Extreme meteorological disaster effects on grain production in Jilin Province, China

Extreme meteorological disaster effects on grain production is mainly determined by the interaction between danger degree of hazard-induced factors and vulnerability degree of hazard-affected bodies. This paper treats physical exposure, sensitivity of the response to the impact, and capabilities of disaster prevention and mitigation as a complex system for vulnerability degree of hazard-affected bodies, which included the external shocks and internal stability mechanism. Hazard-induced factors generate external shocks on grain production systems though exposure and sensitivity of hazard-affected body, and the result can be represented as affected area of grain. By quantile regression model, this paper depicts the quantitative relationship between hazard-induced factors of extreme meteorological disaster and the affected area in the tail of the distri- bution. Moreover, the model of production function have also been utilized to expound and prove the quantitative relationship between the affected area and final grain output under the internal stability mechanism of the agricultural natural resources endowment, the input factors of agricultural production, and the capacity of defending disaster. The empirical study of this paper finds that impact effects of drought disaster to grain production system presents the basic law of ＂diminishing marginal loss＂, namely, with the constant improvement of the grade of drought, marginal affected area produced by hazard-induced factors will be diminishing. Scenario simulation of extreme drought impact shows that by every 1% reduction in summer average rainfall, grain production of Jilin Province will fell 0.2549% and cut production of grain 14.69% eventually. In re- sponse to ensure China＇s grain security, the construction of the long-term mechanism of agricultural disaster prevention and mitigation, and the innovation of agricultural risk management tools should be also included in the agricultural policy agenda.

Evaluation of Forest Damaged Area and Severity Caused by Ice-snow Frozen Disasters over Southern China with Remote Sensing

The accurate assessment of forest damage is important basis for the forest post-disaster recovery process and ecosystem management. This study evaluates the spatial distribution of damaged forest and its damaged severity caused by ice-snow disaster that occurred in southern China during January 10 to February 2 in 2008. The moderate-resolution imaging spectroradiometer(MODIS)13 Q1 products are used, which include two vegetation indices data of NDVI(Normalized Difference Vegetation Index) and EVI(Enhanced Vegetation Index). Furtherly, after Quality Screening(QS) and Savizky-Golay(S-G) filtering of MODIS 13 Q1 data, four evaluation indices are obtained, which are NDVI with QS(QSNDVI), EVI with QS(QSEVI), NDVI with S-G filtering(SGNDVI) and EVI with S-G filtering(SGEVI). The study provides a new way of firstly determining the threshold for each image pixel for damaged forest evaluation, by computing the pre-disaster reference value and change threshold with vegetation index from remote sensing data. Results show obvious improvement with the new way for forest damage evaluation, evaluation result of forest damage is much close to the field survey data with standard error of only 0.95 and 1/3 less than the result that evaluated from other threshold method. Comparatively, the QSNDVI shows better performance than other three indices on evaluating forest damages. The evaluated result with QSNDVI shows that the severe, moderate, mild damaged rates of Southern China forests are 47.33%, 34.15%, 18.52%, respectively. By analyzing the influence of topographic and meteorological factors on forest-vegetation damage, we found that the precipitation on freezing days has greater impact on forest-vegetation damage, which is regarded as the most important factor. This study could be a scientific and reliable reference for evaluating the forest damages from ice-snow frozen disasters.

Climatic Characteristics of Extreme Cold and Frost Disaster and the Effects on Flowers and Trees in Mountain City in 2010

[Objective] The aim was to explore climatic characteristics of cold and frost disaster and the effects on flowers and trees in mountain city in 2010. [Method] Extremism of cold and frost disaster in temperature and lasting period, and the effects on flowers and trees in 2010 were researched based on information of average ten-day temperatures and extreme lowest temperature in 1951-2010 and Michelia alba DC. growth in a Hou in 2008-2010, as per statistical analysis technique. [Result] Cold and frost disaster in winter of 2010 proved the longest in lasting period, lowest in average temperature, and most serious for flowers and trees, resulting in serious loss of flowers and trees in Beibei area. [Conclusion] Countermeasures in the research would reduce owners’ loss in flowers and trees.

