Program

Measurement of water-leaving radiance in the field is a critical component in the researches of ocean optics and ocean color remote sensing, and commonly above-water, in-water, and on-water-surface approaches have been taken. For the latter two approaches, because a sensor is looking down while the illumination from the sun and the sky is behind the sensor, inevitably there will be a self-shadow effect. In addition, there could be shadow effects from supporting platforms used to hold the sensors. The shadow effects of a sensor just below the surface (0- or ~0.5 m) were characterized with Monte Carlo simulations, but there are no studies on the effects of the Skylight-Blocked Approach (SBA) system, which has been developed for a direct measurement of water-leaving radiance, where its shadow effect is not clear yet. In this study, we used Monte Carlo simulations to characterize the shadow error of the current SBA system with the effects due to the supporting platform also considered. It is found that shadow error increase with higher absorption of water, lower bottom reflectance and deeper immersion depth. It is found that the saturated depth is a factor that is hard to control or monitor which will result high uncertainties for self-shading correction in high absorption water.