Trend detection in hydrological series: when series are negatively correlated

The objective of this paper is to verify the applicability of the trend-free pre-whitening (TFPW) approach, developed by Yue et al. (2002) for positively correlated series, to negatively correlated series using similar Monte Carlo simulations. This study was initiated when a project on trend detection for streamflow and baseflow series across Canada revealed that a significant number of series had negative correlation coefficients. The TFPW procedure confirmed to be also well suited for negatively correlated series. This study also showed that the estimated values for slopes (trends) and correlation coefficients of the pre-whitened series are affected by the sample size, especially for negatively correlated series. Copyright © 2009 Her Majesty the Queen in right of Canada. Published by John Wiley & Sons. Ltd.