@Article{JesusCoelCebaCorr:2023:VaUsGr,
               author = "Jesus, Hallan Souza de and Coelho, Simone Marilene Sievert da 
                         Costa and Ceballos, Juan Carlos and Corr{\^e}a, M. P.",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Universidade Federal de 
                         Itajub{\'a} (UNIFEI)}",
                title = "Cloud modification factor parametrization for solar UV based on 
                         the GOES satellite: Validation using ground-based measurements in 
                         S{\~a}o Paulo city, Brazil",
              journal = "Atmospheric Environment",
                 year = "2023",
               volume = "39",
                pages = "e119942",
                month = "Sept.",
             keywords = "Cloud modification factor, Clouds, Ultraviolet index, UV 
                         radiation.",
             abstract = "A novel approach for parametrization of the cloud effect on 
                         ultraviolet (UV) sun wavelengths is proposed. Diagnostic and 
                         observational studies show that solar reflectance at 0.65 
                         \μm (R0.65\μm) could be a proxy for cloud optical 
                         depth, and it can be applied to parametrize the cloud modification 
                         factor (CMF), which is often applied to estimate the UV index. For 
                         all sky conditions, a linear relation between broadband CMF 
                         (0.20.4 \μm) and R0.65\μm is derived, given by 
                         CMF(theory) = 1.091.19·R0.65\μm using a radiative transfer 
                         model, which is close to CMF(observed) = 1.15 \− 1.55 Rch1 
                         based on ground-based radiation measurements and geostationary 
                         satellite channel 1 reflectance data (Rch1). The observationally 
                         derived CMF versus Rch1 fitting was applied for four different 
                         cloud classes from the satellite scene classification products: 
                         cirrus, cumulus, stratus and deep convective clouds. CMF varies 
                         with Rch1 from 1 for optically thin clouds to 0.05 for stratus and 
                         convective clouds, while CMF >0.7 denotes cirrus clouds. These 
                         values differ significantly from the constant CMF values suggested 
                         in the literature, particularly for convective clouds. The 
                         parameterization found here for each cloud is assessed by 
                         comparing the UVI estimated using the novel CMF function to UVI 
                         ground-based observations during a four-year period in S{\~a}o 
                         Paulo, Brazil. Because of high temporal and spatial satellite data 
                         availability, the parametrized CMF in terms of Rch1 is well suited 
                         for incorporation into operational weather services, estimating 
                         UVI under cloudy conditions with high correlation (r > 0.8) and 
                         low errors (root mean square error [removed].",
                  doi = "10.1016/j.atmosenv.2023.119942",
                  url = "http://dx.doi.org/10.1016/j.atmosenv.2023.119942",
                 issn = "1352-2310",
             language = "en",
           targetfile = "1-s2.0-S1352231023003680-main.pdf",
        urlaccessdate = "28 abr. 2024"
}