Several numerical models can be used to predict UV index or the daily dose, both on short- and long-term. Radiative transfer models (RTMs) are sophisticated codes which solve the radiative transfer equation in a multi-layered atmosphere, given the amount and optical properties of its components. Hence, the reliability of the radiation field calculated/predicted by such physical models depends on the accuracy of the data provided as input, which is not always available. In this study, we explore the effectiveness of alternative approaches to deterministic methods, in order to predict the UV index for the following day with less detailed input and less computational resources: 1) using the climatological value for the corresponding day of the year as a projection; 2) using the measurement from the previous day (persistence hypothesis); 3) statistical-empirical relationship linking the UV index to a set of predictors (e.g., solar zenith angle, ozone, clouds, etc.) and 4) the method of analogues. Τhe first, the second and the last approach do not need predictors and rely on the quantity and quality of the available data. For this study, we use the long series of high-quality UV and ozone data from the Italian stations of Rome (41.9° N, 12.5° E, 75 m a.s.l., urban environment), and Aosta (45.7° N, 7.4° E, 570 m a.s.l., mountain valley station) over the period 2006 -2020, during which both observatories have been operating. These two grounds-based stations, located at quite different latitude, altitude, and environmental context, are chosen since they regularly underwent quality control/quality data assurance and are traceable to the SI through international reference standards. Furthermore, the sensitivity to additional input parameters, such as the OMI products of UV aerosol index, radiative cloud fraction and effective surface reflectivity, is assessed. Pros and cons of the considered approaches are discussed in order to assess their application as an alternative to the physical ones.
A COMPARATIVE STUDY AMONG DIFFERENT EMPIRICAL APPROACHES FOR THE SHORT-TERM PREDICTION OF THE UV INDEX / Siani, A. M.; Casale, G. R.; Frasca, F.; Diémoz, H.; Fountoulakis, I.; Pedone, M.; Colosimo, A.. - (2022). (Intervento presentato al convegno UV Monitoring in the European Countries - Personal UV Exposure tenutosi a Vienna).
A COMPARATIVE STUDY AMONG DIFFERENT EMPIRICAL APPROACHES FOR THE SHORT-TERM PREDICTION OF THE UV INDEX
Siani A. M.;Frasca F.;Pedone M.;
2022
Abstract
Several numerical models can be used to predict UV index or the daily dose, both on short- and long-term. Radiative transfer models (RTMs) are sophisticated codes which solve the radiative transfer equation in a multi-layered atmosphere, given the amount and optical properties of its components. Hence, the reliability of the radiation field calculated/predicted by such physical models depends on the accuracy of the data provided as input, which is not always available. In this study, we explore the effectiveness of alternative approaches to deterministic methods, in order to predict the UV index for the following day with less detailed input and less computational resources: 1) using the climatological value for the corresponding day of the year as a projection; 2) using the measurement from the previous day (persistence hypothesis); 3) statistical-empirical relationship linking the UV index to a set of predictors (e.g., solar zenith angle, ozone, clouds, etc.) and 4) the method of analogues. Τhe first, the second and the last approach do not need predictors and rely on the quantity and quality of the available data. For this study, we use the long series of high-quality UV and ozone data from the Italian stations of Rome (41.9° N, 12.5° E, 75 m a.s.l., urban environment), and Aosta (45.7° N, 7.4° E, 570 m a.s.l., mountain valley station) over the period 2006 -2020, during which both observatories have been operating. These two grounds-based stations, located at quite different latitude, altitude, and environmental context, are chosen since they regularly underwent quality control/quality data assurance and are traceable to the SI through international reference standards. Furthermore, the sensitivity to additional input parameters, such as the OMI products of UV aerosol index, radiative cloud fraction and effective surface reflectivity, is assessed. Pros and cons of the considered approaches are discussed in order to assess their application as an alternative to the physical ones.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
