光学遥感卫星大气校正研究综述

由于高分辨率遥感应用需求增加的牵引,国内外发射了越来越多的光学遥感卫星载荷.然而,随着传感器分辨率的增加,大气对地表信息干扰的问题也越来越突出,光学遥感图像的大气校正问题,因载荷特点和应用需求的改变面临着一些新的挑战,有必要对其进行总结和分析.本文在介绍大气校正现状和原理的基础上,按照光学遥感卫星大气校正输入信息来源不同,把大气校正方法归纳为基于图像和图形处理方法、基于辐射传输计算、基于图像自身信息反演大气参数、基于大气同步校正仪的大气校正4类进行介绍.最后,结合我国高分辨率光学卫星的发展方向,对当前的大气校正应用方案和未来发展进行了讨论和展望.     

基于植被指数的绿地信息提取的比较

运用遥感图像处理系统(ENVI)对快鸟(Quickbird)高分辨率遥感影像进行预处理,利用归一化差值植被指数(NDVI)、归一化差异绿度指数(NDGI)、土壤调节植被指数(SAVI)和修正土壤调节植被指数(MSAVI)对南京市鼓楼区进行了绿地信息提取,通过Matlab软件比较了其灰度图像、直方图和二值图像,并分析其方差,在C语言的平台上进行了精度评定.实验结果表明:在该研究区中,SAVI、NDVI的绿地提取能力较好;NDGI、MSAVI出现了明显的漏分、错分情况,但MSAVI在建筑物、植被边缘提取上表现出相对的优越性.     

基于Mask R-CNN的遥感影像土地分割与轮廓提取

传统的模式识别难以对土地遥感影像一次性精确统计分析.在精确分割出土地种类的前提下,本文提出了一种基于骨干网络为ResNet-101-RPN的Mask R-CNN的遥感影像土地分割与轮廓提取方法.该方法包括以下步骤：数据获取、图像去雾、遥感影像土地统计分析、土地分割和轮廓获取.在一个具有挑战性的卫星地图瓦片数据集上对所提出的方法进行训练和测试.实验结果表明,该方法以0.907的均值平均精度（mAP）和31.33像素的均值平均距离误差（mADE）获得了令人满意的不同种类土地分割和轮廓提取结果.     

气象卫星大雾遥感自动识别技术研究

鉴于大雾对城市和沿海地区国民经济和人们生命财产带来的巨大灾害,迫切需要研制快速、有效、准确的雾遥感监测和识别方法。在对雾的辐射特性与卫星光谱特征试验分析基础上,找出不同时相可见光遥感图像下垫面反射率与云雾反射率之间的相对关系,并通过对图像反射率的相对变化率进行计算分析,自动生成准雾区动态判别阈值,并在准雾区范围初步确定基础上,采用基于图像游程编码的快速连通区域标记技术,结合纹理分形分析、形态分形分析、平滑度分析、模板特征分析等实用方法,对气象卫星遥感图像进行雾自动识别和云雾分离研究,取得了良好的应用效果。     

基于空-谱先验条件随机场的高分辨率遥感影像变化检测方法

高空间分辨率遥感影像能够提供丰富的空间细节信息,使利用遥感影像进行精细变化检测成为可能.为充分挖掘高分辨率影像中的光谱、空间信息,本文提出一种基于影像空-谱先验信息的条件随机场（Conditional Random Field based on Spectral-Spatial Prior,SSPCRF）模型,该方法使用显著性检测方式自动提供先验光谱-空间样本信息,提高一元势能构建精度,有效缓解一元势能构建不准确导致的推理过程中的误差传递问题,并在二元势能中综合考虑标记场与观察影像的空间上下文信息以保持变化地物轮廓信息.最后,使用基于消息传递机制的推理方法将模型进行全局优化.在2组高分辨率影像数据集上的实验结果表明该方法能够提供较精确的初始变化检测信息,使得在减少变化检测结果中虚警点的同时保持变化地物细节信息.     

TWR-01型天气雷达回波特征参数的提取和应用

TWR-01型天气雷达是小型数字化雷达,具备GIS和GPS功能,可适应移动式、固定式的增雨防雹作业指挥和气象保障服务.TWR-01型天气雷达回波特征参数的提取技术是基于影像的目标轮廓提取方法.目标轮廓提取方法在图像识别与图像分析中占有重要地位,广泛应用于测量和遥感领域.TWR-01型天气雷达同波特征参数提取的技术方法是...     

