Abstract
Abstract. Ground-based total ozone and surface UV irradiance measurements have been collected since 1992 using Brewer spectrophotometer at Rome station. Erythemal Dose Rates (EDRs) have been also determined by a broad-band radiometer (model YES UVB-1) operational since 2000. The methodology to retrieve the EDR and the Erythemal Daily Dose (EDD) from the radiometer observations is described. Ground-based measurements were compared with satellite-derived total ozone and UV data from the Ozone Monitoring Instrument (OMI). OMI, onboard the NASA EOS Aura spacecraft, is a nadir viewing spectrometer that provides total ozone and surface UV retrievals. The results of the validation exercise showed satisfactory agreement between OMI and Brewer total ozone data, for both OMI-TOMS and OMI-DOAS ozone algorithms (biases of −1.8% and −0.7%, respectively). Regarding UV data, OMI data overestimate ground based erythemally weighted UV irradiances retrieved from both Brewer and YES Radiometer (biases about 20%). The effect of aerosols on UV comparisons was investigated in terms of Aerosol Optical Depth (AOD), showing medium-large correlation at SZA larger than 55°. Further sources of uncertainty, such as the difference in the atmospheric conditions between local noon and OMI overpass time and the OMI spatial resolution, were also discussed.
Highlights
The amount of solar ultraviolet (UV) radiation (200–400 nm) reaching the Earth’s surface is affected mainly by atmospheric ozone absorption, cloudiness and aerosols
Erythemal Dose Rate (EDR) is defined as the incoming solar radiation on a horizontal surface convolved with the erythema action spectrum (Diffey and McKinlay, 1987) over the whole UV range
The Erythemal Dose can be obtained integrating the EDR values over a given time interval and it provides the degree of effectiveness of UV radiation in producing the reddening of the skin
Summary
The amount of solar ultraviolet (UV) radiation (200–400 nm) reaching the Earth’s surface is affected mainly by atmospheric ozone absorption, cloudiness and aerosols. Erythemal Dose Rate (EDR) is defined as the incoming solar radiation on a horizontal surface convolved with the erythema action spectrum (Diffey and McKinlay, 1987) over the whole UV range. The Erythemal Dose can be obtained integrating the EDR values over a given time interval and it provides the degree of effectiveness of UV radiation in producing the reddening of the skin. Both broadband radiometers and spectroradiometers can provide measurements of erythemal UV quantities. Satellite-based instruments offer a better geograical distribution but continuous validations with ground-based measurements are required to assess the accuracy of satellite data
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
