| Inter-decadal climate variability in northwestern North America was assessed in two ways: (1) determining the spatial and temporal patterns of climate variability in instrumental temperature records along the northwestern coast of North America, and: (2) assessing climate variability recorded in tree ring and varve proxy records at Meziadin Lake, British Columbia. The leading factor (F1) from a factor analysis of temperature data from 20 stations in northwestern North America for the period 1930–1990 was able to reproduce Pacific decadal variability, best represented by the Pacific Decadal Oscillation (PDO). This record is significantly correlated with the PDO and reproduces extreme years, as well as the phase changes of the PDO. An analysis of the spatial patterns shows that stations between the Aleutian Islands to southern British Columbia have similar characteristics, whereas stations further south to southern Oregon are more varied in terms of their relationship to PDO. Stations located further inland are better correlated to the PDO, likely due to synoptic climatology. Both geomorphic and hydroclimatic conditions influence the record of sedimentation in Meziadin Lake. In general, it appears that changing glacial cover in the drainage basin had the greatest effect on sedimentation prior to 1900, whereas PDO has significantly influenced sedimentation from 1900–1999, and especially from 1948 to 1999, where major changes in sedimentation occur at, or around changes in the PDO (∼1948, ∼1958, ∼1977). The relative influence of each, and the impact of Pacific decadal variability on the glacial record is difficult to assess due to the lack of a pre-1900 PDO record. Tree ring and varve records from the basin are significantly correlated to monthly temperature and precipitation records from nearby Stewart and Smithers, British Columbia. Tree rings and varves were strongly correlated to yearly averages of temperature and precipitation, meaning that both can potentially be used to reconstruct the yearly hydroclimatic signal. A multiple regression model was able to reproduce PDO variability (r2 = 0.63) for the period 1903–1996. A multi-proxy approach may be able to reproduce PDO over the past millennium, and highlight the relationship between the Little Ice Age and PDO.*; *This dissertation is compound (contains both a paper copy and CD as part of the dissertation). The CD requires the following system application: Microsoft Office. |
