...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Journal of Geophysical Research. Biogeosciences >Foliage moisture content estimation from one-dimensional and two-dimensional spectroradiometry for fire danger assessment
【24h】

Foliage moisture content estimation from one-dimensional and two-dimensional spectroradiometry for fire danger assessment

机译：一维和二维光谱辐射法估算植物的水分含量，以评估火灾危险性

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

Moisture content in live fuels is a critical variable in fire ignition and fire behavior assessment, but it is very difficult to estimate using traditional methods. Remote sensing measurements provide adequate temporal and spatial coverage to be used operationally in fire danger estimation. Before such applications can be routinely undertaken, reflectance changes caused by water content variations must be clearly separable from other factors in reflectance variation (leaf area index, chlorophyll content, dry matter, observation-illumination angles, etc.). This paper analyzes the effect of these variables in a controlled experiment using young Holm oak (Quercus Ilex) plants, a common Mediterranean species. Spectro-radiometric measurements were performed systematically in laboratory conditions using a GER 2600 spectroradiometer (point measurements, one-dimensional (1-D)) and a Specim hyperspectral camera system (matrix measurements, 2-D). Leaf and canopy biophysical parameters were sampled to control their influence on reflectance as water stress increased. Equivalent water thickness (EWT) and fuel moisture content (FMC) were correlated against several variations of a new index: the Normalized Difference Spectral Index, (NDSI(λ1,λ2)). Results indicate that the choice of suitable spectral bands is critical to control plant physiological effects on reflectance. Strong correlations were obtained between NDSI and both EWT and FMC by applying operational bands at 1108 and 1242 nm (NDSI(1108,1242): r > 0.93), while the shorter near infrared bands (1000 and 860 nm) show a stronger influence of external factors. A combination of 2-D pixel selection techniques and first derivative spectroscopy successfully solved absolute reflectance inconsistencies between 2-D and 1-D measurements, which may prove to be a helpful means of scaling up from leaf to canopy level, and from the ground to airborne observation.
机译：活性燃料中的水分含量是火灾着火和火灾行为评估中的关键变量，但是使用传统方法很难估算。遥感测量提供了足够的时间和空间覆盖范围，可用于火灾危险评估。在常规进行此类应用之前，必须将由水分含量变化引起的反射率变化与反射率变化中的其他因素（叶面积指数，叶绿素含量，干物质，观察照明角度等）清楚地区分。本文在一个对照实验中，使用地中海常见的年轻霍姆栎（Quercus Ilex）植物分析了这些变量的影响。光谱辐射测量是在实验室条件下使用GER 2600光谱辐射仪（点测量，一维（1-D））和Specim高光谱相机系统（矩阵测量，二维）进行的。对叶片和冠层的生物物理参数进行采样，以控制其在水分胁迫增加时对反射率的影响。当量水厚度（EWT）和燃油水分含量（FMC）与新指标的几种变化相关：归一化差异光谱指标（NDSI（λ1，λ2））。结果表明，选择合适的光谱带对于控制植物对反射率的生理影响至关重要。通过在1108和1242 nm处应用工作频带（NDSI（1108,1242）：r> 0.93），在NDSI与EWT和FMC之间获得了很强的相关性，而较短的近红外波段（1000和860 nm）显示出更强的影响。外在因素。二维像素选择技术和一阶导数光谱技术的结合成功地解决了二维和一维测量之间的绝对反射率不一致问题，这可能被证明是从叶面扩展到冠层水平，从地面扩展到地面的有用方法。空中观察。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号