Nonstationary frequency analysis of extreme daily precipitation amounts in Southeastern Canada using a peaks-over-threshold approach
| Autor: | Taha B. M. J. Ouarda, Alida Nadège Thiombiano, Salaheddine El Adlouni, André St-Hilaire, Nassir El-Jabi |
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| Rok vydání: | 2016 |
| Předmět: |
Atmospheric Science
010504 meteorology & atmospheric sciences 0208 environmental biotechnology Regression analysis 02 engineering and technology 01 natural sciences 020801 environmental engineering Arctic oscillation 13. Climate action Generalized Pareto distribution Climatology Covariate Environmental science Precipitation Scale parameter Pacific decadal oscillation 0105 earth and related environmental sciences Quantile |
| Zdroj: | Theoretical and Applied Climatology. 129:413-426 |
| ISSN: | 1434-4483 0177-798X |
| DOI: | 10.1007/s00704-016-1789-7 |
| Popis: | In this paper, a statistical inference of Southeastern Canada extreme daily precipitation amounts is proposed using a classical nonstationary peaks-over-threshold model. Indeed, the generalized Pareto distribution (GPD) is fitted to excess time series derived from annual averages of independent precipitation amount events above a fixed threshold, the 99th percentile. Only the scale parameter of the fitted distribution is allowed to vary as a function of a covariate. This variability is modeled using B-spline function. Nonlinear correlation and cross-wavelet analysis allowed identifying two dominant climate indices as covariates in the study area, Arctic Oscillation (AO) and Pacific North American (PNA). The nonstationary frequency analysis showed that there is an east-west behavior of the AO index effects on extreme daily precipitation amounts in the study area. Indeed, the higher quantiles of these events are conditional to the AO positive phase in Atlantic Canada, while those in the more southeastern part of Canada, especially in Southern Quebec and Ontario, are negatively related to AO. The negative phase of PNA also gives the best significant correlation in these regions. Moreover, a regression analysis between AO (PNA) index and conditional quantiles provided slope values for the positive phase of the index on the one hand and the negative phase and on the other hand. This statistic allows computing a slope ratio which permits to sustain the nonlinear relation assumption between climate indices and precipitation and the development of the nonstationary GPD model for Southeastern Canada extremes precipitation modeling. |
| Databáze: | OpenAIRE |
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