• Allsopp, D., 2004: History of the digital climate archive. Extended Abstracts, Workshop on Climate Data Homogenization, Toronto, Ontario, Canada, 1–11.

    • Search Google Scholar
    • Export Citation
  • Hasenauer, H., , K. Merganicova, , R. Petritsch, , S. A. Pietsch, , and P. E. Thornton, 2003: Validating daily climate interpolations over complex terrain in Austria. Agric. For. Meteor., 119, 87107.

    • Search Google Scholar
    • Export Citation
  • Hutchinson, M. F., 1995: Interpolating mean rainfall using thin plate smoothing splines. Int. J. Geogr. Inf. Sci., 9, 385403.

  • Hutchinson, M. F., cited 2010. ANUSPLIN version 4.3. Centre for Resource and Environmental Studies, Australian National University, Canberra. [Available online at http://fennerschool.anu.edu.au/publications/software/anusplin.php.]

    • Search Google Scholar
    • Export Citation
  • Hutchinson, M. F., , D. W. McKenney, , K. Lawrence, , J. H. Pedlar, , R. F. Hopkinson, , E. Milewska, , and P. Papadopol, 2009: Development and testing of Canada-wide interpolated spatial models of daily minimum/maximum temperature and precipitation 1961–2003. J. Appl. Meteor. Climatol., 48, 725741.

    • Search Google Scholar
    • Export Citation
  • Milewska, E., , and W. D. Hogg, 2002: Continuity of climatological observations with automation. Atmos.–Ocean, 40, 333359.

  • Shen, S. S. P., , P. Dzikowski, , G. Li, , and D. Griffith, 2001: Interpolation of 1961–97 daily temperature and precipitation data onto Alberta polygons of ecodistrict and soil landscapes of Canada. J. Appl. Meteor., 40, 21622177.

    • Search Google Scholar
    • Export Citation
  • Vincent, L. A., , E. J. Milewska, , R. F. Hopkinson, , and L. Malone, 2009: Bias in minimum temperature introduced by a redefinition of the climatological day at the Canadian synoptic stations. J. Appl. Meteor. Climatol., 48, 21602168.

    • Search Google Scholar
    • Export Citation
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Impact of Aligning Climatological Day on Gridding Daily Maximum–Minimum Temperature and Precipitation over Canada

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  • 1 Custom Climate Services, Inc., Regina, Saskatchewan, Canada
  • 2 Canadian Forest Service, Natural Resources Canada, Sault Ste. Marie, Ontario, Canada
  • 3 Climate Research Division, Science and Technology Branch, Environment Canada, Toronto, Ontario, Canada
  • 4 Australian National University, Canberra, Australian Capital Territory, Australia
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Abstract

On 1 July 1961, the climatological day was redefined to end at 0600 UTC at all principal climate stations in Canada. Prior to that, the climatological day at principal stations ended at 1200 UTC for maximum temperature and precipitation and 0000 UTC for minimum temperature and was similar to the climatological day at ordinary stations. Hutchinson et al. reported occasional larger-than-expected residuals at 50 withheld stations when the Australian National University Spline (ANUSPLIN) interpolation scheme was applied to daily data for 1961–2003, and it was suggested that these larger residuals were in part due to the existence of different climatological days. In this study, daily minimum and maximum temperatures at principal stations were estimated using hourly temperatures for the same climatological day as local ordinary climate stations for the period 1953–2007. Daily precipitation was estimated at principal stations using synoptic precipitation data for the climatological day ending at 1200 UTC, which, for much of the country, was close to the time of the morning observation at ordinary climate stations. At withheld principal stations, the climatological-day adjustments led to the virtual elimination of large residuals in maximum and minimum temperature and a marked reduction in precipitation residuals. Across all 50 withheld stations the climatological day adjustments led to significant reductions, by around 12% for daily maximum temperature, 15% for daily minimum temperature, and 22% for precipitation, in the residuals reported by Hutchinson et al.

Corresponding author address: Ewa J. Milewska, Climate Research Division, Science and Technology Branch, Environment Canada, 4905 Dufferin St., Toronto ON M3H 5T4 Canada. E-mail: ewa.milewska@ec.gc.ca

Abstract

On 1 July 1961, the climatological day was redefined to end at 0600 UTC at all principal climate stations in Canada. Prior to that, the climatological day at principal stations ended at 1200 UTC for maximum temperature and precipitation and 0000 UTC for minimum temperature and was similar to the climatological day at ordinary stations. Hutchinson et al. reported occasional larger-than-expected residuals at 50 withheld stations when the Australian National University Spline (ANUSPLIN) interpolation scheme was applied to daily data for 1961–2003, and it was suggested that these larger residuals were in part due to the existence of different climatological days. In this study, daily minimum and maximum temperatures at principal stations were estimated using hourly temperatures for the same climatological day as local ordinary climate stations for the period 1953–2007. Daily precipitation was estimated at principal stations using synoptic precipitation data for the climatological day ending at 1200 UTC, which, for much of the country, was close to the time of the morning observation at ordinary climate stations. At withheld principal stations, the climatological-day adjustments led to the virtual elimination of large residuals in maximum and minimum temperature and a marked reduction in precipitation residuals. Across all 50 withheld stations the climatological day adjustments led to significant reductions, by around 12% for daily maximum temperature, 15% for daily minimum temperature, and 22% for precipitation, in the residuals reported by Hutchinson et al.

Corresponding author address: Ewa J. Milewska, Climate Research Division, Science and Technology Branch, Environment Canada, 4905 Dufferin St., Toronto ON M3H 5T4 Canada. E-mail: ewa.milewska@ec.gc.ca
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