板桥稀土矿遥感找矿信息提取与矿产预测研究

通过对离子吸附型稀土矿成矿规律的分析,从浙江省板桥地区的遥感地质特征研究入手,在研究区地表范围内进行稀土遥感找矿信息的提取。首先利用SPOT图像和DEM数据构建的坡度数据对与稀土成矿相关的地貌单元进行解译;然后通过光谱特征分析和基于ASTER图像的矿物遥感异常提取,获取与成矿相关的高岭土、绢云母、绿泥石等风化特征矿物的分布信息;最后叠合分析地貌、坡度及异常提取结果,进行稀土遥感找矿预测。与地质调查资料及化探数据的对比分析证实,上述方法对圈定1∶5万的大比例尺离子吸附型稀土矿分布范围是有效的,可为更详细的稀土矿产资源潜力评价提供依据。     

A microscale three-dimensional urban energy balance model for studying surface temperatures

A microscale three-dimensional (3-D) urban energy balance model, Temperatures of Urban Facets in 3-D (TUF-3D), is developed to predict urban surface temperatures for a variety of surface geometries and properties, weather conditions, and solar angles. The surface is composed of plane-parallel facets: roofs, walls, and streets, which are further sub-divided into identical square patches, resulting in a 3-D raster-type model geometry. The model code is structured into radiation, conduction and convection sub-models. The radiation sub-model uses the radiosity approach and accounts for multiple reflections and shading of direct solar radiation. Conduction is solved by finite differencing of the heat conduction equation, and convection is modelled by empirically relating patch heat transfer coefficients to the momentum forcing and the building morphology. The radiation and conduction sub-models are tested individually against measurements, and the complete model is tested against full-scale urban surface temperature and energy balance observations. Modelled surface temperatures perform well at both the facet-average and the sub-facet scales given the precision of the observations and the uncertainties in the model inputs. The model has several potential applications, such as the calculation of radiative loads, and the investigation of effective thermal anisotropy (when combined with a sensor-view model).     

“三北”防护林建设以来河西走廊林地变化的遥感监测

为了对中国\!三北\"防护林工程重点建设区河西走廊的防风固沙林工程建设成效进行客观评估,选取4期Landsat MSS、TM/ETM数据,在GIS技术支持下对1978-2007年期间面状林地的动态进行遥感监测。监测结果表明,整个研究区林地面积呈先下降后上升趋势,表现为1978-1990年林地面积明显减少,1990-2000年林地面积大幅度上升,2000-2007年林地呈缓慢上升状态;在不同空间范围内,山区各县林地变化较为缓和,平原区各县林地变化较为明显。在此基础上,分析不同林地变化特征,得出人为因素是本地区林地变化的主要原因。     

青海省柴达木盆地西北缘盐类矿产遥感预测研究

利用ETM多光谱遥感图像,在对盐湖区的遥感影像特征和主要地物光谱特征分析的基础上,通过波段组合变换,压抑粘土及砂砾层等地物的影响,将盐类矿产信息增强提取出来。对比前人的钾盐矿田勘查成果,所提取的盐类信息异常与现代新盐带、湿盐滩和现正在开采的钾盐矿区十分吻合。结合区域地质背景与成矿条件的分析研究,圈定了4个预测区、9处有利地段,为进一步盐类矿产勘查提供了科学依据和目标地。     

招远市金矿区环境遥感调查研究

以遥感图像为基本数据源,以实地调查数据为样点,建立解译标志,利用遥感和地理信息系统新技术对金矿区地质环境条件进行研究,实现航片与卫片校正、地质环境信息的解译、空间数据库的建立.为恢复矿区自然环境提供准确、详实的资料.     

遥感技术在植物物候研究中的应用综述

通过遥感技术研究植物物候现象的机理分析,认为植被指数可反映植被各物候期的特征。国内外在探测植物生长季始末日期、花期变化、净第一性生产力变化、全球碳收支等方面的研究促进了植物物候的发展;同样物候研究也可提高遥感影像植物分类和作物估产的精度,同时可促进高光谱遥感的发展。通过我国物候研究从传统的农林业应用转向注重遥感探测、生态学应用的现状分析,展望了我国物候发展方向：关注植物生长季始末时间的时空分布规律;遥感监测植物季相变化;遥感监测植物花期;注重探讨植物生理和生态特征;植物高光谱遥感物候研究;重视物候科普普及工作。     

