Western Mediterranean Climate Response to Dansgaard/Oeschger Events: New Insights From Speleothem Records
Western Mediterranean Climate Response to Dansgaard/Oeschger Events: New Insights From Speleothem Records
复制标题
DOI：
10.1029/2019gl084009
复制
发表时间：
2019-08-16
影响因子：
5.2
通讯作者：
Scholz, Denis
中科院分区：
文献类型：
--
作者：
Budsky, Alexander;Wassenburg, Jasper A.;Scholz, Denis
全新世西地中海气候在大气环流模式的驱动下具有强降水梯度的特征。由于陆地古气候档案的缺乏，使得在海洋同位素第5 ~ 3阶段无法探索这种水文气候模式。本文对来自伊比利亚东南部的3块流岩进行了稳定的碳、氧同位素记录，表明Dansgaard/Oeschger事件与较为湿润的环境有关。这与来自伊比利亚半岛、地中海和西欧的其他记录一致，这些记录都以类似的方式对格陵兰岛千年尺度的气候变化做出了反应。Dansgaard/Oeschger事件期间降水的普遍增加不能用任何现代或全新世冬季大气环流模式来解释。相反，我们认为海表温度的变化在决定西地中海的降水量方面发挥了主导作用。格陵兰冰芯记录了末次冰期在不到几十年的时间内温度突然升高10摄氏度的气候事件。这些突然变暖，即Dansgaard/Oeschger事件，影响了北半球的大部分地区。由于覆盖末次冰期的陆地气候记录数量有限，因此对这些气候变化期间降水的区域响应的了解在西地中海地区是有限的。洞穴化石及其稳定的同位素组成可以根据准确的年代框架追踪气候和植被的变化。在这里，我们提出了一个洞穴稳定的同位素记录，表明Dansgaard/Oeschger事件与地中海西部降雨量增加和植被密集有关。在西欧和地中海其他地区也观察到类似的模式，我们认为这与周围海洋普遍较高的海面温度有关，而不是大气环流的重组。
The climate of the western Mediterranean was characterized by a strong precipitation gradient during the Holocene driven by atmospheric circulation patterns. The scarcity of terrestrial paleoclimate archives has precluded exploring this hydroclimate pattern during Marine Isotope Stages 5 to 3. Here we present stable carbon and oxygen isotope records from three flowstones from southeast Iberia, which show that Dansgaard/Oeschger events were associated with more humid conditions. This is in agreement with other records from the Iberian Peninsula, the Mediterranean, and western Europe, which all responded in a similar way to millennial-scale climate variability in Greenland. This general increase in precipitation during Dansgaard/Oeschger events cannot be explained by any present-day or Holocene winter atmospheric circulation pattern. Instead, we suggest that changes in sea surface temperature played a dominant role in determining precipitation amounts in the western Mediterranean.Plain Language Summary Climate events characterized by a sudden temperature increase of up to 10 degrees C occurring in less than a few decades during the last glacial are recorded in Greenland ice cores. These abrupt warmings, the Dansgaard/Oeschger events, affected large regions of the Northern Hemisphere. The understanding of the regional response in precipitation during these climate shifts is limited for the western Mediterranean, due to the restricted number of terrestrial climate records that cover the last glacial period at sufficient resolution. Speleothems and their stable isotope compositions allow to trace changes in climate and vegetation based on an accurate chronological framework. Here we present a speleothem stable isotope record that shows that the Dansgaard/Oeschger events were associated with increased rainfall and a denser vegetation in the western Mediterranean. A similar pattern was observed for western Europe and other parts of the Mediterranean, and we propose that this was related to generally higher sea surface temperatures of the surrounding oceans rather than a reorganization of atmospheric circulation.