基于TM影像数据的林分冠层郁闭度反演技术研究

本文以崂山林场为研究区域,利用森林资源二类调查数据和TM影像数据,分析了林分郁闭度与遥感因子之间的定量关系,在此基础上利用多元回归分析法结合实测数据构建郁闭度估测模型,并对模型精度进行检验,结果表明,预估精度达到81.6%,估测效果较好。利用该模型,反演了研究区的林分冠层郁闭度,将崂山林场的林分冠层郁闭度分为四个等级,即非林地区,低郁闭度区,中郁闭度区和高郁闭度区,研究区的森林郁闭度分布呈现西北部和东南部较低,而中部和南部相对较高。     

基于INFORM模型与GEE的根河火烧迹地冠层含水量反演研究

[目的]提出一种结合辐射传输模型与遥感云平台反演火烧迹地冠层含水量(Canopy water content,CWC)的新方法,弥补目前对火烧迹地恢复阶段植被含水量的监测,为定量监测植被水分与火灾预警提供理论参考.[方法]以内蒙古自治区根河市火烧迹地为研究对象,基于INFORM辐射传输模型,使用查找表的方法反演森林冠层...     

基于TanDEM-X数据和改进三阶段算法反演森林冠层高度

【目的】提出一种基于TanDEM-X SAR数据的RVoG模型三阶段算法反演森林冠层高度,以解决RVoG模型实际应用中模型成立条件难以严格满足、受地形影响导致森林冠层高度估测精度不高的问题。【方法】以云南省普洱市思茅区思茅松纯林和混交林为研究对象,开展经典三阶段算法、地面相位优化的三阶段算法、纯体散射复相干优化的三阶段算法和低估补偿改进的三阶段算法反演森林冠层高度试验。【结果】RVoG模型经典三阶段算法反演森林冠层高度存在低估现象(r=0.11, bias=-26.20 m, RMSE=7.16 m),地面相位优化的三阶段算法、纯体散射复相干优化的三阶段算法、低估补偿改进的三阶段算法反演森林冠层高度的估测精度较经典三阶段算法提高,其中低估补偿改进的三阶段算法反演森林冠层高度的改善效果最佳(r=0.79, bias=-1.69 m, RMSE=2.56 m);思茅松纯林的估测效果(r=0.81, bias=1.40 m, RMSE=2.27 m)优于思茅松混交林(r=0.72, bias=-3.09 m, RMSE=2.87 m)。【结论】相比经典三阶段反演算法,基于TanDEM-X S...     

帽儿山地区叶面积指数遥感反演

以黑龙江省尚志市帽儿山林场(东北林业大学试验林场)为研究区,利用现代卫星遥感技术,结合实地调查采样数据和GPS测量技术,建立了从Landsat TM影像数据提取的植被指数(Vegetation Index,VI)与地面实测的叶面积指数(Leaf Area Index,LAI)的统计回归模型。然后再从众多统计模型中按照各自的相关系数(R)和确定系数(R2),选出反演LAI的最佳模型。     

叶面积指数(LAI)测定方法研究进展

叶面积指数(LAI)是指植物植株所有叶片单面面积总和与植株所占的土地面积的比值,能反映可用于光能截获和气体交换的植物潜在叶片面积,是研究农学、林学、生态学、气象学等学科的重要参数。本文总结了国内外测定叶面积指数的主要方法,地面测定LAI和遥感反演LAI两大类方法的研究进展,同时阐述了LAI尺度转换的问题,并对各种测定方法进行了讨论,提出了一些改进的方法。     

崂山林场林分生物量遥感反演估算研究

以Landsat TM影像和高分一号影像为数据源,结合外业实测数据,利用遥感影像和实测数据建立崂山林场生物量多元线性反演模型,比较分析不同数据源下反演出的模型精度,估测了崂山林场森林生物量。研究发现,利TM遥感影像作为数据源的崂山林场森林生物量反演模型平均精度为77.12%。高分一号遥感数据反演的生物量模型平均反演精度达到80.75%,高于TM数据源下的生物量反演模型精度。分别根据TM遥感影像和高分一号遥感影像林分生物量估测模型,估测的崂山林场2009年的林分生物量为401185.62t,2013年的林分生物量为402485.44t。     

