A Review of Field Technologies for Long-Term Monitoring of Ordnance-Related Compounds in Groundwater
Abstract
As the most basic knowledge of remote sensing, spectral radiances are a function of many factors. These functions include varying incident solar irradiance, atmospheric conditions, meteorological conditions, reflectance properties of the surface, and sensor viewing conditions. Above the mentioned background, we considered the methodology how to measure the point-wise spectral characteristics and how to convert its point-wise spectral information to spatial-wise spectral information over tropical rainforest canopy. Here our research site is Lambir Hills national park, covered by lowland mixed Dipterocarp forests as one of the typical tropical rain forests, Sarawak, Malaysia and the used measurement platform is canopy access crane with 85m height and 75m arm length approximately. By using this canopy access system, we can access to 2.3 ha cylinder area three- dimensionally. Also the average canopy height is about 40-50 meters. Our main purpose of this study is to quantify the canopy dynamics using measured spectral characteristics. Most fundamental is the spectral measurement with nadir angle. The used spectral measurement instrument is Fieldspec VNIR with 350-1050nm region. In this study, total 84 points are deployed over the canopy crane accessible area. The leaf area index (LAI) at canopy surface is also measured at the almost same number of points. For all of obtained data, the spatial-wise spectral data with 10m grid size conversion was performed. After this conversion, we calculated some spectral indices related canopy dynamics such as Normalized Vegetation Index (NDVI) and Photochemical Reflectance Index (PRI) and compared with measured LAI. Through this study, the spectral characteristics were confirmed to be most useful for quantifying the canopy dynamics of tropical rain forest.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 2005
- Accession Number
- ADA439456
Entities
People
- David E. Splichal
- Denise K. Macmillan
Organizations
- Engineer Research and Development Center