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1.
The results of the analysis of long-term radar research of the hailstorms over the central part of the Northern Caucasus are presented. Radar observations which formed the basis of experimental material were carried out continuously from the moment of the first radar echo registration until complete dissipation of the hailstorm. The computerized system of collecting, processing and the analysis of the radar information was used. Time discretization of the radar parameters of the full spatial observation averaged 3 min. Statistical sampling of radar data included 392 hail cells, for each of which the time distributions of the radar parameters both measured and calculated using the computerized system were compiled. Distribution of the hailstorms first radar echo formation zones over the observation region was compiled. Areas with the maximum frequency of the hailstorms first radar echo formation were defined. The hailstorm trajectories were analyzed. Four main types of hail cell trajectories were selected, which included 86 % of the supercells and 64 % of the long-lived multicells. The dynamic parameters of the hail core formation and development were analyzed. The hail storm characteristics of the Northern Caucasus are compared to the hail storms of Mendoza, Argentina, and Alberta, Canada. The bases of the organization of regional hail suppression services which use the rocket technology of cloud seeding are presented. The results of the cloud seeding operations during recent years are shown. 相似文献
2.
利用C波段新一代多普勒天气雷达监测资料和探空数据,对新疆南疆阿克苏地区西部绿洲2009-2015年28个降雹个例、32个对流风暴降雹单体进行分析,把发生在该区域的暴雹单体分为弱、中、强等三种类型,并综合分析不同强度降雹单体的“初生”、“跃增”和“酝酿”三个冰雹云生命史关键阶段的空间分布、演变规律以及不同温度层之间的关系,筛选出了能够提前识别各类冰雹云的雷达回波特征参量及指标阈值,并以此作为判识因子,建立了三种冰雹云提前识别及预警概念模型,同时对其识别能力进行验证,获得了三类冰雹云80%以上的识别准确率和合适的早期识别与有效作业指挥时间提前量,为该区域强冰雹云的早期识别与有效实施人工防雹作业决策提供科学依据。 相似文献
3.
The results of the analysis of long-term radar research of the hailstorms over the central part of the Northern Caucasus are presented. Radar observations which formed the basis of experimental material were carried out continuously from the moment of the first radar echo registration until complete dissipation of the hailstorm. The computerized system of collecting, processing and the analysis of the radar information was used. Time discretization of the radar parameters of the full spatial observation averaged 3 min. Statistical sampling of radar data included 392 hail cells, for each of which the time distributions of the radar parameters both measured and calculated using the computerized system were compiled. Distribution of the hailstorms first radar echo formation zones over the observation region was compiled. Areas with the maximum frequency of the hailstorms first radar echo formation were defined. The hailstorm trajectories were analyzed. Four main types of hail cell trajectories were selected, which included 86 % of the supercells and 64 % of the long-lived multicells. The dynamic parameters of the hail core formation and development were analyzed. The hail storm characteristics of the Northern Caucasus are compared to the hail storms of Mendoza, Argentina, and Alberta, Canada. The bases of the organization of regional hail suppression services which use the rocket technology of cloud seeding are presented. The results of the cloud seeding operations during recent years are shown.
相似文献4.
5.
Gökhan Demir 《Natural Hazards》2018,91(1):133-153
Numerical modelling techniques enable forcing function at the point of contact in a hail impact to be predicted, but many models available in commercial software have not been verified by experiments. A recently developed deterministic model is only able to simulate the impact action of an idealised spherical hailstone. Results recorded from the impact testing of non-spherical simulated hail ice specimens show wide scatters and are different to spherical specimens. A stochastic model has been developed in this study to incorporate the variability of the modelling parameters representing the behaviour of non-spherical ice specimens and to generate time histories of contact force for given impact scenarios. A probabilistic model which was developed previously to provide predictions of the distribution of the size of hailstones in a severe category hailstorm has also been further developed to provide predictions of the maximum contact force values in probabilistic terms. For any given pre-defined forcing function denting into the surface of a steel plate can be estimated by finite element analysis or experimentally on a test machine. The new knowledge base introduced in this paper can be used by manufacturers and designers to re-assess existing products and in making improvements to future installations taking into account cost–benefit considerations. 相似文献
6.
