Design of a Handheld LED-based Sun-Photometer for Studies of Atmospheric Transmittance due to Aerosols

Tiny suspended particles in the atmosphere, called as aerosols, play a pivotal role in modulating Earth's climate by scattering and/or by absorbing incoming solar radiation, exerting both warming and cooling influences in the atmosphere depending upon their composition, size and distribution. Monitoring these effects typically relies on indirect methods, such as assessing the amount of sunlight that reaches the ground. To facilitate this monitoring, a compact handheld Sun photometer was devised utilizing light-emitting diodes (LEDs) at wavelengths of 530 and 630 nm. Additionally, a program was developed to compute atmospheric transmittance due to aerosols from the LED voltages by using the Langley technique. This novel approach offers a portable and efficient means to estimate the amount of light absorbed or scattered by aerosols in the atmosphere.