In this work, an algorithm that uses the polarization angle of the backscattered solar
radiation to detect clouds with optical depth (OD) <∼ 0.3 is further developed. We find
that at viewing angles within ± ∼ 8◦ around the backscattering direction, the p-polarized
5 intensity that is parallel to the meridian plane of reflected light from surface is sensitive
to and nearly linearly related to the optical depth of super-thin clouds. Moreover, our
sensitivity study suggests that the p-polarized intensity at these viewing angles is not
sensitive to the ocean surface conditions. Using this property of p-polarized intensity,
super-thin clouds’ optical depth can be retrieved.