Rainfall regimes of the Green Sahara.
Rainfall regimes of the Green Sahara.
复制标题
绿色撒哈拉的降雨状况。
DOI：
10.1126/sciadv.1601503
复制
发表时间：
2017-01
期刊：
影响因子：
13.6
通讯作者：
deMenocal PB
中科院分区：
文献类型：
--
作者：
Tierney JE;Pausata FS;deMenocal PB
我们估计“绿色撒哈拉”期间的降雨量。在“绿色撒哈拉”时期（距今11,000年至5000年），撒哈拉沙漠获得了大量的降雨，支持了多样化的植被，永久性湖泊和人口。由于缺乏连续的沉积物记录，我们对降雨率和潮湿条件的时空范围的了解受到了影响。我们提出了一个定量重建西撒哈拉降水来自海洋沉积物中的叶蜡同位素。我们的数据表明，绿色撒哈拉沙漠延伸到31°N，并可能突然结束。我们发现了8000年前绿色撒哈拉条件下长时间“暂停”的证据，与新石器时代人类暂时放弃职业场所相吻合。从我们的数据中推断出的降雨率最好用强烈的植被和灰尘反馈来解释;没有这些机制，气候模型系统地无法重现绿色撒哈拉。这项研究表明，要准确模拟撒哈拉和萨赫勒地区未来的气候变化，需要提高我们模拟植被和灰尘反馈的能力。
We estimate rainfall during the “Green Sahara” period. During the “Green Sahara” period (11,000 to 5000 years before the present), the Sahara desert received high amounts of rainfall, supporting diverse vegetation, permanent lakes, and human populations. Our knowledge of rainfall rates and the spatiotemporal extent of wet conditions has suffered from a lack of continuous sedimentary records. We present a quantitative reconstruction of western Saharan precipitation derived from leaf wax isotopes in marine sediments. Our data indicate that the Green Sahara extended to 31°N and likely ended abruptly. We find evidence for a prolonged “pause” in Green Sahara conditions 8000 years ago, coincident with a temporary abandonment of occupational sites by Neolithic humans. The rainfall rates inferred from our data are best explained by strong vegetation and dust feedbacks; without these mechanisms, climate models systematically fail to reproduce the Green Sahara. This study suggests that accurate simulations of future climate change in the Sahara and Sahel will require improvements in our ability to simulate vegetation and dust feedbacks.