Obliquity forcing of low-latitude climate
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 i...
Published in: | Climate of the Past |
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Main Authors: | , , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
Copernicus Publications
2015
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Subjects: | |
Online Access: | https://doi.org/10.5194/cp-11-1335-2015 http://www.clim-past.net/11/1335/2015/cp-11-1335-2015.pdf https://doaj.org/article/86356c80653643e29eeafe7f19283d8d |
Summary: | 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° N summer insolation curve. |
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