Initiation of a stable convective hydroclimatic regime in Central America circa 9000 years BP
Initiation of a stable convective hydroclimatic regime in Central America circa 9000 years BP
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DOI：
10.1038/s41467-020-14490-y
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发表时间：
2020-02
影响因子：
16.6
通讯作者：
A. Winter;A. Winter;D. Zanchettin;M. Lachniet;R. Vieten;R. Vieten;F. Pausata;F. Ljungqvist;
中科院分区：
文献类型：
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作者：
A. Winter;A. Winter;D. Zanchettin;M. Lachniet;R. Vieten;R. Vieten;F. Pausata;F. Ljungqvist;
许多全新世水文气候记录显示降雨量随当地轨道日照变化而变化。然而，一些热带地区的降雨演变不同于渐进的岁差速度，这表明直接降雨强迫效应主要是由海面温度阈值或海洋间温度梯度驱动的。在这里，我们提供了来自危地马拉洞穴的12,000年连续U/ th降水记录，表明中美洲的降雨量在2000年期间从持续干旱状态增加到9000年BP的活跃对流状态，此后一直保持强劲。我们的数据表明，中美洲降雨的全新世进化是由附近热带海洋超过温度阈值驱动的。因此，该地区对辐射强迫缓慢变化的敏感性是由在更快的时间尺度上起作用的内部动力学所强烈介导的。
Many Holocene hydroclimate records show rainfall changes that vary with local orbital insolation. However, some tropical regions display rainfall evolution that differs from gradual precessional pacing, suggesting that direct rainfall forcing effects were predominantly driven by sea-surface temperature thresholds or inter-ocean temperature gradients. Here we present a 12,000 yr continuous U/Th-dated precipitation record from a Guatemalan speleothem showing that Central American rainfall increased within a 2000 yr period from a persistently dry state to an active convective regime at 9000 yr BP and has remained strong thereafter. Our data suggest that the Holocene evolution of Central American rainfall was driven by exceeding a temperature threshold in the nearby tropical oceans. The sensitivity of this region to slow changes in radiative forcing is thus strongly mediated by internal dynamics acting on much faster time scales.