Extreme temperature and precipitation events over Italy: assessment of high‐resolution simulations with COSMO‐CLM and future scenarios

Abstract

This study presents a detailed analysis of the present and expected future extreme climate conditions over Italy through the use of some extreme indicators. Climate data for this analysis were provided by the regional climate model COSMO-CLM, using different grid spacing to ascertain the real importance of using higher resolution climate data, especially over such a complex topography as Italy. Four simulations were carried out at spatial resolutions of 0.125 ∘ and 0.0715 ∘ , driven by ERA-Interim Reanalysis and the CMCC-CM global model. We investigated the ability of the model to represent realistically the climatology of a subset of climate indicators defined by the Expert Team on Climate Change Detection and Indices (ETCCDI) for precipitation and temperature. Several high-resolution observational data sets available over some Italian regions were therefore used in order to offset the limited number of observations available over Italy in the E-OBS data set and its coarse grid. We found that the increase in resolution could have interesting benefits in representing such extreme indices, especially in the more orographically complex areas. Finally, we investigated future climate changes regarding extreme weather events expected under anthropogenic climate change scenarios, employing the IPCC RCP4.5 and RCP8.5 greenhouse gas concentrations, showing that such events are expected to increase over Italy.

Simulations of quantitative shift in bio-climatic indices in the viticultural areas of Trentino (Italian Alps) by an open source R package

“…The simulations have been deeply analysed in Bucchignani et al (2015) and -in terms of extreme events -in Zollo et al (2015a), showing a general good agreement with observed data. Furthermore, as explained in Bucchignani et al (2015), the results of these simulations are consistent, in terms of both mean bias and projections, with those obtained from the EURO-CORDEX ensemble data (Giorgi et al, 2009), which represent the 'state-of-the-art' of regional climate simulations over Europe at 0.11°of horizontal resolution.…”

“…However, the huge computational costs required to perform high-resolution simulations with model ensembles represent a limit, leaving this solution to future works. Indeed, COSMO-CLM results have been proved to be consistent with the 'state-of-the-art' of regional climate simulations (Bucchignani et al, 2015;Zollo et al, 2015a).…”

Numerical Simulation of the Period 1971–2100 over the Mediterranean Area with a Regional Model, Scenario SRES-A1B

“…The good capabilities of the model in reproducing PDFs observed in the present work, combined with the finding of several literature works (e.g., [33,37]) confirm that, especially in some complex areas, high-resolution simulations could provide good improvements in the data quality. Indeed, there is no ideal resolution appropriate for every geographical area, since it depends on the climate variability of the context considered.…”

Scale dependency of regional climate modeling of current and future climate extremes in Germany

“…If the comparison was made with lower-resolution data sets, many features of the finer-resolution simulations would have been smoothed out (Vautard et al 2013). Although Kotlarski et al (2014) recommended interpolation to the coarsest-resolution grid, we employed the first approach to provide information for impact studies, as supported by Zollo et al (2015). This method allowed preservation of extreme values and temporal variability (Vautard et al 2013).…”