A Correlation Analysis of Extreme Climate Indices and River Flood Events in Northwestern Italy
Abstract
The occurrence of floods is strongly related to specific climatic conditions that favor extreme precipitation events. Although the impact of precipitation and temperature patterns on river flows is a well discussed topic in hydrology, few studies have focused on the rainfall and temperature distributions extremes in their relation with peak discharges. This work presents a comparative analysis of Climate Change Indices (ETCCDI) annual time series, calculated using the NorthWestern Italy Optimal Interpolation (NWIOI) dataset, and maximum daily discharge time series in Piedmont Region. The Spearman's rank correlation was used to determine which indices mostly correlate with river peak flows, allowing to infer on the main physical processes involved in the production of floods. The correlation hypothesis was verified with the Spearman's rank correlation test, considering a Student's t distribution and a 5% significance level. Moreover, the influence of climate variability on river flows was examined by correlating the filtered time series and analysing trends. The methodology was first applied at the catchment scale and then extended to the regional scale, by matching a spatially averaged flood magnitude index with the spatially averaged ETCCDI indices. It is suggested that the results obtained at the local scale can be effectively extended to the regional scale, providing a distributed picture of the temporal correlation between climate forcings and peak discharges in Northwestern Italy.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2020
- Bibcode:
- 2020AGUFMH172.0001P
- Keywords:
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- 1812 Drought;
- HYDROLOGY;
- 1817 Extreme events;
- HYDROLOGY;
- 1821 Floods;
- HYDROLOGY;
- 1874 Ungaged basins;
- HYDROLOGY