Spatio-temporal changes in heat waves and cold spells: an analysis of 55 U.S. cities     

Michael J. Allen  Scott C. Sheridan 《自然地理学》2016,37(3-4):189-209

With observed increases in global temperatures indicating changes to anomalous temperature events (ATE), few studies have considered the changes associated with both heat and cold together. This study evaluates the changes in heat waves and cold spells for 55 U.S. metropolitan areas (1948–2012). Using surface observations, thresholds of mean apparent temperature were used to define heat, extreme heat, cold, and extreme cold events. Days that exceeded the 95th temperature percentile were considered heat days. Similar values were used to define extreme heat (97.5th), cold (5th), and extreme cold (2.5th). Thresholds were calculated independently for each of the locations, incorporating spatial variability into the ATE definition. Changes in duration, seasonal timing, and frequency, all of which have been shown to be important characteristics in regard to heat and cold events, were evaluated. Significant changes in some characteristics were found. Across many locations, heat events have become more frequent, longer lasting, and earlier occurring, while cold spells have experienced an opposite trend. Since heat and cold events impact a range of ecological and bioclimatological processes, understanding the variability and changes associated with ATE remains an important aspect to consider as society prepares for future events.  相似文献   

Sulfur Isotope Tracing of Ore-forming Hydrothermal Fluid for Metallic Sulfide Deposit     

Wang Yunfeng  Yang Hongmei 《地球科学进展》2016,31(6):595-602

How to utilize sulfur isotope for many domestic and foreign researchers to trace the sulfur source of metallic sulfide deposit has been explored for many years. Fruitful results have been gained now. Based on summing up the characteristics of sulfur isotopic composition of hydrothermal mineral from metallic sulfide deposits, this paper illuminated the total sulfur isotopic composition of ore-forming fluids is the key factor in estimating the sulfur source. This paper also summarized three approaches about how to obtain the total sulfur isotopic composition (δ³⁴S_∑S) of ore-forming fluids. They are physical-chemical equilibrium analysis, mineral paragenetic association analysis and Pinckey-Rafter, respectively. We gave some applied examples and made a brief comment of them as well. There are three points worth noting. Firstly, choosing appropriate approach is a critical factor to acquire the δ³⁴S_∑S successfully according to the characteristics of different types of metallic sulfide deposit. Secondly, currently, these above mentioned approaches and applications are effective after the establishment of equilibrium state of sulfur isotope. As to the sulfur isotopic disequilibrium condition in metallic sulfide deposits probably resulted from lower temperature or rapid emplacement, there are quite some problems in theory and technique. Therefore, an in-depth study should also be continued. Thirdly, it is a new development trend to study isotope composition of different forms of sulfur and to discuss their source, forming environment and process respectively, which is probably more effective and significant for tracing sulfur sources of metallic sulfide deposits.  相似文献   

Mineralogical evolution of indium in high grade tin-polymetallic hydrothermal veins — A comparative study from Tosham, Haryana state, India and Goka, Naegi district, Japan   总被引：3，自引：0，他引：3  

S. Murao  M. Deb  M. Furuno 《Ore Geology Reviews》2008,33(3-4):490-504

Two tin-polymetallic vein-type deposits widely separated in time and space but with strong similarities in terms of mineralization style, ore mineralogy and chemistry have been studied comparatively with the aim of understanding the mineralogical evolution of In-rich hydrothermal systems. The Tosham deposit, Bhiwani district, Haryana, India, is of Neoproterozoic age and constitutes a Sn–Cu prospect with unusually high In content. The disseminated, crude stockwork and vein mineralization is hosted by greisenised metasedimentary rocks intruded by a porphyritic granite stock and by later rhyolitic effusives. The Goka deposit, Naegi district, Japan is probably of uppermost Cretaceous age and occurs close to a well fractionated ilmenite series granitoid body. The tin-polymetallic vein in the Goka deposit is hosted by a welded tuff unit close to a subvolcanic granodiorite porphyry.The main host minerals of indium in the Tosham and Goka ores are sphalerite, stannite, unidentified Zn–Cu–Fe–In–Sn–S phases and chalcopyrite. Up to 0.48 wt.% In has been noted in the Goka chalcopyrite, whereas at Tosham, the mineral has a maximum In concentration of 1220 ppm. At Goka the sphalerite contains up to 1.89 wt.% In, whereas In-bearing stannite carries up to ca. 9 wt.% of the metal. Roquesite is the other indium mineral present in the Tosham ores, but is absent in Goka. The mineral chemistry of the Tosham and Goka ores suggest that the In-bearing minerals belong to a multi-component Zn–Cu–Fe–(Ag)–Sn–In–S system. Based on various triangular plots of the atomic proportions of the main metals, it is inferred that there are end-member phases, roquesite and stannite, in the Tosham ores co-existing with chalcopyrite. The sphalerite is both pure end-member and Cu–In-bearing in both the Tosham and Goka ores. Some of the analysed stannite grains in Tosham ores could possibly be petrukite. The Zn–Cu–Fe–Sn–In–S system in the two ores has a Sn-poor, high-In solid solution phase and also a Sn-rich, low-In solid solution phase. It seems possible that these two solid solutions were the first to form during hydrothermal ore deposition at high temperatures from a disordered solid solution located at the (Cu + Ag):(Zn + Fe):(In + Sn) = 3:5:2 intersection in the (Cu + Ag)–(Zn + Fe)–(In + Sn) field. With decreasing temperatures, the Sn-poor, In-rich solid solution exsolved the Zn–In-mineral of Ohta [Ohta, E., 1980. Mineralization of Izumo and Sorachi veins of the Toyoha mine, Hokkaido, Japan. Bulletin, Geological Survey of Japan 31, 585–597. (in Japanese with English abstract).] and sphalerite, while the Sn-rich, In-poor solid solution was broken down to stannite and relatively-Cu-rich sphalerite.  相似文献   

