Physically and Mineralogically Based Spectroscopic Dielectric Model for Moist Soils

In this paper, the error of dielectric predictions for moist soils was estimated, regarding the semiempirical mixing dielectric model (SMDM) developed by Dobson et al, which is a universally recognized one, and the generalized refractive mixing dielectric model (GRMDM) recently elaborated by Mironov et al. The analysis is based on the measured dielectric data presented in by Curtis et at, and the papers of Dobson et al. These data cover a broad variety of grain-size distributions observed in 15 soils and the frequency range from 45 MHz to 26.5 GHz, with the temperature being from 20 degrees C to 22 degrees C. The SMDM was found to deliver predictions with substantially larger error for the soils, whose dielectric data were not used for its development, while the GRMDM ensured dielectric predictions for all the soils analyzed with as small error as the SMDM did in the case of the soils that it was based on. To secure the same convenience in application of the GRMDM, which the SMDM possesses, the spectroscopic parameters of that model were correlated with the clay percentages of the respective soils. As a result, a new mineralogy-based dielectric model was developed. For the moist soils other than those whose dielectric data were used for its development, this model was shown to demonstrate noticeably smaller error of dielectric predictions, with clay percentage being the only input parameter, as compared with the error observed in the case of the SMDM.