@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 = "13 maio 2024"
}