川东北不同含硫物质硫同位素组成及H2S成因探讨     

谢增业  李志生  黄志兴  王晓波  马成华 《地球化学》2008,37(2):187-194

自1995年川东北地区渡1井在飞仙关组获得高产的高含硫天然气以来,相继在该地区的罗家寨、滚子坪、渡口河、铁山坡、七里北、普光等构造发现高含硫大中型气田和含气构造,这些构造中的H2S含量一般分布在9%～17%之间.飞仙关组天然气中H2S的б34S值主要分布在 10.3‰～ 13.7‰之间,地层中硬石膏的б34S值则分布在 11.0‰～ 26.1‰之间,即天然气的б34S值比硬石膏的б34S值轻.针对不同含硫物质生成H2S的硫同位素分馏特征进行了一系列实验研究,包括硫化亚铁与盐酸反应,硫磺、硫酸钙分别与正己烷反应,泥灰岩加热生成H2S等,实验结果表明,无机反应生成的H2S的б34S值均比反应物的重.理论上,在硫离子与氢离子结合生成H2S的反应过程中,S2-和H 通过离子的碰撞方式形成的34S2-与H 结合形成H2S的稳定性比32S-与H 结合形成H2S的稳定性高.由此推测,若天然气中的H2S是由地层中硬石膏与烃类的反应生成的,那么H2S的б34S值应该比硬石膏中的б34S值重.综合各种因素认为单质硫与烃类的反应可能是川东北飞仙关组H:S形成最主要的原因.  相似文献   

吉林省临江市横路岭金矿地质特征及找矿思路     

梁世福  刘强  靳皇玉  张维山 《吉林地质》2008,27(2)

吉林省临江市横路岭金矿位于辽吉古元古宙裂谷中段太子河至浑江陷褶断束(Ⅲ)老岭断块(Ⅳ)以及浑江上游凹褶断束(Ⅳ)鸭绿江凹褶断束(Ⅳ)三个构造单元交汇区域,荒沟山"S"型构造带的中南部。矿体产于珍珠门组(Pt1z)与花山组(Pt1hs)接触带附近,受接触带之间的断裂构造(F1)控制,容矿构造为与F1断裂平行或小角度斜交的次级断裂,从容矿构造的规模及所处位置分析,Ⅰ-3号、Ⅰ-8号矿体具有较大的工作价值。  相似文献   

以“3S”集成技术为基础的“LBS”极地应用研究     

殷福忠  吴文会  孙立民 《测绘软科学研究》2008,(3)

分析了极地环境特点,并根据极地的基本情况确定极地位置服务(LBS)的系统架构,详细介绍了在极地位置服务中所用到的技术内容及技术特点,主要包括车辆和人员的监控技术、基于PDA的定位技术及极地的通讯技术等。  相似文献   

基于“3S”技术土地利用基础图件与数据更新的应用   总被引：1，自引：1，他引：0  

刘乾忠  刘术堂  娄忠军 《北京测绘》2008,(2):54-56

以潍坊市土地利用基础图件与数据更新项目为例,采用内外业相结合的作业方式,讨论了基于“3S”技术土地利用基础图件与数据库更新方法的应用、关键问题和解决方案以及成果应用。  相似文献   

从汶川大地震看空间信息技术在震后救灾中的应用   总被引：2，自引：0，他引：2  

张勇  陈正阳 《测绘与空间地理信息》2008,31(5)

目前,以"3S"为代表的空间信息技术已经为抗震救灾提供了极具潜力的技术支持.本文简要分析了"3S"技术集成和北斗导航系统在抗震救灾中的应用现状,并结合其在汶川大地震后的实际应用,分别探讨RS,GPS,GIS和北斗导航系统在震害调查研究及抗震救灾中的作用.  相似文献   

基于WebGIS的气象预报实时资料共享系统研究   总被引：1，自引：0，他引：1  

阮惠华  肖文名 《地理空间信息》2008,6(4):95-98

讨论了如何将WebGIS技术应用于气象业务,并对海量的气象数据的抽取,进行数据展现和数据分析,为气象预报提供决策支持;对其中的主要技术难点和系统功能进行了详细的讨论。  相似文献   

3S技术在城市建设用地执法检查中的应用研究   总被引：1，自引：0，他引：1  

张世全  吴训伟  张伟杰  魏峰远 《测绘与空间地理信息》2008,31(3)

选用2004年、2005年和2006年三个时相的QuickBird卫星遥感图像作为信息源,用GIS作为遥感数据处理工具来识别违法地块,利用GPS进行地块实际测量来确定违法用地的位置和面积,以郑州市城市建设用地执法检查为例,探讨3S技术在建设用地执法检查中的应用。  相似文献