Author(s): E. H. Ishak; A. Rahman; S. Westra; A. Sharma; G. Kuczera
Linked Author(s):
Keywords: Trend analysis; Serial correlation; Cross-correlation; Floods; Mann-Kendall Test
Abstract: Investigation of trends in hydrological time series data generally rely on the assumption that observed records are generally independent or having short-term perseverance. It is known that the presence of serial correlation in a time series can manipulate the ability of the detection test to evaluate the site significance of a trend; while the existence of cross-correlation among sites in a network can affect the ability of the test to assess the field significance of trends over the station network. At the significance level of 0.1, the site significance of trends in Australian annual maximum flood series data with 30-, 40-and 50-year records was assessed by the non-parametric MannKendall test, with the trend free pre-whitening approach to remove and eliminate the effects of serial correlation from the time series. The field significance of trends over the whole country was evaluated by using a bootstrap re-sampling approach that considers preservation of the cross-correlation structure of the network. It is concluded that a greater number of downward trends are observed than are expected to occur by chance for all the three time periods.
Year: 2011