CGRG Bibliography of Canadian Geomorphology
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Author : Adamowski, K.; and Bougadis, J.
Date : 2002.
Title : Detection of trends in annual extreme rainfall.
Publication : Annual Meeting of the Canadian Geophysical Union. May 18-21, 2002, Banff, Alberta.
Issue :
Page(s) :
Abstract
Information on intensity-duration-frequency of rainfall is commonly required for a variety of hydrologic applications. In this study, trends are estimated for different durations of annual extreme rainfall using the regional average Mann-Kendall’s S trend test over three time frames. The method of L-moments was employed to delineate homogeneous regions. The trend test was modified to account for observed autocorrelation, and a bootstrap methodology was used to account for the observed spatial correlation. The latter was found using binomial distribution. Numerical analysis was performed on 44 rainfall stations from the province of Ontario, Canada for a 20 year time frame; and for 37 and 17 stations for a 25 and 30 year time frame, respectively. Separate analysis was performed using data from individual sites as well as homogeneous regions for the annual maximum observations for the following duration: 5 , 10 , 15, 30 minute, and 1, 2, 6, and 12 hour, respectively. Depending on different rainfall durations, 1 to 6 homogeneous regions were delineated. Based on a 5% significance level, approximately 22% of the regions tested had a significant trend, predominantly for short duration storms. For all time frames and storm duration, serial dependency was observed in 3.5% of sites and spatial correlation was found in 20% of the regions. The presence of serial and spatial correlation has a significant impact on trend determination.
Bibliography of Canadian Geomorphology