains than to the west. Atmospheric circulation at 500 hPa over Asia and sea surface temperature anomalies of the equatorial eastern Pacific are analyzed, with the finding that they are closely connected with the anomaly of typhoon precipitation influencing Fujian, possibly mainly by modulating the northbound track of typhoons via changing the atmosphere circulation to lead to the anomaly of typhoon precipitation over the province

CLIMATIC CHARACTERISTICS OF TYPHOON PRECIPITATION OVER CHINA

The spatio-temporal characteristics of typhoon precipitation over China are analyzed in this study. The results show that typhoon precipitation covers most of central-eastern China. Typhoon precipitation gradually decreases from the southeastern coastal regions to the northwestern mainland. The maximum annual typhoon precipitation exceeds 700 mm in central-eastern Taiwan and part of Hainan, while the minimum annual typhoon precipitation occurs in parts of Inner Mongolia, Shanxi, Shaanxi and Sichuan, with values less than 10 mm. Generally, typhoons produce precipitation over China during April - December with a peak in August. The annual typhoon precipitation time series for observation stations are examined for long-term trends. The results show that decreasing trends exist in most of the stations from 1957 to 2004 and are statistically significant in parts of Taiwan, Hainan, coastal Southeast China and southern Northeast China. The anomaly of typhoon precipitation mainly results from that of the general circulation over Asia and the Walker Cell circulation over the equatorial central and eastern Pacific. Typhoon torrential rain is one of the extreme rainfall events in the southeastern coastal regions and parts of central mainland. In these regions, torrential rains are mostly caused by typhoons.

IMPROVEMENT OF NUMERICAL SIMULATION OF TYPHOON RANANIM (0414) BY USING DOPPLER RADAR DATA

Typhoon Rananim （0414） has been simulated by using the non-hydrostatic Advanced Regional Prediction System （ARPS） from Center of Analysis and Prediction of Storms （CAPS）. The prediction of Rananim has generally been improved with ARPS using the new generation CINRAD Doppler radar data. Numerical experiments with or without using the radar data have shown that model initial fields with the assimilated radar radial velocity data in ARPS can change the wind field at the middle and high levels of the troposphere; fine characteristics of the tropical cyclone （TC） are introduced into the initial wind, the x component of wind speed south of the TC is increased and so is the y component west of it. They lead to improved forecasting of TC tracks for the time after landfall. The field of water vapor mixing ratio, temperature, cloud water mixing ratio and rainwater mixing ratio have also been improved by using radar refiectivity data. The model＇s initial response to the introduction of hydrometeors has been increased. It is shown that horizontal model resolution has a significant impact on intensity forecasts, by greatly improving the forecasting of TC rainfall, and heavy rainstorm of the TC specially, as well as its distribution and variation with time.

IMPROVED SCHEME OF AXISYMMETRIC TYPHOON BOGUS MODEL AND ITS IMPACT ON NUMERICAL SIMULATION OF TYPHOON NOCKTEN (NO.0405)

There is distinct difference in the tangential wind profile between different typhoons in the western North Pacific. At present, only two parameters, maximum wind and radius of maximum wind, are used in NCAR-AFWA bogus for MM5 mesoscale numerical model. As a result, sometimes the outer structure of typhoon cannot be described accurately. The tangential wind profile of NCAR-AFWA bogus is improved by introducing radii of 25.7 m/s and 15.4 m/s, and then the track and intensity of Typhoon Nockten (No.0425) are simulated. The results show that the simulations of track and intensity of typhoon both have been improved by simultaneously introducing the radii in the tangential wind profile of typhoon bogus. At the same time, there is improvement in the gale wind range of the typhoon simulated.

