岩溶天生桥纵向分层旅游开发方式——以重庆黔江蒲花天生桥群为例

本文按发育岩性(可溶岩和非可溶岩), 发育规模(如桥高、拱高、跨度等), 桥下河谷的发育特征(常年性、季节性河流和干谷), 及发育成因(地表和地下), 提出天生桥的4大分类方案, 简要介绍和概括了近年来中国发现的典型岩溶天生桥的类型、分布格局、发育规模及景观组合和对比特征。然后以重庆黔江蒲花天生桥群为例, 初步分析和探讨了它的形成与演化, 系统分析和评价了它的资源系统, 通过与黔江区、武陵山区旅游资源及国内其它相似景区的对比, 概括其资源特色为“一河两桥三窗”, 并结合其市场条件, 将旅游开发主题定格为“桥下游暗河, 桥上走天桥, 上游漂激流”, 提出“一心二带一区三环”的功能布局, 探讨不同功能区的开发思路, 划分出主导、重要和配套3个层次的旅游产品项目, 构建连通桥上桥下的三大游览环线, 设计出“河-人-桥”三位一体的灯光效果。最后, 通过对中国典型岩溶天生桥旅游开发方式的概括、对比和分析, 提出岩溶天生桥纵向分层旅游开发方式, 并概括出3大分层方式: (1)“桥下观光, 桥上保护”式; (2)“桥下桥上观光”式; (3)“桥下保护, 桥上观光”式。     

天然气水合物加热开采机理及数学模型

在目前已有的主要水合物开采方法研究的基础上,进一步研究了天然气水合物加热开采法的机理。研究认为,水合物是加热分解、热传导和含化学分解的液、气两相渗流流动,它们之间既相互独立,又相互联系。并将水合物区划分为分解区和未分解区,将分解区前缘作为可移动的分界面,分区建立了加热分解热传导数学模型及含分解化学反应的液、气两相渗流流...     

Impact cratering — fundamental process in geoscience and planetary science

Impact cratering is a geological process characterized by ultra-fast strain rates, which generates extreme shock pressure and shock temperature conditions on and just below planetary surfaces. Despite initial skepticism, this catastrophic process has now been widely accepted by geoscientists with respect to its importance in terrestrial — indeed, in planetary — evolution. About 170 impact structures have been discovered on Earth so far, and some more structures are considered to be of possible impact origin. One major extinction event, at the Cretaceous-Paleogene boundary, has been firmly linked with catastrophic impact, but whether other important extinction events in Earth history, including the so-called “Mother of All Mass Extinctions” at the Permian-Triassic boundary, were triggered by huge impact catastrophes is still hotly debated and a subject of ongoing research. There is a beneficial side to impact events as well, as some impact structures worldwide have been shown to contain significant (in some cases, world class) ore deposits, including the gold-uranium province of the Witwatersrand basin in South Africa, the enormous Ni and PGE deposits of the Sudbury structure in Canada, as well as important hydrocarbon resources, especially in North America. Impact cratering is not a process of the past, and it is mandatory to improve knowledge of the past-impact record on Earth to better constrain the probability of such events in the future. In addition, further improvement of our understanding of the physico-chemical and geological processes fundamental to the impact cratering process is required for reliable numerical modeling of the process, and also for the correlation of impact magnitude and environmental effects. Over the last few decades, impact cratering has steadily grown into an integrated discipline comprising most disciplines of the geosciences as well as planetary science, which has created positive spin-offs including the study of paleo-environments and paleo-climatology, or the important issue of life in extreme environments. And yet, in many parts of the world, the impact process is not yet part of the geoscience curriculum, and for this reason, it deserves to be actively promoted not only as a geoscientific discipline in its own right, but also as an important life-science discipline.     