Typhoon/Hurricane/Tropical Cyclone Disasters: Prediction, Prevention and Mitigation

Since 1972 Rita typhoon attacked on Dalian Port and induced severe catastrophe, we were studied on statistical prediction model of typhoon induced wave height and wind speed. With an increasing tendency of the natural hazards frequency and intensity, risk assessment of some design codes for coastal defence infrastructures should be of paramount importance influencing the economic development and a lot of lifes in China. Comparison between existing extreme statistical model like Gumbel, Weibull, P-III distribution or Probable Maximum Typhoon/Hurricane (PMT/PMH), Design Basis Flood (DBF) with our 1975-1980 proposed (CEVD) model showed that all the planned, designed and constructed coastal infrastructures accepted the traditional safety regulations are menaced by possibility of future ty-phoon/hurricane disasters and cannot satisfy the safety requirements with the increasing tendency of the extreme natural hazards. Our first publication in US (J. of Waterway Port Coastal & Ocean Eng. ASCE, 1980, ww4) proposed an new model “Compound Extreme Value Distribution” used for China sea, after then the model was used in “Long term Distribution of Hurricane Characteristics” for Gulf of Mexico & Atlantic coasts, U.S. (OTC.1982). 2005 hurricane Katrina, Rita and 2012 hurricane Sandy induced disasters proved 1982 CEVD and CEVD has been developed into Multivariate Compound Extreme Value Distribution (MCEVD). 2006 MCEVD predicted extreme hazards in New Orleans, Gulf of Mexico and Philadelphia areas. 2013 typhoon Fitow induced disaster in China also proved MCEVD 2006 predicted results.

Extreme Events Assessment Methodology Coupling Debris Flow,Flooding and Tidal Levels in the Coastal Floodplain of the Sao Paulo North Coast(Brazil)

The North Coastal Region of the State of S?o Paulo, which comprises the Municipalities of Caraguatatuba, S?o Sebasti?o, Ilhabela and Ubatuba, is one of the most prone to flooding and debris flow deposition Brazilian areas, owing to hydrological extreme rainfall events usually coupled with extreme tidal levels. This risk is also high due to human lives and material assets, with increasing population rates and the establishment of large companies such as the Oil industry, with reduced defense/prevention measures and works.The catastrophic scenario of the city of Caraguatatuba, in March 1967, resulting from one of the most serious natural disasters in Brazil, fosters discussions about probabilities of heavy rainfall-caused events and rise in the sea level in coastal areas. Hence, this research is a consequence of this reality. The research is founded on an innovative methodology based on the analysis of past data of rainfall and tidal stations, complemented with debris flow registers in the region of the north coastal zone of the State of S?o Paulo (Brazil). The anaysis developed involved the meteorological, hydraulic, geotechnical and statistical knowledge areas.Practical results are intended to be used for urban planning, designs of macro-drainage, fluvial, maritime projects and debris flow retention structures. These practical applications will then associate the probability of occurrence of certain types of heavy rainfall-caused events such as flooding or debris flow coupled with a corresponding increase in tidal levels.

Disaster prevention design criteria for the estuarine cities:New Orleans and Shanghai The lesson from Hurricane Katrina

The accurate prediction of the typhoon （hurricane） induced extreme sea environments is very important for the coastal structure design in areas influenced by typhoon （hurricane）. In 2005 Hurricane Katrina brought a severe catastrophe in New Orleans by combined effects of hurricane induced extreme sea environments and upper flood of the Mississippi River. Like the New Orleans City, Shanghai is located at the estuarine area of the Changjiang River and the combined effect of typhoon induced extreme sea en- vironments, flood peak runoff from the Changjiang River coupled with the spring tide is the dominate factor for disaster prevention design criteria. The Poisson-nested logistic trivariate compound extreme value distribution （PNLTCEYD） is a new type of joint probability model which is proposed by compounding a discrete distribution （typhoon occurring frequency） into a continuous multivariate joint distribution （ typhoon induced extreme events）. The new model gives more reasonable predicted results for New Orleans and Shanghai disaster prevention design criteria.

