F - measurement frequency 
k - normalized attenuation coefficient (NAC)
n - refractive index (RI)
r - bulk density of soil sample
t - measurement temperature
W - volumetric moisture of soil sample

BV - soil selected on the Yamal Peninsula at the coordinates N70.4310, E68.4227, organic matter content is 50%
MS1 - soil selected on the Yamal Peninsula at the coordinates N69.7165, E66.8107, organic matter content is 61%
MS2 - soil selected on the Yamal Peninsula at the coordinates N69.7152, E66.8180, organic matter content is 35%
AK1 - soil selected on the North Slope of Alaska at the coordinates N68.6333, W149.5833, organic matter content is 80%
AK2 - soil selected on the North Slope of Alaska at the coordinates N68.6333, W149.5833, organic matter content is 90%
TM - soil selected on the Taimyr Peninsula at the coordinates N69.3523, E88.2832, organic matter content is 38%
SI - soil selected on the Samoylov Island at the coordinates N72.3697, E126.4834, organic matter content is 30%