The second type of wind speed data is unadjusted, or “raw” weather station observations. This data can be used to assess extreme wind speeds since hourly and daily data are available. Raw station data is not adjusted using the homogenization procedure applied to AHCCD. For most stations, this data can be accessed using the Climate Data Extraction Tool. Read more about how to access hourly data at all available stations.
Hourly station observations have been used to assess historical trends of extreme wind speed in Canada. The results indicate increases in extreme wind speeds in the North and minor decreases in most other Canadian cities. However, most analyses of historical extreme wind speeds in Canada find that trends are weak or not robust. [13],[14] Consequently, it is difficult to determine how climate change may be affecting extreme wind speeds.
Reanalysis
Station observations represent historical observations and are limited by the number of stations, the longevity of the stations, and the periodicity of the measurements. Stations are sparsely located in many parts of Canada, especially in Northern Canada.
An alternate source of historical wind speed data is reanalysis. Reanalysis is weather data produced by a weather forecast model that is blended with observations, making it consistent with the real-world historical record and spatially complete. It is available on a regular grid, so no locations are missing. Reanalyses can be used to “fill gaps” where observations are not available. Reanalysis typically has higher spatial resolution than most climate model data because reanalyses are usually produced with weather models, which generally resolve finer spatial scales than climate models. The size of the model Most Global Climate Models (GCMs) have spatial resolution ranging from 250 km to 100 km, whereas state-of-the art reanalysis have spatial resolution of 30 km or finer.
Several reanalysis datasets exist. The most widely used reanalysis dataset is ERA5 [15], produced by the European Centre for Medium-Range Weather Forecasts (ECMWF). ERA5 provides global hourly data at ~30 km resolution from 1940 until almost the present day (new data is added on a daily basis with a delay of only about 5 days).
The Canadian Surface Reanalysis (CaSR, formerly named RDRS), developed by the Meteorological Research Division at ECCC, focuses on Canada.[16] The CaSR has ~10 km spatial resolution and provides hourly data for the period 1980 to 2018. Read more about the CaSR, including how to access the data.
Like all model outputs, reanalysis data are not always perfectly consistent with observations. Several studies have found that ERA5 wind speed data underestimate extreme values in Canada.[17], [18], [19] The developers of the CaSR note that the average difference between the reanalysis and observed wind speed data (the root mean squared error, or RMSE) is about 2 m/s. This difference is slightly larger in winter and spring, and smaller in summer and autumn. A detailed analysis of extreme winds using the CaSR has not yet been carried out.
Climate Model Projections
Global climate models (GCMs) are important tools for understanding many aspects of the future climate, but they are not ideally suited to simulate near-surface wind speed, in part due to their coarse spatial resolution (100 km to 250 km). Many of the processes driving extreme winds, such as convection, require spatial resolution of 4 km or smaller to be modelled directly.[8] GCMs also tend to underestimate the frequency of intense ETCs compared to higher-resolution models.[21],[22]
To refine GCM projections, climate scientists employ downscaling techniques that produce finer-scale information. Statistical downscaling combines high-resolution observational data with data from GCMs. Daily, high-resolution wind speed observations are not available for Canada. This limits the ability to apply statistical downscaling techniques to GCM data.
An alternate approach to statistical downscaling is dynamical downscaling using Regional Climate Models (RCMs). RCMs are similar to GCMs but have finer spatial resolution (smaller grid boxes) and simulate the climate for a limited geographical area, like North America. RCMs combine GCM data with improved representation of topography and physical climate processes. Most available RCM simulations for Canada have spatial resolution between 25 km and 50 km. Resolution in this range can improve representation of intense ETCs but cannot simulate convective storms.[23] RCMs that directly simulate convective storms require a large amount of computer power to run, so they are primarily used for research purposes only.
References
[1] Sandink, D., Kopp, G., Stevenson, S., & Dale, N. (2019). Increasing High Wind Safety for Canadian Homes: A Foundational Document for Low-Rise Residential and Small Buildings (62; ICLR Research Paper Series, p. 128). Institute for Catastrophic Loss Reduction.
