Raman scattering and in-water ocean optical properties

Area of Science:

• Marine Optics
• Oceanography
• Spectroscopy

Background:

• Inelastic scattering, including Raman scattering and fluorescence, significantly influences the in-water light field.
• Raman scattering is particularly important in clear ocean waters, while fluorescence may dominate in turbid conditions.

Purpose of the Study:

• To quantify the Raman cross section for liquid water.
• To assess the impact of Raman scattering on marine bio-optical properties.
• To validate a modified two-stream model incorporating inelastic scattering.

Main Methods:

• Determined the Raman cross section for liquid water.
• Employed a modified two-stream model to predict the influence of Raman scattering.
• Compared model predictions with measured spectral reflectance and diffuse attenuation coefficients.

Main Results:

• The Raman cross section for liquid water was determined to be 8.2 x 10⁻³⁰ cm² sr⁻¹ molecule⁻¹.
• The modified two-stream model, incorporating Raman scattering, accurately predicted measured spectral reflectance and diffuse attenuation coefficients.
• Raman scattering's influence aligns with observed spectral properties in clear ocean waters.

Conclusions:

• Inelastic scattering, specifically Raman scattering, plays a critical role in the marine light field.
• Accurate optical property determination in oceans requires accounting for inelastic scattering.
• Findings have implications for algal photobiology and understanding clear ocean water optical properties.