The Mistral and Tramontane are important wind phenomena that occur over southern France and the northwestern Mediterranean Sea. Both winds travel through constricting valleys before flowing out towards the Mediterranean Sea. The Mistral and Tramontane are thus interesting phenomena, and represent an opportunity to study channeling effects, as well as the interactions between the atmosphere and land/ocean surfaces. This study investigates Mistral and Tramontane simulations using five regional climate models with grid spacing of about 50 km and smaller. All simulations are driven by ERA-Interim reanalysis data. Spatial patterns of surface wind, as well as wind development and error propagation along the wind tracks from inland France to offshore during Mistral and Tramontane events, are presented and discussed. To disentangle the results from large-scale error sources in Mistral and Tramontane simulations, only days with well simulated large-scale sea level pressure field patterns are evaluated. Comparisons with the observations show that the large-scale pressure patterns are well simulated by the considered models, but the orographic modifications to the wind systems are not well simulated by the coarse-grid simulations (with a grid spacing of about 50 km), and are reproduced slightly better by the higher resolution simulations. On days with Mistral and/or Tramontane events, most simulations underestimate (by 13 % on average) the wind speed over the Mediterranean Sea. This effect is strongest at the lateral borders of the main flow—the flow width is underestimated. All simulations of this study show a clockwise wind direction bias over the sea during Mistral and Tramontane events. Simulations with smaller grid spacing show smaller biases than their coarse-grid counterparts.

Near‐surface wind over the Adriatic region are examined under present‐day and future climate conditions for two greenhouse gas scenarios (RCP4.5 and RCP8.5) with an ensemble of high‐resolution (0.11°) CORDEX simulations. The influence of particular combinations of regional climate models (RCMs) and global climate models (GCMs) and emission scenarios on the future changes in the near‐surface wind field has been explored in more detail. Starting with the seasonal climate change signal in large‐scale flow over the entire CORDEX domain, we focus to regional daily wind fields over the Adriatic domain and subdaily features of well‐known regional winds (Bora and Sirocco winds). The analysis reveals the strong sensitivity of the climate change signal in the simulated wind flow to (i) the choice of the GCM that provides the boundary conditions and (ii) the analyzed locations across the Adriatic region. The results of the 21^st century projections indicate that the changes in synoptic activity have an impact on the wind field at the (sub) daily time scale. We found a reduction in the number of Bora events and increase in the number of Sirocco events in northern Adriatic during the winter season, with an increase in pressure in the middle of the 21^st century. Overall, the mean wind speed during Bora and Sirocco events is reduced, except for Bora in northern Adriatic. For the summer season, we found a large increase in the number of thermally induced flows, which is probably caused by the weakening of the Azores High.

The characteristics of the mesoscale Mistral and Tramontane winds under changing climate conditions are of great interest for risk assessments. In this study, a classification algorithm is applied to identify Mistral and Tramontane-permitting sea-level pressure patterns, thus allowing for estimates of their future characteristics. Five simulations with three regional climate models on a 0.44\(^\circ\) grid and five global circulation models are assessed for the representative concentration pathways (RCPs) 4.5 and 8.5. Regional climate simulations driven by ERA-Interim are used to test the classification algorithm and to estimate its accuracy. The derived Mistral and Tramontane time series are discussed. The results for the ERA-Interim period show that the classification algorithm and the regional climate models work well in terms of the number of Mistral and Tramontane days per year, but the results overestimate the average length of such events. For both the RCPs, only small changes in Mistral frequency were found in both regional and global climate simulations. Most simulations show a decrease in Tramontane frequencies and average period lengths during the 21st century. Regional climate simulations using RCP8.5 show fewer Tramontane events than those using RCP4.5.

Mistral and tramontane are mesoscale winds in southern France. Both winds emerge in valleys and cause deep water formation in the Mediterranean Sea, which makes them interesting phenomena for studying several orographic effects and relevant for Earth system models. However, climate simulations are performed on a finite numerical grid with a coarse‐gridded orography and processes on subgrid scales are parameterized. This study surveys the effect of orographic grid spacing (2.6–45 km) on mistral and tramontane by performing idealized simulations with a 1.3 km horizontal numerical grid. Reduction of the orographic detail leads to a wind pattern change and a wind speed reduction. If orographic features on smaller scales are parameterized, the effects of the smoothing are weaker, but a systematic decrease in channeling and wind speed still persists.

Maritime transport is a vital sector for global trade and the world economy. Particularly for islands, there is also an important social dimension of this sector, since island communities strongly rely on it for a connection with the mainland and the transportation of goods and passengers. Furthermore, islands are exceptionally vulnerable to climate change, as the rising sea level and extreme events are expected to induce severe impacts. Such hazards are anticipated to also affect the operations of the maritime transport sector by affecting either the port infrastructure or ships en route. The present study is an effort to better comprehend and assess the future risk of maritime transport disruption in six European islands and archipelagos, and it aims at supporting regional to local policy and decision-making. We employ state-of-the-art regional climate datasets and the widely used impact chain approach to identify the different components that might drive such risks. Larger islands (e.g., Corsica, Cyprus and Crete) are found to be more resilient to the impacts of climate change on maritime operations. Our findings also highlight the importance of adopting a low-emission pathway, since this will keep the risk of maritime transport disruption similar to present levels or even slightly decreased for some islands because of an enhanced adaptation capacity and advantageous demographic changes.

The Mediterranean region is a densely populated and economically relevant area with complex orography including mountain ranges, islands, and straits. In combination with pressure gradients, this creates many mesoscale wind systems that cause, e.g., wind gusts and wildfire risk in the Mediterranean. This article reviews the recent state of the science of several mesoscale winds in the Mediterranean and associated processes. Previous work, including case studies on several time ranges and resolutions, as well as studies on these winds under future climate conditions, is discussed. Simulations with grid spacings of 25 to 50 km can reproduce winds driven by large-scale pressure patterns such as Mistral, Tramontane, and Etesians. However, these simulations struggle with the correct representation of winds channeled in straits and mountain gaps and around islands. Grid spacings of 1–3 km are certainly necessary to resolve these small-scale features. The smaller grid spacings are widely used in case studies, but not yet in simulations over large areas and long periods, which also could help to understand the interaction between small-scale phenomena in separate locations. Furthermore, by far not all Mediterranean straits, islands, and mountain gaps were studied in-depth and many interesting Mediterranean small-scale winds still need to be studied.