面向对象的土地利用遥感分类——以邛海流域为例

利用google earth提取的SPOT5高分辨率遥感影像为研究数据,基于The Environment for Visualizing Images （ENVI） EX软件平台,采用面向对象的多尺度分割方法,获得了邛海流域土地利用类型.结果表明：该分类方法不仅能够克服传统基于像元分类方法中的“椒盐效应”问题,而且能够综合利用DEM、NDVI等辅助信息和地物本身的光谱特征与纹理特征.对分类结果进行了检验,分类精度达89.18％,分类结果达到要求.     

基于分形维数的离线图像分割方法

为了能够提高图像分割的精度,提出了一种基于统计学和分形维数的图像分割方法,能够对自然景物中树木、道路和天空进行分割,并且可以应用于机器人导航的视觉系统.该方法首先通过统计大量的道路和树木和天空的分形维数(LFD),分析三者对应的LFD值分布特点,然后利用该特点对图像进行分割,最后对分割后的图像进行平滑处理,得到分割结果.实验结果表明:利用统计结果进行图像分割能够提高分割速率,而且使用分形维数作为特征能够得到比较精确的分割效果.     

《资源环境高分辨率遥感应用研究》

正该书详细介绍了高分辨率对地观测技术的特点,并对高空间分辨率、高时间分辨率、高光谱分辨率三种载荷的数据处理及应用方法进行了详细阐述;基于多年在高分辨率对地观测技术方面的研究成果,介绍了进行多源数据融合的方法;结合我国高分辨率对地观测重大专项的发展,提出了高分辨率对地观测技术在生态环境的具体应用方法。本书的研究内容涵盖了资源环境高分辨率遥感应用的多个关键环     

光谱地质遥感研究进展

地质遥感是最能体现与发挥光谱遥感技术特点与优势的应用领域之一.本文从矿物岩石光谱模拟、矿物岩石光谱特征分析、遥感光谱仪技术指标的优化设计、辐射定标与数据辐射校正、地表光谱反演、信息提取、信息产品验证、地质应用8个方面总结了最新的研究进展,并对目前光谱遥感地质应用存在的问题和发展趋势进行了深入的论述.     

基于城市交通脆弱性核算的大雾灾害风险评估

选用大雾观测资料测算城市地区的雾灾危险性指数,以规则网格作为评估单元,逐网格计算网格区域内的路网密度,以此作为雾灾的空间脆弱性指标,并针对重点设施的分布情况对脆弱性指数进行空间叠加订正;选用网格内的人口密度作为雾灾的易损性指标;危险性、脆弱性及易损性3项指标按5:2:1的分配比例综合测算雾灾的风险指数。实例研究选用北京地区1996年1月—2006年12月的大雾资料,按空间网格化方法对大雾灾害风险进行评估,结果表明:北京地区雾灾脆弱性指数的高值区域与高速路及环城路延伸方向一致,城市中心为人口集中分布地区,其综合风险指数高,与高速路段、环城路及机场等地段均为雾灾的高风险区域,北京东南部地区年平均雾日数相对较多,危险性指数值也较高,是雾灾较高风险区域。     

Thermal bioclimate in idealized urban street canyons in Campinas, Brazil

Among several urban design parameters, the height-to-width ratio (H/W) and orientation are important parameters strongly affecting thermal conditions in cities. This paper quantifies changes in thermal comfort due to typical urban canyon configurations in Campinas, Brazil, and presents urban guidelines concerning H/W ratios and green spaces to adapt urban climate change. The study focuses on thermal comfort issues of humans in urban areas and performs evaluation in terms of physiologically equivalent temperature (PET), based on long-term data. Meteorological data of air temperature, relative humidity, wind speed and solar radiation over a 7-year period (2003–2010) were used. A 3D street canyon model was designed with RayMan Pro software to simulate the influence of urban configuration on urban thermal climate. The following configurations and setups were used. The model canyon was 500 m in length, with widths 9, 21, and 44 m. Its height varied in steps of 2.5 m, from 5 to 40 m. The canyon could be rotated in steps of 15°. The results show that urban design parameters such as width, height, and orientation modify thermal conditions within street canyons. A northeast–southwest orientation can reduce PET during daytime more than other scenarios. Forestry management and green areas are recommended to promote shade on pedestrian areas and on façades, and to improve bioclimate thermal stress, in particular for H/W ratio less than 0.5. The method and results can be applied by architects and urban planners interested in developing responsive guidelines for urban climate issues.     

