内蒙古呼包鄂地区近56年来大气环境容量变化特征分析     

刘新  刘林春  尤莉 《气象与环境科学》2019,42(1):86-92

为探讨内蒙古呼包鄂地区大气对污染物承载能力的变化,科学评价气候变化对大气环境的影响,利用1961—2016年呼包鄂地区8个国家气象站降水量、风速、云量资料,分析了该地区气象条件的变化特征及大气环境容量的时空分布特征,并对大气环境容量与气象要素之间的相关性进行了分析。结果显示:呼包鄂地区大气环境容量1月的最小、4月的最大,春季的>秋季的>夏季的>冬季的,年平均大气环境容量为62.4 t/d/km^2;月、季、年平均大气环境容量呈波动减小趋势,特别是20世纪70年代末期之后减小趋势更为显著;有明显的空间分布特征,由城区向郊区逐渐增大,城郊差异冬季最为明显,夏季差异最小;大气环境容量与降水相关性差,与风速和日最大混合层高度呈显著的正相关关系,特别是与风速相关性更显著,与小风日数呈显著的负相关关系。  相似文献   

太原汛期短时强降水环流分型及环境参量分析     

周晋红  赵彩萍  董春卿 《干旱气象》2019,37(3):392-399

应用太原1996-2015年7个国家气象站、2008-2015年63个区域站6-9月逐时降水资料及相关探空、地面观测资料,对太原短时强降水日环流配置进行天气学分型,分析各流型下关键环境参数分布特征。结果表明,太原发生短时强降水的500 hPa环流形势有四种:冷涡型、高空槽型、高空槽加副高型、西北气流型。太原短时强降水常发生在比较温和的对流有效位能(CAPE)环境下,大部分过程CAPE值≤1500 J·kg^-1,冷涡型则≤1000 J·kg^-1。西北气流型850 hPa与500 hPa温差(ΔT850-500)大,静力不稳定度比其他型更强,且500 hPa有明显的干层存在。高空槽加副高型K指数大,且暖云厚度均值达3576 m,明显大于其他型2471~2608 m的均值。冷涡型全部、高空槽型85%的过程出现在弱0~6 km垂直风切变环境下,而高空槽加副高型、西北气流型0~6 km垂直风切变相对较大,35%以上达到中等强度。冷涡型、西北气流型短时强降水太原上空700 hPa水汽常比850 hPa更充沛。太原超过70 mm·h^-1的极端降水出现在西北气流型下,有中等强度的CAPE值、强层结不稳定、弱0~6 km垂直风切变、3550 m以上暖云厚度,中低空水汽充足,这些环境参量的配合对强降水效率有很好的指示意义。  相似文献   

Climate change perceptions and their individual-level determinants: A cross-European analysis     

《Global Environmental Change》2019

There is now an extensive literature on the question of how individual-level factors affect climate change perceptions, showing that socio-political variables, notably values, worldviews and political orientation, are key factors alongside demographic variables. Yet little is known about cross-national differences in these effects, as most studies have been conducted in a single or small number of countries and cross-study comparisons are difficult due to different conceptualisations of key climate change dimensions. Using data from the European Social Survey Round 8 (n = 44,387), we examine how key socio-political and demographic factors are associated with climate change perception across 22 European countries and Israel. We show that human values and political orientation are important predictors of climate change beliefs and concern, as are the demographics of gender, age, and education. Certain associations with climate change perceptions, such as the ones for the self-transcendence versus self-enhancement value dimension, political orientation, and education, are more consistent across countries than for gender and age. However, even if the direction of the associations are to a large extent consistent, the sizes of the effects are not. We demonstrate that the sizes of the effects are generally smaller in Central and Eastern European countries, and that some demographic effects are larger in Northern European as compared to Western European countries. This suggests that findings from one country do not always generalize to other national contexts.  相似文献   

基于逆推法和德尔菲法的地质灾害气象服务效益评估     

狄靖月  徐辉  许凤雯  杨寅  包红军  张国平 《气象》2019,45(5):705-712

地质灾害气象服务发挥越来越重要的作用,既有可量化的经济效益,也有不可忽视难以量化的、潜在的社会效益和生态效益。根据历年地质灾害调查与分析数据,运用逆推法结合德尔菲法,建立地质灾害气象服务效益评估模型,并根据已有研究及防汛经验对模型的系数进行量化。模型以地质灾害气象预报评分和灾害直接经济损失为输入,以防灾减灾效益值、防灾减灾效益百分率、气象服务直接经济效益、气象服务直接经济效益百分率为输出,可同时对各区域、各时间段的地质灾害过程进行气象服务效益分段评估,也可评估年度地质灾害气象服务效益。该模型在2017年地质灾害气象效益评估中表现良好,有一定指导意义。  相似文献   

