Obliquity forcing of low-latitude climate
Obliquity forcing of low-latitude climate
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DOI：
10.5194/cp-11-1335-2015
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发表时间：
2015-01-01
影响因子：
4.3
通讯作者：
Lourens, L. J.
中科院分区：
文献类型：
--
作者：
Bosmans, J. H. C.;Hilgen, F. J.;Lourens, L. J.
在低纬度地区，地球自转轴倾斜对入射太阳辐射的影响很小，但许多热带和亚热带古气候记录显示出明显的地球自转信号。已经提出了几种机制来解释这种信号，如高纬度冰川的远程影响，在中高纬度独立于冰川周期性的日照变化的远程影响，在热带的纬度范围内的变化，以及纬度日照梯度的变化。使用一个复杂的耦合海洋-大气全球气候模式，EC-Earth，没有动态冰盖，我们进行了两个理想化的实验极端湿度。我们的研究结果表明，在热带气候中，由冰川引起的变化可以在没有高纬度冰盖波动的情况下发生。此外，热带环流的变化是一致的，在越赤道太阳辐射梯度的变化与赤道度引起的，这表明该梯度可以用来解释在低纬度古气候记录，而不是经典的65度N夏季太阳辐射曲线的赤道度信号。
The influence of obliquity, the tilt of the Earth's rotational axis, on incoming solar radiation at low latitudes is small, yet many tropical and subtropical palaeoclimate records reveal a clear obliquity signal. Several mechanisms have been proposed to explain this signal, such as the remote influence of high-latitude glacials, the remote effect of insolation changes at mid-to high latitudes independent of glacial cyclicity, shifts in the latitudinal extent of the tropics, and changes in latitudinal insolation gradients. Using a sophisticated coupled ocean-atmosphere global climate model, EC-Earth, without dynamical ice sheets, we performed two idealized experiments of obliquity extremes. Our results show that obliquity-induced changes in tropical climate can occur without high-latitude ice sheet fluctuations. Furthermore, the tropical circulation changes are consistent with obliquity-induced changes in the cross-equatorial insolation gradient, suggesting that this gradient may be used to explain obliquity signals in low-latitude palaeoclimate records instead of the classical 65 degrees N summer insolation curve.