Spatiotemporal distributions of ultraviolet radiation from OMI orbital data and relationships with Total O3 and Total NO2Spatiotemporal distributions of ultraviolet radiation from OMI orbital data and relationships with Total O3 and Total NO2

Abstract

Ultraviolet radiation (UVR) plays a key role in the photochemistry of the atmosphere, through absorption or dispersion processes by its constituents (ozone, cloudiness, aerosols, and pollutants in the troposphere). Quantifying UVR in a spatial-temporal way and knowing its relationships with modulating variables is important for Rio Grande do Sul State, a region with one of the highest skin neoplasms rates in Brazil. Ultraviolet radiation data for the region, acquired by the Ozone Monitoring Instrument (OMI) for the 2006 to 2020 period, and expressed in terms of Erythemal Daily Dose (EDD), was used in this study, with the objectives of quantifying UVR incidence, its stability in time and spatial distribution. Our results show that for this study area the radiation varies from 3300 to 3700 J/m2, with a latitudinal gradient of 66.7 J/m2 per degree, with maxima recorded in December (6028 J/m2, summer) and minima in June (1123 J/m2, winter). 29.76% of the area had a long-term decreasing trend (z value =5), while 6.19% of the area had an increasing trend (z value=2). During the studied period of fifteen years, occurrences of high values of Erythemal Daily Dose are negatively correlated with Total O3 as the dominant relationship, being also recorded positive or negative correlations with Total NO2, depending of the investigated epoch or region.