降雨型地质灾害预报方法研究进展          下载免费PDF全文

陈悦丽  赵琳娜  王英  王成鑫 《应用气象学报》2019,30(2):142-153

开展降雨型地质灾害预报是减少灾害损失的有效方法。该文在讨论降雨型地质灾害预报相关概念的基础上,结合国内外已有的研究成果,系统总结了隐式统计模型、显式统计模型和动力模型等降雨型地质灾害预报模型的特点和适用条件。近几年区域降雨型地质灾害的预报技术研究有以下新特点:统计模型简单实用,目前已经由单一考虑降雨特征的第1代隐式统计模型,进一步发展为考虑地质、地貌等静态因子的显示统计模型;动力模型逐渐由基于垂直入渗理论的边坡稳定性模型开始向基于水土耦合机制的复杂预报模型发展;降雨型地质灾害业务预报预警的核心是地质灾害预报模型的本地化运行,我国已经基于统计模型搭建了服务于不同区域的业务预报预警系统。结合多源预报降雨资料,搭建基于水土耦合机制的降雨型地质灾害集合预报预警系统是未来可能的发展方向。  相似文献   

1822号“山竹”台风龙卷过程观测与预警分析     

黄先香  炎利军  王硕甫  蔡康龙  余乐福 《热带气象学报》2019,35(4):458-469

2018年9月17日09:37—10:00,在登陆台风“山竹”外围螺旋雨带中,广东省佛山市三水区到肇庆市四会区发生了EF2级强龙卷,龙卷路径长度18 km,持续时间23 min,平均时速47 km/h,导致不少建筑物损毁。本次过程佛山市进行了龙卷预警试验,提前37 min发布了龙卷预警,龙卷没有造成人员伤亡。利用观测资料对产生强龙卷的环境场特征、地面自动站和雷达观测的中小尺度特征以及龙卷预警试验进行了分析,结果表明:产生龙卷的微型超级单体出现在台风外围和副高边缘之间的强东南急流中,具有低层辐合、高层辐散、水汽充足等典型台风外围龙卷环流形势特征;强的低空0~1 km垂直风切变、大的风暴相对螺旋度和低的抬升凝结高度等环境条件利于龙卷的生成;龙卷影响时,邻近地面自动气象站观测要素表现出明显的信号,瞬时大风和最低气压的极值区呈东南至西北向带状分布,与龙卷路径一致,龙卷过境前后,单站气压“漏斗”明显,5 min降压/升压幅度达-2.5 hPa/+2.1 hPa;广州多普勒天气雷达探测到龙卷母体风暴的低层钩状回波和入流缺口特征,以及低层强中气旋和类TVS特征。预警试验初步表明,对台风龙卷高发区,在环境场有利情况下,若低层出现中等或以上强度中气旋,其底高在1 km以下,可以考虑发布龙卷预警。   相似文献   

Dynamic propagation criteria for catastrophic failure in planar landslides          下载免费PDF全文

Wangcheng Zhang  Dong Wang  Mark F. Randolph  Alexander M. Puzrin 《国际地质力学数值与分析法杂志》2016,40(17):2312-2338

Quantitative assessment of the risk of submarine landslides is an essential part of the design process for offshore oil and gas developments in deep water, beyond the continental shelf. Landslides may be triggered by a reduction in shear strength of subsea sediments over a given zone, caused for example by seismic activity. Simple criteria are then needed to identify critical conditions whereby the zone of weakness could grow catastrophically to cause a landslide. A number of such criteria have been developed over the last decade, based either on ideas drawn from fracture mechanics, or considering the equilibrium of the initial weakened zone and adjacent process zones of gradually softening material. Accounting for the history of the weak zone initiation is critical for derivation of reliable propagation criteria, in particular considering dynamic effects arising from accumulating kinetic energy of the failing material, which will allow the failure to propagate from a smaller initial zone of weakened sediments. Criteria are developed here for planar conditions, taking full account of such dynamic effects, which are shown to be capable of reducing the critical length of the softened zone by 20% or more compared with criteria based on static conditions. A numerical approach is used to solve the governing dynamic equations for the sliding material, the results from which justify assumptions that allow analytical criteria to be developed for the case where the initial softening occurs instantaneously. The effect of more gradual softening is also explored. Copyright © 2016 John Wiley & Sons, Ltd.  相似文献   

Geological interpretation of a deep seismic‐reflection transect across the boundary between the Delamerian and Lachlan Orogens,in the vicinity of the Grampians,western Victoria     

R. J. Korsch  T. J. Barton  D. R. Gray  A. J. Owen  D. A. Foster 《Australian Journal of Earth Sciences》2013,60(6):1057-1075