ENTROPY FLOW CHARACTERISTICS ANALYSIS OF TYPHOON MATSA (0509)

The evolution of Typhoon Matsa (0509) is examined in terms of entropy flow through an entropy balance equation derived from the Gibbs relation, according to the second law of thermodynamics. The entropy flows in the various significant stages of (genesis, development and decaying) during its evolution are diagnosed based on the outputs of the PSU/NCAR mesoscale model (known as MM5). The results show that: (1) the vertical spatial distribution of entropy flow for Matsa is characterized by a predominantly negative entropy flow in a large portion of the troposphere and a positive flow in the upper levels; (2) the fields of entropy flows at the middle troposphere (500 hPa) show that the growth of the typhoon is greatly dependent on the negative entropy flows from its surroundings; and (3) the simulated centres of heavy rainfall associated with the typhoon match well with the zones of large negative entropy flows, suggesting that they may be a significant indicator for severe weather events.

EXPERIMENTS OF ENSEMBLE FORECAST OF TYPHOON TRACK USING BDA PERTURBING METHOD

A new method, BDA perturbing, is used in ensemble forecasting of typhoon track. This method is based on the Bogus Data Assimilation scheme. It perturbs the initial position and intensity of typhoons and gets; a series of bogus vortex. Then each bogus vortex is used in data assimilation to obtain initial conditions. Ensemble forecast members are constructed by conducting simulation with these initial conditions. Some cases of typhoon are chosen to test the validity of this new method and the results show that： using the BDA perturbing method to perturb initial position and intensity of typhoon for track tbrecast can improve accuracy, compared with the direct use of the BDA assimilation scheme. And it is concluded that a perturbing amplitude of intensity of 5 hPa is probably more appropriate than 10 hPa if the BDA perturbing method is used in combination with initial position perturbation.

ANALYSIS OF EXTRATROPICAL TRANSITION OF TROPICAL CYCLONE OVER China's Mainland

Typhoon Winnie (1997) experienced three stages after landfall on China: weakening, transition, and re-intensification. The transition is similar to the "complex transition" model proposed by Matano and Sekioka. During the re-intensification stage, the transformed cyclone developed into a pattern of Shapiro-Keyser Cyclone model. From the diagnosis we can find that the cause of Winnie’s transition is the intrusion of cold air from the mid- and upper- troposphere and the warm temperature advection in the lower. Winnie redeveloped after transition, which is the result of three vital factors: the warm temperature advection in the lower troposphere, the divergence on the right side of the upper jet entry and the cyclonic vorticity advection in the upper.

ANALYSIS OF TYPHOON MATSA (NO.0509) AFFECTING SHANDONG PROVINCE

The characteristics of the moving course of Typhoon Matsa (No.0509), associated heavy rain and physical quantities fields have been analyzed, with the focus on the reason of the typhoon’s abrupt northeastward turn in Anhui Province and heavy rain concentrating in the northeast of typhoon center instead of near it. Meaningful conclusions are as follows. The reasons for typhoon abrupt turning are that the subtropical high pressure was moving southward and divergence fields of 200 hPa were to the right of the typhoon center; there was no obvious cold air invading Shandong after the typhoon entered the westerly belt; the southeasterly jet of typhoon and shear brought heavy rainfall to the Shandong peninsula before the typhoon entered Shandong. But after the typhoon’s movement into Shandong, the typhoon’s inverted trough brought the rainfall to the northern and central Shandong.

THE INFLUENCE OF SOUTH CHINA SEA SUMMER MONSOON ON THE RAINSTORM ASSOCIATED WITH THE LANDFALLING STRONG TROPICAL STORM BILIS (0604)

Bilis (0604) is a strong tropical storm that sustained over land for a long time, bringing torrential rain. With conventional observation data, radar data and infrared satellite imagery, Mesoscale Convective Systems (MCSs) are found to form and develop successively, which cause torrential rain. Then numerical simulation is conducted using MM5 to simulate a 66-h post-landfall process. The simulated distribution and intensity of precipitation match the observation well. With the simulated result, the characteristics and process of MCS development are analyzed with the finding that the convergence of the tropical depression and South China Sea (SCS) summer monsoon over The south of China causes the formation of a mesoscale vortex, mesoscale convergence center and mesoscale convergence line, which are favorable to the development and sustaining of the MCSs. A sensitivity experiment indicates that the SCS summer monsoon transports unstable energy and water vapor continuously, which is of vital importance to rainstorms.