2023年中国气候异常特征及主要天气气候事件

2023年,我国气候主要表现为暖干的特征,全国平均气温10.71℃,较1991—2020年气候平均偏高0.82℃,为1951年以来最暖;全国平均降水量615.0 mm,较常年偏少3.9%,为2012年以来第二少。四季气温均较常年同期偏高,其中夏、秋季分别为历史同期次高和最高;除秋季降水偏多外,其余三季降水均偏少。汛期(5—9月),全国平均降水量较常年同期偏少4.3%,为2012年以来第二少,我国中东部降水总体呈“中间多南北少”的分布。2023年,我国区域性气象干旱多发,西南地区遭遇冬春连旱;春季北方沙尘天气过程偏多;夏季前期,华北和黄淮遭受1961年以来最强高温过程;7月底至8月初,受台风杜苏芮影响,京津冀地区发生历史罕见极端强降水过程,华北地区出现“旱涝急转”;华西秋雨开始早、结束晚、雨量多;1月中旬发生年内最强寒潮过程;秋末冬初冷空气频繁入侵,12月华北和黄淮等地降雪日数偏多、积雪偏深。

联合国全民早期预警目标下中国气候风险管理前景分析

全球气候变暖对自然生态系统和人类社会产生了广泛而深远的影响,特别是加剧了气候变化风险,未来这种风险将更加复杂且难以管理。早期预警是减轻灾害风险和适应气候变化的重要手段。文章系统回顾了国内外早期预警发展及早期预警技术的全球演变历程,归纳总结了国际早期预警从概念提出到多灾种早期预警系统发展的4个阶段,剖析了气候变化背景下联合国全民早期预警倡议的3方面内涵。结合我国早期预警服务的现状和发展模式,以及新形势下面临的气候风险、预警需求和技术差距,提出了在联合国全民早期预警目标下,我国在气候风险管理方面的3个优先方向。一是加强对复合型极端天气气候事件发生发展机理和预报预警的科学研究,以及人类社会经济系统中潜在临界要素的研究,评估极端事件和临界要素引爆后的潜在级联影响和规模,提高灾害风险认知能力,拓深、拓广已有多灾种早期预警系统,提升防范新型气候灾害风险能力;二是识别气候变化对行业、领域和区域绿色低碳转型可能造成的产业风险,加快构建面向气候和气候变化尺度的国家级气候安全早期预警平台,提升全社会应对气候风险的能力;三是开展多灾种早期预警国际合作,帮助尚无早期预警系统或早期预警系统效力不足的国家建立和完善早期预警系统,重点是厘清区域和国家存在的主要气候灾害风险和等级,以及适应气候变化的紧迫需求,提供多品类气象防灾减灾公共产品,提高国际影响力。

应对极端冰灾的电力系统多阶段韧性提升策略

为提升冰灾下电力系统的韧性,降低系统负荷削减量,提高系统恢复速率,提出一种应对极端冰灾的电力系统多阶段韧性提升策略。对冰灾场景以及受冰灾影响的线路故障率进行建模;从线路抗冰能力、系统负荷损失、系统恢复情况、线路受损情况、维修资源充裕度多个角度构建电力系统综合韧性评估指标,以定位冰灾下系统的薄弱环节;在此基础上,通过灾前线路故障风险预测、灾中机组出力调整以及除冰线路筛选和主动停运除冰、灾后维修顺序规划等策略提升冰灾下的系统韧性。基于IEEE 39和IEEE 118节点系统进行仿真分析,结果验证了所提韧性评估方法和提升策略的有效性。

利比亚德尔纳2023年极端洪水模拟复盘分析

全球气候变化背景下,极端强降雨和洪涝等水文事件的极值屡屡刷新历史记录,造成重大损失。2023年9月10—11日,在地中海飓风“丹尼尔”的影响下,利比亚东北部地区发生罕见特大暴雨,引发德尔纳市上游两座水库接连溃决,造成巨大人员伤亡。本文对德尔纳市极端洪水事件进行了梳理,并以德尔纳市洪灾及受影响区域为研究对象,建立了二维水动力模型,对溃坝洪水进行了模拟和复盘分析。通过哥白尼应急管理服务(Copernicus Emergency Management Service,CEMS)提供的受灾数据对模型结果进行对比验证(CEMS持续监测欧洲和全球即将发生或实时发生的灾难事件)。结果显示,影响德尔纳市的溃坝洪水持续了2 h左右,对城市的破坏主要集中在前30 min。本次复盘分析了德尔纳市溃坝洪水演进与风险分布特征,可为我国城市地区大坝溃决风险防控、早期预警和应急管理提供参考借鉴,同时也可为世界其他地区的大坝溃决风险防控、早期预警和应急管理提供参考借鉴。

