Annual-resolution hydroclimate variability during the MCA–LIA transition in southern Iberia: insights into the role of cut-off lows (DANAs) from a speleothem record in Ardales Cave

Abstract. High-resolution paleoclimate records from southern Iberia remain scarce, limiting the understanding of hydroclimatic variability during the transition from the Medieval Climate Anomaly (MCA) to the Little Ice Age (LIA). Here, we present an annually resolved multiproxy reconstruction based on the laminated Zerolín stalagmite from Ardales Cave, a climatically sensitive site influenced by both Atlantic and Mediterranean moisture sources. The chronology is constrained through the integration of U–Th dating, lamina counting, and color-based modelling. Hydroclimatic variability was investigated using a combined analysis of trace elements, stable isotopes, petrography, and forward geochemical modelling. The results reveal alternating humid and arid phases, with four major drought intervals (~1125, 1250, 1500, and 1560 CE) and wetter periods consistent with increased recharge and higher growth rates. Two additional intervals (1320–1450 and 1600–1700 CE) display increased variability and are interpreted as reflecting an increased influence of Mediterranean convective precipitation (cut-off lows) during transitional atmospheric conditions. At the regional scale, the main hydroclimatic phases are consistent with North Atlantic Oscillation variability, while these transitional periods show a weaker correspondence with large-scale Atlantic forcing. Overall, the record highlights the interplay between Atlantic and Mediterranean dynamics in shaping southern Iberian hydroclimate during the last millennium.