Calculation of lava effusion rates from Landsat TM data

 We present a thermal model to calculate the total thermal flux for lava flowing in tubes, on the surface, or under shallow water. Once defined, we use the total thermal flux to estimate effusion rates for active flows at Kilauea, Hawaii, on two dates. Input parameters were derived from Landsat Thematic Mapper (TM), field and laboratory measurements. Using these parameters we obtain effusion rates of 1.76±0.57 and 0.78±0.27 m³ s^–1 on 23 July and 11 October 1991, respectively. These rates are corroborated by field measurements of 1.36±0.14 and 0.89±0.09 m³s^–1 for the same dates (Kauahikaua et al. 1996). Using weather satellite (AVHRR) data of lower spatial resolution, we obtain similar effusion rates for an additional 26 dates between the two TM-derived measurements. We assume that, although total effusion rates at the source declined over the period, the shut down of the ocean entry meant that effusion rates for the surface flows alone remained stable. Such synergetic use of remotely sensed data provides measurements that can (a) contribute to monitoring flow-field evolution, and (b) provide reliable numerical data for input into rheological and thermal models. We look forward to being able to produce estimates for effusion rates using data from high-spatial-resolution sensors in the earth observing system (EOS) era, such as Landsat 7, the hyperspectral imager, the advanced spaceborne thermal emission spectrometer, and the advanced land imager. Received: 25 July 1997 / Accepted: 26 February 1998     

TM影像在河西地区荒漠化土地调查中的应用

遥感及其技术应用和卫星技术的发展为资源环境调查提供了丰富的信息，在人类社会经济活动中发挥着巨大作用。文章根据全国荒漠化土地调查要求及美国陆地资源卫星ＴＭ影像特点，分析了甘肃河西地区１２景、２４幅ＴＭ影像色调特征及形态特征。在此基础上，结合荒漠化土地类型划分建立了图像解译标志，并详细阐述了ＴＭ影像解译程序。通过评价此次荒漠化土地卫星遥感调查中ＴＭ影像的特点及应用效果，充分表明了该现代技术用于此类工作的极大成功     

TM资料在断裂构造及山地灾害调查中的应用

M资料经过定向滤波、主成分分析、线性增强和假彩色合成处理后,采用目视综合解译,获得线性影像综合解译图,经野外校核后编制完成庆元县15万断裂构造分布图。文章最后讨论了断裂分布与山地灾害空间分布的相关性,得出了在受深(大)断裂强烈影响的区域,山地灾害的空间分布与断裂交叉度和断裂密度具有一定的正相关,但不显著;火山构造作用引起的山地灾害斑块状分布较为明显。     

黑河流域TM/ETM+影像数字镶嵌图的制作与应用研究

对研究区内两个时期(1986-1990年和1999-2000年)20景Landsat TM5或Landsat ETM7影像图进行多波段合成、色彩优化、几何配准和数字镶嵌等预处理工作,生成试验区两个时期的TM/ETM+影像数字镶嵌图,并利用均方根(Root mean square, RMS)误差法评价几何配准的精度,用采样法评价数字镶嵌的精度. 结果表明,单景TM/ETM+影像图几何配准的精度可以控制在1个像元以内. 多景数字镶嵌时多数点的RMS误差小于2个像元,总的RMS误差在1.3～1.5之间. 利用影像图作为几何配准的数据源的方法要优于利用地形图作为几何配准的数据源的方法.     

基于TM影像的太湖悬浮物反演模型

1 Introduction Suspended sediment (SS) is the non-dissolved matter in water which reflects the physical and chemical property of water. Suspended sediment plays an important role in water quality management, which influences the total primary productivity…     

二连盆地西部SAR影像与TM影像复合处理及其地质应用

针对SAR与TM数据的不同特征,研究了SAR与TM影像的几何校正方法及波谱信息复合方法,将SAR影像与复合图像进行比较,并且分别用SAR图像和复合图像对内蒙二连盆地进行地质解译,发现雷达图像能够较好地反映沙漠覆盖区的隐伏构造信息,而TM与SAR的复合图像能够较好地发挥两种数据的优势,拓宽了遥感的波段范围,对于图像解译和实际应用都有重要的意义。      

Modeling of multi-strata forest fire severity using Landsat TM Data

Most of fire severity studies use field measures of composite burn index (CBI) to represent forest fire severity and fit the relationships between CBI and Landsat imagery derived differenced normalized burn ratio (dNBR) to predict and map fire severity at unsampled locations. However, less attention has been paid on the multi-strata forest fire severity, which represents fire activities and ecological responses at different forest layers. In this study, using field measured fire severity across five forest strata of dominant tree, intermediate-sized tree, shrub, herb, substrate layers, and the aggregated measure of CBI as response variables, we fit statistical models with predictors of Landsat TM bands, Landsat derived NBR or dNBR, image differencing, and image ratioing data. We model multi-strata forest fire in the historical recorded largest wildfire in California, the Big Sur Basin Complex fire. We explore the potential contributions of the post-fire Landsat bands, image differencing, image ratioing to fire severity modeling and compare with the widely used NBR and dNBR. Models using combinations of post-fire Landsat bands perform much better than NBR, dNBR, image differencing, and image ratioing. We predict and map multi-strata forest fire severity across the whole Big Sur fire areas, and find that the overall measure CBI is not optimal to represent multi-strata forest fire severity.     

基于移动窗口分析法的西安市热岛效应研究

本文利用西安市两期Landsat5 TM影像,提取了西安市土地利用变化信息、NDVI指数、MNDWI指数和地表亮温,并基于移动窗口分析法进行了热岛效应边界的定量研究,旨在为陕西省地理国(省)情监测中环境监测部分探索一些可行的研究方法。研究结果表明:11年间,西安市热岛效应的发展趋势与城市扩张情况基本一致;地表亮温与植被指数和水体指数存在负相关关系,因此增加植被和水体面积有助于调节城市热岛效应的强度。     

A disaggregation approach for estimating high spatial resolution broadband emissivity for bare soils from Landsat surface reflectance

High spatial resolution land surface broadband emissivity (BBE) is not only useful for surface energy balance studies at local scales, but also can bridge the gap between existing coarser resolution BBE products and point-based field measurements. This study proposes a disaggregation approach that utilizes the established BBE–reflectance relationship for estimating high spatial resolution BBE for bare soils from Landsat surface reflectance data. The disaggregated BBE is compared to the BBE calculated from spatial–temporal matched Advanced Spaceborne Thermal Emission and Reflectance Radiometer emissivity product. Comparison results show that better agreement is achieved over relative homogeneous areas, but deteriorated over heterogeneous and cloud-contaminated areas. In addition, field-measured emissivity data over large homogeneous desert were also used to validate the disaggregated BBE, and the bias is 0.005. The comparison and validation results indicated that the disaggregation approach can obtain high spatial resolution BBE with better accuracy for homogeneous area.     

青岛近海浒苔光谱特征研究

针对从2008年以来,每年夏季我国黄海南部暴发大面积的浒苔(Enteromorpha)灾害,对海洋环境及经济造成不利影响的状况,为了进一步研究浒苔特性,为利用遥感手段监测浒苔提供一定的理论依据,通过实地测量不同条件下浒苔的光谱反射率曲线,定性分析了浒苔的光谱特征。结果表明,浒苔的基本光谱特征表现为在蓝光波段和红光波段形成反射谷,在绿光波段形成反射峰,而在近红外波段反射率明显增大,形成高反射峰。因此将红光波段和近红外波段作为敏感波段,利用NDVI(归一化植被指数)提取遥感图像上的浒苔信息,可取得较好效果,有利于浒苔监测。