Shannon Allen has successfully defended her departmental defence on July 9th and PhD final defence on September 3, 2020.
Congratulation, Shannon!
Here is the information for her dissertation:
Trends in the Frequency of Extreme Temperatures for Canadian Urban Centres from 1971 to 2000
Extreme temperature trends for Canadian urban centres during the latter portion of the 20th century was explored in four complimentary research studies. The analysis used a novel methodology of frequency of extreme occurrences using extreme temperature records as the metric. A second methodological innovation, day-to-day temperature variability, was used to characterize climate stations as urban, rural and peri-urban. The first study examined extreme temperature seasonal trends for five stations in the Greater Toronto Area over a thirty year period. This analysis also completed a 50-year annual extreme temperature analysis for two of the stations. Statistically significant decreases in extreme minimum temperature counts annually and seasonally, in the spring and winter months, indicated localized urban heat islands were present. The second study characterized urban-rural station pairings for Vancouver, Edmonton, Montreal and Halifax using day-to-day temperature variability. A subset of the urban stations were identified as peri-urban using this analysis. The third study using these characterizations examined annual extreme temperature record counts for 14 stations across four urban centres in Canada. Urban and peri-urban stations had statistically significant decreasing extreme cold temperature record counts while rural stations tended not to. The coincident increase in minimum temperatures was indicative of urban heat island development. Montreal experienced statistically significant decreases at all stations that likely indicated an underlying localized climate change signal or nascent urbanization at the local rural station. Edmonton experienced an above average warm 1980s and thus net temporal trends in extreme temperature record counts were not evident. In the fourth study the results of the frequency of occurrence analysis for Halifax was compared to standard climate extreme indicators. The comparison of the results determined that the frequency of occurrence methodology aligned with the more generally used climatic indicator findings. These studies indicated that the extreme frequency of occurrence and day-to-day variability methodologies could be effectively used in climate data analysis. These studies have also shown that trends in extreme minimum temperatures have decreased more rapidly than extreme maximum temperatures have increased for multiple urban centres across Canada for the latter portion of the 20th century.