Prolonged droughts can cause environmental stress, even in ecosystems that are already adapted to dry conditions. In these areas life greatly depends on rare, sporadic rainfall events that can produce flash floods. Today, urban expansion, population growth and development are occurring worldwide, including along hyperarid coastlines, an ecological zone on the extreme of habitability. In such places, the absence of the already limited precipitation can lead to long‐lasting damage, and recognizing drought conditions in the past is useful for planning. Recognizing droughts, however, is challenging because they are not known as depositional events, and therefore may be under‐recognized in the sedimentological record. Floods in these hyperarid deserts carry eroded sediments and deposit them in either terrestrial or marine terminal basins. In the hyperarid (ca 30 mm rain per year) desert surrounding the northern Gulf of Aqaba‐Eilat some flash floods reach the sea and deposit alluvial sediments (mostly silt and clay) on the shelf. Following a recent 17 year drought period (1995 to 2012) a coarser surface layer was recognized offshore the outlet of an ephemeral river, despite the lack of incoming flood material. This coarsened layer resulted from a prolonged period wherein mixing and winnowing of fine particles at the surface was not interrupted by recurrent flash floods. In the bottom of two sediment cores collected from the same shelf, a similarly coarsened layer was observed. The terminal level of this deep coarse layer was dated to ca 660 yr bp, corresponding with the end of the Medieval Warm Period (ca 1350 ad). These findings suggest that the medieval anomaly resulted in a prolonged drought period in this already arid region. These results present a new interpretation of grain‐size distribution records that provides a means to reconstruct drought histories in hyperarid regions globally.

中文翻译：

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沙漠干旱：中世纪暖期，与红海亚喀巴-埃拉特湾的较厚沉积层有关

长时间的干旱甚至会对已经适应干旱条件的生态系统造成环境压力。在这些地区，生活很大程度上取决于罕见的零星降雨事件，这些事件可能引发山洪暴发。如今，全球范围内的城市扩张，人口增长和发展都在发生，包括高干旱地区的海岸线，这是一个极端宜居的生态区。在这样的地方，没有已经有限的降水会导致长期的破坏，因此认识到过去的干旱状况对于规划是有用的。但是，认识到干旱是一项挑战，因为干旱不被称为沉积事件，因此在沉积学记录中可能未被充分认识。这些高干旱沙漠的洪水携带着侵蚀的沉积物，并将其沉积在陆地或海洋终端盆地中。CA每年）沙漠周边亚喀巴-埃拉特北部湾30毫米雨有些山洪到达大海，并存入了冲积物（主要是淤泥和粘土）在货架上。在最近的17年干旱期（1995年至2012年）之后，尽管缺少洪水物质，但在短暂河流出口附近发现了较粗糙的表层。该粗化层是由延长的时间导致的，其中表面上细颗粒的混合和风选不会因反复的山洪而中断。在从同一架子收集的两个沉积物核心的底部，观察到了类似的粗化层。此深粗糙层的终端水平日给CA 660年 基点，与中世纪暖期的结束时（对应CA1350 广告）。这些发现表明，中世纪的异常导致该干旱地区的干旱时间延长。这些结果提供了对粒度分布记录的新解释，为重建全球高干旱地区的干旱历史提供了一种手段。