快速城镇化背景下建设用地扩展驱动力研究述评与展望

 快速城镇化及经济发展背景下,我国建设用地扩展特征明显,建设用地扩展驱动力研究可为政府制定土地利用管控策略提供依据。采用文献分析法、归纳法,对已有研究成果进行了综述,综合分析表明：已有研究存在理论体系不健全;驱动因子遴选缺乏科学性;尺度界定不清晰;数据获取口径不一,遥感数据与统计数据不匹配;研究方法存在一定缺陷等不足与弊端。从人类与环境相互作用的系统观视角出发,加强学科交流,构建完整理论体系框架;注重驱动因子遴选的整体性、层次性、动态性、差异性;构建揭示空间异质差异的非线性模型,创建对模型可靠性和科学性进行检验方法;将数学模型方法、数据库技术和3S技术结合起来,创新研究方法;规范数据获取口径;加强时空尺度的敏感性研究;建设用地扩展对自然、社会经济反馈机制等方面进行了展望,以期为建设用地扩展驱动力进一步研究提供借鉴。     

Coseismic surface deformation of the 2014 Napa earthquake mapped by Sentinel-1A SAR and accuracy assessment with COSMO-SkyMed and GPS data as cross validation

ABSTRACT

The new land observation satellite Sentinel-1A was launched on 25 April 2014 with a C-band synthetic aperture radar (SAR) sensor, which has the significant enhancements in terms of revisit period and high resolution. The Mw 6.1 Napa, California earthquake occurring on 24 August 2014, almost 4 months after the launch, is the first moderate earthquake imaged by the Sentinel-1A. This provides an opportunity to map the coseismic deformation of the event and evaluate the potential of Sentinel-1A SAR for earthquake study. Two techniques including the interferometric SAR (InSAR) and pixel offset-tracking (PO) are, respectively, employed to map the surface deformation along the radar line of sight (LOS), azimuth and slant-range directions. The cross comparison between Sentinel-1A InSAR LOS deformation and GPS observations indicates good agreement with an accuracy of ～2.6?mm. We further estimate the earthquake source model with the external COSMO-SkyMed InSAR and GPS data as constraints, and forward calculate the surface deformation as cross validation with the Sentinel-1A observations. The comparison between the observed and modeled deformation shows that the Sentinel-1A measurement accuracy can achieve 1.6?cm for InSAR technique along LOS direction, and 6.3 and 6.7?cm for PO along azimuth and range directions, respectively.     

冰雷达探测数据处理方法研究——以南极冰盖Dome A地区的数据处理为例

提出了冰雷达数据处理的流程,详细论述了冰雷达数据处理中常规修正的关键技术：静态校正、增益控制、带通滤波以及偏移处理等。以中国第24次南极科学考察（CHINARE 24）所获取的Dome A 地区30 km×30 km范围冰雷达原始数据处理作为实例,提取得到了该区域冰盖内部等时层埋深以及冰盖的冰厚数据。通过插值展现了冰盖等时层以及冰岩界面的三维空间形态。结合该区域ICESat冰盖表面高程数据,构建出了Dome A地区涵盖冰盖表面、冰盖等时层以及冰岩界面形态特征的三维模型。     

TIMBER HARVESTING AND THE HYDROLOGIC RESPONSE OF REDWOOD CREEK,CALIFORNIA

Timber removal on publicand private land surrounding Redwood National Park exacerbates naturally high rates of erosion that are common to this region and alters hydrologic processes within the park boundaries. These alterations of the natural environment complicate the efforts of the National Park Service to preserve a remnant of the once extensive coastal redwood ecosystem in the park. A watershed model for Redwood Creek calibrated to pre-logging conditions is employed to define and quantify changes in the hydrologic response of the basin during the years when timber harvesting reduced significantly the acreage of redwoods. Analysis of modeled and observed runoff indicates that timber removal is related to increased runoff during wet months and wet years, but runoff is reduced during dry months and dry years. These alterations in the hydrologic system occur at the least beneficial time because they augment high flows, whereas low flows are depleted. Such changes in runoff contribute to magnified erosion and deposition problems and increased stress for the flora and fauna that reside in and along Redwood Creek. [Key words: Redwood National Park, hydrology, watershed model, timber harvesting.]     