鄂西南山区一次罕见的秋季暴雨转暴雪天气成因分析

利用常规的地面观测资料、micaps卫星资料以及NCEP再分析资料,对2016年11月7到9日发生在湖北西南山区一次大范围暴雨转暴雪灾害天气的成因进行了分析。结果表明：此次极端雨雪灾害天气,是东移南下强冷空气与西南强暖湿气流共同作用的结果。低空急流的形成与维持,南支槽前正涡度的加强,以及中层正好处于冷暖气流交汇区,这种高层辐散、低层辐合的有利配置,是7到8日产生大范围大雨,局部暴雨的主要天气背景。8日夜间到9日的暴雪产生,除中层西南暖湿气流加强对降雪增幅的贡献外,还主要受东、西两路冷空气汇合加强共同影响;动力锋生产生的正、反两支锋面次级环流是造成降雪最直接的中尺度系统;此次雨雪持续期间,水汽充沛,并伴有强的水汽辐合上升运动,在强降雪影响期间,影响区上空存在NE-SW带状动力结构,这种锋面斜压性特征,加强了暖湿气流沿冷空气垫的爬升;针对秋季雨雪转换的温度层结特点,重点关注中层逆温和近地层气温变化。综合相关文献及本次研究结果,针对湖北地区降雪,850 hPa在0℃或以下,地面气温在2℃或以下,可作为雨转雪或雨夹雪的温度指标。中层逆温不是降雪必备条件,但对于产生强降雪需要适宜的中层逆温,本次降雪逆温出现在-1℃附近,该指标也可作为秋季降雪的参考指标。     

微生物地质工程技术及其应用

微生物地质工程技术是将微生物参与的生化过程加以控制和利用,来解决工程地质问题的一类新型岩土体水—力学特性改性技术。研究表明该技术具有低成本、环境友好、低能耗和过程可控的优点,是工程地质界近些年的一个热门研究内容,也是现代工程地质学科的重要发展方向。文章基于当前该技术取得的研究进展,系统总结了能被加以控制和高效利用的三种代表性微生物地质工程技术（微生物成矿作用、微生物膜作用及微生物产气作用）的原理及其应用领域。着重对研究最多、应用前景最广的微生物成矿作用改性岩土体力学特性、渗透特性、抗侵蚀性等工程性质及机理进行了阐述,并深入探讨了影响微生物成矿作用改性效果的关键因素（细菌种类、菌液浓度、环境温度、pH值、胶结液、土体性质及灌浆工艺）。此外,文章还详细论述了微生物成矿作用在地基处理、岛礁建设、防风固沙、水土保持、抗裂防渗、文物保护、地灾防治等领域的应用现状,并探讨了该技术当前面临的主要挑战及未来的重点研究方向。     

自然灾害风险地图中的制图综合研究——以点状承灾体为例

为提高多尺度灾害风险地图表达中高风险区承灾体的准确、有效、快速识别,基于灾害风险理论,运用地理学规律,在GIS等技术支持下,结合数据挖掘和空间分析技术,探讨了在尺度转换过程中点状承灾体的制图综合问题,并结合承灾体自身及在灾害系统中的属性特征,抽象概括了点状承灾体在灾害地图中的制图综合类型,即重要性综合、特殊性综合、邻近性综合、条件性综合、完整性综合、随机性综合。针对每一种综合类型,给出了可能的灾害情景假设及制图综合方法,并进行了技术实现及可视化表达。结果表明,基于上述6种类型的点状承灾体制图综合,不仅有效解决了尺度转换过程中的数据冗余问题,而且还能准确反映出特定孕灾环境下高风险区承灾体的空间分布,同时也为灾害风险地图的制图综合提供一种新的思路。本研究为区域灾害风险识别、风险防范与管理提供理论与技术支持,进而为区域的防灾减灾提供科学依据。     

基于Flex和ArcGIS Server的城市防汛指挥系统的设计与实现

针对淮安目前防汛工作上存在的问题,在介绍了ArcGIS Server、RIA/Flex和.NET等相关技术的基础上以及分析研究了系统的总体设计结构、数据库管理设计等,结合淮安防汛减灾相关情况,设计开发了WebGIS城市防汛指挥系统,并介绍了该系统所实现的功能,以及系统开发过程中所采用的关键技术等。通过对该系统的研究应用...     

