Backscattering models for bare soil surface parameters

Hello all

I have been looking in to some options for soil moisture retrieval from Sentinel-1 GRD-data. Change detection using “dry” and “wet” scenes, produced poor outcomes in my case. Method discussed here:

Therefore, I would be interested to know more of bare soil backscattering model options for Sentinel-1 VH & VV -polarized data sets. I have ran in to studies suggesting HH-pol as optimal for soil property retrieval. This option hast o be omitted due to availability, caused by Sentinel-1 observation scenario:

I have couple of questions that I am looking answers to

  • What kind of backscattering model options exists that are usable with VH&VV GRD-data available?
  • Do these models require other auxiliary data, or can all parameters be retrieved from GRD-data?
    (soil surface roughness estimate, dielectric constant or other parameters needed)

Thank you in advance.