Projected future wave climate in the NW Mediterranean Sea

Abstract

[1] Projected future regional wave climate scenarios at a high temporal-spatial scale were obtained for the NW Mediterranean Sea, using five combinations of regional-global circulation models. Changes in wave variables were analyzed and related to the variations of the forcing wind projections, while also evaluating the evolution of the presence of the different types of sea states. To assess the significance of the changes produced, a bootstrapbased method was proposed, which accounts for the autocorrelation of data and correctly reproduces the extremes. For the mean climate, relative changes of H s up to 610% were obtained, whereas they were around 620% for the extreme climate. In mean terms, variations of H s are similar to those associated with wind speed but are enhanced/ attenuated, respectively, when fetch conditions are favorable/unfavorable. In general, most notable alterations are not in the H s magnitude but rather in its direction. In this regard, during the winter season, it is interesting to note that the significant deviations between the results derived from the two global circulation models are larger than those between regional models. ECHAM5 simulated an enhanced west wind flow that is translated into more frequent W-NW waves, whereas the HadCM3Q3 global model gives rise to the east component, which contributes to a higher intensity and number of storms coming from such a direction and directly affects the wind-sea/swell distribution of coastal stretches that face east, like the Catalan coast. Different patterns of change were obtained during the summer when a common rise of NE-E waves was found.

Impacts of sea-level rise-induced erosion on the Catalan coast

“…However, the uncertainty about projections of extreme wave events is relatively large since the use of different atmospheric models can result in different wave fields (Planton et al 2012). This variation in wave projections was also detected by Casas-Prat and Sierra (2013) in the study area by using different combinations of Regional and Global Circulation Models.…”

Impacts on wave-driven harbour agitation due to climate change in Catalan ports

“…As mentioned in the Introduction, the high spatial (0.125 • ) and temporal (3 h) resolution wave projections developed by Casas-Prat and Sierra (2013) have been used in this study to evaluate the impact on harbour agitation. They were obtained with the SWAN wave model (Booij et al, 1999) forced by winds generated with five combinations of global (GCMs) and regional circulation models (RCMs) considering the A1B scenario of the 4th Assessment Report from IPCC (2007).…”

“…However, their results were based on trend analysis, which is a simple and non-computational technique that can be used to provide a preliminary assessment only because it does not consider explicitly the greenhouse scenarios and because it assumes that the obtained tendency is valid into the future. Conversely, the current study uses the high-resolution wave projections developed by Casas-Prat and Sierra (2013) that explicitly take into account the greenhouse effect. These wave projections were obtained with the SWAN model using atmospheric climate projections available from four regional circulation models (RCMs), one of them being forced by two different global circulation models (GCMs).…”

Global changes of extreme coastal wave energy fluxes triggered by intensified teleconnection patterns

“…The few global studies discussing large-scale projections of waves in view of climate change mainly focus on average wave conditions [Hemer et al, 2013a]. In global studies changes in extreme wave conditions have been marginally explored by focusing on high percentile values or on low return levels [Mori et al, 2010;Hemer et al, 2013aHemer et al, , 2013bSemedo et al, 2013;Wang et al, 2014;Perez et al, 2015], omitting the rare extremes that may give rise to catastrophic impacts, although more detailed local studies exist [De Winter et al, 2012;Lionello et al, 2012;Casas-Prat and Sierra, 2013;Erikson et al, 2015;Shimura et al, 2016].…”