2021-06-10

## What is the spectral reflectance of soil?

Spectral reflectance, under laboratory conditions, for all the soils increases with wavelength from visible to infrared region except at 950 nm and 1200 nm, where reflectance decreased in all soils, due to weaker water absorption bands and also at 1350 nm, due to strong water absorption at this band.

What does a reflectance spectral curve tell us?

A spectrophotometer produces a reflectance curve that can indicate the color being measured. White light contains all the colors of the rainbow in the visible spectrum. When white light falls upon an opaque object, the object interacts with that light. Reflectance curves are like fingerprints.

### What is spectral reflectance explain typical soil and vegetation spectra?

The reflectance characteristics of earth surface features expressed as the ratio of energy reflected by the surface to the energy incident on the surface, measured as a function of wavelength is called spectral reflectance, Rλ. Reflectance of vegetation is also generally low, but varies with the canopy density.

What is spectral reflectivity?

Spectral reflectance is defined as (Equation [6.2]):[6.2]ρλ=PλP0λwhere Pλ is the spectral concentration of the radiant power reflected by the medium and P0λ is the spectral concentration of radiant power incident on the medium. From: Principles of Colour and Appearance Measurement, 2014.

## How is spectral reflectance measured?

Relative total reflectance is measured by shining light on the sample at an incident angle of about 10 degrees or less (8 degrees for Shimadzu integrating spheres) and using an integrating sphere to measure not only the diffuse reflected light, but also the specular reflected light.

What is high spectral resolution?

Spectral resolution describes the ability of a sensor to define fine wavelength intervals. Their very high spectral resolution facilitates fine discrimination between different targets based on their spectral response in each of the narrow bands.

### What is spectral field?

Field spectroscopy is the technique used to measure the reflectance properties of. vegetation, soils, rocks, and water bodies in the natural environment, generally under. solar illumination. Many disciplines are interested in the measurement of light reflected.

What is the difference between reflectance and reflectivity?

Another way to interpret this is that the reflectance is the fraction of electromagnetic power reflected from a specific sample, while reflectivity is a property of the material itself, which would be measured on a perfect machine if the material filled half of all space.

## Where is spectral resolution used?

Spectral resolution describes the ability of a sensor to define fine wavelength intervals. The finer the spectral resolution, the narrower the wavelength range for a particular channel or band. Black and white film records wavelengths extending over much, or all of the visible portion of the electromagnetic spectrum.

Why is spectral resolution important?

Spectral resolution is an important experimental parameter. If the resolution is too low, spectral information will be lost, preventing correct identification and characterization of the sample. If the resolution is too high, total measurement time can be longer than necessary.

### How is the spectral reflectance of soil controlled?

The spectral reflectance of soil is controlled, for the most part, by six variables a) Moisture content b) Organic matter content c) Particle size distribution d) Iron oxide content e) Soil mineralogy f) Soil structure. Of these variables, moisture content is the most important due to its dynamic nature and large overall impact on soil reflectance.

What are the factors that affect the spectral reflectance curve?

The spectral reflectance curve is affected by factors such as soil nutrient status, the growth stage of the vegetation, the colour of the soil (which may be affected by recent weather conditions).

## How is the reflectance of bare soil related to wavelength?

The reflectance of bare soil generally depends on its composition. In the spectral reflectance curves shown in Figs 5 and 6, the reflectance increases with increasing wavelength. The reflectance of clear water is generally low. However, the reflectance is maximum at the blue end of the spectrum and decreases as wavelength increases.

How is the reflectance of soil related to moisture?

The reflection of soil is influenced by factors such as moisture, texture and mineral composition, soil that contains moisture has low reflectance because it absorbs much of the incident radiation and this effect is more evident within the absorption bands (1.4, 1.9, 2.2 and 2.5µm), however soil moisture is strongly related to soil texture,