GPS/GLONASS定位系统融合的坐标转换研究

GPS和GLONASS卫星定位系统分别采用WGS-84和PZ-90坐标系。为统一两种卫星定位成果,欧、美、俄于20世纪90年代各自求出两坐标系之间的转换参数。目前三种参数尚未统一,对GPS/GLONASS联合定位造成较大影响。本文针对国外介绍PZ-90和WGS-84坐标系相互转换时常用的转换模型及三种不同转换参数进行比较分析。分别选用地面GPS参考站坐标和GLONASS卫星轨道坐标,用三种坐标转换参数进行转换,对转换结果差异及其对单点定位和相对定位精度造成的影响进行全面分析比较,得出一些有益结论。     

Flocculation improves uptake of Sr and Cs from radioactive effluents

This paper presents the results of investigation on uptake of radioactive species ⁹⁰Sr and ¹³⁷Cs present in the liquid effluents from nuclear processing plants. Chemical precipitation process is adopted to remove radioactivity from the effluents with low and intermediate level of activity. In this process, radioactive ⁹⁰Sr and ¹³⁷Cs are co-precipitated along with copper ferrocyanide, ferric hydroxide and either calcium phosphate or barium sulphate. These precipitates being fine in size require flocculation for enhanced settling rate in clarifier/thickener. The flocculation by some selected high molecular weight polyacrylamide based polymers has improved the uptake of radioactive metal ions. The adsorption of these radioactive species has been found to increase in the presence of these flocculants thereby improving the decontamination factor (DF). While flocculating the precipitates, there may be some complex formation with Sr²⁺/Cs⁺, flocculant and the substrate. This has enhanced the uptake of the radioactive metal ions from the liquid component. The plant trials have indicated the improvement of DF value due to flocculation by cationic flocculant.     

OPA 90's impact at reducing oil spills

OPA 90 set out stringent requirements and liabilities for tankers operating in US national waters. OPA 90 was in response to the public concern caused by the grounding of the Exxon Valdez in 1989. It made ship owners responsible for the cost of pollution incidents and required all tank ships/barges operating in US waters have double hulls by 2015. We model factors influencing oil spills and test whether OPA 90 helped reduce the number of those spills. After accounting for causal factors, both increased liability and double hulls were statistically significant factors in reducing the number of spills.     

豫北及其外围地区地壳上地幔结构研究

利用菏泽～长治和郑州～济南深地震测深剖面资料，进行了一维、二维射线追踪走时拟合与合成地震图计算，获得了该区地壳上地幔速度结构。结果表明，地壳上地幔速度结构在纵向和横向上具有明显的不均一性。浅部断裂较发育，对应其地壳深部界面和速度等值线起伏变化较明显。在华北坳陷区南部上地幔隆起的背景上存在两个局部凸起，凸起最高处与浅部的东濮凹陷、汤阴地堑基本对应，Ｍ面埋深分别约３１ｋｍ和３４ｋｍ     

粘滑失稳及其物理场时空分布的实验研究

摩擦滑动的物理场实验研究表明：（１）能量空间分布的差异是失稳的重要条件，单发型大事件常发生于高能量向低能量的突变带或高能量背景区内的相对低能量区；（２）单发型大事件的孕育过程常常经历若干个能量输入输出循环，产生多个前兆阶段，并在失稳前源区常有一个弱化过程。小震或群发型事件失稳前常常只有一个能量积累与强化的过程，失稳前兆阶段性反映较差；（３）粘滑失稳时断层的位错与声发射的大小未见明显关系     

湘东─赣西NNE向走滑构造

湘东─赣西构造岩浆带位于郯庐断裂南延的关键性部位。中生代以来，该区 NNE向左旋走滑构造主要由会聚走滑和 K─ E离散走滑构造叠加而成。会聚走滑作用造就了 NNE向雁列式剪切断裂系、剪切弯曲和旋转构造、压剪性煤盆地以及断层动热变质─剪切重熔型花岗岩；而离散走滑作用则控制了该区广泛发育的张剪性红盆地、盆岭式构造地貌、以及大规模中低温热液矿床的形成。湘东─赣西复杂的平移构造型式很可能与该区地壳结构分层特征、前期断裂构造格局、平移幅度和多期走滑构造作用四个因素有关。     

