27 Jul 2023
 | 27 Jul 2023

A comparison of RCMs and meteorological time series (1950–1996) of southern Italy as a fine calibration for hydrogeological scenarios

Daniele Lepore, Edoardo Bucchignani, Myriam Montesarchio, Vincenzo Allocca, Delia Cusano, and Pantaleone De Vita

Abstract. Nowadays the phenomenon of Global Warming is unequivocal, as confirmed by the latest reports of the IPCC and studies of the climate-change impacts on ecosystems, global economy, and populations. Among these analyses the effect of climate change on groundwater is a very relevant task especially for regions whose economic and social development depends chiefly on groundwater availability, as for the southern Italy. In such a territorial framework, this research was focused on analyzing: i) comparison of precipitation and air temperature obtained by Regional Climate Models (RCMs) and meteorological time series recorded in a part (1950–1996) of the “historical experiment” period (1950–2005); ii) effects of climate change on scenarios of air temperature (T) and precipitation (P) and, consequently, on scenarios of actual evapotranspiration (ETR) and effective precipitation Pe (P – ETR). The latter was considered as a proxy of groundwater recharge of the principal aquifer systems of the region, represented chiefly by the karst aquifers.

To achieve a detailed hydro-climatological characterization, an Ensemble of 15 RCMs (E15) derived from the European Coordinated Regional Downscaling Experiment (EURO-CORDEX), at a spatial resolution of 0.11° (~12 km), was analyzed. Specifically, two IPCC Representative Concentration Pathways of greenhouse gases (RCP4.5 and RCP8.5) were considered. The E15 was calibrated in the validation period (1950–1996) by a statistical comparison with data observed by the regional meteorological network managed by the former National Hydrological Service (SIMN), Department of Naples, which was active in the period 1921–1999.

As a principal result, the E15 was found with a statistical structure very similar to those of observed annual precipitation (OBSP) and mean annual air temperature (OBST), characterized by a very similar frequency distribution. Accordingly, an inferential statistical approach was performed for calibrating E15 precipitation (E15P) and air temperature (E15T) based on the compensation of the difference with OBSP (+7 %) and OBST (-16 %). The E15 projects a reduction in precipitation and an increase in air temperature under both RCPs, with a divergence point between the two scenarios occurring by about 2040. As a principal result, Pe shows declining trends for both RCP scenarios, reaching a decrease of the 11-yrs moving average down to -20 %, for RCP4.5, and -50 %, for RCP8.5, even if characterized by relevant inter-annual fluctuations.

Daniele Lepore et al.

Status: final response (author comments only)

Comment types: AC – author | RC – referee | CC – community | EC – editor | CEC – chief editor | : Report abuse
  • RC1: 'Comment on egusphere-2023-1505', Anonymous Referee #1, 07 Sep 2023
    • AC1: 'Reply on RC1', Daniele Lepore, 15 Sep 2023
  • RC2: 'Comment on egusphere-2023-1505', Anonymous Referee #2, 19 Sep 2023

Daniele Lepore et al.

Daniele Lepore et al.


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Short summary
This study focused on reconstructing climate scenarios for the principal climatological and hydrogeological variables for the principal aquifer systems of southern Italy. What sets this research apart is the introduction of a new methodology to analyze and correct data from Regional Climate Models (RCMs), distinguishing it from other studies and revealed the potential of RCMs in predicting future groundwater recharge processes scenarios.