能见度目标物图自动化制作系统设计与实现     

黄向荣  吴春燕  范裕祥  左敦苗 《气象》2012,38(3):377-380

针对目前国家气象观测站能见度目标物图是手工绘制的现状,开发了能见度目标物图自动化制作系统,实现了任意距离的能见度目标物图的自动化制作。具有观测站信息管理、目标物管理、绘图面板管理和图片输出等功能,图片大小、圆圈系数及生成半径可自行设置,还可以在一张图片上将1000和50000 m目标物图合成,满足现行最小能见度观测业务需要。该系统自动化程度高,操作简单,具有较强的可操作性和实用性。  相似文献   

20世纪70年代末前后北半球冬季对流层遥相关的时空演变研究   总被引：2，自引：1，他引：1  

曹杰  李湘瑞  应俊 《大气科学》2012,36(2):283-296

应用NOAA提供的1950～2008年月平均500 hPa高度场再分析资料、海表温度、太平洋年代际振荡(PDO)指数和大西洋三极模(ATM)指数, 研究了20世纪70年代末前后北半球冬季对流层遥相关的时空演变规律。相关分析、Mann-Kendall分析和凝聚小波分析的结果表明, 20世纪70年代末以来, 太平洋—北美(PNA)型、欧亚(EUP)型、西太平洋(WP)型和西大西洋(WA)型四种遥相关空间分布和时间演变产生较为显著的变化。空间分布的变化既体现在遥相关正、负异常中心的强度上, 也体现在正、负异常的范围上; 时间演变方面的变化则体现在PNA和WP遥相关指数具有上升趋势, EUP和WA遥相关指数具有一定下降趋势。20世纪70年代末以来, 影响北半球冬季5种遥相关型的海温关键区均有所改变。其中, 各大洋上影响EUP遥相关型的海温关键区面积显著缩小, 影响WA遥相关型的太平洋海温关键区面积显著缩小, 影响EA遥相关型海温关键区在北大西洋中南部改变明显; 在16年以上时间尺度上, PDO变化是造成北半球冬季PNA、 EUP、 WP三种遥相关型变化的主要原因; ATM变化是造成北半球冬季WA和EA两种遥相关型变化的主要原因。  相似文献   

Analysis of pile groups in a poroelastic medium subjected to horizontal vibration     

Xiang-Lian Zhou  Jian-Hua Wang 《Computers and Geotechnics》2009

This work investigates the dynamic response of pile groups embedded in a poroelastic medium subjected to horizontal loading. The dynamic response is analyzed using the Muki and Sternberg Method. The load transfer problem is formulated in terms of a second-kind Fredholm integral. The dynamic impedance of the pile groups is computed using the pile–soil–pile dynamic interaction factors. The shear force, bending moment and pore pressure is obtained using the superposition method. Numerical results indicate that the pile flexibility ratio and the pile distance have considerable influence on the dynamic response of the piles and the poroelastic medium.  相似文献   

A contrasting study of freezing disasters in January 2008 and in winter of 1954/1955 in China     

Yihui Ding  Xiaolong Jia  Zunya Wang  Xianyan Chen  Lijuan Chen 《Frontiers of Earth Science》2009,3(2):129-145

The present paper has made a comparison of major similarities and differences of extreme cold events between the cold and warm periods for recent 50 years, in order to gain a better insight into the impact of the global warming on extreme cold events in China. Two typical events of low temperature, ice freezing and snow disasters that occurred in January 2008 and in the winter of 1954/1955, respectively, are selected as representative cases for the cold period (1950’s–1970’s) and the warm period (1980’s-present). The contrasting study has revealed that these two events both occurred under long-persistent blocking circulation over Eurasian continent, with continuous invasions of strong cold air into China mainland. They nearly brought about similar weather disasters such as extensive low temperature, record-breaking freezing rains and exceptionally heavy snowfalls. However, due to active northward transport of warm and moist air from Bay of Bengal and Indo-China Peninsula in the warm period, the January 2008 case had longer freezing rain days and heavier snowstorms in South China, thus leading to much more severe damage to electric grids and transportations. The case of the 1954/1955 winter was a stronger, extreme cold event than the case of January 2008, in terms of magnitudes of temperature drop and severity of impact on river icing. It was gradually recovered to normal condition while the case of January 2008 had a very rapid recovery to warming condition due to impact of the global warming.  相似文献   