Understanding the relative impacts of natural processes and human activities on the hydrology of the Central Rift Valley lakes,East Africa

Significant changes have been observed in the hydrology of Central Rift Valley (CRV) lakes in Ethiopia, East Africa as a result of both natural processes and human activities during the past three decades. This study applied an integrated approach (remote sensing, hydrologic modelling, and statistical analysis) to understand the relative effects of natural processes and human activities over a sparsely gauged CRV basin. Lake storage estimates were calculated from a hydrologic model constructed without inputs from human impacts such as water abstraction and compared with satellite‐based (observed) lake storage measurements to characterize the magnitude of human‐induced impacts. A non‐parametric Mann–Kendall test was used to detect the presence of climatic trends (e.g. a decreasing or increasing trends in precipitation), while the Standard Precipitation Index (SPI) analysis was used to assess the long‐term, inter‐annual climate variability within the basin. Results indicate human activities (e.g. abstraction) significantly contributed to the changes in the hydrology of the lakes, while no statistically significant climatic trend was seen in the basin, however inter‐annual natural climate variability, extreme dryness, and prolonged drought has negatively affected the lakes. The relative contributions of natural and human‐induced impacts on the lakes were quantified and evaluated by comparing hydrographs of the CRV lakes. Lake Abiyata has lost ~6.5 m in total lake height between 1985 and 2006, 70% (~4.5 m) of the loss has been attributed to human‐induced causes, whereas the remaining 30% is related to natural climate variability. The relative impact analysis utilized in this study could potentially be used to better plan and create effective water‐management practices in the basin and demonstrates the utility of this integrated methodology for similar studies assessing the relative natural and human‐induced impacts on lakes in data sparse areas. Copyright © 2015 John Wiley & Sons, Ltd.     

东亚陆地星载微波成像仪新增通道观测质量评估

基于2014年8月1—16日AMSR-2的观测资料,采用谱差法重点对东亚陆地低频7.3 GHz的无线电频率干扰(RFI)进行识别与分析。研究发现,东亚地区7.3 GHz通道观测存在无线电频率干扰,其中韩国京畿道、大邱市,孟加拉国,越南及柬埔寨东南部地区的干扰源是稳定、持续的地面主动源。日本地区7.3 GHz通道RFI仅出现在AMSR-2升轨观测上,而降轨观测则几乎不受干扰,且RFI污染区出现的位置与强度随时间及辐射计扫描角度周期性变化,探究其污染源,发现主要来自地面反射的静止通信/电视卫星信号对星载微波被动传感器观测的干扰。     

土壤遥感分类识别推理决策器的设计

介绍了干旱区土壤遥感分类识别推理决策器的设计原理与实现方法。在用TM遥感图像对土壤类型进行非监督分类的基础上，建立了正向推理与逆向推理相结合的推理机制，对土壤类型进行分类识别决策。用知识表示的产生式规则与框架式规则相结合的数据结构表示土壤学专家的土壤分类识别知识。用像结构模式建立了土壤分类识别的规则，构造了土壤分类判决树，并用典型像例模式进行了各类型土壤判据文件的组织。用该方法对新疆天山北麓阜康试验区的土壤分类识别进行了试验研究。结果表明，该方法分类精度可靠，为干旱区土壤分类识别开辟了一条新的途径。     

Automatic estimation of olive tree dendrometric parameters based on airborne laser scanning data using alpha-shape and principal component analysis

The aim of this study is to present an automatic approach for olive tree dendrometric parameter estimation from airborne laser scanning (ALS) data. The proposed method is based on a unique combination of the alpha-shape algorithm applied to normalized point cloud and principal component analysis. A key issue of the alpha-shape algorithm is to define the α parameter, as it directly affects the crown delineation results. We propose to adjust this parameter based on a group of representative trees in an orchard for which the classical field measurements were performed. The best value of the α parameter is one whose correlation coefficient of dendrometric parameters between field measurements and estimated values is the highest. We determined crown diameters as principal components of ALS points representing a delineated crown. The method was applied to a test area of an olive orchard in Spain. The tree dendrometric parameters estimated from ALS data were compared with field measurements to assess the quality of the developed approach. We found the method to be equally good or even superior to previously investigated semi-automatic methods. The average error is 19% for tree height, 53% for crown base height, and 13% and 9% for the length of the longer diameter and perpendicular diameter, respectively.