Fig. 8. Comparison of reflectivities R_radio measured with the L-band radiometer ELBARA (thick black line) at horizontal (upper graph) and vertical (lower graph) polarization with reflectivities calculated using the Fresnel equations (Eq. [6] and [7]) based on water contents measured in situ by TDR at the 2-cm depth (thin black line), the coherent radiative transfer model (R_t, thick dark-gray line), and the same model but introducing a roughness correction to the coherent reflectivities according to Shi et al. (2002) (thick light-gray line).