[2] Wang, X. L., Wan, H., & Swail, V. R. (2006). Observed Changes in Cyclone Activity in Canada and Their Relationships to Major Circulation Regimes. Journal of Climate, 19(6), 896–915. https://doi.org/10.1175/JCLI3664.1
[3] Priestley, M. D. K., & Catto, J. L. (2022). Future changes in the extratropical storm tracks and cyclone intensity, wind speed, and structure. Weather and Climate Dynamics, 3(1), 337–360. https://doi.org/10.5194/wcd-3-337-2022
[4] Booth, J. F., Wang, S., & Polvani, L. (2013). Midlatitude storms in a moister world: Lessons from idealized baroclinic life cycle experiments. Climate Dynamics, 41(3–4), 787–802. https://doi.org/10.1007/s00382-012-1472-3
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[7] Seiler, C., & Zwiers, F. W. (2016). How will climate change affect explosive cyclones in the extratropics of the Northern Hemisphere? Climate Dynamics, 46(11–12), 3633–3644. https://doi.org/10.1007/s00382-015-2791-y
[8] Prein, A. F. (2023). Thunderstorm straight line winds intensify with climate change. Nature Climate Change, 13(12), 1353–1359. https://doi.org/10.1038/s41558-023-01852-9
[9] Cheng, C. S., Lopes, E., Fu, C., & Huang, Z. (2014). Possible Impacts of Climate Change on Wind Gusts under Downscaled Future Climate Conditions: Updated for Canada. Journal of Climate, 27(3), 1255–1270. https://doi.org/10.1175/JCLI-D-13-00020.1
[10] Wan, H., Wang, X. L., & Swail, V. R. (2010). Homogenization and Trend Analysis of Canadian Near-Surface Wind Speeds. Journal of Climate, 23(5), 1209–1225. https://doi.org/10.1175/2009JCLI3200.1
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[13] Li, S., Irwin, P., Kilpatrick, J., Gibbons, M., & Valerie, S. (2017). A Review of Historical Extreme Wind Speeds in a Changing Climate At Some Major Canadian Cities. Leadership in Sustainable Infrastructure. CSCE Annual Conf. and Annual General Meeting, Montreal. https://legacy.csce.ca/elf/apps/CONFERENCEVIEWER/conferences/2017/pdfs/ENV/FinalPaper_850.pdf
[14] Leung, A. C. W., Gough, W. A., Butler, K. A., Mohsin, T., & Hewer, M. J. (2022). Characterizing observed surface wind speed in the Hudson Bay and Labrador regions of Canada from an aviation perspective. International Journal of Biometeorology, 66(2), 411–425. https://doi.org/10.1007/s00484-020-02021-9
[15] Hersbach, H., Bell, B., Berrisford, P., Hirahara, S., Horányi, A., Muñoz‐Sabater, J., Nicolas, J., Peubey, C., Radu, R., Schepers, D., Simmons, A., Soci, C., Abdalla, S., Abellan, X., Balsamo, G., Bechtold, P., Biavati, G., Bidlot, J., Bonavita, M., … Thépaut, J. (2020). The ERA5 global reanalysis. Quarterly Journal of the Royal Meteorological Society, 146(730), 1999–2049. https://doi.org/10.1002/qj.3803
[16] Gasset, N., Fortin, V., Dimitrijevic, M., Carrera, M., Bilodeau, B., Muncaster, R., Gaborit, É., Roy, G., Pentcheva, N., Bulat, M., Wang, X., Pavlovic, R., Lespinas, F., Khedhaouiria, D., & Mai, J. (2021). A 10 km North American precipitation and land-surface reanalysis based on the GEM atmospheric model. Hydrology and Earth System Sciences, 25(9), 4917–4945. https://doi.org/10.5194/hess-25-4917-2021
[17] Betts, A. K., Chan, D. Z., & Desjardins, R. L. (2019). Near-Surface Biases in ERA5 Over the Canadian Prairies. Frontiers in Environmental Science, 7, 129. https://doi.org/10.3389/fenvs.2019.00129
[18] Morris, M., Kushner, P. J., Moore, G. W. K., & Mercan, O. (2023). Atmospheric Circulation Patterns Associated with Extreme Wind Events in Canadian Cities. Journal of Climate, 36(13), 4443–4460. https://doi.org/10.1175/JCLI-D-22-0719.1
[19] Chen, T., Collet, F., & Di Luca, A. (2024). Evaluation of ERA5 precipitation and 10‐m wind speed associated with extratropical cyclones using station data over North America. International Journal of Climatology, 44(3), 729–747. https://doi.org/10.1002/joc.8339
[21] Jiaxiang, G., Shoshiro, M., Roberts, M. J., Haarsma, R., Putrasahan, D., Roberts, C. D., Scoccimarro, E., Terray, L., Vannière, B., & Vidale, P. L. (2020). Influence of model resolution on bomb cyclones revealed by HighResMIP-PRIMAVERA simulations. Environmental Research Letters, 15(8), 084001. https://doi.org/10.1088/1748-9326/ab88fa
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[23] Pryor, S. C., Nikulin, G., & Jones, C. (2012). Influence of spatial resolution on regional climate model derived wind climates. Journal of Geophysical Research: Atmospheres, 117(D3), 2011JD016822. https://doi.org/10.1029/2011JD016822
[24] Cannon, A. J., Jeong, D. I., Zhang, X., & Zwiers, F. (2020). Climate-resilient buildings and core public infrastructure 2020: An assessment of the impact of climate change on climatic design data in Canada (En4-415/2020E-PDF). Environment and Climate Change Canada. publications.gc.ca/pub?id=9.893021&sl=0