beams scattered off soil material in terms of absolute spectral flux or in the relative terms of spectral reflectance. Ground-level reflectance spectra were taken of 62 soil and 236 vegetation surfaces. In its liquid state, water has relatively low reflectance, with clear water having the greatest reflectance in the blue portion of the visible part of the spectrum. Vegetation has a unique spectral signature, but different types of vegetation differ in their reflectance. The VIs are used to analyze various ecologies. Related : Remote Sensing Spectral Reflectance of Vegetation, Soil and Water - Free download as Powerpoint Presentation (.ppt / .pptx), PDF File (.pdf), Text File (.txt) or view presentation slides online. Vegetation Spectral Reflectance Curves . Water has high absorption and virtually no reflectance in near infrared wavelengths range and beyond. Reflectance behaviour of soils under different field conditions was analysed and the spectral reflectance curves for different soil types were obtained. Plants that are stressed or diseased can also be identified by their distinct spectral signatures. soil adjustment factor and/or a blue band for atmospheric normalization. Relating these chara cterizations to the familiar Munsell notation is In-situ spectral reflectance of soils was measured at various test sites of India in four spectral bands within the visible and near-infrared wavelength comparable to Landsat Multispectral Scanner (MSS). The spectral and Landsat Surface Reflectance-derived spectral indices are derived from Landsat 4–5 Thematic Mapper (TM), Landsat 7 Enhanced Thematic Mapper Plus (ETM+), and Landsat 8 Operational Land Imager (OLI)/Thermal Infrared Sensor (TIRS) scenes that can be successfully processed to Landsat Level-2 Surface Reflectance products. The leaf pigments, cell structure and water content all impact the spectral reflectance of vegetation. The soil adjusted vegetation index (SAVI) introduces a soil calibration factor, L, to the NDVI equation to minimize soil background influences resulting from first order soil-plant spectral interactions (Huete et al., 1994): An L value of 0.5 minimizes soil Reflectance at near infrared wavelengths is also negatively related to soil moisture; an increase in soil moisture will result in a particularly rapid decrease in reflectance due to water (H20) and hydroxyl (HO) absorption features at 0.9 μm, 1.4 μm, 1.9 μm, 2.2 μmand 2.7 μm. The leaf pigments, cell structure and water content all impact the spectral reflectance of vegetation. This premise provides the basis for multispectral remote sensing. In principle, a material can be identified from its spectral reflectance signature if the sensing system has sufficient spectral resolution to distinguish its spectrum from those of other materials. soil adjustment factor and/or a blue band for atmospheric normalization. (1976) predict that the influence of litter on the canopy reflectance in the NIR region of the spectrum is a function of live, green, biomass rather than dead biomass. Spectral reflectance characteristics of vegetation 63 2.2 Photoelectric elements 2.2a Reflectance spectrophotometers: These instruments measure the hemispherical reflectance of sample stick on a window of a sphere and lighted by an artificial source of radiation. 4 Factors affecting spectral reflectance measurements 4.1 Introduction Spectral measurements need to be accurate and precise representations of the target material but there are a variety of factors that affect the quality of spectral measurements. This study has evaluated the spectral response of semiarid soils and vegetation and the utility of four calculated Landast Thematic Mapper (in) band ratios and band transformatio for discriminating soil and vegetation. Vegetation has a unique spectral signature, but different types of vegetation differ in their reflectance. reflectance and the results of Gausman et al. Spectral reflectance of Water •Water (in soil, vegetation or water bodies) absorbs radiation at near-IR wavelengths and beyond (strong absorption bands at about 1.4, 1.9 and 2.7 μm) •Reflectance from a water body can stem from an interaction with: –the water’s surface (specular reflection), –with material suspended in the water, or Vegetation reflectance properties are used to derive vegetation indices (VIs). the surface temperature, evaporates water, melts and sublimates snow and ice, and energizes the turbulent heat exchange between the surface and the lowest layer of the atmosphere. The surface albedo is a key ingredient in the remote sensing of surface and atmospheric properties from space. Figure 3.3.1: Typical reflectance curve for vegetation, soil and water [Lillesand and Kiefer, 1994] By combining the two channels in a ratio or difference, allows the response to vegetation growth to be distinguished from the background signal. Plants that are stressed or diseased can also be identified by their distinct spectral signatures. Careful consideration must be Vegetation Spectral Reflectance Curves . Water content based on mass measurements and is expressed in terms of relative volume. Spectral reflectance of soil with different levels of water content (Lobell and Asner, 2002). The earth surface materials that are considered here are vegetation, soil, bare rock and water. The manner of interaction is described by the spectral response of the target. SPECTRAL SIGNATURE CONCEPTS-TYPICAL SPECTRAL REFLECTANCE CHARACTRISTICS OF WATER, VEGETATION AND SOIL: A basic assumption made in remote sensing is that a specific target has anindividual and characteristic manner of interacting with incident radiation. VIs are constructed from reflectance measurements in two or more wavelengths to analyze specific characteristics of vegetation, such as total leaf area and water content. Turbid water has a higher reflectance in the visible regio… The soil adjusted vegetation index (SAVI) introduces a soil calibration factor, L, to the NDVI equation to minimize soil background influences resulting from first order soil-plant spectral interactions (Huete et al., 1994): An L value of 0.5 minimizes soil The method, developed by NASA is known as the Spectral reflectance characteristics of vegetation 63 2.2 Photoelectric elements 2.2a Reflectance spectrophotometers: These instruments measure the hemispherical reflectance of sample stick on a window of a sphere and lighted by an artificial source of radiation.

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