@InProceedings{DallaFaveraMaScCeLuPe:2010:AeOpTh,
               author = "Dalla Favera, Alexandre Ceretta and Martins, Fernando Ramos and 
                         Schuch, Nelson Jorge and Ceconi, Marcio and Luiz, Eduardo Weide 
                         and Pereira, Enio Bueno",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)} and {Instituto Nacional de Pesquisas 
                         Espaciais (INPE)} and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)} and {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Aerosol optical thickness influence over the Photosynthetically 
                         Active Radiation (PAR) in earth surface - I",
                 year = "2010",
         organization = "The Meeting of the Americas (AGU).",
             abstract = "The atmosphere is made up of several components, among them are 
                         present solid and liquid particles in suspension called aerosols. 
                         Aerosols make an important role by absorbing and reflecting 
                         radiation from space. The work aims to evaluate the relationship 
                         between aerosols and Photosynthetically Active Radiation (PAR) 
                         reaching the earth's surface on cloudless-sky days with 
                         development of statistical models. PAR radiation data were 
                         acquired in the SONDA Project network sites located in Campo 
                         Grande - MS, Cuiab{\'a} - MT and Petrolina PE. In addition, data 
                         acquired in Alta Floresta - MT were provided by AERONET. Aerosol 
                         Optical Thickness (AOT) daily average data for all stations were 
                         obtained from the AERONET. The time periods vary according to PAR 
                         and AOT data availability in cloudless-sky days. For Campo Grande, 
                         43 clear sky days in 2008 were analyzed; 116 days from 2006 to 
                         2008 for Cuiab{\'a}; 31 days for the years 2005 and 2007 in 
                         Petrolina; and for Alta Floresta 30 days from 1999 to 2003. Most 
                         of the available data occurs in June, July and August due to dry 
                         season in Brazilian Mid-West and Central regions. Due to the 
                         spectral range of the PAR radiation, 400 nm to 700 nm, AOT data at 
                         wavelengths 675 nm, 500 nm and 440 nm were used in this work. 
                         Linear, polynomial of second degree and exponential empirical 
                         models were developed with 70% of the available data relating the 
                         KPAR parameter and AOT at the specified wavelengths. The KPAR 
                         index is defined as the ratio between the daily PAR irradiation at 
                         the surface and the solar radiation incident on the top of the 
                         atmosphere. The 30% of the remaining data were used to evaluate 
                         model performance. The statistical deviations MBE (Mean Bias 
                         Error) and RMSE (Root Mean Square Error) were used for the models 
                         validation. In general, all models showed satisfactory 
                         performance, as indicated by low statistical deviations. The 
                         polynomial models have presented higher deviations from that of 
                         the others regressions models used. The polynomial models achieve 
                         RMSE values of 11.54% for Alta Floresta in the wavelength of 500 
                         nm, while the exponential and linear models showed, respectively, 
                         2.94 % and 5.78%. The statistical models showed lower deviations 
                         at Campo Grande and Petrolina with an RMSE values around 1.5%. For 
                         the future, it is intend to perform further analysis with larger 
                         data numbers aiming better performance for empirical models, using 
                         also, data from the Reference Station SONDA SMS, installed at the 
                         Southern Space Observatory - SSO/CRS/CCR/INPE - MCT, (29º26' S 
                         53º48' W), for a Brazilian territory extensive investigation.",
  conference-location = "Foz do Igua{\c{c}}u",
      conference-year = "8-12 Aug. 2010",
             language = "en",
           targetfile = "01.09.04.11.pdf",
        urlaccessdate = "25 abr. 2024"
}