Speaker
Description
This work studies the impact of overirradiance events on the irradiance’s spectral distribution quantified by the average photon energy (APE). The experimental data were measured on a tilted surface in Lima, Peru, from October 2019 to March 2020. Due mainly to Lima’s low latitude, the spectrum is blue-shifted concerning the AM1.5G spectrum. The clear‑sky‑tilted index was defined and calculated using the experimental and simulated irradiance data from the PVLIB database. Based on the clear-sky‑tilted index, we differentiate between clear sky, cloudy sky, and overirradiance events. For cloudy conditions, the APE increases, i.e. the spectrum is blue-shifted relative to the clear sky. Whereas, for overirradiance events, the APE decreases due to a red-shifted spectrum. This red-shift was observed for all the overirradiance events studied during the experimental campaign. Finally, the cloud optical depth (COD) data from the satellite GOES-16 shows that thick clouds are present when overirradiance events occur. Thus, it may give new insights into the cloud enhancement phenomena.
