Multi-scale assessment of high-resolution reanalysis precipitation fields over Italy

Francesco Cavalleri; Cristian Lussana; Francesca Viterbo; Michele Brunetti; Riccardo Bonanno; Veronica Manara; Matteo Lacavalla; Simone Sperati; Mario Raffa; Valerio Capecchi; Davide Cesari; Antonio Giordani; Ines Maria Luisa Cerenzia; Maurizio Maugeri

arXiv · 2407.11517

Multi-scale assessment of high-resolution reanalysis precipitation fields over Italy

Francesco Cavalleri·Cristian Lussana·Francesca Viterbo·Michele Brunetti·Riccardo Bonanno·Veronica Manara·Matteo Lacavalla·Simone Sperati·Mario Raffa·Valerio Capecchi·Davide Cesari·Antonio Giordani·Ines Maria Luisa Cerenzia·Maurizio Maugeri

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Abstract

This study focuses on the validation of high-resolution regional reanalyses to understand their effectiveness in reproducing precipitation patterns over Italy, a climate change hotspot characterized by coastal sea-land interaction and complex orography. Nine reanalysis products were evaluated, with the ECMWF global reanalysis ERA5 serving as a benchmark. These included both European (COSMO-REA6, CERRA) and Italy-specific (BOLAM, MERIDA, MERIDA-HRES, MOLOCH, SPHERA, VHR-REA\_IT) datasets, using different models and parametrizations. The inter-comparison involved determining the effective resolution of daily precipitation fields using wavelet techniques and assessing intense precipitation statistics through frequency distributions. In-situ observations and observational gridded datasets were used to independently validate reanalysis precipitation fields. The capability of reanalyses to depict daily precipitation patterns was assessed, highlighting a maximum radius of precipitation misplacement of about 15 km, with notably lower skills during summer. An overall overestimation of precipitation was identified in the reanalysis climatological fields over the Po Valley and the Alps, whereas multiple products showed an underestimation of precipitations across the North-West coast, the Apennines, and Southern Italy. Finally, a comparison with a time-consistent observational dataset (UniMi/ISAC-CNR) revealed a non-stable deviation from observations in the annual precipitation cumulate of the reanalysis products analyzed. This should be taken into account when interpreting precipitation trends over Italy.

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Francesco Cavalleri, Cristian Lussana, Francesca Viterbo, Michele Brunetti, Riccardo Bonanno, Veronica Manara, Matteo Lacavalla, Simone Sperati, Mario Raffa, Valerio Capecchi, Davide Cesari, Antonio Giordani, Ines Maria Luisa Cerenzia, Maurizio Maugeri. 2024-07-16. Multi-scale assessment of high-resolution reanalysis precipitation fields over Italy. https://arxiv.org/abs/2407.11517

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