基于机理模型人工针叶林叶面积指数反演

以内蒙古赤峰市旺业甸实验林场人工针叶林为研究区域,以哨兵2A(Sentinel-2A)多光谱遥感影像和外业测量的LAI为基础,探讨了5-scale+Liberty机理耦合模型和经验统计模型反演人工针叶林LAI的规律。结果表明：基于一元线性模型估测的LAI精度较低,R²=0.619,RMSE=1.6107;基于机理模型反演的LAI较高,R²=0.8222,RMSE=0.9414,并进一步分析了不同步长情况下,5-scale+Liberty模型反演的LAI与实测的LAI之间的关系,步长的大小一定程度上影响LAI反演精度。     

高光谱遥感森林叶面积指数估测研究现状

文中简要概述了叶面积指数和高光谱遥感的概念, 分析比较了高光谱遥感与传统的宽波段遥感估测森林叶面积指数的优势, 以及利用高光谱遥感数据估测森林叶面积指数的常用方法, 并对目前高光谱遥感估测森林叶面积指数存在的问题行了讨论。     

城市绿地园林树种叶面积指数测定方法研究——以小叶榕为例

分别采用半球面影像技术和LAI-2000冠层分析仪对华南地区最常用园林树种小叶榕(Ficus microcarpa)的叶面积指数(Leaf Area Index,LAI)进行测定、比较和分析。研究表明,2种测量仪器所测LAI值存在极显著正相关(P<0.001);用半球面影像技术测量的LAI值与冠幅、胸径和树高之间也存在极显著一元线性关系,构建回归模型分别为:LAI=0.0444Cw+1.6526,LAI=0.0088D+1.8327,LAI=0.0543H+1.6404;通过模型可估测小叶榕单株的叶面积指数,达到95%的置信区间的估测值范围。     

基于冠层分区的辽东山区长白落叶松叶面积模拟研究

文章以辽东山区长白落叶松林(Larix olgensis)为研究对象,通过调查树冠及枝条解析因子、实测叶面积,构建基于最优冠层分区形式的枝条叶面积模型,结果表明:基径(BD)是枝条叶面积(BLA)的最佳解释变量,相对冠层深度(H)0.67是模拟效果最优的冠层分区界限,树冠上层枝条叶面积最优模型为CAR模型:BLA=0.006BD1.746,决定系数(R2)为0.796,预估精度(P)达到90.61%;下层枝条叶面积最优模型为二次曲线:BLA=0.009BD2-0.476BD+7.186,决定系数(R2)为0.709,预估精度(P)达到80.65%。     

Canopy Structure and Leaf Area Index in a Mature Scots Pine Forest

The projected leaf area index (LAI) of a mature stand of Scotspine (Pinus sylvestris L.) at Thetford Forest, south-east Englandwas measured by sampling the needle populations on harvestedand wind-thrown trees covering the range of girth sizes. Thevertical distribution of leaf area for individual trees waspolymodal while that for the canopy as a whole was adequatelydescribed by the curve for a normal distribution with the inclusionof a term for positive skewness. The fitted curve defined themidpoint of the canopy at a height of 14.3 m and the standarddeviation of leaf area with respect to height as 13% of thecanopy depth. The fitted curve explained 90 per cent of thevariation and the estimates of the parameters were close tothe measured values. Using previous measurements showing that needle production andfall could be described by linear regression equations, a modelwas developed to predict the annual changes of current and oldneedles in a closed canopy. The maximum LAI at Thetford was2.73 on 12th August of which 36 per cent was new (current) needles.Leaf area index varied by only 7 per cent between November toMay inclusive; higher values occurred between June and Octoberat times of potentially high photosynthetic and transpirationrates. The leaf characteristics of the stand were similar to thoseof a stand of Scots pine of similar age at Roseisle in north-eastScotland.     

