Regional winds over the Iberian Peninsula: evaluation and future projections from an ensemble of regional climate models

This work investigates the capacity of several regional climate models to describe the main characteristics of Cierzo, Levante and Poniente, the main regional winds over the Iberian Peninsula, using as the evaluation period 1995-2011, by comparing them against reanalysis. For this purpose, regional wind classification algorithms have been proposed, based on previous detailed studies made. Then three models (REMO, MPIOM-REMO and CNRM-RCSM4) have been selected based their capability to describe those winds for present conditions, to inspect their projections for future climate conditions, under the RCP 8.5 emissions scenario (2006-2099), using MPI-ESM-LR and CRNM-CM5 as the forcing global models for them. Changes are obtained comparing them with the historical period (1950-2005) simulation results. Several results are obtained related to the sensitivity of resolution and parameterizations employed by the models. Thus, spatial resolution seems to be a key aspect to detect these winds, especially in terrestrial flows such as Cierzo. The internal physics of each model also causes increased variability for spatial resolutions larger than 10 kilometres. A low subdaily temporal resolution introduces inaccuracies in the calculation of regional wind events. The effect of using atmosphere-ocean coupled simulations does not show robust results, as it depends on the analzyed flows. In general, models are able to simulate historical frequencies of Cierzo events (100-130 days), Levante and Poniente (150-160 days), which is similar to what has been seen with observations and previous studies. Temporal trends shows that Cierzo extension could decrease by 1.5% of the valley in a statistically significant way by the end of the century. The results also indicate a strong increase of 10-20 annual Levante events depending on the model. Poniente wind shows a weakening of its characteristics for all models, specifically a decrease in the number of annual Poniente events by 5-20 days.