Monday, 13 May 2002: 2:15 PM
Homogeneity Assessment of Canadian Precipitation Data for Joined Stations
Climate stations in Canada are often relocated within the same city or area. Station joining is crucial to produce long time series for the detection of climate change. Homogeneity assessment must be done to filter out the artificial changes due to the joining of station observations. When overlapping period is available, the so-called “simple ratio method” is used as a first step to estimate the magnitude of changes caused by relocation. The purpose of this study is to test the station observations around the joining year using the Alexandersson and Vincent methods, find and adjust for further non climatic significant changes, which could not be detected by the simple ratio method. Case-study locations are selected from different climate regimes across Canada. The surrounding stations used in the homogeneity tests are carefully chosen based on data availability and quality around the joining year. The surrounding stations were also adjusted for all known inhomogeneities - using the method described in Mekis and Hogg - before running the homogeneity tests. The highest correlated and closest surrounding stations are grouped as “best” stations to be used as reference series in the study. Results from simple ratio method are also compared to the homogeneity test results.