Characterization of local wind patterns in complex mountain valleys

ABSTRACT In this work, the wind patterns in high mountain areas with complex orography are characterized using hourly data provided by a network of weather stations. The key novelty of the study is the methodology. Data are grouped separately by wind speed and wind direction using two cluster analyses. The groups are analysed and described according to measurements at key stations in the network and their hourly presence. Both classifications are subsequently compared using contingency tables, and the main wind patterns are identified. The uncertainties associated with the average values of each wind pattern are quantified by principal component analysis of the wind vectors at each station. One year of data from nine stations located in the area of La Oroya, Peru was used to validate the proposed method. The local wind behaviour was characterized, the wind patterns were compared with respect to the seasons, and the winter morning transitions were analysed in detail. The methodology allows quantitative description of the local wind patterns and their temporal dynamics in complex mountain valleys. Both wind speed and direction were found to be relevant in wind pattern characterization. In particular, both parameters have proven helpful in identifying and quantifying the prevailing winds during cold dawns and thermal inversion periods.