What is the spectral reflectance of vegetation?
Reflectance of vegetation is also generally low, but varies with the canopy density. Albedo of forest areas with good canopy cover is as low as 5-10%. Reflectance of water ranges from 5 to 70%. Reflectance is low at lower incidence angle and increases for higher incidence angles.
Which wavelength region is most sensitive to water content in vegetation?
greatest sensitivity were in the infrared, located near 1,450, 1,920, and 2,500 nm. Sensitivity was also high at visible wavelengths, with max- ima centered at 480 and 680 nm.
What is the spectral reflectance of soil?
Spectral reflectance, under laboratory conditions, for all the soils increases with the wavelength from visible to infrared region except at 950 nm and 1200 nm, where reflectance decreases in all soils, which might be due to weaker water absorption bands and also at 1350 nm, which is strong water absorption band.
What is the standard spectral reflectance curve for almost all healthy green vegetation?
between 0.7 and 1.3 µm
Chlorophyll strongly absorbs light at wavelengths around 0.45 (blue) and 0.67 µm (red) and reflects strongly in green light, therefore our eyes perceive healthy vegetation as green. The high reflectance between 0.7 and 1.3 µm results primarily from the internal structure of plant leaves.
Why is the spectral signature of water low?
As water has almost no reflection in the near infrared range it is very distinct from other surfaces. Water surfaces will therefore be clearly delimited as dark areas (low pixel values) in images recorded in the near infrared range.
What is the spectral reflectance characteristics of water and vegetation in blue green and NIR bands?
Compared to vegetation and soils, water has a lower reflectance. Vegetation may reflect up to 50% and soils up to 30–40%, while water reflects at most 10% of the incident radiation. Water reflects EM radiation in the visible range and a little in the NIR range. Beyond 1.2 μm, all radiation is absorbed.
What is a spectral reflectance?
3.2. The spectral reflectance is the reflectance measured at a given Ts and λ, within a small wavelength interval, Δλ, centered at λ [7]. Spectral reflectance is typically named monochromatic reflectance and may be specular, diffuse, or hemispherical.
What is spectral reflectance?
What is the spectral reflectance?
What is the difference in between spectral reflectance and spectral signature?
Spectral signature is the variation of reflectance or emittance of a material with respect to wavelengths (i.e., reflectance/emittance as a function of wavelength). The spectral signature of stars indicates the composition of the stellar atmosphere. Each substance will have its own unique pattern of spectral lines.
How does the spectral signature of healthy vegetation differ from stressed vegetation?
BIOGEOCHEMICAL PROPERTIES. Spectral reflectance signatures result from the presence or absence, as well as the position and shape of specific absorption features, of the surface. Stressed vegetation will give off a different spectral signature corresponding to the effect of the stress on the various leaf pigments.
What is the spectral signature of healthy vegetation?
FIGURE 11.4. Spectral reflectance signatures of healthy vegetation, dry soil, gray grass litter, water, and snow. Soils are complex mixtures of a number of mineral and organic constituents and have spectral signatures unlike those of vegetation.
What is the reflectance of vegetation in the near infrared spectrum?
Within the visible spectrum (0.4 – 0.7µm ), vegetation typically has high reflectance in the green region due to the internal structure of plant leaves called mesophyll, it produces a green pigment enabling photosynthesis to take place, however the reflectance observed within the Near Infrared Radiation
What is the spectral signature of soil?
Spectral reflectance signatures of healthy vegetation, dry soil, gray grass litter, water, and snow. Soils are complex mixtures of a number of mineral and organic constituents and have spectral signatures unlike those of vegetation.
What are the factors that affect the spectral reflectance?
Furthermore, at certain wavelength, the spectral reflectance are influenced by the vegetation structure, soil and vegetation moisture, the texture and external factor like sensor geometry.