NOAA/WDS Paleoclimatology - Touchan - Dahllia - PIHA - ITRDB TUNI002

Changes in precipitation patterns and the frequency and duration of drought are likely to be the feature of anthropogenic climate change that will have the most direct and most immediate consequences for human populations. The latest generation of state-of-the-art climate models project future widespread drying in the subtropics. Here, we reconstruct spatially-complete gridded Palmer drought severity index values back to A.D. 1179 over Morocco, Algeria, and Tunisia. The reconstructions provide long-term context for northwest African hydroclimatology, revealing large-scale regional droughts prior to the sixteenth century, as well as more heterogeneous patterns in sixteenth, eighteenth, and twentieth century. Over the most recent decades a shift toward dry conditions over the region is observed, which is consistent with general circulation model projections of greenhouse gas forced enhanced regional subtropical drought.

降水格局变化以及干旱的发生频率与持续时长，大概率是人为气候变化中对人类群体造成最直接、最即时影响的特征。当前最先进的新一代气候模型预测，未来亚热带地区将出现大范围干旱化趋势。本研究针对摩洛哥、阿尔及利亚及突尼斯区域，重建了可追溯至公元1179年的空间全覆盖格点化帕默尔干旱强度指数（Palmer Drought Severity Index）序列。该重建结果为西北非洲水文气候学研究提供了长期背景视角，揭示出16世纪之前曾发生大规模区域性干旱，同时展现出16、18及20世纪的干旱格局具有更强的异质性。近数十年来，该区域观测到向干旱状态的转变，这与温室气体强迫下亚热带区域干旱加剧的大气环流模型（General Circulation Model）预测结果相一致。