极端灾害下基于综合需求响应的电-水-气综合能源系统负荷恢复策略

在地震等极端自然灾害下,电-水-气综合能源系统的元件故障概率会大幅提升,进而严重影响系统的正常运行。针对目前忽略用户在提升系统弹性上的潜力,基于综合需求响应对电-水-气综合能源系统负荷恢复策略进行研究。首先基于多能源之间的耦合特性与用户的动态响应特性建立综合需求响应模型。其次设计系统与用户协同的需求响应参与机制,将用户的综合需求响应作为灵活性资源融入极端灾害下的负荷恢复策略中,有效、合理地提升系统弹性。最后建立电-水-气综合能源系统负荷恢复优化模型,通过改造的电-水-气综合能源系统对所提出的方法进行了模拟和验证。结果表明,所提出的负荷恢复策略能够提高灾后系统负荷的恢复比例,有效增强系统的弹性。

极端降雨与强人类活动复合作用下山洪灾害研究构想和成果展望

全球气候变暖导致山丘区极端降雨事件多发,降雨强度与量级不断突破区域历史极值,同时叠加区域脆弱环境和强人类活动影响,致使山洪形成及演进致灾成因复杂多变,由此加重了暴雨山洪引发的人员伤亡和财产损失。山洪灾害具有显著的自然和社会双重属性,其形成发展是山丘区环境孕灾承灾因子复合作用的结果。中国山丘区局地气候独特,地质地貌类型众多,溪河水系复杂,人类活动影响突出。大量重大山洪灾害事件表明,极端降雨诱发的山洪过程及致灾特征各异,给山洪灾害预报预警防御造成极大困扰,山洪灾害研究仍是当前重大自然灾害防控的重点和难点。长期以来,中国山洪灾害研究多偏重于雨水情时空变化规律,着重研究降雨影响的山洪洪水淹没特征,据此推算山洪灾害防治区的临界雨量与水位阈值,在山洪灾害防治实践应用中取得了较为显著的成效,山洪灾害事件导致的人员伤亡数总体显著下降。然而,受山丘区降雨特征、下垫面组成、溪河形态及人类活动等多因素影响,山洪洪水形成演进时挟带大量泥沙,从而表现为山洪水沙、山洪泥石流等物理过程,导致的局地冲毁、淤埋、淹没等致灾成因及阈值与山洪洪水致灾也存在本质差异,这也是近年来中国重大山洪灾害事件多发的主要原因。针对极端降雨诱发多类型山洪形成演进与强人类活动复合作用致灾防御难题,亟需利用气象学、水文学及河流动力学等多学科知识,采用现场调查、物理试验、数值模拟及理论分析相结合的方法,从传统单一的山洪洪水灾害研究扩展为全类型山洪灾害(山洪洪水灾害、山洪水沙灾害、山洪泥石流灾害)研究,开展全类型山洪引发的冲毁—淤埋—淹没等复合致灾研究,系统探究中国重灾省区重大山洪灾害事件的强降水时空演变规律,剖析极端降雨与强人类活动复合作用下多类型山洪形成及其演进致灾范围、规模特征,揭示气象水文溪河响应与强人类活动影响的不同类型山洪灾害致灾成因,建立气象水文水沙动力过程模拟方法,辨识山丘区流域全类型山洪冲毁—淤埋—淹没风险,提出不同类型山洪灾害易发区识别方法,构建山洪洪水灾害、山洪水沙灾害及山洪泥石流灾害分区分级多指标预警防御方法。该研究有利于提升中国山洪灾害理论技术研究水平,进一步完善中国山洪灾害防治对策。

