ABSTRACTS

Oral Session 7 | Wednesday, October 5, 11:40–12:00 | Abstract 531

A practical model to determine the across water surface effect on remote sensing reflectance

Several models to extrapolate underwater remote sensing reflectance (rrs) to the above water term (Rrs) have been proposed in previous studies, in which only the nadir viewing direction is considered, and the effect of the water refractive index on the spectral dependency of this transmittance has not been considered in detail. Based on measured inherent optical properties and radiative transfer model, this study tries to solve the across water surface effect for different viewing geometries including the spectral effects of the refractive index of water. It is shown that ignoring this spectral dependency results in a ~4% bias at shorter wavelengths, which is avoidable. When in terms of the viewing geometry inappropriate transmittance coefficients are used, a ~5% difference of Rrs estimated from rrs was observed, leading to a ~10% difference of phytoplankton absorption in the quasi-analytical algorithm. These results demonstrate that the proposed rrs-to-Rrs model is applicable to a wide range of measurement conditions and provides more accurate estimates of Rrs than previous models.

Shun Bi, Helmholtz-Zentrum Hereon, 0000-0002-2668-5808

Rüdiger Röttgers, Helmholtz-Zentrum Hereon

Martin Hieronymi, Helmholtz-Zentrum Hereon