Urban green commons: Insights on urban common property systems

The aim of this paper is to shed new light on urban common property systems. We deal with urban commons in relation to urban green-space management, referring to them as urban green commons. Applying a property-rights analytic perspective, we synthesize information on urban green commons from three case-study regions in Sweden, Germany, and South Africa, and elaborate on their role for biodiversity conservation in urban settings, with a focus on business sites. Cases cover both formally established types of urban green commons and bottom-up emerged community-managed habitats. As our review demonstrates, the right to actively manage urban green space is a key characteristic of urban green commons whether ownership to land is in the private, public, the club realm domain, or constitutes a hybrid of these. We discuss the important linkages among urban common property systems, social–ecological learning, and management of ecosystem services and biodiversity. Several benefits can be associated with urban green commons, such as a reduction of costs for ecosystem management and as designs for reconnecting city-inhabitants to the biosphere. The emergence of urban green commons appears closely linked to dealing with societal crises and for reorganizing cities; hence, they play a key role in transforming cities toward more socially and ecologically benign environments. While a range of political questions circumscribe the feasibility of urban green commons, we discuss their usefulness in management of different types of urban habitats, their political justification and limitation, their potential for improved biodiversity conservation, and conditions for their emergence. We conclude by postulating some general policy advice.     

The Influence Of Urban Canopy Configuration On Urban Albedo

We propose a calculation method for shortwave radiation flux and longwave radiation flux within the urban canopy and investigate the influence of urban canopy configuration on net radiation flux. In the assumed urban configuration, buildings of equal size are arranged in a regular lattice within the urban canopy. The net shortwave radiation flux and longwave radiation flux within the urban canopy were calculated by the photon tracking method based on the Monte Carlo method. The albedo value obtained by this method shows close agreement with experimental data, and the average sky view factor shows almost perfect agreement with the theoretical value. Moreover, we calculated the urban albedo for the urban canopy configuration including roads and building height distribution.%Moreover, we calculated net radiation within the urban canopy in %consideration of roads and building height distribution.We found that the sky view factor of the ground surface is high when building coverage is low, building height is low, open space by roads exists, and building height is non-uniform. Moreover, we found that the albedo value is high when building height is small, open space by roads is wide, and building height is uniform. The albedo value was found to vary in a complicated manner with change in building coverage.     

1980~2013年安徽霾天气变化趋势及可能成因

对1980~2013年安徽省霾日数的时空变化趋势及可能原因进行了分析,结果表明:(1)1980年以来,霾天气年均发生日数总体呈上升趋势,年际波动较大。不同年代,霾高发区的位置不同:20世纪80年代平均为5.5 d,沿江到江淮之间有零星的高发区;20世纪90年代平均为8.5 d,高发区在沿江中西部的望江和池州、省会合肥、淮北北部的萧县和灵璧;2000年代,平均发生日数为8.7 d,有3个高发区,分别是以合肥为中心的江淮之间中部、沿淮中部地区和沿江中东部地区。(2)按地理位置把安徽省分为6个子区,不同子区年霾日数的变化趋势不同:皖南山区变化较平缓,沿淮地区2000年后上升明显,淮北北部和沿江有先升后降的趋势。(3)地级市平均霾日数呈显著上升的趋势,而县城霾日数上升速度缓慢,且在2008年之后有下降趋势。(4)城市化和汽车拥有量激增导致氮氧化物排放量快速增多,可能是2000年之后地级市霾日数显著增多的主要因子,而县城霾日数变化的驱动因子可能是气候变化原因,如东亚季风强度的变化。     

基于雨声识别的雨量测量方法

针对传统雨量测量耗时长,维护不方便的问题,本文在分析声信号识别技术的基础上,提出了基于雨声识别的雨量测量方法,模拟人耳听觉中对频域划定的非线性性和对同一频率群声信号作叠加评价的机理,将傅里叶变换后的能量谱通过梅尔(Mel)滤波器,提取雨声的梅尔频率倒谱系数(MFCC)作为雨声信号的特征向量。在此基础上,构建一个三层BP神经网络,将归一化后的样本数据用于神经网络训练,最后将测试样本用于对雨量的识别。试验结果表明,在少量样本训练的基础上神经网络即能有效识别雨量大小,为声信号识别技术应用于更为精准的雨量测量提供了理论依据。     

