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The use of NIR as an analytical technique did not come from extending the use of mid-IR into the near-IR range, but developed independently. A striking way this was exhibited is that, while mid-IR spectroscopists use wavenumbers ( cm −1 ) when displaying spectra, NIR spectroscopists used wavelength ( nm ), as is used in ultraviolet–visible ...
The Balmer series is calculated using the Balmer formula, an empirical equation discovered by Johann Balmer in 1885. The visible spectrum of light from hydrogen displays four wavelengths , 410 nm , 434 nm, 486 nm, and 656 nm, that correspond to emissions of photons by electrons in excited states transitioning to the quantum level described by ...
NDVI is functionally and linearly equivalent to the ratio NIR / (NIR+VIS), which ranges from 0 to 1 and is thus never negative nor limitless in range. [6] But the most important concept in the understanding of the NDVI algebraic formula is that, despite its name, it is a transformation of a spectral ratio (NIR/VIS), and it has no functional ...
Normalized Difference Water Index (NDWI) may refer to one of at least two remote sensing-derived indexes related to liquid water: . One is used to monitor changes in water content of leaves, using near-infrared (NIR) and short-wave infrared (SWIR) wavelengths, proposed by Gao in 1996: [1]
By calculating the values for R and T for successively thinner samples (s, 1 / 2 s, 1 / 4 s, … ) using the Benford's equations for half thickness, a place will be reached where, for successive values of n (0,1,2,3,...), the expression 2 n (−log( R + T )) becomes constant to within a some specified limit, typically 0.01 ...
The free spectral range of a diffraction grating is the largest wavelength range for a given order that does not overlap the same range in an adjacent order. If the ( m + 1)-th order of λ {\displaystyle \lambda } and m -th order of ( λ + Δ λ ) {\displaystyle (\lambda +\Delta \lambda )} lie at the same angle, then
Wet-bulb potential temperature, sometimes referred to as pseudo wet-bulb potential temperature, is the temperature that a parcel of air at any level would have if, starting at the wet-bulb temperature, it were brought at the saturated adiabatic lapse rate to the standard pressure of 1,000 mbar.
The Arden Buck equations are a group of empirical correlations that relate the saturation vapor pressure to temperature for moist air. The curve fits have been optimized for more accuracy than the Goff–Gratch equation in the range −80 to 50 °C (−112 to 122 °F). [1]