Study of global solar irradiance in Northeast Brazil with considerations on superirradiance and extreme superirradiance events

Superirradiance events are phenomena caused by cloud edges that enhance the global solar irradiance measured at the surface. On the other hand, extreme superirradiance is characterized by irradiance values higher than the estimated extraterrestrial irradiance. In this sense, the purpose of this work is to understand superirradiance and extreme superirradiance in the Brazilian Northeast and to describe all the aspects identified in the research. Four stations are analyzed: Caic & oacute;, Natal, Petrolina and S & atilde;o Lu & iacute;s. The methodology includes data with a 1-minute period and two criteria for event identification: superirradiance and extreme superirradiance. The Spearman's coefficient is used to correlate the monthly distribution of superradiance with some meteorological variables. As a result, it is observed that superirradiance events can occur throughout the year in the Brazilian Northeast, but extreme superirradiance is more common in the summer months. The duration of both types of events is, in most observations, around 1 min. It is also noted that superirradiance at the S & atilde;o Lu & iacute;s station is positively correlated with precipitation and cloudiness but negatively with insolation. In Natal, superradiance showes a positive correlation with precipitation only. The impacts of superradiance can affect the performance of photovoltaic modules, human and animal health, agriculture, and other activities.