Exact Rayleigh scattering calculations for use with the Nimbus-7 Coastal Zone Color Scanner.

Area of Science:

• Ocean optics
• Atmospheric radiative transfer
• Remote sensing

Background:

• Accurate atmospheric correction is vital for analyzing satellite imagery, particularly for ocean color data.
• Existing methods often use single scattering approximations for Rayleigh radiance, which can introduce significant errors.

Purpose of the Study:

• To compute Rayleigh radiance using an exact multiple scattering code, including polarization, for improved Coastal Zone Color Scanner (CZCS) imagery analysis.
• To quantify the errors associated with single scattering approximations and scalar transfer theory.

Main Methods:

• Developed and utilized an exact multiple scattering code incorporating polarization.
• Compared results with single scattering approximations and scalar transfer theory computations.
• Assessed the impact of solar zenith angles and surface pressure variations.

Main Results:

• Single scattering approximations can cause errors up to 5% at small/moderate solar zenith angles and over 10% at large angles.
• Scalar transfer theory also introduces significant errors compared to exact computations.
• The new method allows accurate atmospheric corrections for solar zenith angles up to 65-70 degrees.

Conclusions:

• Exact multiple scattering computations provide more accurate Rayleigh radiance, crucial for precise atmospheric corrections.
• The developed algorithm enhances pigment retrieval consistency, especially for high-latitude CZCS data.
• The method is adaptable for future, more sensitive remote sensing instruments.