Radiant intensity of light scattered from clouds

Area of Science:

• Atmospheric optics
• Radiative transfer theory
• Cloud physics

Background:

• Understanding how clouds interact with solar radiation is crucial for climate modeling.
• Accurate simulation of radiative transfer through clouds requires accounting for multiple scattering events.

Purpose of the Study:

• To calculate reflected and transmitted radiance and flux of visible radiation interacting with cumulus clouds.
• To investigate the influence of solar zenith angle, cloud optical thickness, and surface albedo on radiative properties.

Main Methods:

• A Monte Carlo method was employed to simulate radiative transfer.
• The method accurately accounts for numerous small-angle scattering events within the cloud medium.

Main Results:

• Reflected radiance shows a relative maximum at the horizon for zero surface albedo, with exceptions for thick clouds and near-zenith incident beams.
• Incident beam near the horizon creates a strong reflected radiance maximum on the solar horizon and a zenith minimum.
• Transmitted radiance peaks around the incident beam direction until the cloud becomes optically thick.

Conclusions:

• Surface albedo significantly modifies the reflected and transmitted radiance patterns.
• Cloud optical thickness and solar zenith angle are key determinants of radiative properties.
• The findings provide insights into cloud-atmosphere-surface interactions for visible radiation.