Changing hydrological conditions in the Po basin under global warming

Erika Coppola; Marco Verdecchia; Filippo Giorgi; Valentina Colaiuda; Barbara Tomassetti; Annalina Lombardi

doi:10.1016/j.scitotenv.2014.03.003

Changing hydrological conditions in the Po basin under global warming

Sci Total Environ. 2014 Sep 15:493:1183-96. doi: 10.1016/j.scitotenv.2014.03.003. Epub 2014 Mar 19.

Authors

Erika Coppola¹, Marco Verdecchia², Filippo Giorgi³, Valentina Colaiuda⁴, Barbara Tomassetti⁴, Annalina Lombardi⁴

Affiliations

¹ Abdus Salam International Centre for Theoretical Physics, Trieste, Italy. Electronic address: coppolae@ictp.it.
² CETEMPS, Center of Excellence, University of L'Aquila, L'Aquila, Italy; Department of Physical and Chemical Sciences, University of L'Aquila, L'Aquila, Italy.
³ Abdus Salam International Centre for Theoretical Physics, Trieste, Italy.
⁴ CETEMPS, Center of Excellence, University of L'Aquila, L'Aquila, Italy.

PMID: 24656403
DOI: 10.1016/j.scitotenv.2014.03.003

Abstract

The Po River is a crucial resource for the Italian economy, since 40% of the gross domestic product comes from this area. It is thus crucial to quantify the impact of climate change on this water resource in order to plan for future water use. In this paper a mini ensemble of 8 hydrological simulations is completed from 1960 to 2050 under the A1B emission scenario, by using the output of two regional climate models as input (REMO and RegCM) at two different resolutions (25 km-10 km and 25 km-3 km). The river discharge at the outlet point of the basin shows a change in the spring peak of the annual cycle, with a one month shift from May to April. This shift is entirely due to the change in snowmelt timing which drives most of the discharge during this period. Two other important changes are an increase of discharge in the wintertime and a decrease in the fall from September to November. The uncertainty associated with the winter change is larger compared to that in the fall. The spring shift and the fall decrease of discharge imply an extension of the hydrological dry season and thus an increase in water stress over the basin. The spatial distributions of the discharge changes are in agreement with what is observed at the outlet point and the uncertainty associated with these changes is proportional to the amplitude of the signal. The analysis of the changes in the anomaly distribution of discharge shows that both the increases and decreases in seasonal discharge are tied to the changes in the tails of the distribution, i.e. to the increase or decrease of extreme events.

Keywords: CHyM model; Climate change; Hydrological ensemble; Hydrological simulation; Po river.