Please join us for the following AOS Seminar Thursday, May 19 at 4:00pm in Spiess Hall 330:
Speaker: Linhai Li, Scripps Institution of Oceanography
Title: Uncertainties in the Water-leaving Spectral Radiance Derived from Extrapolation of Near-surface Underwater Measurements
Extrapolation of near-surface underwater measurements is the most common method to estimate the water-leaving spectral radiance, Lw( λ) (where λ is the light wavelength in vacuum), and remote-sensing reflectance for validation and vicarious calibration of satellite sensors, as well as for ocean color algorithm development. However, uncertainties in Lw( λ) arising from the extrapolation process have not been investigated in detail with regards to the potential influence of inelastic radiative processes such as Raman scattering and fluorescence. Using radiative transfer simulations, we examine high-depth resolution vertical profiles of these quantities within the top 10 m of the ocean surface layer and assess the uncertainties in extrapolated values of Lw( λ) caused by these processes. We found that many existing approaches result in significant errors in the estimate of Lw( λ). These errors approach ~100% at 900nm, and the desired threshold of 5% accuracy or less cannot be achieved at wavelengths greater than 650 nm for many underwater radiometric measurement systems. New deployment strategies are proposed based on our analysis.