极端天气城市特大暴雨洪涝灾害特征再分析及应对策略

随着全球变暖和城市化快速发展,城市特大暴雨洪涝灾害风险日趋加剧。通过文献调研、科学分析与社会实践,首先凝练极端天气影响下城市特大暴雨洪涝灾害主要特征:包括降雨强度与累计降雨量大,突发性更强、预报极为困难,时空动态性明显、洪涝灾害耦合交互,分布范围广、多发群发,诱发次生灾害、级联效应明显,善于钻空子、找防汛漏洞,灾害破坏性与影响力更大。从多尺度自然环境、防洪排涝能力建设、洪涝减灾技术设备、防汛应急组织管理和洪灾防治政策法规等方面揭示城市特大暴雨洪涝灾害的主要成因,提出极端天气城市特大暴雨洪涝灾害科学应对策略,即:深化城市暴雨洪涝灾害级联效应理论,研发城市极端暴雨洪涝预测与精细化计算模型,提升城市暴雨洪涝应急防御技术与装备,推进城市防洪排涝体系全局协同防灾。研究成果有助于科学应对气候变化与极端天气影响下城市洪涝灾害面临的新挑战,进一步完善城市洪涝灾害防御理论技术与风险管理体系,对城市特大暴雨洪涝灾害的科学防控具有重要指导意义。

台风场景下基于多种分布式资源协同的弹性配电网两阶段供电恢复策略

近年来频发的自然灾害极大威胁配电网安全运行,统筹考虑不同分布式资源特点,发挥分布式资源互补互济优势,有助于解决灾后配电网部分线路损坏、电力供应不足问题,实现电网灾后快速恢复。在电网中分布式资源种类不断丰富的背景下,本文提出一种台风场景下基于多种分布式资源协同的弹性配电网灾前及灾后两阶段供电恢复策略。首先,考虑配电网和交通网耦合的影响,灾前阶段在考虑电动汽车调度的同时,以加权失电量期望最小为目标建立移动储能和抢修队应急仓库选址模型;其次,根据以上3种分布式资源以及柔性负荷的灾后响应特征,将灾后阶段分为紧急功率支撑和负荷快速恢复两个过程,搭建了配电网灾后多时段恢复优化模型;然后,通过深入研究多种分布式资源的优缺点,设计了配电网两阶段供电恢复框架;最后,设计了多组算例,验证了所提方法的有效性和可行性。

计及台风灾害全过程模拟的配电网差异化加固规划韧性提升方法

台风会对配电网系统造成严重影响,制定架空线路的防风加固规划方案至关重要。为提高配电网抵御自然灾害的韧性,提出一种计及台风灾害全过程模拟的配电网差异化加固规划韧性提升方法,通过模拟台风登陆至消亡时刻全过程实时风况信息,对各线路实施差异化加固。首先,利用狄利克雷过程混合模型(dirichlet process mixture model,DPMM)聚类算法提取典型台风登陆场景,结合风暴轨迹模型和Batts风场模型模拟实时台风移动路径和台风风场,计算配电网线路实时故障概率。然后,结合台风场景模拟结果和不同设计风速标准下的差异化的架空线路故障率,建立以多等级线路加固年投资成本、台风过境过程中失负荷成本、停电损失和维修成本最小为目标的双层随机规划模型,并利用Benders分解算法进行求解。最后,以改进IEEE33节点系统为例,对所提方法有效性进行了验证。

基于CMIP6的秦岭北麓未来极端降水洪涝风险分析

随着全球变暖,极端降水的风险评估已成为学术界和各国政府广泛关注的焦点。为准确分析秦岭北麓在全球变暖情景下未来洪涝灾害事件风险时空分布,基于CMIP6降水数据、地理数据及社会经济数据,采用博弈论组合赋权法结合熵权法和层次分析法构建洪涝灾害风险评估模型,对未来两种情景(SSP245和SSP585)、两个时段(2040—2060年和2070—2090年)的洪涝灾害风险进行评估。结果表明:1)危险性较高的地区主要分布于蓝田县和山区低洼地区,随着年份及情景的变化,危险性有明显的增高趋势;2)脆弱性较高的地区主要在周至县、鄠邑区和长安区北部及山区公路地区;3)极端降水洪涝致灾风险等级较高的地区主要集中在蓝田县和临潼区,不同情景下洪涝致灾风险随时间呈增加趋势。

