@Article{MartinsGonçPere:2016:ObStWi,
               author = "Martins, F. R. and Gon{\c{c}}alves, Andr{\'e} Rodrigues and 
                         Pereira, Enio Bueno",
          affiliation = "{Universidade Federal de S{\~a}o Paulo (UNIFESP)} and {Instituto 
                         Nacional de Pesquisas Espaciais (INPE)} and {Instituto Nacional de 
                         Pesquisas Espaciais (INPE)}",
                title = "Observational study of wind shear in Northeastern Brazil",
              journal = "American Journal of Engineering and Applied Sciences",
                 year = "2016",
               volume = "9",
               number = "3",
                pages = "484--504",
             keywords = "Atmospheric boundary layer, Experimental data, Wind energy, Wind 
                         shear.",
             abstract = "The wind energy share is growing fast in Brazil and a better 
                         understanding of wind speed vertical profiles is essential for 
                         accurate power density estimates. The wind shear is highly 
                         variable in space and time, being influenced by surface layer 
                         stability. Studies concerning wind vertical profiles may have a 
                         significant contribution to the Brazilian energy sector. However, 
                         wind observational data are very scarce and most of them were 
                         acquired in automated weather stations. This work investigates the 
                         wind vertical profile data acquired at a wind mast in a semi-arid 
                         region of Brazilian Northeastern region, correlating it to 
                         stability conditions of the surface boundary layer, surface 
                         roughness and friction velocity. The results indicated that strong 
                         winds (>7 m sec\−1) overcome the stability effects, 
                         allowing a better estimate of roughness length, friction velocity 
                         and exponential coefficient. In a second step, the wind speed at 
                         50 m agl. Were estimated from wind measurements at 25 m agl. The 
                         wind estimates were compared to observations, showing that 
                         exponential and logarithmic approaches were able to simulate wind 
                         profile. The exponential approach presented the lowest BIAS for 
                         rainy season, but overestimated high wind velocities. Finally, a 
                         sensitivity analysis demonstrated how uncertainties on roughness 
                         length and exponential coefficient impacts on BIAS deviation and 
                         reduce the confidence on wind power density estimates. The results 
                         demonstrated the importance in understanding how wind vertical 
                         profile is related to atmospheric stability condition in order to 
                         get reliable values for the shear parameters from mast 
                         observations. It is still more critical if wind database is 
                         short-term and when dealing with lower wind speeds.",
                  doi = "10.3844/ajeassp.2016.484.504",
                  url = "http://dx.doi.org/10.3844/ajeassp.2016.484.504",
                 issn = "1941-7020",
             language = "en",
           targetfile = "enio_study.pdf",
        urlaccessdate = "28 abr. 2024"
}