Concurrent observations are used to assess continuity of daily minimum and maximum temperatures records at modernized reference climate stations. The preliminary analysis is conducted using two methods. In the first technique (Milewska and Hogg, 2002), days with certain meteorological conditions, defined by sky cover and wind speed, are grouped together. Biases computed for each group emphasize instrumental and siting differences and are well suited for adjustment of daily values. The second technique, based on regression models that include a reference series from the surrounding stations, was developed to identify discontinuities in temperature time series caused by station relocation and changes in observing procedures (Vincent et al. 2002). A similar approach is used in this study to establish if the join of manned and automated observations has created an artificial discontinuity at the joining year and furthermore to determine if the daily adjustments are reliable to create a suitable temperature series. The results from both methods are compared.
Milewska, E. and W.D. Hogg. 2002. Continuity of climatological observations with automation. Atmosphere-Ocean 40(3): 333-359.
Vincent, L.A., X. Zhang, B.R. Bonsal and W.D. Hogg. 2002: Homogenization of daily temperatures over Canada. J. Climate 15: 1322-1334.