A deep seismic‐reflection transect in western Victoria was designed to provide insights into the structural relationship between the Lachlan and the Delamerian Orogens. Three seismic lines were acquired to provide images of the subsurface from west of the Grampians Range to east of the Stawell‐Ararat Fault Zone. The boundary between the Delamerian and Lachlan Orogens is now generally considered to be the Moyston Fault. In the vicinity of the seismic survey, this fault is intruded by a near‐surface granite, but at depth the fault dips to the east, confirming recent field mapping. East of the Moyston Fault, the uppermost crust is very weakly reflective, consisting of short, non‐continuous, west‐dipping reflections. These weak reflections represent rocks of the Lachlan Orogen and are typical of the reflective character seen on other seismic images from elsewhere in the Lachlan Orogen. Within the Lachlan Orogen, the Pleasant Creek Fault is also east dipping and approximately parallel to the Moyston Fault in the plane of the seismic section. Rocks of the Delamerian Orogen in the vicinity of the seismic line occur below surficial cover to the west of the Moyston Fault. Generally, the upper crust is only weakly reflective, but subhorizontal reflections at shallow depths (up to 3 km) represent the Grampians Group. The Escondida Fault appears to stop below the Grampians Group, and has an apparent gentle dip to the east. Farther east, the Golton and Mehuse Faults are also east dipping. The middle to lower crust below the Delamerian Orogen is strongly reflective, with several major antiformal structures in the middle crust. The Moho is a slightly undulating horizon at the base of the highly reflective middle to lower crust at 11–12 s TWT (approximately 35 km depth). Tectonically, the western margin of the Lachlan Orogen has been thrust over the Delamerian Orogen for a distance of at least 25 km, and possibly over 40 km.  相似文献   

Coral assemblages and reef growth in the Commonwealth of the Northern Mariana Islands (Western Pacific Ocean)     

Peter Houk  Robert Van Woesik 《Marine Ecology》2010,31(2):318-329

Reef development varies considerably around the high, raised‐limestone islands of the Commonwealth of the Northern Mariana Islands (CNMI). Here we examine the modern assemblages at 30 sites for coral composition, colony density, colony size, and fidelity. We defined four reef types and hypothesize the presence of environmentally driven ecological stasis, whereby the environment continuously selects for coral species membership, defines colony sizes, and over time creates the noted reef types. Our results show that constructional spur‐and‐groove reefs supported significantly larger coral‐colony sizes and higher coral species richness compared with high‐relief interstitial framework, low‐relief incipient, and non‐constructional coral assemblages. Non‐constructional reefs supported much smaller coral colony sizes, despite similar population densities, and were consistently found in association with high wave exposure. The distinct coral assemblages found on interstitial framework and low‐relief incipient reefs were not affiliated with any wave exposure regime, but were located adjacent to large watersheds and on islands with unique geological history. These assemblages were nested within the spur‐and‐groove species pool. Overall, modern coral cover was well predicted by bathymetric slope and watershed size, while species richness was additively influenced by two proxies of pollution, suggesting the latter is better suited for establishing management targets. In contrast with previous studies that suggested modern assemblages were biologically controlled in the CNMI, we show reef assemblages and reef development are highly influenced by long‐term environmental forcing.  相似文献   

Engineering characteristics and uses of duricrusts in Australia     

G. H. McNally 《Australian Journal of Earth Sciences》2013,60(6):535-547

The uses and shortcomings of duricrusts (ferricrete, calcrete and silcrete) in engineering construction (as used for road‐base, aggregate, foundation materials and aquifers) are reviewed. Australian production of these materials represents about one‐third of all unprocessed road‐base and they are especially important as pavement courses for lightly trafficked, low‐cost rural and outback roads. However, duricrusts are regarded as marginal materials at best because of their typically poor grading, particle unsoundness, high fines plasticity, and absorption of water and bitumen. These materials are used because they are available locally in areas that are otherwise lacking in hard rock materials, such as deeply weathered and sedimentary rock terrains. The weathering profiles of which they form part are characterized by high permeability (despite being clay‐rich), variable cementation, low compressibility and a tendency to become weaker with depth. Although the more indurated layers are unrippable, they are also difficult to blast. Pedogenic (nodular) duricrusts were formerly sought for natural road‐base, because they occur widely and require only rudimentary processing. However, well‐cemented groundwater (vadose) duricrusts are now the preferred deposits, even though they require crushing and screening. Ferricrete is the most widely exploited of the duricrusts for engineering purposes, especially in northern and southwestern Australia, although calcrete is important in South Australia and in the Murray Basin. Silcrete is only a minor source of aggregate and road‐base, mainly in western Queensland.  相似文献