Analysis of Turbulence and Wind Shear Characteristics in the Hilly Terrain of Geba Catchment, Tigray, North Ethiopia

This study examines wind speed, wind shear, and turbulence intensity across three sites in the Geba Catchment, Tigray, Ethiopia. Wind speed analysis shows significant spatial and temporal variations, with Hagere Selam exhibiting the highest annual average wind speeds (8.0 m/s). Dera’s wind speeds vary more, reflecting the influence of rugged terrain and elevation. Wind shear exponent (WSE) analysis highlights the impact of topography on wind profiles. At Dera (2870 m), WSE values ranged from 0.1 to 0.3, indicating strong wind gradients influenced by steep terrain. In contrast, Hagere Selam and Mayderhu, at lower elevations, exhibited WSE values of 0.0 to 0.1, suggesting smoother wind flow. Dera also showed pronounced diurnal WSE variations linked to nighttime cooling. Turbulence intensity (TI) was highest at Dera (up to 0.5 at 10 m), with significant diurnal variation, while Hagere Selam and Mayderhu showed lower and more stable TI values (0.12–0.2). Analysis of wind speed variability revealed that Dera experiences greater turbulence compared to the IEC standards but remains within acceptable limits for wind turbine operations. Prevailing winds at Dera, predominantly from the North, Northeast, and Southeast, correspond to higher wind shear and turbulence levels, emphasizing the role of local topography. These findings underscore the need for tailored wind energy strategies, highlighting Hagere Selam’s potential for stable energy production and the challenges posed by Dera’s complex wind dynamics.