两种测定天然次生林叶面积指数方法的比较

采用叶面积指数直接测定方法（称重法）与间接测定方法（冠层分析仪测定法）,对帽儿山天然次生林区叶面积指数进行测定,运用相关性分析和对比分析对测定结果进行研究。研究结果表明,直接测定法结果为实测叶面积指数,间接测定方法结果小于前者,精度比前者低25％-40％,但两组结果相关关系显著,间接测定值能较好地反映林木的叶面积指数大小变化。天然次生林中林层结构对冠层分析仪测定有很大的影响,是造成两种方法差异的主要原因。     

不同林地和郁闭度对香榧幼苗营建的影响

为比较不同林地类型和郁闭度对香榧幼苗栽培的影响,从2006～2009年连续四年记录在松阳县52块标准地香榧幼苗的成活率和新梢生长量,因素分析法结果表明:郁闭度、林地类型、郁闭度和林地交互作用对成活率均有极显著性影响,郁闭度对新梢生长量有显著影响。在郁闭度为0.4的板栗林、针阔混交林和杉木林种植香榧幼苗,其成活率均达到96%以上,新梢生长量达到21.5cm以上。     

岳阳市城市森林建设评价指标体系

以中部地区城市岳阳市为例,确立了城市森林评价指标体系的原则、结构,并对岳阳市城市森林评价指标进行了研究.结果表明：当目标值实现时（2015年）,岳阳市城市森林的综合状况将优于现状2.19倍,城市森林结构、功能和协调性分别提高到现在的2.18、2.11、2.32倍,城市森林综合质量将有较大提高.     

Simulating Spatial Distribution of Canopy Rainfall Interception of Forests in China

The canopy rainfall interception modei linked to environmental conditions and biological features is established on the basis of stationary observation and measurements in China. Upscaling from site observation to regional Ievel estimation of canopy rainfall interception has been made. The potential interception value of forests during the rainfall season in China according to rainfall records of May, July and September in the year 1982, has been simulated and mapped under the GIS software package Idrisi. It coincides well with the spatial and chronological pattern of rainfall in China and can be concluded to reflect the reality. The potential canopy rainfall interception of forests in China based on the potential distribution of forests provides a basis to regional water budget as well as rational use of regional water resources. It is also important to the assessment of forest ecosystem service in China, which is demanded by both scientists and policy makers for the evaluation of afforestation and nat     

广东韶关创建森林生态市指标体系研究

创建森林生态市的历程实际上就是构筑某一地理区域完善的、平衡的森林生态系统的过程。论述了森林生态系统指标的内涵、界定、基本特征，指标的目标性和理论性依据，选择指标的原则，指标体系的建立和用途；提出韶关创建森林生态市的指标和指标体系的评价、指标的重要度。     

Assessing Point Accuracy of DGPS Under Forest Canopy Before Data Acquisition,in the Field and After Postprocessing

A low-cost, hand-held, 10-channel, single-frequency Global Positioning System (GPS) receiver observing pseudorange and carrier phase was used to determine the positional accuracy of 35 points under tree canopies. The mean position error based on differential postprocessing ranged from 0.49 to 3.60 m for 2-20 min of observation at points with basal area <30 m 2 ha -1 . For points with basal area S 45 m 2 ha -1 the mean position error ranged from 2.15 to 5.60 m. Regression analysis revealed that basal area and observation period were the most significant factors to predict the position error that could be obtained by GPS data collection before or during data acquisition ( R 2 = 0.37). After differential postprocessing, the most significant factors to predict position error were the standard deviation reported by the postprocessing software and whether both pseudorange and carrier phase were used to compute the coordinates or pseudorange only ( R 2 = 0.57). The position error decreased with decreasing density of forest, increasing length of observation period, decreasing standard deviation, and combined use of pseudorange and carrier phase.