UV index seasonal variability in an Amazonian city of Brazil based on satellite data

Abstract

The solar ultraviolet radiation - UV (280-400 nm) is a highly energetic component of the solar spectrum that needs to be monitored especially because of the effects on human health and on the ecosystems. The UV index (UVI) is a dimensionless indicator designed to report the intensity of UV incident on the Earth’s surface. It has five exposure categories, ranging from low to extreme, with recommended sun protections at each level. The higher the value, the greater the health risk. With only few stations reporting long-term ground-based UV measurements in several countries, which significantly restricts its extrapolations to all populated areas, a way for continuous monitoring UV on a global scale is through satellites. In this work, the monthly and seasonal variability of the incident UVI in Santarém, Pará, was analyzed. For this, a 13-year time series of daily UVI data from the OMI satellite instrument was used, as well as the 13-year UVI time series from the GOME-2 satellite instrument. According to the results, the dry period (July to December) shows higher average UVI than the rainy period (January to June) for the GOME-2 time series. The rainy period, on the other hand, in both series presents greater amplitude in the variability of the UVI.