Density section of the Earth’s crust in the Deryugin Basin (Sea of Okhotsk): Gravity modeling results     

P. F. Volgin  L. M. Lyutaya  A. V. Kochergin 《Russian Journal of Pacific Geology》2009,3(3):210-219

A geological density section of the Deryugin Basin (western part of the Sea of Okhotsk) was studied along the profile Sakhalin Island-Deryugin Basin-Central Okhotsk Rise. The investigations were conducted by the method of gravity modeling, which allowed us to trace the density variations of the Earth’s crust layers along the lateral. The horizontal density stratification of the Earth’s crust layers was found, which assumes a stratified-block model of its structure. The established density structure of the Earth’s crust showed that the Deryugin Basin is located in the junction zone between the Sakhalin-Hokkaido microplate and the Okhotsk Sea Plate separated by a structural suture. The western and eastern edges of the basin belong to the aforementioned plates, respectively. It was assumed that accumulations of various mineral associations are confined to the suture zone, while the “granite” layer (basement) of the Deryugin trough walls in the western edge of the Deryugin Basin presumably contains secondary reservoirs of hydrocarbons.  相似文献   

在役输油气管道沿线滑坡灾害监测预警技术及应用     

荆宏远  郝建斌  陈开智  刘建平  韩冰  吴张中 《中国地质灾害与防治学报》2009,20(4):124-129

滑坡灾害是浅埋输油气管道的主要风险源之一,监测预警是管道滑坡风险控制的重要手段。管道滑坡灾害的监测预警需要滑坡体和管道的联合监测,注重管体轴向应变监测。为获得管道轴向应变的准确值,每截面至少需要布置3个应变计。推导了已知截面上3点、9点、12点钟位置应力时,管体监测截面上任意点应力的计算方法;探讨了基于材料强度破坏的管道预警阈值的确定方法。汶川地震期间,在兰成渝成品油管道羊木山滑坡获得了成功应用,为管道滑坡灾害监测预警的推广提供了借鉴。  相似文献   

松科1井南孔白垩系泉头组沉积序列精细描述:岩石地层、沉积相与旋回地层   总被引：2，自引：0，他引：2       下载免费PDF全文

王国栋  程日辉  王璞珺  高有峰  王成善  任延广  黄清华 《地学前缘》2009,16(2):324

中国白垩纪大陆科学钻探松科1井南孔连续取泉四段至泉三段顶岩心,心长132.07m,岩心收获率为100.00%。松科1井南孔泉头组岩心的精细描述,揭示其岩性-岩相-旋回地层的序列及其过程。松科1井南孔泉头组取心段识别出9种基本岩石类型,相类型主要有曲流河、浅湖和三角洲前缘3种亚相,以及点砂坝、天然堤、决口扇、决口水道、河漫滩、河漫湖、河口砂坝、水下分流河道间、湖相静水泥质沉积和浊流沉积等10种沉积微相。相应井段可识别出2类8种米级旋回(六级旋回),整个井段由76个米级旋回构成,叠加成25个五级旋回、8个四级旋回和2个三级旋回。泉三、四段厘米级刻画的陆相红层为全球白垩纪富氧事件研究提供了可能的立典剖面。泉头组三、四段发育的在盆地内广泛分布的储层砂岩是大规模坳陷形成前的必然沉积产物,这一时期是松辽盆地由断陷向坳陷转化的阶段,也是大规模坳陷的初始阶段。  相似文献   