基于遥感和GIS信息的上海城市绿地生态改善效应研究

为了动态地分析和客观评估城市绿地改善生态环境的作用,本文将气象卫星及资源卫星分别作为城市热力分布、可吸人颗粒物污染分布,绿地分布监测的主要信息源,研究、建立了卫星光谱与地面气温、可吸人颗粒物指数(PM10)观测要素之间的反演模式,也研究和建立了GIS动态监测和空间分析模式,对城市"热岛、浊岛、绿岛"的分布特征及相关关系、作用效果进行监测评估,得出6×104m2以上绿地的降温范围在9×104m2～13×104m2之间;8×104m2以上的绿地降尘效果较为明显,通常当绿地面积增加4×104m2上下时,对降尘的影响距离约增加50 m.     

中小城市地表温度空间分异及其与下垫面关系的遥感影像研究

以Landsat TM 影像为主要数据源,采用单窗算法反演河南省南阳市市区的地表温度。在GIS支持下,研究全区地表温度的空间分异特征,并探讨了地表温度与下垫面特征的关系。结果显示：研究区内高温斑块主要集中在仓储区和商业与公共服务区,该类区域过高的LST对城市环境有明显的负面影响;拦蓄河流所营造的水体是面积较大的低温斑块,对改善城市热环境和中小型城市拦蓄河流措施有一定意义;研究区内LST的空间自相关性在不同方向上有明显差别,东-西方向和东北-西南方向上空间自相关的范围较大,这种格局与区内水体走向有关;地表温度与道路密度指数呈明显正相关。提出中小城市可在仓储用地和交通发达地段周边规划绿地和水体,以抑制热岛呈大面积连片分布。     

Outstanding challenges for urban conservation research and action

Researchers, advocates and policymakers have proposed urban conservation as an emerging, integrative discipline that can contribute to sustainable cities by delivering co-benefits to human and non-human components of biodiversity. Given the recent growth in biodiversity-friendly designs and management schemes, there is an urgent need for a synthesis of this fragmented research base to inform planners and decision-makers. We conducted a systematic multidisciplinary literature review (787 papers) and found that the importance of urban areas for general conservation is not convincingly supported by empirical research. Only few studies demonstrated that cities can directly contribute to conservation efforts, by hosting viable populations of rare or endangered species, or by providing green corridors for the passage of natural populations. From a social perspective, while several studies demonstrated that green infrastructure could provide services for people (notably cultural services), only few studies explored the role of species diversity per se. Our review also shows strong geographical, location and taxonomic biases in urban biodiversity conservation research that make generalisations difficult. It is a disturbing paradox that while research in urban biodiversity conservation is rising exponentially, the main motivations for conserving urban biodiversity remain largely untested and unproven. We thus propose a framework for promoting integrative urban conservation research to bridge those gaps. Together, these findings warn against expanding cities under green planning and call for enhancing biodiversity experience by improving the quality of existing green spaces throughout the entire urban matrix. We provide a set of recommendations for practitioners and decision-makers to continue action.     

Global social and environmental change drives the management and delivery of ecosystem services from urban gardens: A case study from Central Coast,California

Urban community gardens are vital green spaces threatened by global social and environmental change factors. Population growth has reduced the amount of space available in cities, and climate change challenges plant growth thresholds. Urban community gardens provide dynamic socio-ecological systems to study how such social and environmental change factors affect the management and delivery of ecosystem services. They provide spaces where urban citizens purposefully interact with nature and receive multiple benefits. In this paper, we synthesize the results of three years of research in a case study of urban community gardens across the Central Coast of California and present a framework showing how both social and environmental change factors at the regional scale affect the ecological make-up of urban community gardens, which in turn affect the ecosystem services coming from such systems. Our study reveals that global environmental change felt at the regional level (e.g., increased built environment, climate change) interact with social change and policy (e.g., population growth, urbanization, water use policy), thus affecting regulations over garden resources (e.g., water availability) and management decisions by gardeners (e.g., soil management, crop planting decisions). These management decisions at the plot-scale, determine the ecological complexity and quality of the gardens and affect the resulting ecosystem services that come from these systems, such as food provision for both humans and urban animals. A greater understanding of how environmental and social change factors drive the management processes of urban community gardens is necessary to design policy support systems that encourage the continued use and benefits arising from such green spaces. Policies that can support urban community gardens to maintain ecological complexity and increase biodiversity through active management of soil quality and plant diversity have the potential to increase social and environmental outcomes that feedback to the larger environmental and social system.