1961-2014年新疆冰雹灾害时空分布特征 总被引：2，自引：0，他引：2
通过整理、 普查得到1961-2014年新疆以县为单位的雹灾频次、 受灾面积、 经济损失的样本序列, 在此基础上定义了表征雹灾程度的无量纲数损失指数. 结果表明: 新疆雹灾频次集中出现在阿克苏地区、 博州、 石河子地区, 5-8月为多发期, 6月最多. 雹灾的年际变化呈现出2～5 a的短周期和7～8 a的长周期, 20世纪60、 70年代为新疆雹灾的少发期, 1980-1994年、 2001-2014年为雹灾的两个集中高发期. 按照地区累计灾损指数将新疆雹灾划分为5个等级, 阿克苏地区属严重雹灾区, 喀什地区、 塔城地区、 伊犁州属重雹灾区, 石河子地区、 博州、 昌吉州、 巴州、 克拉玛依市属中雹灾区, 阿勒泰地区、 克州、 和田地区、 哈密地区属轻雹灾区, 吐鲁番地区和乌鲁木齐市属微雹灾区. 相似文献
7.
南疆近60 a来冰雹灾害时空变化特征分析 总被引：4，自引：1，他引：3
冰雹是新疆主要灾害性天气之一, 利用新疆南疆各地州1949-2008年发生的冰雹频次及其造成的受灾农田面积、 经济损失、 死亡牲畜等资料, 分析了南疆冰雹频次时空变化特征及各县市雹灾灾情.结果表明: 南疆冰雹发生频次近60 a间呈明显上升趋势, 1950年代至1980年代中期发生频次较低, 1986年开始发生频次显著上升, 至1991年达最高值, 由1996年起又减少到2003年谷底.冰雹发生主要集中在3-10月, 其中6月频次最多, 年均3.6次, 其次5月为3.1次. 巴州、 阿克苏、 喀什和克州以春末到夏季型降雹为主, 和田以春季型降雹为主.冰雹一天之内多发生在白天到傍晚时段, 持续时间多为1~20min. 南疆冰雹空间分布上西北部多于东南部, 山脉的背风坡多于迎风坡, 山间盆地多于开阔平原.对各地州而言, 阿克苏冰雹发生频次最多, 属于严重雹灾区; 喀什和巴州次于阿克苏, 属于重雹灾区; 克州与和田冰雹发生频次较少, 属于中雹灾区. 冰雹受灾农田面积和经济损失随着工农业生产总值的增长而增加, 而且增长速度比经济增长速度快. 建议加大防雹投入力度, 建立人工防雹系统, 以减少雹灾损失, 遏制工农业发达地区雹灾损失严重和随着国民经济的增长雹灾损失增加的现象. 相似文献
8.
基于灾损评估的青海高原冰雹灾害风险区划 总被引：2，自引：1，他引：1
利用青海高原1961-2010年42个气象站逐次冰雹过程及其灾情信息, 采用滑动平均、 标准归一化及线性回归等方法, 在分析致灾因子危险性、 承灾体易损性评估指标的基础上, 建立了冰雹灾害区划模型, 并结合ArcGIS9.3平台得到青海高原冰雹灾害风险区划图. 结果表明: 青海东部农业区、 环青海湖地区、 柴达木盆地东部及三江源地区中东部为易受冰雹灾害影响的特高风险或高风险区域; 祁连山地区为中风险区, 而低风险区则位于柴达木盆地中、 西部. 区划结果与历史冰雹灾情基本吻合, 旨在为该区防灾减灾提供科学依据. 相似文献
9.
China’s regional meteorological disaster loss analysis and evaluation based on grey cluster model 总被引：3，自引：1，他引：2
To evaluate the regional meteorological disaster loss of China, this paper analyzed the different types of meteorological disasters, including droughts, floods, tropical storms, snowstorms and hail disasters. Based on the analysis about Chinese geographical features, the historical characteristics of different meteorological disasters are analyzed. In particular, these meteorological disasters influence to agriculture production are discussed. According to the analysis of data from 2004 to 2010, we know that the distribution characteristics are very different about different disasters. Provinces like Heilongjiang, Liaoning, Jilin, Inner Mongolia, Gansu, Shanxi and Yunnan are serious affected areas of drought influence. And Anhui, Shandong, Jiangsu, Henan, Jiangxi, Hubei, Hunan, Guangxi, Sichuan and Heilongjiang are serious affected areas by floods and heavy rain. While Guangdong, Fujian, Zhejiang, Shanghai, Jiangsu and Shandong are mainly affected by tropical storms, Henan, Hebei, Hunan and Hubei are serious affected by snowstorms and hail disasters. Then, a novel method based on grey cluster model is constructed and combined with the regional meteorological disaster loss evaluation index system. A total of 31 provinces are considered to evaluate the integrated meteorological disaster losses. The results indicated that Beijing, Tianjin, Shanghai, Xizang, Qinghai and Ningxia belong to the lighter loss grey class. Jiangxi, Hubei, Hunan, Hainan, Sichuan and Gansu belong to the serious loss grey class. Other regions belong to the general loss grey class that the influence caused by meteorological disasters not better than the lighter loss grey class and not worst than the serious loss grey class. 相似文献
10.
