3.2.1. Effective Variables

In previous studies, various spectral indices, including MCRC, SGNDI, DFI, STI, NDSVI, NDTI, NDI5, NDI7, NDVI, 3BI1, 3BI2, 3BI3, BAI and SRNDI, have been developed for RCF modeling [16,25,30,32–34]. Reflective band information was used to calculate these indices. In this study, in addition to spectral indices based on reflective band information, backscatter data obtained from VV and VH bands of Sentinel 1 were also used in RCF

modeling. The details of spectral indices and radar bands used as independent and primary variables in RCF modeling are shown in Table 1. To compare the efficiency of each of these independent variables in RCF modeling, their correlation coefficient with the values of RCF at the validation sampling points was calculated.


**Table 1.** Spectral indices and radar bands used as independent and primary variables in RCF modeling.
