@InProceedings{VendrascoHerd:2016:EvDiIn,
               author = "Vendrasco, Eder Paulo and Herdies, Dirceu Luis",
          affiliation = "{Instituto Nacional de Pesquisas Espaciais (INPE)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)}",
                title = "Evaluation of the direct and indirect assimilation of radar 
                         reflectivity using the WRFDA 3D-Var",
            booktitle = "Posters",
                 year = "2016",
         organization = "AMS Annual Meeting, 96.",
             abstract = "It is known that developments have being made in the concern of 
                         radar data assimilation and many studies point out some 
                         improvements on the quantitative precipitation forecast. However, 
                         it is not clear whether the most common way of assimilating 
                         reflectivity, i.e., directly as a control variable, is the best 
                         choice. We have made experiments using the Weather Research 
                         Forecasting model three-dimensional data assimilation system 
                         (WRFDA 3D-Var) over Brazil and we have found that the improvement 
                         achieved when using the direct assimilation is short-lived. 
                         Besides that, there are some works which point out this problem 
                         and suggest that the best way of assimilating reflectivity is 
                         indirectly through the assimilation of rainwater mixing ratio 
                         obtained from reflectivity. It would avoid problems related to the 
                         linearization of the reflectivity-rainwater mixing ratio 
                         relationship (Z-qr) that is needed in the incremental formulation 
                         used in WRFDA 3D-Var. Therefore, the aim of this work was to 
                         perform experiments over a specific region in Brazil to evaluate 
                         whether the indirect assimilation of reflectivity outperform the 
                         results obtained using the direct assimilation. It was chosen six 
                         cases of precipitation and 3 experiments for each case were 
                         performed. The three experiments were: i) a control without any 
                         radar data assimilation; ii) using direct assimilation and; iii) 
                         indirect assimilation of reflectivity. Radial velocity was 
                         assimilated in both cases. The Fractional Skill Score (FSS) and 
                         the Root Mean Square Error (RMSE) were used to compare 
                         quantitatively the performance of each experiment against 
                         observations. The results have shown that the indirect 
                         assimilation can produce better QPF than the one where 
                         reflectivity is assimilated directly and the improvement tends to 
                         last longer.",
  conference-location = "New Orleans, Louisiana",
      conference-year = "10-14 jan.",
           targetfile = "vendrasco.pdf",
        urlaccessdate = "27 abr. 2024"
}