An empirical model to estimate the microwave penetration depth of frozen soil

The technique of microwave remote sensing has been used to monitor the soil frozen/thawed status for many years. The dielectric constant of frozen soil is relatively lower than that of unfrozen soil, so that microwave could penetrate deeper into frozen soil. However, we are still lack of the knowledge of the Microwave Penetration Depth (MPD) of frozen soil. In this study, a noncoherent microwave radiation was used to find the factors that influence the MPD of frozen soil and then validated by experiments. The results showed that the frequency of microwave, the temperature of frozen soil and the soil texture are the main factors that determine the MPD of frozen soil. An empirical model that estimates the MPD of frozen soil was proposed based on the simulation data.