呼伦贝尔市2016年3月31日-4月2日暴雪过程天气学特征研究

利用常规观测资料及NCEP 1.0°×1.0°再分析资料,对2016年3月31日至4月2日发生于呼伦贝尔市的一次暴雪天气过程的环流形势、成因机制进行分析,以期总结出此次暴雪的特殊之处,为今后的暴雪天气预报提供可参考的经验。从天气学角度详细地分析此次暴雪过程的高低空影响系统的生消演变,特别对产生极端降水的水汽输送条件、水汽辐合情况、局地水汽聚集以及垂直运动情况进行详尽的分析。研究结果表明：此次暴雪天气过程是由短波扰动叠加低空锋区,导致斜压有效位能释放转变为扰动动能,并促使扰动发展加深为大型涡动而产生;水汽通量分布形态在一定程度上决定了水汽输送效果,“均匀狭长”的分布形态具有更高的水汽输送效率;涡度差动平流与温度平流表明动力因子与热力因子在本次过程中对垂直运动均有显著贡献,而水平散度作为直接反映质量汇集、流失的参量可以更为直观地反映垂直运动的强弱与分布;整层水汽通量散度积分作为与降水强度直接相关的物理量,对于降水量级的反映异常精准,配合中低空气流强度与方向,可对降水落区与时段进行精确判断。     

高光谱遥感地空综合预测方法在新疆卡拉塔格地区铜金矿床找矿中的应用

新疆卡拉塔格地区位于东天山成矿带,地质矿产资源丰富,铜金及多金属矿床集中,找矿潜力较大。铜金矿床地表矿化蚀变现象明显,发育的褐铁矿化+黄钾铁矾化+绢云母化形成地物反射光谱特征,为高光谱遥感地空综合预测方法用于探测铜金矿化蚀变信息成为可能,并成为寻找铜金矿床的有效技术方法。本文在卡拉塔格地区开展了航空高光谱和地面高光谱在铜金多金属矿床找矿研究,分别采用Hy Map航空成像光谱仪和Field Spec Pro FR光谱仪,获取了研究区Hy Map航空高光谱数据、地面准同步定标数据、地面高光谱数据,提取并筛选了基于Hy Map航空高光谱影像的成矿有利蚀变信息,在此基础上对该区红山铜金矿床航空-地面高光谱提取的蚀变信息进行了综合剖析,并结合矿区地质背景,建立了红山铜金矿床高光谱遥感地空综合找矿模型,经对比分析在该区圈定了2处找矿预测区。说明高光谱遥感地空综合预测方法在该区得到了很好的应用效果。     

Diagnostics of the shape and orientation of a rock failure zone based on electrical measurements as an inverse problem of geophysics

Exploration geophysics is concerned with the development of methods and techniques for remote search for mineral deposits, solution of various engineering and geological problems, mining monitoring, and diagnostics of zones of rock bursts and natural and technogenic tectonic earthquakes. In this paper, we consider the diagnostic problem of exploration geophysics related to the determination of the shape and inclination angle of a plane source of natural geoelectric field, which, under certain conditions, simulates a rock failure zone, e.g., during the preparation of rock bursts at the sites of developed mineral deposits. This approach may also be useful in determining the shape and size of ore shoots by electrical measurements on the ground surface. Evaluation of the parameters of a rock failure zone is required in the case of accumulation of multiple fractures having charges of the same sign before a catastrophic failure. This problem is formulated as a Fredholm-Urysohn integral equation of the first kind. The solution of the integral equation is sought using the Tikhonov regularization method of the second order.     

农户土地转出行为调查与分析

以成渝城乡统筹区农地转出户为研究对象,根据农地转出率的大小将农户分为完全转出户、高度转出户和基本转出户,运用多元线性回归模型和OLS回归模型对农户农地转出行为的影响因素及收入效应进行分析。研究结果表明:成渝城乡统筹区农地转出户的农地转出率不尽相同,完全转出户、高度转出户和一般转出户并存,农地转出方式和转出对象虽然存在多样性,但农地仍以小规模分散转出为主;稳定的非农收入、政府的积极推动以及合理的农地转出价格促进了农户农地转出率的提高,而土地细碎化和较多的家庭常年务农人口数量在一定程度上阻碍了农户农地转出行为;农户农地转出是一种理性决策行为,农地转出率越高,农户的收入效应就越明显,收入由多至少依次为完全转出户、高度转出户和一般转出户。     

断裂带油气幕式运移:来自物理模拟实验的启示

断裂结构对油气运移的影响是当前油气输导体系研究的前沿与薄弱环节。本文在调研断裂结构及其流体流动机制的基础上,利用物理模拟实验研究断裂带油气幕式运移过程,探讨断裂带油气运移机理及相关问题。实验结果表明,断裂内部结构控制着油气运移的路径和方式,含油饱和度在一定程度上影响油气运移的路径;破碎带是油气幕式运移的优势通道,且油气聚集成藏的潜在圈闭为位于油源断裂主动盘一侧的圈闭。单次幕式充注过程中运移量与时间之间的对数型关系表明,流体沿断裂幕式运移具有非线性流的特征,且流动速率可能介于一个相对固定的范围,其数量级约为10~2~10~3m/a;流体沿断裂幕式流动过程包含高速非线性流、过渡流动机制和线性达西流3种流体流动机制,其间的相互转换是一个多物理场相互作用的复杂过程。此外,断层体油气藏的形成条件为油气沿断裂运移时,运移动力与阻力在断裂带内达成平衡状态。     

