多源三维模型融合技术在三调城镇村内部细化调查中的应用研究

城镇村内部土地利用细化调查是第三次全国土调查中的重要组成部分,全面细化和完善的城镇村庄内部土地利用调查成果,有助于掌握翔实准确的全国国土利用现状和自然资源变化情况。本文基于多源三维模型融合技术,生成高精度高空地面、室内室外一体化三维模型,将其应用于城镇村内部土地利用细化调查工作中,修正城镇村内部土地利用现状图斑边界和地类属性等内容,最终形成准确的城镇村内部土地利用现状成果。利用融合后的三维模型上开展城镇村内部土地利用细化调查是一种有效的调查模式,可为三调高精度高效率调查工作提供技术支撑。     

赤道中、东太平洋表层流速20d振荡特征分析

通过对1985年1月1日—1986年12月31日沿赤道5个锚定浮标站表层流速资料的分析,发现在140°W与108°W之间表层流速v存在一周期约为20d的显著振荡。该振荡是由波长约2000km、以1.15-1.23m／s的波速向西传播的波动引起的。该波动被推断为第二斜压模态混合Rossby惯性重力波。带通滤波和低通滤波结果表明,以110°W测站为例,20d振荡流速构方根为21.8cm／s（纬向）和22.1cm／s（经向）;单一流速振幅的特征值为30-50cm／s,最大振幅可达70cm／s;u季节变化的均方根小于17cm／s,v无明显季节变化。年平均流速通常小于5cm／s。以上各统计量表明,20d周期波动引起的v振荡在赤道东太平洋表层流速变化中非常显著。     

中国邻海海-气热量、水汽通量计算和分析

使用长年代、高质量海洋气象观测资料,选用适合研究海域的计算参数,按2°×2°网格计算了中国邻海（黄、渤、东、南海及140°E以西西北太平洋）辐射平衡和海-气热量、水汽通量,讨论了它们的年、月分布和时空变化,并以海面热量净收支为主要指标进行了海洋气候区划。     

地球化学屏障中添加剂的选择研究

设置一系列加有不同添加剂的地球化学屏障,利用静态平衡实验,并与未加添加剂的空白实验对比,分析其对Ｕ,Ｃｏ,Ｓｒ的阻滞性能;并通过计算Ｋｄ值,对屏障的综合阻滞性能进行分析,选出恰当的添加剂。结果表明：ＮａＳ２作碱性－还原添加剂,利于核素的化学沉淀反应,而且Ｋｄ值显著地增加,屏障对Ｕ,Ｃｏ,Ｓｒ的阻滞性能最好。     

关于悬沙级配沿垂线分布的有效悬浮指标

讨论了要流悬沙中某级泥沙所占全体悬沙之Ｐｉ的两种定义,根据Ｈ．Ｒｏｕｓｅ含沙量分布公式,导出了相应的Ｐｉ／Ｐａ、Ｐｉ／Ｐｉｐｊ、Ｐｉ／ＰｉｐｊＱ等３种形式的悬沙级配沿垂线相对分布表达式;表达了有效悬浮δｉ的物理函义及其实际应用取值问题。     

Role of time variant and invariant terms on soil moisture spatio-temporal variability in a subhumid coastal wetland

The knowledge of soil moisture spatio-temporal variability is highly relevant for water resources management. This paper reports an analysis of the spatial–temporal variability of soil moisture data for a small to medium-scale soil-sensors network in a coastal wetland of southwestern Spain. Measurements were taken from five sites located in the Doñana National Park over the time-period of one hydrological year from September 2017 to September 2018. The total area of the soil-sensors network shows an extension about 25 × 3 km. Soil moisture data was separated into time invariant (the temporal mean of the whole period at each site) and time-variant terms (the deviations of soil moisture from the mean, or anomalies). The time-invariant component was generally the main contributor to the total spatial variance of soil moisture and it was mostly controlled by the groundwater levels in the area. Nevertheless, the time variant terms have a huge effect on soil moisture variability in very dry states. Characteristic convex time-dependent patterns for this field site were found between spatially averaged soil moisture and its variability. This information could be used for the up and downscaling of soil moisture from satellite data. Those patterns of relation between spatial mean and variability of soil moisture were only affected by heavy rainfalls giving rise to hysteretic behaviour. This study shows that even though groundwater level is a time-variant variable, it significantly affects soil moisture's time-variant but also time-invariant terms due to the different average groundwater level depths at the different sites.     

DQM2000d、UGM05和EGM2008地球重力场模型精度比较

给出由地球重力场模型计算重力异常和垂线偏差的公式,利用36阶、360阶、1 800阶DQM 2000d、UGM 05以及EGM 2008地球重力场模型计算国内某地区格网点重力异常和地面垂线偏差,并将其与实测数据进行比较,从而对三种模型的精度进行评估。结果表明,在表示国内某地区格网点重力异常时,UGM 05模型精度最高,DQM 2000d模型精度次之,EGM 2008模型精度最低;在表示地面垂线偏差时,三种模型的精度相当。     

基于级配方程的粗粒料压实特性试验研究

级配显著影响着堆石料的压实特性,定量表述级配对堆石料压实特性的影响至关重要。基于连续级配土的级配方程,设计了16组不同级配的试验粗粒料,进行了表面振动压实试验和侧限压缩试验,定量研究了级配对粗粒料压实特性的影响。研究表明：由表面振动压实（动应力）试验和侧限压缩（静应力）试验得到的干密度与级配曲线面积之间均呈二次函数关系,且干密度中的最大值对应的级配曲线面积均在0.9附近;无论是表面振动压实试验还是侧限压缩试验,堆石料都存在干密度最优（最大）的级配。依据试验成果,给出了所试验堆石料的最优级配区间（级配上、下包络线）;同时,利用相似级配法论证了实际级配粗粒料的最优级配区间,并根据国内外多座土石坝粗粒料的设计级配验证了该最优级配区间的普遍适用性,为土石坝粗粒料的级配设计提供了理论依据。     

Effect of urbanization on runoff characteristics of the On-Cheon Stream watershed in Pusan,Korea

This study investigated the effect of urbanization on runoff from the On-Cheon Stream watershed in Pusan, Korea. This watershed has been experiencing considerable urbanization since the 1960s. There are two gauging stations in the watershed. For one of the stations there are recent flow data and for the other flow data were observed in the past. A linear reservoir model was chosen and runoff was analysed for several flood events. The linear reservoir model has been found to generate flood hydrographs accurately for both gauging stations, and its applicability to the study area has also been established. Using two methods of computing effective rainfall or rainfall excess (ϕ-index and constant percentage method), the results of runoff analyses were investigated. The ϕ-index method yielded better results than the constant percentage method. A comparison of hydrographs observed in the past with the simulation results at the Ie-Sup bridge site revealed that the peak discharge increased and the mean lag time of the study area decreased owing to urbanization over the past two decades. It is also possible to evaluate the effect of urbanization quantitatively. © 1998 John Wiley & Sons, Ltd.     

土的连续级配方程在粗粒料中的应用

粗粒料的级配对其物理力学性质具有重要影响。土体的级配通常用级配曲线来表示,级配方程则是对土体级配曲线的定量描述。利用土的连续级配方程,对各种粗粒料级配的适用性进行了验证,进一步总结了土石坝工程中粗粒料级配参数的常用取值范围;同时,分析了利用该方程进行粗粒料配料计算的实用性。主要结论如下：粗粒料的级配参数常用取值范围集中在-2相似文献