Most studies on wind variability have deepened into the stilling vs. reversal phenomena at global to regional scales, while the long-term changes in local-scale winds such as sea-breezes (SB) represent a gap of knowledge in climate research. The state-of-the-art of the wind variability studies suggests a hypothetical reinforcement of SB at coastal stations. We first developed a robust automated method for the identification of SB days. Then, by using homogenized wind observations from 16 stations across Eastern Spain, we identified 9,349 episodes for analyzing the multidecadal variability and trends in SB speeds, gusts and occurrence for 1961–2019. The major finding is the opposite trends and decoupled variability of SB speeds and gusts: the SB speeds declined significantly in all seasons (except for winter), and the SB gusts strengthened at the annual scale and in autumn–winter, being most significant in autumn. Our results also show that the SB occurrence has increased across most of Eastern Spain, although presenting contrasting seasonal trends: positive in winter and negative in summer. We found that more frequent anticyclonic conditions, NAOI + and MOI + are positively linked to the increased winter occurrence; however, the causes behind the opposite trends in SB speeds and gusts remain unclear. The SB changes are complex to explain, involving both large-scale circulation and physical-local factors that challenge the understanding of the opposite trends. Further investigation is needed to assess whether these trends are a widespread phenomenon, while climate models could simulate the drivers behind these decoupled SB changes in a warmer climate.

<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>

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