Statistical Uncertainty in Hydrometeorological Trend Analyses
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Date
2016
Authors
Journal Title
Journal ISSN
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Publisher
Advances in Meteorology
Abstract
This study demonstrates the existence of uncertainty in hydrometeorological trend analyses using historical rainfall from Kenya
in East Africa. With respect to the influence of short- and long-term persistence on trend analyses, a total of 13 approaches of
rank-based techniques including Mann-Kendall, Spearman’s Rho, and Cumulative Rank Difference (CRD) tests were employed.
Graphically, CRD-based diagnoses of trends and subtrends were performed. To assess data-related uncertainty, a resampling
procedure was applied. It was shown that at a selected significance level, the null hypothesis𝐻0 (no trend) can be rejected for trend
direction while the evidence to reject 𝐻0 (zero trend magnitude) is statistically insufficient. Graphical and statistical approaches
when combined yield more influential and comprehensive information for inference than relying purely on statistical results.
Alongside an apparent linear trend, variations in the nonlinear (e.g., cyclical) component of the series may also not be due to
natural randomness. Method-related uncertainty is not negligible especially for series with persistent fluctuations.These findings
shed light on the need to assess uncertainty on trend results. Furthermore, it is recommended that the conclusiveness of trends be
cautiously premised not only on statistical grounds but also on more considered physical and/or theoretical understanding of the
hydrometeorological processes.
Description
Keywords
Hydrometeorological, Trend analysis
Citation
Onyutha, C. (2016). Statistical uncertainty in hydrometeorological trend analyses. Advances in Meteorology, 2016. http://dx.doi.org/10.1155/2016/8701617