<p>The Antarctic Peninsula is one of the most affected regions in a warming climate. Climate change not only involves rising air temperatures or changing precipitation patterns, but also wind. Over the past few decades, one of the most prominent changes in the near-Antarctic climate has been the southward shift of the westerly winds, associated with a positive trend in the Southern Annular Mode index (SAM). Some studies revealed that the poleward shift of the westerlies results in an increased in the seasonality of the coastal easterlies, concretely an increase in the difference between weak easterly winds in summer and strong easterlies in winter. The assessment and attribution of the variability of the easterly winds that encircle the coastline is crucial due to its influence e.g. (i) in the sea ice formation and export, (ii) a variation in the easterly winds can modify the Antarctic Bottom Water formation and properties, (iii) the heat transport trough the continent. Due to operational challenges of measuring weather data in the Antarctic region, there are few long-terms time series and studies dealing with wind trends and variability. In this work, wind series from 1988 to 2019 from the Spanish Juan Carlos I Base, located in the South Shetland Islands, specifically in Livingston Island , have been used for the first time to fill this research niche. Speed series have been subjected to a robust quality control and homogenization protocol in Climatol. The results of the magnitude, sign and decadal variability of this series have been compared with the same results for the same time period for the data of ERA5 reanalysis, all of them at three time scales: annual, seasonal and monthly. For both observations and ERA5 we investigate the relationship between speed series and SAM.</p>

<p>Near-surface wind speed has been one of the forgotten parts of the climate system due to poor quality of observational data and the challenges in its homogenization.  During the last two decades the interest in near-surface wind variability and trends has increased and two main phenomena have been found: the first one is termed “stilling”, indicating a decline of near-surface wind speed between around 1978 and 2010; the other is related to an interruption in the “stilling” since 2000s, known as a “reversal” of the wind speed trends at global and regional scales like China, Sweden or Iberian Peninsula, among others. There are uncertainties about the plausible causes of the variability of the near-surface wind speed, but last research pointed to the role played by decadal atmosphere-ocean oscillations. Under this assumption and a climate change context, a new “stilling” phase is expected for the 21<sup>st</sup> century. In order to advance in the evaluation and attribution of the causes of the “stilling” and the “reversal” phenomena, the main objective of this study is to analyze projected changes in near-surface wind speed at regional scale, e.g. the Iberian Peninsula. The methodology consists in a comparison between observed wind speed data of the Iberian Peninsula and historical simulations from CMIP6 models, followed by a study of wind speed variability and trends of CMIP6 models under low to high greenhouse gas forcing scenarios in the future. The analyses will focus on quantifying the long-term changes in near surface wind speed and their relationship with dominant modes of variability in the Pacific and Atlantic (e.g., the Pacific Decadal Oscillation and the Atlantic Multi-decadal Oscillation).</p><p> </p>