Local cloud cover, ground-based and satellite measurements of erythemal dose rate for an urban, tropical site in Southern Hemisphere

Clouds are the main tropospheric agent in the modulation of solar ultraviolet (UV) radiation in the Earth's surface. Clouds produce both attenuation and enhancement of radiation. This work shows how the local cloud cover (LCC) can partially explain mismatches between overpass satellite and ground-based instruments in the erythemal dose rate (EDR) for an urban, tropical site in Southern Hemisphere. Best agreement occurs for the scarcer cloud cover of winter. The Ozone Monitoring Instrument (OMI) EDR is on average 15% higher than ground-based measurements for cloudless skies. This value is due to both OMI algorithm misconception about aerosols and instrumental uncertainty.

► It brings new and recent erythema UV data from a scarce data region on Earth.
► Aerosols cause on average 15% overestimation of UV satellite data.
► Clouds are the main cause of mismatch between satellite and ground-based instruments.
► Satellite data still miss correction for low troposphere contents at urban sites.