Those components of the received echo that return from first-surface reflections (as from a smooth or mirror-like surface) are dominated by the OC component as there is a reversal in polarization upon reflection.
ðoʊz kəmpˈoʊnənts ʌvðə ɹᵻsˈiːvd ˈɛkoʊ ðæt ɹᵻtˈɜːn fɹʌm fˈɜːstsˈɜːfɪs ɹᵻflˈɛkʃənz æz fɹʌm ɐ smˈuːð ɔːɹ mˈɪɹɚlˈaɪk sˈɜːfɪs ɑːɹ dˈɑːmᵻnˌeɪɾᵻd baɪ ðɪ ˌoʊsˈiː kəmpˈoʊnənt æz ðɛɹ ɪz ɐ ɹᵻvˈɜːsəl ɪn pˌoʊlɚɹᵻzˈeɪʃən əpˌɑːn ɹᵻflˈɛkʃən.