Major and trace element characterization of tephra layers offshore Pantelleria Island: insights into the last 200 ka of volcanic activity and contribution to the Mediterranean tephrochronology

A detailed tephrochronological study was carried out on the deep‐sea core collected from Site 963A in the Sicily Channel during ODP Leg 160. The chronology of the succession is provided by an age–depth model based on isotope stratigraphy and quantitative eco‐biostratigraphy. Major, trace and rare earth element content was obtained on single glass grains through electron probe micro‐analysis and laser ablation–inductively coupled plasma mass spectrometry techniques from six well‐preserved tephra layers, characterized by a discrete thickness found along the succession. These deposits were correlated with the volcanic activity of Pantelleria and dated at 42.5, 127.5, 128.1, 129.1, 188.7 and 197.7 ka. This detailed chemical characterization of the studied deposits aims to provide a valuable reference database for scientists working on both proximal and distal products erupted at Pantelleria island during the Late Pleistocene. This study, moreover, offers the opportunity to better identify Pantelleria‐related marker tephras within the tephrochronological framework of the central and eastern Mediterranean area. Copyright © 2012 John Wiley & Sons, Ltd.     

网络城市研究回顾:概念、特征与发展经验

信息化、全球化与网络化的时代背景下,网络城市成为新的城市空间发展模式。通过构建多中心网络城市来促进均衡、可持续的地域发展成为规划界的研究热点。网络城市不仅是构建形态上的网络,更重要的是成为具备关键功能性关联的功能实体。本文将从概念辨析与特征描述、形态与结构演化、功能联系与整合分析、典型案例研究四个方面,系统地回顾国内外网络城市相关研究的进展,从而更好地指导国内城市空间发展的实践。     

服务业地理空间研究进展与文献述评

与服务业地理空间相关的研究随着实践和理论的发展愈益成为研究的热点,而现实经济也迫切需要探讨经济各部门的地理空间发展规律以加强理论对实践的指导作用。本文在廓清服务业地理空间研究理论与背景的基础上,对其研究进展及趋势给予了分析并做出相关述评。从区位论的探讨到多学科交叉的研究趋势,特别是空间经济学的兴起以及地理学理论与方法的介入,为该领域的研究注入了动力。目前对服务业地理空间规律的研究主要集中在区域服务业、特定服务业部门和高端生产性服务业上。而学科交叉融合及相关理论的创新与突破将奠定服务业地理空间研究坚实的理论基础;研究方法的多元化及创新势必加强对服务业地理空间研究的深度;研究视角的多维化与综合将拓展服务业地理空间研究的平台。     

中国资源地理学发展的现状与趋势

随着人类需求增长与资源本身稀缺性、有限性之间的矛盾日益突出,资源的开发利用问题逐渐成为全球性的热点问题之一。中国当前正面临着人均资源相对贫乏与粗放式、资源消耗式经济增长方式之间的矛盾,这种形势导致资源承载能力不断下降,由此产生了一系列的生态环境问题。因此,以资源为研究对象的资源地理学及其相关学科的迅猛发展也将成为必然。本文首先论述了中国资源地理学学科地位的发展过程;阐述了资源地理学的研究对象和内容;并从资源的广义内涵出发,将资源地理学划分为自然资源地理学和社会资源地理学2大类,初步构建了资源地理学的学科体系。然后回顾了国内外资源地理学产生与发展历史,并总结了资源地理学当前主要研究领域的进展情况。最后从研究内容、方法以及学科建设3个方面提出了中国资源地理学的未来发展趋势。     

A_3钢在MgCl_2溶液中腐蚀行为研究

以MgCl2溶液模拟氯氧镁水泥孔隙液,研究了A3钢在MgCl2溶液中的腐蚀行为和腐蚀速率,并利用电化学测试仪对A3钢腐蚀过程的电化学特征进行了研究。实验结果表明,随着MgCl2浓度的减小以及在MgCl2溶液中浸泡时间的延长,A3钢的腐蚀失重速率逐渐变小;极化曲线测试与腐蚀失重试验结果相吻合;阻抗曲线(EIS)研究发现,随着A3钢在MgCl2溶液中浸泡时间的延长钝化膜的电阻变大;扫描电镜观察表明,经MgCl2溶液腐蚀后,在A3钢样品表面产生了许多腐蚀产物,XRD分析证实主要产物为Fe3O4和MgFe2O4。     

PIC16F877A在新型质子旋进磁力仪中的应用

受制于当时微电子技术的发展,传统质子磁力仪存在电路复杂、元器件分立过多等不足之处,在确保观测原理不变的情况下,选取PIC16F877A作为主控芯片应用于新型质子旋进磁力仪中。介绍了整体的硬软件设计,同时与加拿大GEM公司生产的DiDd三分量磁力仪测量数据进行比较,结果显示在测量精度及准确度上两者非常接近,新型质子旋力进磁仪具有很好的稳定性和抗干扰性,达到了预期的效果。