不同水位垂直流人工湿地中植物及微生物特征

利用4个连续进水的垂直流人工湿地,比较分析水位对污染物去除效果的影响,研究湿地中植物对氮磷去除的贡献,阐析湿地中脱氮功能菌数量的演变规律。3个湿地栽种黄花鸢尾,水位分别控制在19、51和84cm,另一个湿地不栽种植物,水位为51cm。结果表明,水位对氮和有机物的去除有显著影响(p<0.05),栽种植物的湿地中,51cm水位时总氮去除率(67.4%～79.2%)最高,19cm水位时氨氮(85.3%～93.0%)和COD(81.8%～92.9%)去除效果最好。试验中黄花鸢尾均生长良好,植物吸收对总氮(Total nitrogen,简称TN)和总磷(Total phosphorus,简称TP)去除的贡献分别为19.2%～27.3%和14.7%～19.2%;植物地上部分发挥更重要作用,其TN和TP含量及对TN和TP的吸收量均高于地下部分。湿地表层基质中3种脱氮功能菌数量均随运行时间的增加而显著提高,亚硝化细菌和硝化细菌数量分别为10~4～10~6和10~5～10~7 MPN/g,随水位升高而减少;反硝化细菌数量为10~3～10~6 MPN/g,随水位升高而增加。     

利用椭球变换建立独立坐标系的方法

详细阐述了8种利用椭球变换建立独立坐标系的方法,推导了独立坐标系高程面与椭球面之间的相互关系,进而建立了椭球变换模型,减少了高程归化变形;并通过计算实例对其投影变形值进行分析,以探究不同方法间的特点与差异,得出了一些有益的结论。     

海洋湍流观测技术

湍流在海洋能量和水体的交换演化中起着非常重要的作用。海洋湍流研究的发展和海洋湍流观测仪器的研发密切相关。世界上湍流观测仪器的研发起步于上世纪50年代,但是我国在湍流观测设备方面到目前为止仅仅处于起步和引进国外设备阶段。针对我国的情况,文中对海洋湍流观测的平台、探头测量原理及其数据修正、资料后处理等关键技术做一个总结性的介绍,为我国使用引进的海洋湍流设备和自主开发海洋湍流测量设备提供参考。     

Estimates of global M_2 internal tide energy fluxes using TOPEX/POSEIDON altimeter data

TOPEX/POSEIDON altimeter data from October 1992 to June 2002 are used to calculate the global barotropic M2 tidal currents using long-term tidal harmonic analysis. The tides calculated agree well with ADCP data obtained from the South China Sea (SCS). The maximum tide velocities along the semi-major axis and semi-minor axis can be computed from the tidal ellipse. The global distribution of M2 internal tide vertical energy flux from the sea bottom is calculated based on a linear internal wave generation model. The global vertical energy flux of M2 internal tide is 0.96 TW, with 0.36 TW in the Pacific, 0.31 TW in the Atlantic and 0.29 TW in the Indian Ocean, obtained in this study. The total horizontal energy flux of M2 internal tide radiating into the open ocean from the lateral boundaries is 0.13 TW, with 0.06 TW in the Pacific, 0.04TW in the Atlantic, and 0.03 TW in the Indian Ocean. The result shows that the principal lunar semi-diurnal tide M2 provides enough energy to maintain the large-scale thermohaline circulation of the ocean.     

Urban three-dimensional expansion and its driving forces —A case study of Shanghai, China

Urban expansion is a phenomenon of urban space increase, and an important measuring index of the process of urbanization. Taking Shanghai as an example, the changes of urban average height and built-up area were studied to represent city’s vertical and horizontal increases respectively, and statistical methods were used to analyze the driving forces of urban expansion. The research drew following conclusions: 1) The urban expansion process of Shanghai from 1985 to 2006 had a clear periodic feature, and could be divided into three stages: vertical expansion in dominance, coordinated vertical and horizontal expansion, and horizontal expansion in dominance. 2) The average height and quantity of buildings in core city were significantly bigger than those in suburbs, but the changing speed of the latter was faster. And 3) urbanization process was the major driving force for the city’s horizontal expansion, while industrial structure improvement was the key driving factor for the vertical expansion. Those two driving forces were simultaneously affected by city’s political factors.     

北黄海典型水域春夏季浮游植物的昼夜变化

根据黄海西北部2006年夏季3个连续站和2007年春季1个连续站垂直分层拖网的调查资料,研究了黄海西北部典型海区浮游植物的昼夜垂直变化.夏季共检出浮游植物79种,主要优势种为旋链角毛藻Chaetoceros curvisetus、梭角藻Ceratium fusus、三角角藻Ceratium tripos和具槽帕拉藻Paralia sulcata;春季检出51种,主要优势种为浮动弯角藻Eucampia zodiacus、具槽帕拉藻和尖刺伪菱形藻Pseudo-nitzschia pungens.夏季L01站受潮汐的影响各水层低潮期浮游植物细胞丰度高于高潮期,垂直分布趋势为表层细胞丰度最高,底层最低.而由于底栖硅藻的细胞再悬浮作用夏季L02、L03站和春季L02站底层细胞丰度高于表层,但各水层细胞丰度的昼夜变化相对较平缓.     

联合多代测高数据建立中国海域重力异常模型

本文联合T/P数据、T/P新轨道数据、ERS数据、GFO数据、GeosatGM数据和ERS-1/168数据,用测高卫星记录点的位置信息直接计算沿轨大地水准面的方向导数,结合测线轨迹方向的方位角在交叉点处推求垂线偏差,然后利用逆Vening-Meinesz公式计算了中国近海(0o～41oN,105o～132oN)2′×2′格网分辨率的海域重力异常模型。将其与CLS_SHOW99重力异常模型比较,统计结果表示与该模型差异的RMS为8.15mgal,在剔除差值大于20mgal的点(剔除3.3%)以后,RMS为4.72mgal;与某海区船测重力异常比较的RMS为8.91mgal。     

双线性插值近似网格的栅格数据投影变换

在栅格数据投影变换常用算法的基础上,介绍一种新的基于双线性内插近似网格算法的栅格数据投影变换,并详细描述其算法过程,认真分析其特点,并证明该算法在大范围栅格数据投影变换中有显著优点。     

混合式全球网格划分方法及编码研究

根据基于多面体剖分的球面网格划分方案和基于地理坐标的等间隔网格划分方案的优缺点及地图投影的特点,提出了一种混合式全球网格划分方法。这种划分方法将全球分成了六个面片,每个面片的每一边都是90°,其中四个面片处于南北纬45°之间,以等距离圆柱投影为基础,采用矩形网格覆盖;两个面片处于高纬地区,以极地正方形变换为基础,采用不规则四边形网格覆盖。详细地阐述了网格的编码策略及存储方式,并给出了网格编码与地理坐标之间的相互转换方法。     

双重投影在高速铁路测量中的应用分析

针对目前我国高速铁路测量采用的高斯投影独立坐标系每个投影带可控制范围太小,给施工带来很多不便的问题,提出了首先将椭球面经纬度投影至球面后再沿铁路线方向进行斜墨卡托投影的原理、方法和计算步骤,并通过算例分析其在高速铁路测量应用中的可行性,该投影方法与目前施工单位正在使用的高斯投影相比较具有明显的优点。