On 18 March 1990, an intense hailstorm in Sydney, New South Wales, Australia caused insured damage valued at A$million – the third most expensive loss event in Australian insurance history.While damage was widespread with claims for buildings spread across more than 130 postcodes, 20% of the claims came from just two postcodes. The proportion of dwellings of brick construction that made a claim was significantly less than the proportion of policies for this type of construction. Fibro (fibre-cement), timber and aluminium-clad dwellings are more likely to sustain damage than brick buildings in this type of storm.Hail caused the majority of damage to exterior building items while water damage more commonly affected interior building items and contents. While the repair of Interior building items such as ceilings and walls cost more than contents damage on average, the repair/replacement costs of contents contributed more to the total costs. Damage to window glass and roofs together made up more than 50% of the total claim. 相似文献
11.
利用1970 —2001 年1 ～12 月中国西北区冰雹日数的气象实测资料，将年冰雹日数发生的变化趋势看作每年的一个气候现象，分析其发生的气候变化趋势、年代际变化以及与大气环流的相关关系，得出多雹年北半球500 h Pa 极涡强、位置偏东，副热带高压面积小、强度弱、位置偏南，乌拉尔山至巴尔喀什湖高度场为正距平，雅库次克至贝加尔湖高度场为负距平。少雹年北半球500 h Pa
极涡弱、位置偏西，副热带高压面积大、强度强、位置偏北，乌拉尔山至巴尔喀什湖高度场为负距平，雅库次克至贝加尔湖高度场为正距平区。从而找出冰雹气候趋势预测的着眼点，建立冰雹短期气候预测概念模型；此模型对冰雹发生变化趋势的预测具有一定的实用价值。 相似文献
12.
新疆冰雹灾害经济损失评估及风险区划研究 总被引：5，自引：0，他引：5
基于1984-2014年新疆雹灾受灾面积、总成灾面积、农作物播种面积、新疆生产总值及以县为单位的雹灾频次等统计数据,构建雹灾经济损失指标和风险度指标,进行新疆冰雹灾害评估研究。其中雹灾经济损失指标可用于评价新疆雹灾经济损失的趋势变化,风险度指标可借助GIS空间信息处理技术形成新疆雹灾风险区划。研究表明：雹灾经济损失总体呈波动上升趋势,且受环境不稳定度的影响较大,二者保持着较好的正相关性。新疆冰雹灾害总体以中、低度风险为主,高风险次之。高风险区主要集中在喇叭形河谷地带的伊犁地区及其两侧的阿克苏、博州等地,建议通过调整农业产业结构、提升人工防雹能力等方式降低上述区域的雹灾损失。 相似文献
13.
Urban hailstorms are rarely studied in detail. This work documents five urban storms in Alberta where damage has, on three occasions, set the record for Canada's most costly natural disaster. Information from newspapers, insurance companies, and disaster assistance programs was utilized to supplement meteorological records and information obtained from public surveys.The record-breaking hail swath which accompanied the 1987 Edmonton tornado was mapped using over 800 responses to an unprecedented newspaper survey. Tennis ball sized hail struck 125 km2 of the city. Record-sized hailstones for Alberta were collected. Citizens' measurements of giant hailstones were compared to laboratory measurements. The rural storms were tracked using lightning detector information and damage was mapped using crop insurance and disaster assistance claims. The tornado-bearing storm was found to have a unique track.A late-season hailstorm which struck Calgary in 1991 was mapped using homeowner insurance claims organized by postal areas. Nine out of thirty areas had claims rates exceeding 50%, mainly for shingle replacement. Experiences of claims adjustors and an informal public survey were also utilized. Rural storms were mapped using weather radar and crop losses. The radar beam was strongly attenuated when it passed through hail-bearing storms and, thus, its ability to detect large hail was compromised.Weather conditions, urban and rural damaged areas, and insurance payments were compared for all five local hailstorms. These storms were discussed within the context of the long history of Alberta hail research and current trends in technology implementation. Forecasting of these hailstorms using conventional severe weather indicators was difficult in Calgary because of that city's proximity to the mountains. Hailstorms that struck Munich, Denver, and Toowoomba (Australia) were also discussed, and the hailstones collected from the great Munich storm were compared to those collected from the Edmonton storms. 相似文献
14.
