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A regional GEV scale-invariant framework for Intensity–Duration–Frequency analysis

Blanchet, J., Ceresetti, D., Molinié, G., Creutin, J.-D.
Journal of hydrology 2016 v.540 pp. 82-95
hydrology, models, rain, storms, France, Mediterranean region
We propose in this paper a regional formulation of Intensity–Duration–Frequency curves of point-rainfall maxima in a scale-invariant Generalized Extreme Value (GEV) framework. The two assumptions we make is that extreme daily rainfall is GEV-distributed – which is justified by Extreme Value Theory (EVT) – and that extremes of aggregated daily rainfall follow simple-scaling relationships. Following these assumptions, we develop in a unified way a GEV simple-scaling model for extremes of aggregated daily rainfall over the range of durations where scaling applies. Then we propose a way of correcting this model for measurement frequency, giving a new GEV-scaling model for extremes of aggregated hourly rainfall. This model deviates from the simple-scaling assumption. This framework is applied to the Mediterranean region of Cévennes-Vivarais, France. A network of about 300 daily raingage stations covering the last 50years and accumulated to span the range 1day–1week is used to fit the scale invariant GEV-model locally. By means of spatial interpolation of the model parameters, and correction for measurement frequency, we are able to build a regional model with good performances down to 1h duration, even though only one hourly station is used to build the model. Finally we produce mean and return level maps within the region in the range 1h–1week and comment on the potential rain storms leading to these maps.