环境变迁、经济开发与政区演变的相关研究——以上海浦东地区为例

该文以上海浦东地区为典型地域的研究表明 ,政区演变具有内在与外在两种动力机制 ,它们对政区不同要素的作用有所侧重 ,而环境变迁、经济开发等背景因素对政区设置产生的影响 ,具有一定的阶段性。     

2003年以来长春市城市功能用地演替

城市空间的增长不仅仅表现在城市用地的扩张,还表现在城市功能用地的演替。城市功能用地的演替可以更加深刻地揭示城市空间外延式水平扩展的内在特征,是城市功能集聚与扩散的空间反映。以长春市中心城区为例,利用2003、2007、2010、2012年4个年份的遥感影像图、地形图及城市用地现状图等数据资源,借助Arc GIS、Auto CAD等软件,运用GIS分析方法,在分析中心城区城市空间扩展的总体格局及城市用地结构变化的基础上,提出以外部扩展与内部更替来表达城市功能用地的演替,进而阐释城市空间扩展及城市功能集聚与扩散的内在特征,为城市空间扩展的研究提供一种新的、有效的手段,以丰富城市空间研究的理论成果体系。     

基于流强度的中国城市对外服务能力时空演变特征

综合运用城市流强度模型、改良Theil系数和K-means时空聚类法对2004~2010年中国地级以上286个城市对外服务能力的时空演变特征进行探讨,得到以下结论:1城市流强度值的绝对量均有明显上升,但存在显著的区域非均衡现象,并与城市经济实力有较高的相关性。2省内差异对城市对外服务能力的差异贡献率在58%~72%,是其空间尺度差异的主要来源。3时空演变表现出明显的阶段性和等级性规律,且空间等级性特征随阶段演进更趋明显。4对外服务能力的强弱和集聚强化趋势与城市流强度基数值大小和增速快慢有着紧密关系,一定程度上体现了基础乘数效应和循环累积效应配置下的非均衡特征。     

外辐射带区域新建地磁场经验模型的定量研究

准确的磁场模型对于辐射带粒子环境研究至关重要.本文利用美国Van Allen Probes（VAP）在2012至2018年期间测量的磁场数据和GOES15在2011至2017年期间测量的磁场数据,定量地评估了三个较新的外磁场经验模型（TS05、TA15和TA16）对外辐射带区域（3~6.6R_E）磁场的描述性能.本文选择预测效率（Prediction Efficiency,PE）作为评估指标,定量分析各模型在不同空间范围（Lm值）、不同地磁活动水平（Kp）以及不同磁地方时（MLT）下的性能表现,并且计算了观测磁场与模型磁场的夹角θ,以评估模型的磁场方向预测能力.结果表明：PE随Lm值增大,随地磁扰动增强而下降;θ随Lm值增大,随地磁扰动增强而增大.在Lm=5~6.5R_E范围内,PE呈现晨昏不对称性,MLT=12-21时的PE值小于MLT=0-9时的值,说明三个磁场模型可以较好地描述晨侧磁场的强度,但它们并不能很好地反映下午至昏侧磁场的大小;在地球同步轨道附近（Lm~6.6R_E）,PE呈现昼夜不对称性,MLT=9-15时的PE值大于其他时区的值,说明三个磁场模型可以很好地反映昼侧磁场大小,但在夜侧可能存在较大的误差.θ在MLT=6-12时的值小于其他时区的值,呈现昼夜不对称性,说明三个磁场模型可以较好地描述昼侧磁力线的分布位型,但在夜侧存在较大的方向描述误差.在外辐射带3~6.5R_E内,TA16模型与VAP磁场观测数据最为接近,PE均大于0.7,θ均小于3°;在地球同步轨道高度（6.6R_E）,TS05模型与GOES15卫星磁场观测数据最为接近,PE约为0.75,θ约为7°.相关的研究结果可以为我国星载高能粒子探测器探测数据的在轨交叉定标、辐射带高能粒子动态模型研究和相关的磁层环境理论/应用研究提供地磁场模型选择方面的参考.

     

Air quality and view degradations due to copper mining and milling: Preliminary analysis and cost estimates for Green Valley,Arizona

Green Valley, Arizona is a retirement community located near major open-pit copper mines. Mining and milling activities create dust, which degrades air quality, and mine dumps and tailings banks, which degrade the viewscape. Although the tailings banks are highly visible, this study found that consumer surplus lost from dust-polluted air is more than twice that from degradation of viewscape. Consumer surplus lost from both air quality and viewscape degradation is estimated to be between $116,000,000 and $169,000,000. These preliminary estimates are based upon two studies: hedonic property values, and a contingent valuation survey of willingness to pay.     