基于改进的自适应反馈混沌系统同步     

李青芮  陶文华  孙娜 《华东地质学院学报》2009,32(3):293-297

基于LaSalle不变定理和Lyapunov方法,针对混沌系统同步问题提出了一种改进的自适应反馈方法。与一般线性反馈系统不同,这种方法能自动调整更新规则的可变反馈变量。在该自适应更新规则的控制下,反馈强度可自动调整到新的自适应规则,从而使响应系统的状态全局同步于驱动系统的状态。Chen氏混沌系统和Lu氏混沌系统说明了所设计的自适应反馈方法的有效性。  相似文献   

Eclogite varieties and petrotectonic evolution of the northern Guatemala Suture Complex     

Uwe Martens  Tatsuki Tsujimori  Juhn G. Liou 《International Geology Review》2017,59(5-6):721-740

ABSTRACT

Field and petrologic characteristics of two new eclogite localities within the Guatemala Suture Complex (GSC) north of the Motagua Fault are presented. The Tuncaj Hill locality exposes a coherent body of retrogressed eclogite hundreds of metres long that is associated with serpentinite of the North Motagua Unit. The Tanilar River locality exposes numerous bands and lenses of eclogite hosted in sialic gneisses of the Chuacús Complex. The Tuncaj eclogite has a two-stage prograde evolution containing the peak assemblage Grt + Omp + Ttn + Czo + Zo ± Am, formed at temperatures <720°C. In contrast, eclogites of the Tanilar unit are characterized by the paragenesis Omp + Grt + Rt ± Phg ± Qtz ± Ep giving higher peak conditions of T = 720–830°C and P = 2.1–2.7 GPa, near the stability field of coesite. Previously obtained data and our thermobaric calculations suggest distinct petrotectonic evolutions for the various types of eclogites within the suture. The lawsonite eclogites south of the Motagua Fault were probably produced in a mature Farallon subduction zone during the Early Cretaceous. The northern high-pressure (HP) blocks in serpentinite mélange and coherent amphibolite bodies with eclogite relics were generated by the Early Cretaceous subduction of the proto-Caribbean lithosphere under the Great Caribbean Arc. A continental block, the North American passive margin, reached the arc’s trench in the Campanian and was subducted to ca. 80 km depth, producing the eclogites of the Chuacús Complex. As the slab was delaminated and partially exhumed, the continental Chuacús became tectonically juxtaposed with HP blocks of the proto-Caribbean that had been accreted to the Caribbean plate forming the North Motagua Unit. The juxtaposed group migrated to mid-crustal level and was contemporaneously retrogressed under epidote-amphibolite facies conditions.  相似文献   

(Re)Connecting spatial literacy with children’s geographies: GPS,Google Earth and children’s everyday lives     

《Geoforum》2017

This article sets out an agenda for research that (re)connects research on children’s geographies and childhood studies with studies of spatial literacy. Research on children’s environmental cognition and, latterly, spatial literacy, has been artificially and problematically separated from the majority of research in childhood studies. Our fundamental aim in this article is to argue for – and to evidence – greater attention to how spatial literacy and children’s everyday lives are embedded in one another. To support our broader call for a synthetic research agenda, we draw on some more focussed, qualitative empirical material taken from a large-scale project about children’s mobilities and everyday lives in newly-built urban communities. Our analysis focuses upon children’s interpretations of Global Positioning Systems (GPS) tracks of their mobilities, set against a background of Google Earth imagery. In doing so, we showcase one suite of ways in which research on environmental cognition and children’s geographies might proceed together. We demonstrate that children not only displayed analytical skills (for instance, in relation to scaling effects and pattern recognition) but that many also exercised higher-level, critical analysis, especially in relation to errors on Google Earth outputs. Simultaneously, we interrogate the recursive articulation of a range of qualitative indicators of spatial literacy, with children’s everyday mobilities, routines, emotions and memories. The paper analyses how new conceptual languages and technologies being propounded by spatial literacy scholars could afford a more enriched understanding of key contemporary concerns for children’s geographers, and, recursively, what spatial literacy scholars might gain from engaging with (especially qualitative) research prompted by those concerns.  相似文献