Evaluation of uncertainties in mean and extreme precipitation under climate change for northwestern Mediterranean watersheds from high-resolution Med and Euro-CORDEX ensembles

Abstract

Abstract. The climate change impact on mean and extreme precipitation events in the northern Mediterranean region is assessed using high-resolution EuroCORDEX and Med-CORDEX simulations. The focus is made on three regions, Lez and Aude located in France, and Muga located in northeastern Spain, and eight pairs of global and regional climate models are analyzed with respect to the SAFRAN product. First the model skills are evaluated in terms of bias for the precipitation annual cycle over historical period. Then future changes in extreme precipitation, under two emission scenarios, are estimated through the computation of past/future change coefficients of quantile-ranked model precipitation outputs. Over the 1981-2010 period, the cumulative precipitation is overestimated for most models over the mountainous regions and underestimated over the coastal regions in autumn and higher-order quantile. The ensemble mean and the spread for future period remain unchanged under RCP4.5 scenario and decrease under RCP8.5 scenario. Extreme precipitation events are intensified over the three catchments with a smaller ensemble spread under RCP8.5 revealing more evident changes, especially in the later part of the 21st century.

Changes in flood damage with global warming on the eastern coast of Spain

“…6d-f). This is also in line with other studies on projections of extreme precipitation in the region (Drobinski et al, 2018;Colmet-Daage et al, 2018;Tramblay and Somot, 2018;Cramer et al, 2018), which show a likely increase in the extreme precipitation events in Europe and the Mediterranean area with increasing global temperature, mostly during the winter months (Kjellström et al, 2018;Vautard et al, 2014;Rajczak and Schär, 2017;Jacob et al, 2014). Figure 7 shows the change (in %) of the mean 24 h precipitation, averaged across all basins, in the future simulations compared to the reference period , when taking into account the cases that overpassed the 40 mm d −1 precipitation threshold for the different models and warming periods (global warming at 1.5, 2 and 3 • C).…”

“…For example, the flood event of October 1987, when more than 400 mm of rainfall was recorded in 24 h near Barcelona, was favoured by a mesohigh created at the south of the Pyrenees (Ramis et al, 1994). For the 1996-2015 period, a total of 166 flood events were recorded in Catalonia: 13 of them caused catastrophic impacts, 87 caused extraordinary impacts and 66 caused ordinary impacts , following the methodology explained in Llasat et al (2016) and Cortès et al (2017).…”

“…In the last few years, much research has focused on the study of climate change in the Mediterranean region, an area that is identified as highly vulnerable to climate change according to the "Fifth Assessment Report" of the Intergovernmental Panel on Climate Change (IPCC, 2014). Some studies have found an increase in precipitation extremes with global warming projections in the Mediterranean region (Colmet-Daage et al, 2018;Drobinski et al, 2018), although a general decrease in the annual precipitation is projected (Jacob et al, 2014;Cramer et al, 2018;Sillmann et al, 2013;Rajczak and Schär, 2017). Cramer et al (2018) state that future warming in the Mediterranean region is expected to exceed the global mean rates by 25 %, with peaks of 40 % in summer.…”

An ensemble approach for the analysis of extreme rainfall under climate change in Naples (Italy)

“…For the area of interest, the EURO‐CORDEX subproject collects present and future DD simulations at 12.5 km (0.11°) horizontal resolution for different GHG concentration scenarios. Among these, “Representative Concentration Pathways” RCP4.5 and RCP8.5 scenarios (defined as those scenarios providing an increase in global radiative forcing levels of +4.5 and +8.5 W/m 2 by the end of the century, compared with preindustrial era) were considered returning respectively insights about “mid‐term” and pessimistic, but business‐as‐usual, scenarios (Colmet‐Daage et al, ; Jacob et al, ). A summary of EURO‐CORDEX simulations available until September 2018, used in the present research, is provided in Table .…”

Improving hydrological post-processing for assessing the conditional predictive uncertainty of monthly streamflows

“…The climate change projections were obtained from the Spanish National Meteorological Agency -AEMET (http://www.aemet.es), which provides the regionalised projections of 14 climate models (both GCM and RCM) using the statistical technique of analogues (Lorenz, 1969). These projections were obtained from the Fifth Assessment Report (AR5) of the Intergovernmental Panel on Climate Change -IPCC (Magrin et al, 2014) and the CORDEX Project (Colmet-Daage et al, 2018). The historical baseline period was 1987-2000.…”