Effects of a melted greenland ice sheet on climate, vegetation, and the cryosphere

This paper investigates the possible implications for the earth-system of a melting of the Greenland ice-sheet. Such a melting is a possible result of increased high latitude temperatures due to increasing anthropogenic greenhouse gas emissions. Using an atmosphere-ocean general circulation model (AOGCM), we investigate the effects of the removal of the ice sheet on atmospheric temperatures, circulation, and precipitation. We find that locally over Greenland, there is a warming associated directly with the altitude change in winter, and the altitude and albedo change in summer. Outside of Greenland, the largest signal is a cooling over the Barents sea in winter. We attribute this cooling to a decrease in poleward heat transport in the region due to changes to the time mean circulation and eddies, and interaction with sea-ice. The simulated climate is used to force a vegetation model and an ice-sheet model. We find that the Greenland climate in the absence of an ice sheet supports the growth of trees in southern Greenland, and grass in central Greenland. We find that the ice sheet is likely to regrow following a melting of the Greenland ice sheet, the subsequent rebound of its bedrock, and a return to present day atmospheric CO₂ concentrations. This regrowth is due to the high altitude bedrock in eastern Greenland which allows the growth of glaciers which develop into an ice sheet.     

灵台-阿木去乎剖面地壳速度结构

在Ⅰ测线观测资料的基础上,本文结合测区特点给出了高程校正及沉积层校正方法,利用反射波与莫霍面折射波运动学特性进行一维、二维地壳结构的正、反演计算,获得了自甘肃夏河至灵台460公里范围内的分层地壳结构,认为西部地壳厚度约51公里,东部仅为44公里,已属鄂尔多斯地台区结构,与地槽区的分界线大致对应地表陇县固关镇。武山与张家川之间在15-20公里深处存在低速层。结合地震波的动力学特性,可判定本测线通过的超壳断层有鄂尔多斯西缘-六盘山断裂、西秦岭北缘断裂和武山南北向断裂。     

与花岗岩有关锡矿成岩成矿作用研究若干问题讨论

文章基于近年来大量典型锡矿床和成矿区带成岩成矿作用及高温高压实验研究成果,对锡矿成矿年代学、成矿花岗岩类型、物质来源、源区物质的熔融条件及锡在岩浆中的存在形式、熔体-流体相间分配行为及热液流体中的存在形式等方面的研究进展及存在问题进行了系统综述,指出:①锡石原位U-Pb测年已成为直接测定锡成矿年龄的有效手段,近年来发展起来的多种矿石矿物U-Pb测年方法与传统蚀变矿物测年方法的结合,将为研究锡多金属矿床多期次成矿作用叠加、矿集区内不同类型矿床成因联系及区域矿床组合模型的建立提供关键的年代学依据;②锡的富集成矿不仅与花岗质岩浆的高程度的结晶分异密切相关,而且受源区组成及部分熔融条件的制约;③全球锡多金属矿床的不均匀分布、与准铝质花岗岩有关锡矿的富集成矿机制以及各类复杂的锡-钨-铜-钼-铅-锌银多金属矿种组合差异及其金属元素富集机制亟待查明;④已有的关于锡在花岗质熔体、热液流体相中的存在形式及两相间的分配行为的高温高压实验结果受锡与贵金属容器间合金效应的影响,人工合成流体包裹体等新的实验方法的开发及XAS同步辐射和激光拉曼等原位分析技术的应用,将为研究花岗岩浆-热液过程锡的迁移、富集及沉淀成矿机制提供更为直接、可靠的实验依据。     

安徽省东至地区金矿类型及找矿方向

安徽省东至地区位于扬子陆块北缘,跨下扬子前陆带和江南隆起带两个次级构造单元,独特的大地构造环境造就了本区有利的金矿成矿地质条件,形成多种类型的金矿床,其成因类型主要包括岩浆热液型和风化壳型,工业类型主要有破碎带蚀变岩型、含金石英脉型、微细粒浸染型及红土型。各类型金矿分类聚集,形成两个主要的金矿成矿带。沿赵家岭断层带以破碎带蚀变岩型为主,伴有含金石英脉型,中畈—戴家一带,赵家岭—杨家山一带均具较大找矿潜力,是本区金矿勘查重点地区,九华庄等地也具一定的找矿潜力;沿高坦断裂以微细粒浸染型为主,伴有破碎带蚀变岩型及红土型,查册桥地区是其重点勘查区,铜锣尖、小河等地找矿潜力也较大。     

