CGRG Bibliography of Canadian Geomorphology
Search Results
Author : Ehsanzadeh, E.
Date : 2009.
Title : Change detection in Canadian low streamflows: A simultaneous study of trends and abrupt changes.
Publication : MOCA-09, Our Warming Planet. Joint Assembly of the IAMAS, IAPSO and IACS. July 19-29, 2009. Montreal, Quebec.
Issue :
Page(s) :
Abstract
There is a growing evidence of gradual and/or abrupt changes in hydro-climatic variables around the world. However, the majority of change detection studies have been based on the assumption of linearity of time evolution of natural process which may not be consistent with the nature of such phenomena. This study performs a simultaneous evaluation of gradual and abrupt changes as well as changes in trend directions of low flows in Reference Hydrometric Basin Network (RHBN) u sing a modified Mann-Kendall trend test and a Bayesian multi change point detection methodology. Assuming a monotonic trend for the observational period and depending on the low flow index, 20 to 25 percent of RHBN low flow time series experienced significant trends where 2/3 to 3/5 of identified trends were downward. Change point analysis revealed that the majority of time series experienced at least one abrupt change during the observational period. In more than 65% of cases the detected change points were in 1980s and more specifically in 1982. Trend analysis i n stations with abrupt changes for the time period before the common change point (1982) shows that 16% of tested stations experienced significant trends where low flows in 70% of trendy stations were characterized by upward trends. The RHBN low flow records after common change point experienced significant trends in 10% of stations identified with shifts. Detected trends were downward in 75% of stations with significant trends.
Bibliography of Canadian Geomorphology