1 1 Windiness spells in SW Europe since the Last Glacial 2 Maximum 3 Susana Costas *,1, 2 , Filipa Naughton 3 , Ronald Goble 4 and Hans Renssen 5 4 * Corresponding author: scotero@ualg.pt 5 1 Current address. Centro de Investigação Marinha e Ambiental, Universidade do 6 Algarve, Portugal 7 2 Laboratório Nacional de Energia e Geologia, Portugal 8 3 Instituto Português do Mar e da Atmosfera, Portugal 9 4 Department of Earth and Atmospheric Sciences, University of Nebraska, Lincoln, USA 10 5 Department of Earth Sciences, Vrije Universiteit Amsterdam, The Netherlands 11 ABSTRACT 12 Dunefields have a great potential to unravel past regimes of atmospheric 13 circulation as they record direct traces of this component of the climate system. Along 14 the Portuguese coast, transgressive dunefields represent relict features originated by 15 intense and frequent westerly winds that largely contrast with present conditions, clearly 16 dominated by weaker northwesterly winds. Optical dating and subsurface stratigraphy 17 document three age clusters indicating main episodes of dune mobilization during: the 18 last termination (20-11.6 ka), Middle Holocene (5.6 ka), and Late Holocene (1.2-0.98 19 and 0.4-0.15 ka). 20 We find reconstructed windfields to be analogous during all episodes and 21 dominated by strong westerlies. Yet, larger grain size diameters and dune volumes 22 documented for the last termination support amplified patterns compatible with a 23 southward shift and intensification of the North Atlantic westerlies during winters. 24