基于GPS罗经的感潮河段ADCP测验精度研究

受外部磁场、底质流动及仪器性能等因素影响,利用声学多普勒流速剖面仪（ADCP）自带的磁罗经及底跟踪技术难以为流速确定提供准确的方位和船速基准,从而降低了ADCP流速测量精度并限制了其应用。为此,借助GPS和罗经等外部传感器,提出了一种ADCP流速精确测量方法和全套数据处理模型,替代了ADCP测量中的速度和方位基准,显著提高了ADCP成果精度。实验验证了该方法的有效性。     

阻尼对地下隧道结构动力响应的影响

用弹性地基梁来模拟地下隧道结构,推出考虑弯曲、轴力、剪切、内外阻尼以及在双参数地基模型上的振动方程。引用地下管道近似的位移计算方法,计算地下隧道结构,避免积分变换的繁琐,通过一种特殊的分离变量法,使得动力荷载以强加位移和速度的方式施加,实例计算中涉及内外阻尼项,可以方便地求出自振频率和阻尼比的表达式和考虑阻尼后结构位移衰减曲线,得出对于地下结构内阻尼的影响很小的结论。     

A Theoretical Explanation of Anomalous Atmospheric Circulation Associated with ENSO Modoki during Boreal Winter

Based on a linear model, the present study provides analytical solutions for ideal triple forcing sources similar to sea surface temperature anomaly （SSTA） pat- terns associated with El Nino-Southern Oscillation （ENSO） Modoki in winter. The ideal triple pattern is composed of an equatorially symmetric heat source in the middle and equatoriaUy asymmetric cold forcing in the southeast and northwest. The equatorially symmetric heat source excites low-level cyclonic circulation anomalies associated with Rossby waves in both hemispheres, while the northwest- ern and southeastern equatorially asymmetric cold sources induce low-level anomalous anticyclones associated with Rossby waves in the hemisphere where the forcing source is located. Low-level zonal winds converge toward the heat sources associated with Kelvin and Rossby waves. Due to unequal forcing intensity in the northwest and southeast, atmospheric responses around the equatorially symmetric forcing become asymmetric, and low-level cyclonic circulation anomalies in the Southern Hemisphere become greater than those in the Northern Hemisphere. Ascending （descending） flows coincide with heat （cold） sources, resulting in a double-cell structure over the regions of forcing sources. Ideal triple patterns similar to SSTA patterns associated with La Nina Modoki produce opposite atmospheric responses. The theoretical atmospheric responses are consistent with observed circulation anomalies associated with ENSO Modoki. Therefore, the theoretical solutions can explain the dynamics responsible for atmospheric circulation anomalies associated with ENSO Modoki events.     

Comparison of Two Probability Distributions Used to Model Sizes of Undiscovered Oil and Gas Accumulations: Does the Tail Wag the Assessment?

Undiscovered oil and gas assessments are commonly reported as aggregate estimates of hydrocarbon volumes. Potential commercial value and discovery costs are, however, determined by accumulation size, so engineers, economists, decision makers, and sometimes policy analysts are most interested in projected discovery sizes. The lognormal and Pareto distributions have been used to model exploration target sizes. This note contrasts the outcomes of applying these alternative distributions to the play level assessments of the U.S. Geological Survey's 1995 National Oil and Gas Assessment. Using the same numbers of undiscovered accumulations and the same minimum, medium, and maximum size estimates, substitution of the shifted truncated lognormal distribution for the shifted truncated Pareto distribution reduced assessed undiscovered oil by 16% and gas by 15%. Nearly all of the volume differences resulted because the lognormal had fewer larger fields relative to the Pareto. The lognormal also resulted in a smaller number of small fields relative to the Pareto. For the Permian Basin case study presented here, reserve addition costs were 20% higher with the lognormal size assumption.     

MSAS系统在中国区域服务性能评估与分析

为了提高GNSS卫星导航系统服务性能,美国、欧洲各国、日本、印度、俄罗斯、韩国、中国已经建立或者即将建立独立的星基增强系统,通过提供广播星历差分与完好性增强信息,满足高精度高完好性用户使用需求。针对日本MSAS系统在中国区域SBAS增强服务性能不稳定的问题,在理解SBAS增强信息内容和处理流程的基础上,对分布在不同位置的日本两个站(GMSD、MIZU)和中国中东部区域3个站(天津、上海、武汉)的数据进行测试,采用GPS单点定位、MSAS增强单点定位和MSAS双频精密单点定位3种模式进行增强效果的评估和分析。结果表明,在中国区域采用MSAS电离层改正参数效果不佳,距离越远,精度改善程度越差。只采用轨道和钟差改正信息,较单点定位可实现10%的精度提升,精密单点定位可实现60%的精度提升,但需数十分钟的收敛时间,本文也给出了多方面的解决方法。