Solar forced Dansgaard-Oeschger events and their phase relation with solar proxies
Solar forced Dansgaard-Oeschger events and their phase relation with solar proxies
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DOI：
10.1029/2008gl033414
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发表时间：
2008-03-25
影响因子：
5.2
通讯作者：
Chialvo, D. R.
中科院分区：
文献类型：
--
作者：
Braun, H.;Ditlevsen, P.;Chialvo, D. R.
北大西洋气候在冰期的特点是大幅度的开关，Dansgaard-Oeschger（DO）事件，具有明显的趋势，最好在约1470年的倍数重现。最近的工作解释这些时间间隔作为一个高度非线性系统的准周期太阳强迫加上噪声的次谐波响应的结果。这一假设受到质疑，因为它与观测到的太阳活动和格陵兰气候之间的相位关系的变化不一致。在这里，我们拒绝索赔的不一致性表明，这种相位变化是一个强大的，通用的功能的非线性动态DO事件，所描述的模型。这种可变性是预期的事实，即事件的阈值跨越事件，从周期性的强迫和噪声之间的合作过程。这一过程产生了波动的相位关系与周期性的强迫，符合代理的太阳活动和格陵兰岛的气候。
North Atlantic climate during glacial times was characterized by large-amplitude switchings, the Dansgaard-Oeschger (DO) events, with an apparent tendency to recur preferably in multiples of about 1470 years. Recent work interpreted these intervals as resulting from a subharmonic response of a highly nonlinear system to quasi-periodic solar forcing plus noise. This hypothesis was challenged as inconsistent with the observed variability in the phase relation between proxies of solar activity and Greenland climate. Here we reject the claim of inconsistency by showing that this phase variability is a robust, generic feature of the nonlinear dynamics of DO events, as described by a model. This variability is expected from the fact that the events are threshold crossing events, resulting from a cooperative process between the periodic forcing and the noise. This process produces a fluctuating phase relation with the periodic forcing, consistent with proxies of solar activity and Greenland climate.