Analysis of the Dielectric Constant of Saline-Alkali Soils and the Effect on Radar Backscattering Coefficient: A Case Study of Soda Alkaline Saline Soils in Western Jilin Province Using RADARSAT-2 Data

Table 2

Comparisons of Different Backscattering Coefficient Models.

Models	DM	SPM	POM	AIEM
Surface	All	Smooth	Rough	All
RMS (𝑠) cm	0.3~3, 𝑘⋅𝑠<2.5	𝑘⋅𝑠<0.3	𝑘⋅𝑠>2	All
Correlation length (𝑙)	—	𝑘⋅𝑙<3,𝑠/𝑙<0.3	𝑘⋅𝑙>6,𝑙^2>2.76⋅𝑠⋅𝜆	All
Incidence angle (𝜃)	30^∘∼65^∘	>35^∘∼40^∘	<35°	All
Frequency available (GHz)	1.5∼11	Low Frequency	All	All

𝜆 is the wavelength of electromagnetic wave, where 𝑘=2𝜋/𝜆 is the wave-number.