This paper presents hail characteristics for two separate periods (1981–1990,1991–1999) in the western part of the hail protected area along the Croatianand Slovenian border. The first period is characterised by full application ofhail suppression technology. The protected area was covered with a sufficientnumber of hail suppression rockets, rockets launching was permitted across theSlovenian border aimed at early seeding, and Slovenia in that time had also theoperative hail suppression system. The second period is characterised withsignificantly lower application of hail suppression technology compared withfirst period. During the independence war in Croatia, because of a lack ofrockets and other objective circumstances, appropriate rocket hail suppressionwas missing. This work examines whether hail characteristics on the border areahave changed, taking into account the changes in suppression. Results show thatthe average diameter of hailstones and duration of hailfall slightly increasedin second period. Also, there is an increase in the number of areas with alarger ratio of hail producing heavy damage, compared with first period. On thebasis of data from five meteorological stations, it is visible that, as a resultof implementation of the hail suppression system, the average number of dayswith solid precipitation on that area in period April–October has reduced,compared with the period when there was no hail suppression system. 相似文献
15.
Hailstorms represent one of the major sources of damage and insurance loss to residential, commercial, and agricultural assets in several parts of Central Europe. However, there is little knowledge of hail risk across Europe beyond local historical damage reports due to the relative rarity of severe hail events and the lack of uniform detection methods. Here we present a new stochastic catalog of hailstorms for Europe. It is based on satellite observations of overshooting cloud tops (OT) that indicate very strong convective updrafts and hail reports from the European Severe Weather Database (ESWD). Historic hail events are defined based on OT detections from satellite infrared brightness temperatures between 2004 and 2011 for the warm seasons (April–September). The satellite-based historical event properties are complemented by hailstone observations from ESWD to stochastically simulate more than 1 million individual events with an event footprint resolution of 10 km. The final hail event catalog presented in this paper is the first one with a spatial event distribution that is based on a single homogeneous observation source over Europe. Areas of high hail probability or hail risk are found over Central and Southern Europe, including mountainous regions such as the Alps or the Pyrenees. Another region of relatively high hail risk is present over central Eastern Europe. 相似文献
16.
渭干河-库车河绿洲是南疆地区主要棉花生产基地之一, 随着气候变化和棉花种植面积的日益扩大, 雹灾对棉花生产的危害日趋严重. 利用该地区4个气象站44 a逐一地面降雹过程资料和33 a灾情信息, 对冰雹时空变化特征、活动规律、强度、受灾面积和影响因素等进行研究. 结果表明: 降雹空间分布为北部靠山地带多于南部平原地带, 受灾面积的空间分布则相反; 降雹以周期短、强季节性特征为主, 各县中等以上降雹天气占80%以上, 降雹趋于高发和强发的态势. 降雹频次与气温和降水呈较好的相关性, 冰雹多发年气温偏低、降水偏多, 冰雹少发年气温偏高、降水偏少. 位于南部靠近沙漠的沙雅县受灾最为严重, 雹灾与降雹强度、地域、季节和作物面积及类型等有关, 该地区棉花受灾机率大. 相似文献
17.
