An Analysis of Low Level Vertical Wind Shear Climatology in Illinois

Using wind data at various elevations across nearly 40 sites in Illinois, an analysis of the vertical shear at these locations was made. It has been shown through the Wind Profile Power Law that the ratio of wind speeds at two heights is proportional to the ratio of those heights raised to an exponent α. This α, which describes the current stability conditions of the atmosphere, can vary greatly across a region. In most wind power assessments, a constant value of 1/7 has been used to predict wind speeds at certain heights for the strategic placement of wind turbines. This paper attempts to give light to this concept and examine how α varies over time and space.