Abstract:
The present work compares deuterium records (proxy of the surface air temperature) from the Vostok and Dome C stations. We detected some symmetry in the shapes of Late Pleistocene glacial cycles, relative to the warming (the so-called marine isotope stage 11), observed approximately 400 ka BP (this symmetry was not noted by previous researchers). Wavelet transform of these records into three components corresponding to the precession, obliquity, and eccentricity time scales in the Earth’s orbital rotation around the Sun suggests that the symmetry of the cycles is related to the amplitude and frequency modulations of climate responses to orbital insolation variations.