Shifting Economic Impacts from Weather Extremes in the United States: A Result of Societal Changes,Not Global Warming 总被引：4，自引：2，他引：4
Loss values from extremes in the U.S. and elsewhere have been more qualitativethan quantitative, but recent pressures for better information have led to newassessments and better estimates of financial losses from extremes. These pressureshave included concerns over potential impacts of more extremes due to global warmingfostered by ever increasing costs to the insurance industry and government from weather extremes; plus a series of massive losses during the past 15 years (drought of 1988–1989,Hurricane Andrew in 1992, and Midwestern 1993 floods). These recent assessmentsattempted to adjust data for societal changes over time and thus derived new and betterestimates of losses for seven major extremes than existed previously. Three extremeshave annual average losses in excess of a billion dollars (1998 dollars) includinghurricanes ($4.2 billion), floods ($3.2 billion), and severe local storms ($1.6 billion).One extreme and its adjusted losses exhibit upward trends (floods), but all others showno increases with time or temporal decreases (hail, hurricanes, tornadoes, and severethunderstorms). Annual national losses during 1950–1997 from the three major extremes, plus four others (hail, tornadoes, winter storms, and wind storms), collectively reveal no upward or downward trend over time, with an average annual loss of $10.3 billion. The quality loss values do not indicate an increase as has been postulated for global warming. The good news is that better estimates of impacts now exist, but the bad news is that they are still estimates and do not include sizable unmeasured losses. If accurate data on the economic impacts from weather extremes are seen as important for scientific research and policy-making for global warming, the U.S. needs a continuing program to adequately measure losses from weather extremes. 相似文献
18.
Most U.S. metropolitan regions have experienced urban “sprawl,” or the outward spreading of urban development from city centers.
For cities lying in areas prone to severe weather, the sprawl phenomenon exposes greater numbers of developed areas and inhabitants
to a variety of thunderstorm hazards. This study’s principal goal is to determine how urbanization growth patterns affect
a region’s vulnerability to severe weather events. To assess how sprawl may impact vulnerability to tornadoes, hail, and convective
wind events, an analysis examining potential loss may be utilized. This study employs two distinct approaches to examine how
the Atlanta area’s rapid and extensive development during the latter half of the twentieth Century has affected its overall
potential exposure to thunderstorm hazards. First, archived census data are used to estimate overall impacts from hypothetical
significant tornado, nontornadic convective wind, and hail events occurring at different time periods throughout several locations
in the Atlanta metropolitan region. Second, economic factors are integrated into the analysis, which assists in determining
how these hypothetical severe event scenarios may have changed from a cost standpoint if they were to occur in 2006 as opposed
to 1960. 相似文献
19.
New in situ data based on hydraulic fracturing and overcoring have been compiled for eastern Australia, increasing from 23 to 110 the number of in situ stress analyses available for the area between and including the Bowen and Sydney Basins. The Bowen Basin displays a consistent north‐northeast maximum horizontal stress (σH) orientation over some 500 km. Stress orientations in the Sydney Basin are more variable than in the Bowen Basin, with areas of the Sydney Basin exhibiting north‐northeast, northeast, east‐west and bimodal σH orientations. Most new data indicate that the overburden stress (σV) is the minimum principal stress in both the Bowen and Sydney Basins. The Sydney Basin is relatively seismically active, whereas the Bowen Basin is relatively aseismic. Despite the fact that in situ stress measurements sample the stress field at shallower depth than the seismogenic zone, there is a correlation between the stress measurements and seismicity in the two areas. Mohr‐Coulomb analysis of the propensity for failure in the Sydney Basin suggests 41% of the new in situ stress data are indicative of failure, as opposed to 13% in the Bowen Basin. The multiple pre‐existing structural grains in the Sydney Basin further emphasise the difference between propensity for failure in the two areas. Previous modelling of intraplate stresses due to plate boundary forces has been less successful at predicting stress orientations in eastern than in western and central Australia. Nonetheless, stress orientation in the Bowen Basin is consistent with that predicted by modelling of stresses due to plate boundary forces. Variable stress orientations in the Sydney Basin suggest that more local sources of stress, such as those associated with the continental margin and with local structure, significantly influence stress orientation. The effect of local sources of stress may be relatively pronounced because stresses due to plate boundary forces result in low horizontal stress anisotropy in the Sydney Basin. 相似文献
20.
A discrete element code with impact model has been developed and calibrated to simulate the dynamic behavior of rock materials, with special regard to rock fragmentation upon impact during rock-fall analysis. The paper summarizes the discrete element code, the calibration algorithms developed to identify the model microparameters, and the impact model. Experimental work on drop tests is then used to validate the code on modeling impact fragmentation. It has been found that the developed discrete element code and impact model can reasonably simulate rock fragmentation in drop tests. The use of the discrete element code and impact model can provide good reference results in evaluating impact fragmentation in rock-fall analysis. 相似文献