利用多光谱影像检测资源三号卫星平台震颤

卫星平台震颤是影响高分辨率卫星成像质量的因素之一,会引起影像模糊和内部畸变。本文从资源三号卫星多光谱相机的成像特点和多光谱影像配准误差影响因素入手,理论推导和仿真分析了卫星平台震颤对配准误差的影响规律,在此基础上提出了基于多光谱影像高精度密集匹配的平台震颤检测方法和流程,最后利用不同波段、不同时间的成像数据进行试验。试验结果表明资源三号卫星在试验数据成像阶段存在约0.6Hz的平台震颤,且垂轨方向震颤幅值大于沿轨方向,同时引起波段间相同频率周期性配准误差。检测结果为进一步提高资源三号处理精度提供了可能,也为卫星平台震颤源的分析和优化卫星平台设计提供了重要参考依据。     

Spatial optimization of rural settlement relocation by incorporating inter‐village social connections under future policy scenarios

Social connections between villages can represent farmers’ interests and thus benefit participatory rural relocation planning. With rural development, however, these connections will change and may weaken the adaptation of relocation plans to future rural systems. As yet, most studies still use empirical social connections to guide relocation planning, while a few have incorporated predicted connections in the context of rural development into relocation decisions. Meanwhile, spatial optimization approaches have seldom been adopted to solve this geographical decision issue. Accordingly, our study proposes a novel spatial relocation framework that incorporates changed inter‐village social connections under future rural development scenarios. Empirical inter‐village connections and their policy‐induced changes in central China were explored using social network analysis. An integration of particle swarm optimization and geographic information systems was adopted to identify the relocation solutions with maximum inter‐village connections and maximum spatial land use compactness, and to examine how connection changes under different policy scenarios influenced relocation outcomes. The results demonstrate the significance of incorporating policy‐induced social connections into relocation plans, and most importantly, show the negative relations between changed social connections and the migration distance/direction of relocated settlements. Our study is expected to improve the adaptation of relocation plans to future rural development.     

软土路基深层搅拌桩检测方法的探讨

根据长江路三期软土路基的工程地质条件及道路工程的施工特征，分析与探讨了适用于道路工程中深层搅拌桩质量的检测方法和桩身质量的综合评价方法，通过对此道路工程中深层搅拌桩质量的检测，总结出了适合道路工程的，轻便触探结合钻探取心的，快捷、方便、可靠、经济合理的较为理想的检测方法。     

Comparison of debris-flow volume and activity under different formation conditions

Debris flows frequently occurred in Wenchuan earthquake region from 2008 to 2010, resulting in great damage to localities and being a prolonged threat to reconstruction. Forty three events' data including debris-flow volume, sediment volume and watershed area are analyzed and compared with other debris-flow events in Eastern Italian Alps, burned areas in USA and in Taiwan. The analysis reveals that there is a strong empirical relationship between debris-flow volume and loose materials volume in the earthquake region. In addition, the relationship between debris-flow volume and watershed area in the earthquake region has a wider variation range than that in other three regions while the debris volume also appears to be larger than that in the other three regions, which implies the volume of debris flows with strong influence of earthquakes is larger than that with no such influence and it is hard to predict the post-quake volume only by the watershed area. The comparison of the maximal debris-flow erosion modulus in the Wenchuan region and in Taiwan indicates that debris flows will be very active in a short time after strong earthquake.     

Energy distributions of the large-scale horizontal currents caused by wind in the baroclinic ocean

Wind is the main energy source for the generation of the internal waves and the ocean mixing. Wunsch[1] estimated that about 1 TW (1 TW = 1012 W) energy was transported into the ocean from the winds by us-ing the altimeter data. Watanabe et al.[2] numerically calculated that the mixing processes obtained 0.7 TW energy from the global wind, which afforded most of the energy needed by the maintenance of the Merid-ional Overturning Circulation (MOC). During the past 50 years, in the Norther…     

邻近算法在微地震震源位置和一维速度模型同时反演中的应用

微地震事件的空间分布可以用来监测水力压裂过程中裂缝的发育情况.因此,震源定位是微震监测中重要的环节.震源定位依赖准确的速度模型,而震源位置和速度模型的耦合易导致线性迭代的同时反演方法陷入局部极小值.邻近算法作为一种非线性全局优化算法,能够最大程度地避免陷入局部最优解.本文将邻近算法应用于单井监测的微震定位和一维速度模型...     

近远场地震动作用下地铁车站结构地基液化效应的振动台试验

开展了近场和远场地震动作用下3跨3层地铁车站结构地基液化效应的振动台模型试验,测试了地铁车站结构的加速度、应变、水平位移反应和地基土孔隙水压力、加速度、震陷及其作用于模型结构侧墙的动土压力反应。分析和总结了地铁车站结构地基液化效应特征,结果表明：模型结构对其周围地基土孔隙水压力场的分布有明显影响,结构两侧和底部地基土中的孔压峰值小于相同深度离结构较远地基土中的孔压峰值;地基土中孔压的消散速度自下而上呈逐渐减慢的趋势;地震动作用过程中,模型结构产生向上的相对运动,强地震动作用时模型结构上浮现象明显;模型结构侧墙受到的动土压力随深度增大而减小,输入地震动特性对动土压力的大小有显著影响。     

海南省大广坝水电站集水区降水特征及人工增雨潜力分析

本文分析了海南省大广坝水电站集水区降水分布特征并研究了人工增雨的潜力。结果表明,大广坝水电站集水区降水年际差异较大,常年无法满负荷发电,影响了水电站效益的正常发挥。4～7月集水区实施人工增雨的潜力和成云致雨的条件较好,通过人工增雨的手段可以有效提高水电站的发电效益。     

西湖凹陷输导体系特征及其对油气成藏的控制作用

输导体系是东海西湖凹陷油气勘探研究中的重要内容之一。断裂、砂岩层和不整合面作为西湖凹陷输导体系的基本要素,共同构成了盆地各成藏单元流体纵、横向运移的复杂输导网络系统。根据断裂、砂岩层、不整合面等输导要素在空间和时间上的组合关系,总结出顺向断层阶梯型、反转断层丘型、调节断层"Y"型和"T"型4种典型输导体系样式。输导体系对油气成藏的控制作用主要表现为:输导体系类型及分布样式决定着油气藏层位的分布;输导体系组成地质要素控制着油气藏类型的分布。     

Evaporation from seasonally frozen bare and vegetated ground at various groundwater table depths in the Ordos Basin,Northwest China

In cold climates, the process of freezing–thawing significantly affects the ground surface heat balance and water balance. To better understand the mechanism of evaporation from seasonally frozen soils, we performed field experiments at different water table depths on vegetated and bare ground in a semiarid region in China. Soil moisture and temperature, air temperature, precipitation, and water table depths were measured over a 5‐month period (November 1, 2016, to March 14, 2017). The evaporation, which was calculated by a mass balance method, was high in the periods of thawing and low in the periods of freezing. Increased water table depth in the freezing period led to high soil moisture in the upper soil layer, whereas lower initial groundwater levels during freezing–thawing decreased the cumulative evaporation. The extent of evaporation from the bare ground was the same in summer as in winter. These results indicate that a noteworthy amount of evaporation from the bare ground is present during freezing–thawing. Finally, the roots of Salix psammophila could increase the soil temperature. This study presents an insight into the joint effects of soil moisture, temperature, ground vegetation, and water table depths on the evaporation from seasonally frozen soils. Furthermore, it also has important implications for water management in seasonally frozen areas.