Characterization of wind energy resources at La Rumorosa, Baja California, based on anemometric tower measurements, satellite sensor data, and numerical methods

Abstract:

The general objective of this project is to carry out a characterization of wind energy resources at the region of La Rumorosa, Baja California. For this study, data is taken from an anemometric tower located in the region, the characteristics of the probability density distribution are determined, and the time series of speed and direction of the wind at different heights are analyzed. Wind data is also used to determine the effective roughness and displacement parameters observed by the tower. The anemometric tower used for this case study is located at the coordinates [-116.11306 W, 32.4806 N] with four anemometers located at the 80, 60, 40, and 20 meters above ground level and measuring wind speed from December 2017 to November 2019 with a period without data between July and August 2019. Wind direction, meanwhile, was measured at 60 and 80 meters for the same measurement period. It was found that the probability density distribution (PDF) of the wind speed followed a Weibull distribution. The parameters of the distribution were determined using different procedures, but best results were obtained with the Least Squares Method. The dominant direction from which the wind blows, based on wind rose plots, was found to be the West-South-West direction (237.5 degrees from North). After this preliminary analysis, we computed the effective roughness at the tower using the vertical profile of the mean speed. We used an iterative method to adjust a logarithmic profile to the measurements, and determined the vertical displacement () and effective roughness () from the friction speed, with optimal values of and being found. This value of is slightly higher than that reported by Troen et al. (1989) for soils covered with bushes, natural grasslands or eroded fields, but of the same order of magnitude than the values reported by other authors. The effective roughness and displacement observed at the tower, were also compared with the displacement and roughness computed with remote satellite sensor observations, for example from the ICESat-2 and RapidEye Missions, and ESA data. The effective roughness and displacement height estimated by anemometric measurements and those determined from satellite observations will be used in numerical models to evaluate the sensitivity of wind power density predictions to changes in these parameters.