Eastern Ontario climate: Variability and trends during the 20th century.

Abstract

The historical climate record is analyzed to determine trends and variability to develop possible scenarios for future climates. The study area is the Prescott-Russell United Counties and Stormont, Dundas and Glengarry United Counties of Eastern Ontario. Three data sets were used: the Canadian monthly climate data, the Historical Canadian Database Version 2: Monthly Rehabilitated Precipitation and Homogenized Temperature Data Sets and the Eastern Canada daily dataset. The ten warmest years of the past century occurred at the beginning and at the end of the century. However, the last decade (1990--1998) experienced four of the ten warmest years of the century, including the warmest year on record (1998), which was a full degree warmer than the second warmest (1953). Unlike the warmest year, the ten coldest years occurred in the early part of the century, between 1904--1943. The 1990s, although warm in the mean, had fewer extreme heat waves and fewer cold snaps. There is no clear relation between temperature and precipitation, suggesting that future climates may be wet or dry. From the mid 1960s to the present the growing season has started earlier, and since 1984 has been ending later than the long-term average. (Abstract shortened by UMI.)