增强气候诊断及预测程序通用性的一种方法

针对现有气候统计诊断与预测程序在通用性方面的不足,以线性趋势估计的源程序为例,介绍了在微机平台上,利用Fortran 90的动态数组特性,通过增加参数控制文件增强该程序通用性的思路和方法,并利用V isualBasic语言对改进后的程序进行可视化设计,增强了程序的易用性。     

地磁测量中日变观测的常见问题

地磁日变观测质量主要与仪器性能和观测点的环境有关。本文重点研究了目前在地磁日变测量中主要采用的HC90D氦光泵磁力仪的信号失锁问题,日变站的选址二个对于最终观测精度影响很大的问题,并提出了具体的解决方法。     

Chemical and physical properties affecting strontium distribution coefficients of surficial-sediment samples at the Idaho National Engineering and Environmental Laboratory, Idaho

 The U.S. Geological Survey and Idaho State University, in cooperation with the U.S. Department of Energy, conducted a study to determine strontium distribution coefficients (K_ds) of surficial sediments at the Idaho National Engineering and Environmental Laboratory (INEEL). Batch experiments using synthesized aqueous solutions were used to determine K_ds, which describe the distribution of a solute between the solution and solid phase, of 20 surficial-sediment samples from the INEEL. The K_ds for the 20 surficial-sediment samples ranged from 36 to 275 ml/g. Many properties of both the synthesized aqueous solutions and sediments used in the experiments also were determined. Solution properties determined were initial and equilibrium concentrations of calcium, magnesium, and strontium, pH and specific conductance, and initial concentrations of potassium and sodium. Sediment properties determined were grain-size distribution, bulk mineralogy, whole-rock major-oxide and strontium and barium concentrations, and Brunauer-Emmett-Teller (BET) surface area. Solution and sediment properties were correlated with strontium K_ds of the 20 surficial sediments using Pearson correlation coefficients. Solution properties with the strongest correlations with strontium K_ds were equilibrium pH and equilibrium calcium concentration correlation coefficients, 0.6598 and –0.6518, respectively. Sediment properties with the strongest correlations with strontium K_ds were manganese oxide (MnO), BET surface area, and the >4.75-mm-grain-size fraction correlation coefficients, 0.7054, 0.7022, and –0.6660, respectively. Effects of solution properties on strontium K_ds were interpreted as being due to competition among similarly charged and sized cations in solution for strontium-sorption sites; effects of sediment properties on strontium K_ds were interpreted as being surface-area related. Multivariate analyses of these solution and sediment properties resulted in r² values of 0.8071 when all five properties were used and 0.8043 when three properties, equilibrium pH, MnO, and BET surface area, were used. Received: 30 November 1998 · Accepted: 16 February 1999     

Assess hydrological responses to a warming climate at the Lysina Critical Zone Observatory in Central Europe

Climate warming is having profound effects on the hydrological cycle by increasing atmospheric demand, changing water availability, and snow seasonality. Europe suffered three distinct heat waves in 2019, and 11 of the 12 hottest years ever recorded took place in the past two decades, which will potentially change seasonal streamflow patterns and long-term trends. Central Europe exhibited six dry years in a row since 2014. This study uses data from a well-documented headwater catchment in Central Europe (Lysina) to explore hydrological responses to a warming climate. We applied a lumped parameter hydrologic model Brook90 and a distributed model Penn State Integrated Hydrologic Model (PIHM) to simulate long-term hydrological change under future climate scenarios. Both models performed well on historic streamflow and in agreement with each other according to the catchment water budget. In addition, PIHM was able to simulate lateral groundwater redistribution within the catchment validated by the groundwater table dynamics. The long-term trends in runoff and low flow were captured by PIHM only. We applied different EURO-CORDEX models with two emission scenarios (Representative Concentration Pathways RCP 4.5, 8.5) and found significant impacts on runoff and evapotranspiration (ET) for the period of 2071–2100. Results from both models suggested reduced runoff and increased ET, while the monthly distribution of runoff was different. We used this catchment study to understand the importance of subsurface processes in projection of hydrologic response to a warming climate.