The focus is on statistical expressions of climatological wind “progressions” (for example, 24-element arrays of resultant wind statistics covering midnight to midnight), each array describing and contrasting statistically dissimilar idealized patterns of hour-to-hour climatological resultant winds. To create these arrays, raw individual hour wind observations (direction and speed) are decomposed into their u and v components, and then entered into a K-means cluster analysis (for example, 24 pairs of u and v components for a midnight-to-midnight treatment - a cluster analysis in 48-D space) . Resulting centroid values, by cluster, are then recombined into arrays of 24 resultant wind directions and speeds for each hour of the day. The K-Means treatment (i.e., number of clusters and cluster memberships) is enhanced by an optimizing data mining training/testing capability - the V-Fold Cross Validation Algorithm.
A given cluster’s hourly resultant direction and speed results allow inferences on diurnal climatological changes in wind directions and speeds from midnight-to-midnight. Percentage frequencies of the cluster patterns’ can be calculated by calendar month, and an appealing property is that, since a cluster analysis by its very nature assembles individual cases of the same statistical character into the same cluster, this frequently results in relatively high magnitude “constancy” statistics (mean vector wind speed divided by mean scalar wind speed times 100) among the 24-individual hour elements in summary array. Thus, the hourly mean resultants are can be frequently interpretable as reasonable approximations of average wind directions and mean scalar speeds, an intuitively satisfying outcome. Exceptions would be hours of the day which correspond to preferred diurnal changeover times in directions (seabreeze to landbreeze, or vice-versa). Interpretations of these, however, are no less straightforward.
Application of the methodology on the Boston data resolved five modes, and these results are presented in both graphical and tabular forms along with supporting explanations.