Abstracts - Posters

Homogenization of Temperature Series for the Analysis of Climate Evolution in Southern Quebec from 1960 to 2003

Abderrahmane Yagouti¹ and Gilles Boulet
¹Ouranos
abderrahmane.yagouti@menv.gouv.qc.ca

Monitoring Quebec's climate very closely has become very important in the context of expected climate change resulting from increased concentrations of greenhouse gases. Climatological data constitute an invaluable source of information for tracking the current and past trajectory of the climate in Quebec, analyzing and predicting extreme events, and defining tools to assist in risk management decision-making. However, climatological observation series are often contaminated by human bias, which risks creating heterogeneities in the historical series and then masking the real climate signals. A preliminary phase for correcting this bias consists of consulting station metadata and identifying the dates of modifications made at the measurement site. Nevertheless, this method has limited applicability because station files are often incomplete. We must then look to statistical techniques to homogenize climate series.

In this research, we have developed a procedure based on the regression model for the homogenization of Quebec temperature series. This procedure allows the location of one or several ruptures to be identified, and their size to be estimated. The results show that there is a large number of stations with significant ruptures in their observation series. After these series were corrected, the homogenized series allowed the evolution of temperatures in southern Quebec between 1960 and 2003 to be studied.

2005-04-06