Linkam热台与热液金刚石压腔的熔体包裹体均一实验对比研究

熔体包裹体均一实验是利用熔体包裹体研究原始岩浆演化和挥发分组成的基础。目前,开展包裹体均一温度实验的设备主要为Linkam系列的高温热台,而热液金刚石压腔(HDAC)是近年来才被应用到熔体包裹体均一实验中的。文章以义兴寨金矿床石英斑岩为例,对比研究了Linkam TS1500高温热台和HDAC在熔体包裹体均一实验应用中的优劣。利用Linkam TS1500高温热台得出熔体包裹体的均一温度范围为943~1190℃,而HDAC的测试结果为780~890℃。实验研究表明:HDAC能够在加热的同时提供接近熔体捕获条件的外压,更适于开展富挥发分的高内压熔体包裹体的均一实验。实验过程中得到的熔体包裹体固相初熔温度范围,可为估算义兴寨金矿床石英斑岩原始岩浆晚期结晶的压力提供依据。     

光学与微波数据协同反演农田区土壤水分

光学和微波协同遥感反演对于提高农田土壤水分遥感反演精度十分重要。本文采用SMEX02数据集,研究了L波段土壤发射率与地表土壤水分之间的关系,分析了地面植被覆盖对L波段土壤发射率与地表水分之关系的影响规律,推导了以L波段土壤发射率和归一化植被指数NDVI为自变量的土壤水分反演模型。研究表明:L波段土壤发射率与地表土壤水分之间的相关性随NDVI的增加而下降。验证结果表明,本文算法相对常规经验算法,土壤水分反演精度明显提高,H极化条件下,土壤水分的反演精度RMSE由0.0553提高到0.0407,相关系数R2由0.70提高到0.81;V极化条件下,反演精度RMSE由0.0452提高到0.0348,相关系数R2由0.79提高到0.86。     

Experimental investigation of the morphodynamic response of riffles and pools to unsteady flow and increased sediment supply

Gravel-bed rivers characteristically exhibit shallow riffles in wide sections and deeper pools where the channel becomes constricted and narrow. While rivers can adjust to changing flow and sediment supply through some combination of adjustments of channel slope, bed-surface sorting, and channel shape, the degree to which riffle-pools may adopt these changes in response to changing flows and sediment supplies remains unclear. This article presents results from a flume experiment investigating how constant- and variable-width channels adjust their morphology in response to changing flow and increased sediment supply. Two flume geometries were used: (1) constant-width and (2) variable-width, characterized by a sinusoidal pattern with a mean width equal to that of the first channel. The variable-width channel developed bed undulations in phase with the width, representing riffle-pools. The experiment consisted of three phases for each flume geometry: (1) steady flow, constant sediment supply; (2) unsteady flow, constant sediment supply; and (3) unsteady flow, doubled sediment supply. Unsteady flow was implemented in the form of repeated symmetrical stepped hydrographs, with a mean discharge equal to that in the steady flow phase. In all phases the bed and sediment supply were composed of a sand/gravel mixture ranging from 1 to 8 mm. In both the straight and variable-width channels, transitioning from steady flow to repeated hydrographs did not result in significant changes in bed morphology. The two channel geometries had different responses to increased sediment supply: the slope of the straight channel increased nearly 40%, while the variable-width channel reduced the relief between bars and pools and decreased the variability in cross-sectional elevation with a slight slope increase. Bar-pool relief varied with repeat discharge hydrographs. Pool elevation changed twice the distance of bar elevations, emphasizing the relevance of pool scour for riffle-pool self-maintenance in channels with width variations.     

非地理信息系统专业GIS课程实验教学改革与探索

以平顶山学院省级特色专业-资源环境与城乡规划管理专业(以下简称"资环"专业)环专业为例,对GIS课程的性质及GIS教学中存在的问题进行分析,构建非GIS专业GIS课程实验教学内容体系,探索项目教学法在实验教学中的应用,并针对该课程试验教学改革提出几点建议。     

新疆玛河安集海灌区给水度变化规律及试验研究

在对新疆玛纳斯河流域安集海灌区进行地表水地下水转换机理和联合调度研究及利用各类集总式、分布式水文模型进行地下水数值模拟时,给水度都是一个十分重要的输入参数。分析研究区的基本地质情况,选取比较有代表性的地块,利用给水度参数测定装置分别测定常值给水度、变值给水度,揭示该区域给水度随地下水埋深的变化规律。试验得出：在计算地下水降雨入渗补给量和灌溉入渗补给量时要用到给水度这一参数,特别是在地下水埋深不大的地区,对计算成果有比较明显的影响;在地表排水沟设计中,如果考虑了给水度随埋深而变的情况,排水沟的尺寸就会发生变化。