Royal Dutch Meteorological Institute; Ministery Of Infrastructure And The Environment

Publications, presentations and other activities
Obliquity forcing of low-latitude climate.
2015
by J.H.C. Bosmans (KNMI), F.J. Hilgen (Utrecht University), E. Tuenter (KNMI), L.J. Lourens (Utrecht University),

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.

Bibliographic data
Bosmans, J.H.C., F.J. Hilgen, E. Tuenter and L.J. Lourens, Obliquity forcing of low-latitude climate.
Climate of the Past, 2015, 11, 1335-1346, doi:10.5194/cp-11-1335-2015.
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