We found a match
Your institution may have access to this item. Find your institution then sign in to continue.
- Title
Mending Milankovitch theory: obliquity amplification by surface feedbacks.
- Authors
Tabor, C. R.; Poulsen, C. J.; Pollard, D.
- Abstract
Milankovitch theory states that orbitally induced changes in high-latitude summer insolation dictate the waxing and waning of ice-sheets. Accordingly, precession should dominate the ice-volume response because it most strongly modulates summer insolation intensity. However, Early Pleistocene (2.6--0.8 Ma) ice-volume proxy records vary almost exclusively at the frequency of the obliquity cycle. To explore this paradox, we use an Earth system model coupled with a dynamic ice-sheet to separate the climate responses to idealized transient orbits of obliquity and precession that maximize insolation changes. Our results show that positive surface albedo feedbacks between high-latitude annual-mean insolation, ocean heat flux and sea-ice coverage, and bo-real forest/tundra exchange enhance the ice-volume response to obliquity forcing relative to precession forcing. These surface feedbacks, in combination with modulation of the precession cycle power by eccentricity, may explain the dominantly 41 kyr cycles in global ice volume of the Early Pleistocene.
- Subjects
PLEISTOCENE Epoch; ICE sheets; MILANKOVITCH cycles; SOLAR radiation; OBLIQUITY-induced precession; CLIMATE change; ATMOSPHERIC models
- Publication
Climate of the Past Discussions, 2013, Vol 9, Issue 4, p3769
- ISSN
1814-9324
- Publication type
Article
- DOI
10.5194/cpd-9-3769-2013