“23·7”特大暴雨对河北平原玉米产量的影响研究

洪涝是一种破坏力巨大的自然灾害,对粮食生产构成严重威胁。受台风“杜苏芮”和“卡奴”的影响,2023年7月29日至8月1日京津冀地区出现百年一遇的特大暴雨洪水灾害,给京津冀地区造成了重大损失,导致部分农田几乎绝收。为评估极端暴雨事件对当地粮食产量的影响,本研究使用MODIS MOD09GQ数据分析了暴雨前后的归一化植被指数(NDVI)变化,据此划定了本次暴雨造成的受灾农田区域(主要在河北平原)及其受灾程度,同时结合2016—2020年玉米种植空间分布、农业统计数据和NDVI数据,估算了受灾农田区域未发生暴雨和发生暴雨后两种情景下的玉米产量,进而评估了本次暴雨造成的玉米产量损失。主要得到以下结果:1)暴雨发生后,河北平原受灾农田区域的NDVI普遍减少0~0.35,相比之下,未受灾农田区域的NDVI均有所增加。2)本次强降雨导致河北平原约24万hm^(2)农田受到影响,绝产面积约13万hm^(2),减产面积约11万hm^(2)。3)蓄滞洪区周边的22个县(市、区)是本次暴雨的主要受灾区域,据回归分析结果,本次暴雨可能造成的玉米产量损失多达22万t,且92%的产量损失是由作物绝产所致。本研究为遥感手段估算极端降雨导致的粮食减产提供了一个快速且可靠的计算框架,同时强调了极端降雨对粮食安全的巨大威胁。

输电线路气象风险精细化建模及气象灾害的在线预警防御策略

气象因素在输电线路稳定运行中起着重要作用,在评估风险时应予以考虑。为此,提出一种输电线路气象风险预警及防护方法。该方法考虑时空发电预测、设备健康和可靠性评估以及概率负荷预测等方面对气象风险进行精细化建模,并基于气象危害、电网脆弱性和灾后恢复成本提出一种新的风险度量标准。此外,针对负荷中断恢复以及缓解用电拥堵,提出一种气象灾害的在线预警防御策略。最后,在案例中对所提出的方法和策略进行测试分析,其结果可以验证方法和策略的有效性。

城市极端暴雨洪涝灾害成因及对策研究进展

从极端暴雨形成机制、城市洪涝致灾机理及风险评估、防灾减灾措施和应对极端暴雨的城市韧性4个方面对城市暴雨洪涝问题国内外研究进展进行了综述,指出研究中下垫面对强降水和产汇流过程的影响机制认识不清,以单灾种为研究对象的风险评估缺乏对各类灾害关系的厘定,应对极端暴雨的城市韧性研究多停留在理论探讨层面等问题,未来应重点研究城市极端暴雨预报预警能力提升技术、洪涝灾害形成及灾害链传导机制、洪涝灾害治理措施、可实施层面的城市韧性提升方法等。

考虑分布式光伏高效消纳与负荷损失最小的区域配电网应急资源协同配置策略

为实现应急资源的合理配置,综合考虑区域配电网正常运行和故障运行下的经济性,提出一种采用线路加固和分布式储能的应急资源协调配置策略。利用最大风速法和阈值法模拟得到线路故障情况,并采取基于Kantorovich距离的后向削减法得到区域配电网遭遇极端天气时的源荷分布经典场景。综合考虑正常工况下分布式光伏高效消纳和故障工况下负荷损失最小,构建了包含应急阶段失负荷成本、应急资源投资成本以及正常运行成本的优化模型。以改进的IEEE 33节点配电网为例对所提应急配置策略进行验证分析。结果表明,所提应急资源配置策略可以兼顾分布式光伏高效消纳和负荷损失最小,在减少极端灾害下经济损失的同时,促进区域配电网的低碳经济运行。