区域海气耦合模式FROALS模拟的西北太平洋环流及其年际变率

本文利用区域海气耦合模式FROALS(Flexible Regional Ocean-Atmosphere-Land System)对西北太平洋地区1984-2007年连续积分结果,对比SODA(Simple Ocean Data Assimilation)同化资料讨论了西北太平洋海表温度和表层洋流的气候态及年际变率。结果表明,FROALS基本能够再现冬、夏季季节平均的海温型,但均存在一个明显的冷偏差;FROALS对气候平均态的表层洋流有较高的模拟技巧,对于冬、夏季的表层洋流型都能够再现。另外,表层洋流的模拟偏差与海表高度的模拟偏差直接相关。由于模式模拟的黑潮热输送较观测偏强,使得模式模拟的海洋热输送倾向于使黑潮路径上的海温呈现正偏差。从表层洋流的年际变率来看,模式模拟的与ENSO(El Nio-South Oscillation)相联系的年际变率信号与观测相似:在El Nio年,北赤道流和棉兰老流增强,低纬度西太平洋海表高度降低,而在La Nia年则呈现出相反的形态,但是在模式中这种信号稍强于观测。     

南京北郊大气垂直扩散参数特征的测量及其应用

利用平面照相法,以江苏南热发电有限责任公司#Q2号烟囱为研究对象,进行了500次拍摄,通过风向风速、云量、太阳高度角等气象数据,确定了不同稳定度下南京北郊大气扩散参数的特征。与P-G扩散曲线对比发现,在强不稳定A、弱不稳定C、中性D层结中,南京北郊的大气垂直扩散参数在距离排放源200 m范围内更不稳定,而在200—1000 m范围内更稳定。其中,不稳定B层结的扩散曲线与P-G扩散曲线一致,较稳定E、稳定F层结出现于白天的频率很低。对比垂直扩散参数幂函数表达式σ_z=γx~α的系数值γ和α,本研究中α值分别比国家标准增加了28. 6%(A层结)、56. 4%(C层结)、30. 4%(D层结),而B层结的α值却比国家标准减少了22. 9%。此外,通过高斯扩散公式计算得到SO_2和NO_X扩散到观测点的浓度,发现该计算值仅占气象楼污染气体监测平台实测SO_2和NO_X浓度的0. 82%和0. 69%。结合风场发现,SO_2和NO_X实测值受观测点东部工业污染物排放的叠加效应影响较大。其中,NO_X的实测值在受到偏东风和偏南风的影响时具有较大值,且在0. 5～1. 5 m·s~(-1)的较弱风速影响时,NO_X的实测值将达到60μg·m~(-3)以上。     

Review on physical models of lunar brightness temperature

Brightness temperature is a main index to reflect the energy of microwave radiation of an object. Using lunar brightness temperature data, physical properties of lunar regolith, such as thickness, heat flow and dielectric permittivity, could be interpreted. There are two methods to study brightness temperature distribution of the moon: the first is used to measure lunar brightness temperature by radio observation or spaceborne microwave radiometers, and the second is used to simulate calculation by the physical model. On the basis of the measurements of lunar brightness temperature in the history, this study analyzed the main physical model of lunar brightness temperature, also including its theory and influence factors. The authors concluded that surface and subsurface temperatures of the moon, dielectric properties and layered structure of lunar regolith were the main factors affecting the global brightness temperature of the moon. These factors should be quantified in detail in the future research.     

Analysis of geocell-reinforced mattress with consideration of horizontal–vertical coupling

Geocell reinforcement has been increasingly applied to road embankment engineering. Deformation calculation is one of the major concerns during the design process. In this paper, the power-series method was employed to investigate the performance of a geocell-reinforced mattress under symmetric loads. The geocell-reinforced mattress was idealized as a beam on a Winkler foundation. In the analysis, the soil–foundation beam interface resistance, related to the horizontal deformation coupling with the vertical deformation, was considered. Semi-analytic solutions were developed to assess the deformations and internal forces of the foundation beam and verified against an existing finite element method [9]. The results of the proposed method were close to the results from the finite element method. Moreover, the effects of various factors, such as height of embankment, horizontal and vertical foundation coefficients, composite elastic modulus and height of geocell-reinforced mattress, on the foundation beam settlement and the tension force within the beam are discussed. It was found that the interface resistance related to the horizontal deformation of the beam has a reduction effect on the embankment settlement, and it is beneficial to reduce the embankment settlement by increasing the beam rigidity and strengthening the subgrade soil body.     