点分布-双蛇模型用于矢量边界更新

在利用遥感影像更新GIS矢量数据的过程中,往往忽略了对已知信息的有效利用,针对这一问题,本文提出一种基于点分布的双蛇模型用于GIS矢量数据更新,该模型利用已有遥感影像信息计算目标边界点的平均分布,以此为"镜面"建立初始矢量边界的"镜像",将两边界各自演化的结果取平均作为更新后的GIS矢量边界。该方法同时利用了GIS和遥感的历史数据作为先验知识,分别作为蛇模型的初始位置和区域约束信息,使遥感与GIS信息结合更加紧密。仿真实验表明,基于点分布的双蛇模型在GIS矢量边界更新的应用中,可以得到比以传统蛇模型更好的更新准确率和多边形相似度,并且接近手工方法的效果。     

Throughfall patterns in sugarcane and riparian forest: understanding the effect of sugarcane age and land use conversion

Sugarcane is an annual crop with a dynamic canopy that changes over time mainly because of genetic adaptation. There is uncertainty about the temporal trends of throughfall (TF) in this important commercial crop. In the present paper, we used troughs to measure TF in a third and fourth ratoon and subsequently in a fourth and fifth ratoon. Additional measurements were carried out in an adjacent riparian forest. There were no significant differences between cycles of sugarcane, growth phases and riparian forest. The TF results for ratoon crop and riparian forest in 2011/2012 were 76% and 79.5% of gross rainfall, respectively, while in 2012/2013, they were 79% and 78%, respectively. However, TF was remarkably lower in the riparian forest relative to ratoon from the second half of the culm formation and elongation phase (280 days after harvest) until harvest. Copyright © 2016 John Wiley & Sons, Ltd.     

村镇滑移隔震建筑瞬时摩擦耗能的参数敏感性分析

给出了村镇滑移隔震建筑瞬时摩擦耗能的概念,并以此概念为响应指标。通过极差大小的对比,分析了该响应指标对刚度比、第二阶段刚度系数、隔震层屈服位移、隔震层摩擦系数、系统质量比和上部结构自振周期六个参数变化的敏感程度,阐述了上述系统参数对瞬时摩擦耗能这一响应指标的影响规律。研究表明:场地条件和地震动幅值大小对瞬时摩擦耗能均有显著影响;在所考虑的参数范围内,上部结构自振周期总是对瞬时摩擦耗能有较为显著的影响,摩擦系数对瞬时摩擦耗能的影响跟场地条件有关,Ⅰ类场地条件中摩擦系数对瞬时摩擦耗能影响不显著,而Ⅱ、Ⅲ和Ⅳ类场地条件中,摩擦系数对瞬时摩擦耗能的影响则非常显著;隔震层屈服位移、刚度比和第二阶段刚度系数总得来讲对瞬时摩擦耗能影响不显著,质量比对瞬时摩擦耗能影响居中。     

矿产资源管理信息系统设计与开发

基于GIS的矿产资源管理信息系统采用地理信息系统(GIS)技术、SQL Server数据库技术以及网络技术,实现了矿产资源信息图形数据与属性数据统一管理,为矿产资源管理工作提供了现代化的科学管理手段和决策支持。本文介绍了系统的设计与实现、系统包含的工作模块、各个模块的功能结构以及采用的技术特点。     

中国长三角地区PM2.5时空分布数值模拟研究

利用第三代空气质量预报模式LOTOS-EUROS(Long Term Ozone Simulation-European Operational Smog)对2018年中国长三角地区细颗粒物(PM2.5)浓度的时空分布进行数值模拟,通过对比模拟结果与地面观测值,验证模式对PM2.5长期特征模拟的合理性并探讨长三角地区P...