Canadian Homogenized Wind Speed (CanHomW)

Version 2 of the Canadian homogenized wind speed (CanHomW V2) datasets contain homogenized monthly and daily mean wind speed data series for the period 1953-2023 for 154 long-term stations in Canada. As detailed in Wang et al. (2025), the monthly dataset (CanHomW mlyV2) was produced using a modified version of the comprehensive semi-automatic changepoint detection procedure developed by Wang et al. (2023), which includes homogeneity testing with and without using a reference series. To produce the homogenized daily wind speed dataset (CanHomW dlyV2), daily wind speed data series were tested to find the most probable day of an artificial change detected in the corresponding monthly data series whenever the exact date of change in the daily series is undocumented. The Twentieth Century Reanalysis 20CRv3 ensemble-mean series of monthly wind speeds (Slivinski et al., 2019), 49 monthly mean geostrophic wind speeds derived from surface pressure data, and up to four nearest stations’ data series were used as reference in the homogeneity tests. However, no reference was used to adjust the data series to diminish the detected inhomogeneities. This is because the density of long-term wind observing stations in Canada is too low to find a representative reference series to use for estimating reliable adjustments to homogenize the data series. A modified version of the quantile matching (QM) adjustment method with no reference (Wang et al. 2010) was used to homogenize the data series. The QM method adjusts the whole distribution of the data in one segment to match another, rather than just adjust the mean. The modifications here include an approach to prevent having unphysical negative values in the homogenized wind speed series (see Wang et al. 2025 for more details). Despite the higher uncertainty arising from applying adjustments estimated without using a reference series, compared to when applying adjustments estimated using a representative reference series (if such a reference were available), this is the best (i.e., most usable for trend assessment) Canadian homogenized wind speeds dataset that has been produced to date. For transparency and traceability, the raw (original/unhomogenized) data series along with the station joining information are included in the CanHomW datasets. Trends in the raw and homogenized data are analyzed and discussed in Wang et al. (2025).    

References:
Wang, X.L., Y. Feng, V. Isaac, F. W. Zwiers, L. A., Vincent, and M. Hartwell, 2025: Observed Surface Wind Speed Trends Inferred from Homogenized in Situ Data and Reanalysis Datasets. Atmosphere-Ocean iFirst article, 2025, 1-17, https://doi.org/10.1080/07055900.2025.2570920.
Wang, X.L, Y. Feng, V. Y. S. Cheng, H. Xu, 2023: Observed precipitation trends inferred from Canada’s homogenized monthly precipitation dataset, J. Clim., 36, 7957-7971. DOI: 10.1175/JCLI-D-23-0193.1. 
Wang, X. L., Chen, H., Wu, Y., Feng, Y., & Pu, Q. (2010). New Techniques for the Detection and Adjustment of Shifts in Daily Precipitation Data Series. Journal of Applied Meteorology and Climatology, 49(12), 2416–2436. https://doi.org/10.1175/2010JAMC2376.1.
Slivinski, L. and coauthors, 2019: Towards a more reliable historical reanalysis: Improvements for version 3 of the Twentieth Century Reanalysis system. Q. J. R. Meteor. Soc., 2876-2908, https://doi.org/10.1002/qj.3598.

Organization: Environment and Climate Change Canada | Environnement et Changement climatique Canada