A new Voronoi diagram-based approach for matching multi-scale road networks

Journal of Geographical Systems - Object matching is a key technology for map conflation, data updating, and data quality assessment. This article proposed a new Voronoi diagram-based approach for...     

利用HY-2微波辐射计数据反演北极区域海冰密集度方法研究

HY-2是中国自主研发的海洋卫星。 本文研究了利用HY-2卫星扫描微波辐射计亮温数据反演北极海冰密集度的方法。参考NASA TEAM方法,我们对典型海区光谱梯度率和极化梯度率进行了统计分析,确定了计算海冰密集度所需的亮温特征值;利用天气滤波器有效去除了开阔海域由于大气中水蒸气、云中液态水、降雨等现象引起的海冰密集度计算错误。本文计算了2012年全年的北极海冰密集度产品并对产品精度进行了初步验证,验证结果表明：三个海冰类型已知区域的海冰密集度结果与理想值比较接近,多年冰密集度的反演精度需要进一步提高;本文结果与美国冰雪数据中心和德国不来梅大学提供的两种业务化海冰密集度产品一致。本研究为利用HY-2卫星监测极区海冰密集度变化,发布实时产品奠定了基础。     

北冰洋西部表层沉积物矿物学特征及其物质来源

对北冰洋西部79个表层沉积物样品进行了全岩X射线衍射矿物组成分析,结合洋流和地质背景,探讨各矿物分区的物质来源。矿物组合分区表明研究区物质来源变化较为复杂:(1)在楚科奇海的中部靠近白令海峡处长石含量很高,主要是阿纳德尔流携带的来自阿纳德尔河的沉积物;在楚科奇海的西侧的长石含量也较高,且与其他矿物组合分区相比,角闪石含量较高,这是因为受阿纳德尔流和东西伯利亚沿岸流的双重影响,沉积物来自西伯利亚陆地的一些高含长石的火山岩及沉积岩等。在楚科奇海的东侧,石英含量很高,来源为阿拉斯加沿岸流携带的育空河及卡斯奎姆河的沉积物。在阿拉斯加北部,碳酸盐岩和石英含量高,这与马更些河搬运的沉积物有关;(2)北冰洋西部深水区中加拿大海盆的南端和中部方解石和白云石的含量较低,说明受波弗特环流携带的加拿大北极群岛的碳酸盐影响相对较小,且与其他矿物组合分区相比,云母含量最高,说明沉积物主要来源为来自拉普捷夫海的海冰沉积物;此外,一些黏土级细粒物质可能由大西洋中层水携带而来。深水区的其他海域以方解石和白云石含量高为特点,主要受波弗特环流的影响,来源主要为加拿大北极群岛的班克斯岛和维多利亚岛;此外,还受来自西伯利亚陆架,主要是拉普捷夫海沉积物的影响。     

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海岸裂流的研究进展及其展望

近岸裂流是海岸工程和海岸演变中非常重要的动力因素,对污染物排放和游泳者安全有很重要的意义。详细回顾了国内外对海岸裂流方面的研究与进展,具体包括对裂流的实验室实验和现场观测测量技术、理论分析、裂流的形成机理以及数值模拟等方面,概述了该领域的研究现状与发展趋势。总结了已有研究存在的不足,提出了需要进一步研究的课题。     

应用极化合成孔径雷达检测海上溢油研究进展

海上溢油给海洋生态环境带来严重的影响,快速准确地探测溢油对于防灾减灾具有重要的意义。利用卫星遥感探测溢油已成为目前主要的检测手段,大多采用合成孔径雷达(SAR)数据,运用图像处理的方法,开展了多种溢油提取算法的研究,取得了较好的结果,但由于海洋的类溢油现象存在,造成提取信息的精度达不到要求。近年来,国内外运用极化SAR数据开展溢油信息提取研究,从极化分解与相位差等角度对溢油特性分析,能有效地区分一些类溢油现象,得到了较理想的结果。分析了应用SAR数据开展溢油信息提取的研究状况,总结了溢油极化SAR探测的研究,指出了目前研究中存在的不足,并提出了今后溢油极化SAR遥感监测的方向。