@InProceedings{CalvettiIBNMHGDN:2016:MeNuSi,
               author = "Calvetti, Leonardo and Inouye, Rafael Toshio and Beneti, Cesar and 
                         Neundorf, Reverton and Maske, Bianca and Herdies, Dirceu Luis and 
                         Gon{\c{c}}alves, Luis Gustavo Gon{\c{c}}alves de and Diniz, 
                         F{\'a}bio Luiz Rodrigues and Noronha, Tiago",
          affiliation = "{Instituto Tecnol{\'o}gico Simepar} and {Instituto 
                         Tecnol{\'o}gico Simepar} and {Instituto Tecnol{\'o}gico Simepar} 
                         and {} and {} and {Instituto Nacional de Pesquisas Espaciais 
                         (INPE)} and {Instituto Nacional de Pesquisas Espaciais (INPE)} and 
                         {Instituto Nacional de Pesquisas Espaciais (INPE)}",
                title = "Measurements and Numerical Simulations of Wind Gusts on High-Power 
                         Transmission Towers",
                 year = "2016",
         organization = "International Symposium on Nowcasting and Very-short-range 
                         Forecast, 4. (WSN)",
             abstract = "Since high-power transmission towers has been systematically blown 
                         down by wind gust during strong storms, sonic anemometers were 
                         installed in four towers in the west of Parana State, southern 
                         Brazil, to investigate the dynamic characteristics of these winds 
                         and their relationship with the storms. In three towers, sonic 
                         anemometers were installed in three levels, 10m, 20m and 30m. In 
                         another tower it was installed an additional sensor at 44m. The 
                         towers were located within a 60km radius distance of the 
                         dual-polarization S-band weather radar operated by the 
                         Meteorological System of Parana State (Simepar). High-resolution 
                         simulations (3 km) using WRF/NCAR MARS (Model Rapid Assimilation 
                         of Simepar) and 3DVAR data assimilation of radar reflectivity and 
                         radial velocity were performed for strong and moderate convection 
                         events. The assimilation module of MARS runs under a rapid updated 
                         cycle with radar data input every 15 minutes. Lateral boundary 
                         conditions were updated every hour using a 9km-grid WRF model 
                         named CAR, from the Center for Weather Forecasting and Climate 
                         Research of the National Institute for Spatial Research of Brazil 
                         (Cptec/Inpe). CAR is a WRF-based model that runs with GFS lateral 
                         boundary conditions and with an assimilation of satellite 
                         radiances, surface data and sounding observations in South 
                         America. The investigation shows that in some events, it was 
                         possible to verify a qualitative association between weak 
                         reflectivity signals and moderate (10 to 15 ms-1) gust 
                         measurements. High wind peaks (20 27 ms-1) were correlated with 
                         strong long-lived squall lines and severe convection associated 
                         with cold fronts. Although supercells have been observed in the 
                         region, they were not registered in any occurrence over the 
                         campaign area. Another interesting result found in the campaign 
                         was that during events with strong gusts (greater than 15 ms-1) 
                         the vertical structure of the wind becomes linear, probably due to 
                         the propagation of the gust fronts. Therefore, while the average 
                         wind profile has a exponential shape, during the storms the 
                         profile shift to linear with similar values from the 10m up to 44m 
                         level. The model has proven to be a useful tool to simulate the 
                         storms, but it cannot properly solve the observed intensity of the 
                         wind gusts. Better results were found increasing the horizontal 
                         resolution (up to 1km), vertical resolution (up to 60 levels) and 
                         time-step (up to 30s). Even with an assimilation cycle, the 
                         simulations showed a high-dependency with the position of the 
                         phenomena in the GFS initial conditions, indicating that if the 
                         analysis cycle does not indicate a correct location of a cold 
                         front or small troughs, the WRF cannot correct the position. The 
                         results of this research will be presented in this conference.",
  conference-location = "Hong Kong",
      conference-year = "25-29 July",
             language = "en",
           targetfile = "calvetti-measurements2.pdf",
        urlaccessdate = "2024, Apr. 29"
}