@article{3030807,
    title = "Real-time UV index retrieval in Europe using Earth observation-based
techniques: system description and quality assessment",
    author = "Kosmopoulos, Panagiotis G. and Kazadzis, Stelios and Schmalwieser, Alois and W. and Raptis, I, Panagiotis and Papachristopoulou, Kyriakoula and and Fountoulakis, Ilias and Masoom, Akriti and Bais, Alkiviadis F. and and Bilbao, Julia and Blumthaler, Mario and Kreuter, Axel and Siani, Anna and Maria and Eleftheratos, Kostas and Topaloglou, Chrysanthi and Groebner, and Julian and Johnsen, Bjorn and Svendby, Tove M. and Vilaplana, Jose and Manuel and Doppler, Lionel and Webb, Ann R. and Khazova, Marina and De and Backer, Hugo and Heikkila, Anu and Lakkala, Kaisa and Jaroslawski, and Janusz and Meleti, Charikleia and Diemoz, Henri and Huelsen, Gregor and and Klotz, Barbara and Rimmer, John and Kontoes, Charalampos",
    journal = "Atmospheric Measurement Techniques",
    year = "2021",
    volume = "14",
    number = "8",
    pages = "5657-5699",
    publisher = "COPERNICUS GESELLSCHAFT MBH",
    doi = "10.5194/amt-14-5657-2021",
    abstract = "This study introduces an Earth observation (EO)-based system which is
capable of operationally estimating and continuously monitoring the
ultraviolet index (UVI) in Europe. UVIOS (i.e., UV-Index Operating
System) exploits a synergy of radiative transfer models with
high-performance computing and EO data from satellites (Meteosat Second
Generation and Meteorological Operational Satellite-B) and retrieval
processes (Tropospheric Emission Monitoring Internet Service, Copernicus
Atmosphere Monitoring Service and the Global Land Service). It provides
a near-real-time nowcasting and short-term forecasting service for UV
radiation over Europe. The main atmospheric inputs for the UVI
simulations include ozone, clouds and aerosols, while the impacts of
ground elevation and surface albedo are also taken into account. The
UVIOS output is the UVI at high spatial and temporal resolution (5 km
and 15 min, respectively) for Europe (i.e., 1.5 million pixels) in real
time. The UVI is empirically related to biologically important UV dose
rates, and the reliability of this EO-based solution was verified
against ground-based measurements from 17 stations across Europe.
Stations are equipped with spectral, broadband or multi-filter
instruments and cover a range of topographic and atmospheric conditions.
A period of over 1 year of forecasted 15 min retrievals under all-sky
conditions was compared with the ground-based measurements. UVIOS
forecasts were within +/- 0.5 of the measured UVI for at least 70 % of
the data compared at all stations. For clear-sky conditions the
agreement was better than 0.5 UVI for 80 % of the data. A sensitivity
analysis of EO inputs and UVIOS outputs was performed in order to
quantify the level of uncertainty in the derived products and to
identify the covariance between the accuracy of the output and the
spatial and temporal resolution and the quality of the inputs. Overall,
UVIOS slightly overestimated the UVI due to observational uncertainties
in inputs of cloud and aerosol. This service will hopefully contribute
to EO capabilities and will assist the provision of operational early
warning systems that will help raise awareness among European Union
citizens of the health implications of high UVI doses."
}