Spatial Distribution and Temporal Variation of the Winter Wheat Late Frost Disaster in Henan, China

The winter wheat late frost disaster(WFD) occurs mainly in the Yellow and Huaihe River area,of which Henan Province covers the most part.Henan is the major area of wheat production in China,but it is severely hit by the WFD.In this study,we construct a WFD index based on the minimum temperature and the winter wheat development period(WDP).The WFD degrees and days at 30 agrometeorological stations in Henan Province during the period of 1981-2004 are calculated.For the large-scale temporal variation analysis of WFD,the 24-yr WDP observation series is relatively short,so it is expanded by using the relation between the turning green date of winter wheat and the 5-day running mean temperature and that between the stem elongation phase and the effective cumulative temperature above a critical value of 2.5 ℃.The WFD data are also expanded for the last 50 years and are analyzed by using the empirical orthogonal function(EOF) and the Morlet wavelet methods.Characteristics in the spatial distribution and temporal variation of WFD are revealed.The results show that the frequency of WFD is generally high,exceeding 40% in parts of Henan,and exhibits a rising trend in the period of 1970-1990.The variation trend of WFD degrees is similar to that of WFD days,and the areas with higher WFD degrees coincide the areas with more WFD days.Moreover,the WFD degree has a greater impact on the winter wheat yield than the WFD days.The areas with high WFD degrees lie in the southeast and southwest of Henan,and the areas with low WFD degrees lie in the south of the Huaihe River and parts of western Henan.Temporal variations of the first and second EOF modes of the WFD degree display 16-and quasi-22-yr periodicities,respectively.The areas of high(low) WFD frequency are distributed in the northern Henan and the southwest border of Henan(the northeast Henan and the middle part of southwest Henan).The temporal variation of the first(second) EOF mode of WFD days exhibits a periodicity(periodicities) of quasi-4 yr(quasi-3 and quasi-6-7 yr).     

基于综合评价算法的雷电灾害易损度区划模型研究

选取落雷密度、雷灾发生率、雷灾经济损失率及雷灾生命损伤率为评价雷电灾害易损性的指标,运用解析几何的直线方程对指标数据进行了标准化,引入层次分析法对评价指标数据真实性程度对结果的影响进行了修正,采用聚类分析方法对总易损度值进行更为合理科学的区划分级,并以福建省为例对新模型做了实例计算。结果表明,综合评价算法模型在关系计算、级别区划、结果分析等方面体现出一定的数学优势,能较细致、完整地反映出雷灾易损度区划指标之间的联系及各指标因素对雷灾易损度的综合影响关系。     

Spatial and temporal controls on historical channel responses – study of an atypical case: Someşu Mic River,Romania

In this paper the spatial and temporal responses of the Some?u Mic River (Romania) to natural and anthropogenic controls over the past 150 years are analysed, based on a series of morphometric parameters extracted from five successive sets of topographic maps and one set of orthophotos. Prior to the intensive hydrotechnical interventions of the last four decades, the river was characterized by a complex alternation of different channel types, resulting in a mixture of alluvial and mixed sinuous – meandering – sinuous anabranched – meandering anabranched reaches, each a few hundred metres to a few kilometres long. The main cause for this spatial behaviour was the local geology. Its effects were intensified by a larger scale slope, slightly higher than along a longitudinal profile with normal concavity, as a consequence of the presence of a 400 m elevation knick‐point located in the catchment area. A generalized maintenance of river in the floodplain perimeter during the entire interval of study (centennial scale), with local planform adjustments and lack of median scale avulsion in lateral tilting areas and along the anabranched reaches, channel lengthening and meander development during hydrological stable periods and channel shortening and increasing of natural cutoffs during periods with higher incidence of floods (decadal scale), and the incapacity of local morphologic changes resulted from human interventions to completely counterbalance general trends (decadal scale), supports the idea of decreasing the amplitude and frequency of important floods, after the end of the Little Ice Age. Channel metamorphosis by canalization, diminishing/elimination of overflows and medium‐scale avulsions by changes in flow regimes (dams) and the presence of dykes in the floodplain perimeter, channel narrowing (43%) and incision (at least after 1945) downstream from dams, and probably because of in‐channel gravel mining are the main anthropically induced changes along the Some?u Mic River. Even if human impact is important, both at the drainage basin scale and along the Some?u Mic River, it has only local impacts, subordinated to climate. The low level of human impact on this river could be the consequence of the higher general slope downstream from 400 m elevation knick‐point, which probably forces the positioning of its effects under an important internal threshold of the fluvial system. This boundary condition defines Some?u Mic River as an atypical river. This study supports the idea that climate has a more important role in the post‐Little Ice Age (LIA) rivers' behaviour than currently accepted. Copyright © 2011 John Wiley & Sons, Ltd.