Changes in Earth's orbit through time are one of the main drivers of low frequency climate change. Though the influence of Earth's orbit on insolation is known, understanding of the orbit-climate link is incomplete. The orbital characteristics in many Plio-Pleistocene paleoclimate records are not consistent with local insolation forcing. The objective of this work is to investigate how orbital forcing affects the climate system, and to identify climate processes and feedbacks that modulate this forcing. To do this, the PIs have developed an earth system model that includes atmosphere, ocean, ice sheets, and vegetation responses, and is capable of running long transient simulations over multiple orbital cycles. In addition to generally investigating the orbit-climate link, the PIs will also use their model to address paradoxes raised by Plio-Pleistocene proxy records including (i) the glacial 41-kyr problem, (ii) the tropical 41-kyr problem, (iii) the evolution of climate sensitivity to orbital forcing, and (iv) the glacial 100-kyr problem. The award will support a graduate student and research experiences for undergraduates. A museum display on Ice Ages will be developed in collaboration with the University of Michigan?s Exhibit Museum of Natural History.
