New Radiometric Approaches to Compute Underwater Irradiances: Potential Applications for High-Resolution and Citizen...

Area of Science:

• Oceanography and Limnology
• Environmental Monitoring
• Optical Physics

Background:

• Diffuse attenuation coefficient (Kd) is crucial for assessing water quality and euphotic zone depth.
• Citizen science offers cost-effective, broad-coverage water quality monitoring, complementing traditional methods.
• In situ irradiance measurements face limitations in vertical accuracy due to stratification and self-shading.

Purpose of the Study:

• To introduce a novel concept, underwater annular irradiance (Ea), for improved vertical accuracy of irradiance measurements.
• To develop a new sensor design concept to overcome self-shading issues in optical instrumentation.
• To enable more precise Kd measurements, particularly in stratified water bodies.

Main Methods:

• Computing optimal annular angles to maximize light capture while minimizing self-shading.
• Assessing the robustness of the derived diffuse attenuation coefficient (Ka) across various water types, solar angles, and cloud coverages.
• Deriving empirical functions to calculate Kd from Ka measurements.

Main Results:

• The proposed annular irradiance measurement concept effectively addresses self-shading.
• The derived Ka values demonstrate robustness under diverse environmental conditions.
• Empirical functions were successfully developed to compute Kd from Ka.

Conclusions:

• Underwater annular irradiance (Ea) offers a promising approach to enhance the vertical resolution of irradiance measurements.
• The new sensor concept is suitable for citizen scientists due to its ease of deployment and maintenance.
• This innovation supports improved water quality monitoring and decision-making.